[Federal Register Volume 85, Number 87 (Tuesday, May 5, 2020)]
[Rules and Regulations]
[Pages 26786-26820]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-07856]



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Vol. 85

Tuesday,

No. 87

May 5, 2020

Part II





Department of the Interior





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Fish and Wildlife Service





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50 CFR Part 17





Endangered and Threatened Wildlife and Plants; Endangered Status for 
the Island Marble Butterfly and Designation of Critical Habitat; Final 
Rule

  Federal Register / Vol. 85 , No. 87 / Tuesday, May 5, 2020 / Rules 
and Regulations  

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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R1-ES-2016-0145; FF09E21000 FXES11110900000 201]
RIN 1018-BB96


Endangered and Threatened Wildlife and Plants; Endangered Status 
for the Island Marble Butterfly and Designation of Critical Habitat

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Final rule.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), determine 
endangered species status under the Endangered Species Act of 1973 
(Act), as amended, for the island marble butterfly (Euchloe ausonides 
insulanus) and designate critical habitat. In total, approximately 812 
acres (329 hectares) on the south end of San Juan Island, San Juan 
County, Washington, fall within the boundaries of the critical habitat 
designation.

DATES: This rule is effective June 4, 2020.

ADDRESSES: This final rule is available on the internet at http://www.regulations.gov. Comments and materials we received, as well as 
supporting documentation we used in preparing this rule, are available 
for public inspection at http://www.regulations.gov at Docket No. FWS-
R1-ES-2016-0145. Comments, materials, and documentation that we 
considered in this rulemaking will be available by appointment, during 
normal business hours at: U.S. Fish and Wildlife Service, Washington 
Fish and Wildlife Office, 510 Desmond Drive, Suite 102, Lacey, WA 
98503; telephone 360-753-9440.
    The coordinates or plot points or both from which the maps are 
generated are included in the administrative record for this critical 
habitat designation and are available at http://www.regulations.gov at 
Docket No. FWS-R1-ES-2016-0145, on the Service's website at https://www.fws.gov/wafwo/,and at the Washington Fish and Wildlife Office 
(address provided above). Any additional tools or supporting 
information that we developed for this critical habitat designation 
will also be available at the Fish and Wildlife Service website and 
Field Office set out above, and may also be included in the preamble 
and at http://www.regulations.gov.

FOR FURTHER INFORMATION CONTACT: Brad Thompson, Acting State 
Supervisor, Washington Fish and Wildlife Office, 510 Desmond Drive, 
Suite 102, Lacey, WA 98503; telephone 360-753-9440. Persons who use a 
telecommunications device for the deaf (TDD) may call the Federal Relay 
Service at 800-877-8339.

SUPPLEMENTARY INFORMATION:

Executive Summary

    Why we need to publish a rule. Under the Endangered Species Act, a 
species may warrant protection through listing if it is endangered or 
threatened throughout all or a significant portion of its range. 
Listing a species as an endangered or threatened species can only be 
completed by issuing a rule. Further, under the Endangered Species Act, 
any species that is determined to be an endangered or threatened 
species requires critical habitat to be designated, to the maximum 
extent prudent and determinable. Designations and revisions of critical 
habitat can only be completed by issuing a rule.
    What this document does. This rule lists the island marble 
butterfly (Euchloe ausonides insulanus) as an endangered species and 
designates critical habitat for this species under the Endangered 
Species Act. We are designating critical habitat for the species in one 
unit, on public and private property totaling 812 acres (329 hectares) 
on San Juan Island, San Juan County, Washington.
    The basis for our action. Under the Endangered Species Act, we can 
determine that a species is an endangered or threatened species based 
on any of five factors: (A) The present or threatened destruction, 
modification, or curtailment of its habitat or range; (B) 
overutilization for commercial, recreational, scientific, or 
educational purposes; (C) disease or predation; (D) the inadequacy of 
existing regulatory mechanisms; or (E) other natural or manmade factors 
affecting its continued existence. We have determined that the island 
marble butterfly faces the following threats:
     Habitat loss and degradation from plant succession and 
invasion by plants that displace larval host plants; browsing by black-
tailed deer, European rabbits, and brown garden snails; and storm 
surges;
     Predation by native spiders and nonnative wasps, and 
incidental predation by black-tailed deer; and
     Vulnerabilities associated with small population size and 
environmental and demographic stochasticity, and other chance events 
that increase mortality or reduce reproductive success.
    Existing regulatory mechanisms and conservation efforts do not 
address these threats to the island marble butterfly to the extent that 
listing is not warranted.
    This rule also designates critical habitat for the island marble 
butterfly in accordance with the Endangered Species Act. The critical 
habitat areas we are designating in this rule constitute our current 
best assessment of the areas that meet the definition of critical 
habitat for the island marble butterfly.
    Economic analysis. We prepared an economic analysis of the impacts 
of designating critical habitat. We made the draft economic analysis 
available for public comments on April 12, 2018 (83 FR 15900). The 
analysis found no significant economic impact of the designation of 
critical habitat.
    Peer review and public comment. We sought comments from five 
independent specialists to ensure that our species determination and 
critical habitat designation are based on scientifically sound data, 
assumptions, and analyses. We obtained opinions from two knowledgeable 
individuals with scientific expertise to review our technical 
assumptions and analysis, and whether or not we had used the best 
scientific data available. These peer reviewers generally concurred 
with our methods and conclusions, and provided additional information, 
clarification, and suggestions to improve this final rule. Information 
we received from peer review is incorporated into this final rule. We 
also considered all comments and information we received from the 
public during the comment period for the proposed listing and the 
proposed designation of critical habitat.

Previous Federal Actions

    On April 12, 2018, we published in the Federal Register a proposed 
rule (83 FR 15900) to list the island marble butterfly as an endangered 
species and to designate critical habitat for the species under the 
Endangered Species Act of 1973 (Act), as amended (16 U.S.C. 1531 et 
seq.). Please refer to that proposed rule for a detailed description of 
Federal actions concerning the island marble butterfly that occurred 
prior to the proposal's publication.

Summary of Changes From the Proposed Rule

    Based on information we received from peer reviewers and public 
commenters, in this rule, we make the following changes from our April 
12, 2018, proposed rule (83 FR 15900):
    (1) We describe habitat use by the island marble butterfly to 
better reflect

[[Page 26787]]

that the organism exhibits ``patchy'' population dynamics at the local 
scale rather than following a classic metapopulation dynamic model;
    (2) We indicate that the island marble butterfly has been observed 
flying on lands immediately adjacent to the American Camp unit of San 
Juan Island National Historical Park (SJINHP);
    (3) We update portions of the rule to reflect the most current 
information regarding captive rearing and monitoring;
    (4) We indicate that while female island marble butterflies tend to 
use a single host plant species in each of three specific habitat 
types, there are instances (for example, when host plants are scarce) 
when they will use another of the three known host plant species in a 
specific habitat type;
    (5) We revise the description of the time that island marble 
butterflies spend as winged adults from an estimated average of 6 to 9 
days to include the potential to persist as winged adults for up to 16 
days, based on documentation provided by two separate commenters;
    (6) We include information regarding the aversion male island 
marble butterflies have demonstrated for flying over tall vegetation, 
including avoiding flying over fields of tall grasses; and
    (7) We revise the critical habitat discussion and designation to 
address the limitations in the precision of mapped critical habitat, to 
clarify that the critical habitat designation includes road shoulders 
and road margins, and to clarify our intent to designate as critical 
habitat only the steep coastal bluffs on private lands near Eagle Cove.

Summary of Comments and Recommendations

    In our April 12, 2018, proposed rule (83 FR 15900), we requested 
that all interested parties submit written comments on the proposal by 
June 11, 2018. We also contacted appropriate Federal and State 
agencies, scientific experts and organizations, and other interested 
parties and invited them to comment on the proposed determination, 
proposed designation of critical habitat, and draft economic analysis. 
Newspaper notices inviting general public comment were published in the 
Islands' Sounder, Journal of the San Juans, and the Seattle Times. We 
did not receive any requests for a public hearing. All substantive 
information provided during the comment period has either been 
incorporated directly into this final rule or is addressed below.
    During the comment period, we received 23 comment letters 
addressing the proposed determination and/or the proposed critical 
habitat designation. We address all substantive comments either below 
or by making the requested changes to the rule, as described above, 
when we determined that they were correct. We did not receive comments 
from any Federal agencies or Tribes. We received a letter of support 
from the Washington Department of Fish and Wildlife; however, their 
letter did not contain any comments or requests for revision of the 
language.

Peer Reviewer Comments

    In accordance with our peer review policy published on July 1, 1994 
(59 FR 34270), we solicited expert opinion from five knowledgeable 
individuals with scientific expertise that included familiarity with 
the island marble butterfly and its habitat, biological needs, and 
threats; the geographic region in which the species occurs; and 
conservation biology principles. We received responses from two of the 
peer reviewers.
    We reviewed all comments we received from the peer reviewers for 
substantive issues and new information regarding the island marble 
butterfly and its critical habitat. The peer reviewers generally 
concurred with our methods and conclusions, and provided additional 
information, clarifications, and suggestions to improve the final rule. 
Peer reviewer comments are addressed in the following summary and 
incorporated into the final rule as appropriate.
    (1) Comment: One peer reviewer highlighted the lack of clarity 
surrounding what constitutes a ``site,'' both within American Camp and 
outside of the park.
    Our Response: Due to the way data were collected and submitted to 
the Service, we were limited in the way we could reference and analyze 
detection or nondetection of the island marble butterfly in any given 
year. We assign the term ``site'' to each location that has a name and 
survey information associated with it.
    (2) Comment: One peer reviewer indicated that describing the island 
marble butterfly as having a ``low dispersal capacity'' was inaccurate 
and suggested revising the narrative to reflect that the island marble 
butterfly exhibits ``patchy population dynamics.''
    Our Response: We revised the narrative in this rule to reflect that 
the island marble butterfly generally exhibits weak site fidelity and 
low to intermediate dispersal capacity, which are key behavioral 
components of patchy population dynamics.
    (3) Comment: One peer reviewer and one commenter identified 
potential suitable habitat for the island marble butterfly in areas 
known to be previously occupied and stated that these areas should be 
included in critical habitat.
    Our Response: We considered all previously occupied areas in the 
analysis of proposed critical habitat. For the reasons stated below 
under Areas Occupied at the Time of Listing, we are designating 
critical habitat only on and around American Camp. We are unable, at 
this time, to delineate any specific unoccupied areas that are 
essential to the conservation of the island marble butterfly due to the 
ephemeral and patchy nature of the species' habitat and our limited 
understanding regarding the ideal configuration of habitat, the ideal 
size and number of habitat patches, and how these habitat patches may 
naturally evolve on the landscape. This does not mean that other areas 
are not important or valuable to the recovery of the island marble 
butterfly, or that we only need one occupied unit to recover the 
species.

Public Comments

    (4) Comment: One commenter posited that the decline and 
disappearance of the island marble butterfly was caused, in part, by 
the decline in traditional harvest of food resources by pre-European 
peoples who inhabited the Gulf Islands and the San Juan archipelago 
followed by the introduction and establishment of nonnative weedy plant 
species.
    Our Response: While these factors may have contributed to the 
decline of the island marble butterfly and other disturbance-dependent 
native butterfly species, we were unable to locate any substantiating 
evidence that would support this claim.

Background

Species Information

Taxonomy and Species Description
    The island marble butterfly (Euchloe ausonides insulanus) is a 
subspecies of the large marble butterfly (E. ausonides) in the Pieridae 
family, subfamily Pierinae, which primarily consists of yellow and 
white butterflies. The island marble butterfly was formally described 
in 2001, by Guppy and Shepard (p. 160) based on 14 specimens collected 
between 1859 and 1908 on or near Vancouver Island, British Columbia, 
Canada, and is geographically isolated from all other E. ausonides 
subspecies. The taxonomic status of the island marble butterfly is not 
in dispute. Euchloe ausonides insulanus is recognized as a valid 
subspecies by the Integrated Taxonomic Information

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System (ITIS 2015a, entire) based on the phenotypic differences 
documented in Guppy and Shepard (2001). In this rule, we use shorthand 
for simplicity in referring to the island marble butterfly as a species 
because subspecies are treated as species for the purposes of 
evaluating taxa for listing under the Act.
    Island marble butterflies have a wingspan of approximately 1.75 
inches (in) (4.5 centimeters (cm)) (Pyle 2002, p. 142) and are 
differentiated from other subspecies of the large marble butterfly by 
their larger size and the expanded marbling pattern of yellow and green 
on the underside of the hindwings and forewings (Guppy and Shepard 
2001, p. 159). Immature stages of the island marble butterfly have 
distinctly different coloration and markings from Euchloe ausonides; 
specifically, the third and fourth larval instars (instars are the 
larval stages between molting events) have a white spiracular stripe (a 
stripe that runs along the side of a caterpillar) subtended (bordered 
below) by a yellow-green subspiracular stripe and a green-yellow 
ventral area, which is different from the stripe colors and patterns 
described for E. ausonides (James and Nunnallee 2011, pp. 102-103; 
Lambert 2011, p. 15). The island marble butterfly is also behaviorally 
distinct; large marble butterflies pupate (enter the final stage of 
larval development before transforming into a butterfly) directly on 
their larval host plants, whereas the island marble butterflies leave 
their host plants to find a suitable pupation site up to 13 feet (ft) 
(4 meters (m)) away from their larval host plants (Lambert 2011, p. 
19).
Distribution
    The island marble butterfly was historically known from just two 
areas along the southeastern coast of Vancouver Island, British 
Columbia, Canada, based on 14 museum records: The Greater Victoria area 
at the southern end of Vancouver Island; and near Nanaimo and on 
adjacent Gabriola Island, approximately 56 miles (mi) (90 kilometers 
(km)) north of Victoria. The last known specimen of the island marble 
butterfly from Canada was collected in 1908 on Gabriola Island, and the 
species is now considered extirpated from the province (COSEWIC 2010, 
p. 6). Reasons for its disappearance from Canada are unknown. 
Hypotheses include increased parasitoid loads (the number of individual 
deadly parasites within an individual caterpillar) associated with the 
introduction of the cabbage white butterfly (Guppy and Shepard 2001, p. 
38) or heavy grazing of natural meadows by cattle and sheep, which 
severely depressed its presumed larval food plant (SARA 2015).
    After 90 years without a documented occurrence, the island marble 
butterfly was rediscovered in 1998 on San Juan Island, San Juan County, 
Washington, at least 9 mi (15 km) east of Victoria across the Haro 
Strait. Subsequent surveys in suitable habitat across southeastern 
Vancouver Island and the Gulf Islands in Canada (see COSEWIC 2010, p. 
5), as well as the San Juan Islands and six adjacent counties in the 
United States (Whatcom, Skagit, Snohomish, Jefferson, Clallam, and 
Island Counties), revealed only two other occupied areas. One of these 
occupied areas was centered on San Juan Island and the other on Lopez 
Island, which is separated from San Juan Island by just over 0.5 mi (1 
km) at its closest point. These occupied areas were eventually 
determined to comprise five populations, as described in detail in our 
2006 12-month finding (71 FR 66292; November 14, 2006). Since 2006, the 
number and distribution of populations has declined. Four of the five 
populations that once spanned San Juan and Lopez Islands have not been 
detected in recent years, and the species is now observed only in a 
single area centered on American Camp, a part of San Juan Island 
National Historical Park that is managed by the National Park Service 
(NPS). The island marble butterfly has also been sighted using the 
lands adjoining or near American Camp; there were observations of 
island marble butterflies flying beyond the boundaries of these 
adjoining lands in 2015 and 2017 (Potter 2015a, in litt.; Lambert 2018, 
in litt.).
    No current records exist of any life-history stage of the island 
marble butterfly except at or near American Camp at San Juan Island 
National Historical Park. Therefore, we consider only American Camp and 
the immediately adjacent areas to be occupied at the time of this final 
listing.
Survey Effort
    Extensive surveys have been conducted in British Columbia, Canada, 
since 2001, with an estimated 500 survey hours conducted by 
professional surveyors and 2,000 survey hours by volunteer butterfly 
enthusiasts (COSEWIC 2010, p. v). During these surveys, neither the 
island marble butterfly nor suitable habitat was detected (COSEWIC 
2010, p. vi). The species has been considered extirpated in British 
Columbia since 1910, and was formally designated extirpated in 1999 by 
the Canadian government (COSEWIC 2000, p. iii).
    In the United States, surveys for the island marble butterfly have 
also been extensive. In 2005 and 2006, we partnered with NPS, 
Washington Department of Fish and Wildlife (WDFW), Washington 
Department of Natural Resources (WDNR), the University of Washington, 
and the Xerces Society to survey for the presence of the island marble 
butterfly during the adult flight period (when eggs are laid and larvae 
are active; early April-late June). Qualified surveyors conducted 
approximately 335 individual surveys at more than 160 sites in 
potentially suitable habitat across 6 counties (Clallam, Jefferson, 
Island, San Juan, Skagit, and Whatcom Counties) and on 16 islands 
(Miskelly and Potter 2005, pp. 5, 7-16; Miskelly and Fleckenstein 2007, 
pp. 4, 10-19). Outside of American Camp, sites were defined primarily 
by ownership, although some exceptionally large sites were subdivided 
and received unique site names. All surveys followed a set of 
standardized protocols to ensure they were conducted when butterflies 
had the highest likelihood of being detected (see Miskelly and Potter 
2005, p. 4). Island marble butterflies were considered present at sites 
where eggs, larvae, or adults of the species were detected. These 
surveys documented five populations distributed across San Juan and 
Lopez Islands, including the single population persisting today 
centered on American Camp (Miskelly and Fleckenstein 2007, pp. 4-5).
    Annual surveys conducted outside of American Camp from 2007-2012 
focused on areas with suitable habitat on San Juan and Lopez Islands. 
These surveys generally included previously occupied sites, when 
accessible, in order to document whether or not island marble 
butterflies persisted at the sites where they were detected in 2005 and 
2006. After years of observing a rangewide decline in available island 
marble butterfly habitat and dwindling island marble butterfly 
detections, WDFW determined that there was not enough suitable habitat 
remaining outside of American Camp to warrant continued widespread 
survey efforts on San Juan and Lopez Islands. Therefore, surveys in 
2013 and 2014 focused solely on assisting with monitoring at American 
Camp and surveying lands directly adjacent to the park (Potter 2015a in 
litt.). Surveys to monitor the status of the population centered on 
American Camp have been conducted annually from 2004 to 2015, although 
the effort has varied through time (see ``Abundance,'' below, for 
additional information).

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    In 2015, in addition to annual population monitoring at American 
Camp, the Service funded an extensive survey of sites on San Juan 
Island outside of American Camp. Areas surveyed included those sites 
where island marble butterflies had previously been detected, as well 
as areas with suitable habitat with no prior detections. Researchers 
conducted 134 individual surveys at a total of 48 sites, including 24 
sites where the island marble butterfly had been documented previously. 
The survey yielded no detections of the island marble butterfly outside 
of American Camp.
    Multiple years of extensive surveys conducted across formerly 
occupied sites have failed to detect the species. However, it is 
possible that the island marble butterfly continues to exist at a 
handful of small isolated sites where surveyors were not granted access 
or were unable to survey during suitable conditions (Miskelly and 
Potter 2005, entire; Miskelly and Fleckenstein 2007, entire; Miskelly 
and Potter 2009, entire; Hanson et al. 2009, entire; Hanson et al. 
2010, entire; Potter et al. 2011, entire; Vernon and Weaver 2012, 
entire; Weaver and Vernon 2014, entire; Potter 2015a in litt.; Vernon 
2015a, entire).
Abundance
    In our 2006 12-month finding, we estimated the abundance of island 
marble butterflies to be ``probably less than 500 butterflies, and 
possibly as low as 300 individuals'' (71 FR 66292, November 14, 2006, 
p. 66295). These numbers were based on limited data, and their accuracy 
is uncertain. Since 2006, there have been several efforts to either 
directly estimate population size or evaluate changes in relative 
abundance through time (described below). In addition, captive-rearing 
and release of butterflies was initiated in 2013, and as of the spring 
of 2018, over 500 captive-raised butterflies have been released at 
American Camp to supplement the population (SJINHP 2018, in litt.) (see 
the discussions of conservation efforts under Factors A and C, below, 
for more details).
    Site Occupancy--The number of sites where the island marble 
butterfly is detected each year is a useful indicator of coarse-scale 
changes in abundance. The island marble butterfly has been recorded at 
a total of 63 individual sites since rangewide surveys began in 2005: 
The species was found at 37 sites in and around American Camp and 26 
sites outside of American Camp (Miskelly and Potter 2005, pp. 7-14; 
Miskelly and Fleckenstein 2007, pp. 14-19; Miskelly and Potter 2009, 
pp. 7-8, 10-11; Hanson et al. 2009, pp. 10-11, 24-28; Hanson et al. 
2010, pp. 12-13, 26-30; Potter et al. 2011, pp. 10-23, 15-23; Potter 
2012, unpublished; Potter 2013, unpublished; Vernon and Weaver 2012, 
pp. 4-7; Weaver and Vernon 2014, pp. 5-8). The number of occupied sites 
recorded at American Camp is somewhat confounded by changes in survey 
methods and effort through time (see ``Survey Effort,'' above). We 
recognize this as a potential source of uncertainty, but note that both 
transect data and anecdotal observations suggest a population decline 
at American Camp since monitoring began in 2004 (see Transect Counts, 
below).
    The largest number of concurrently occupied sites reported was 25 
in 2007, 10 of which were outside of American Camp (Miskelly and Potter 
2009, pp. 7-8, 10-11; Potter et al. 2011, pp. 15-16). The number of 
occupied sites declined every year from 2007 to 2011, with the species 
detected at only seven sites in 2011, only one of which was outside of 
American Camp. In 2015, adult island marble butterflies were detected 
at only four of the regularly monitored sites at American Camp, the 
fewest occupied sites ever recorded, and no adults, eggs, or larvae 
were detected outside of the greater American Camp area (Potter 2015a 
in litt.; NPS 2015, entire; Vernon 2015b, entire), although there were 
two observations of single adult butterflies flying just beyond the 
boundary of the park that were not recorded in formal surveys by NPS 
(Potter 2015a, in litt.). Island marble butterflies were detected as 
eggs in six additional research plots at American Camp (Lambert 2015d, 
p. 4), but none of the eggs tracked in the research plots survived to 
the fifth larval instar (Lambert 2015d, p. 13). In 2016 and 2017, 
larval habitat for the island marble butterfly at American Camp 
increased substantially, and survivorship of individuals tracked from 
eggs through fifth instar larvae increased from zero in 2015 to 3 
percent in 2016 (Lambert 2016a, pp. 10, 21), but decreased to 1 percent 
in 2017, the last year for which survivorship data were collected 
(Lambert 2017, pp. 3, 12).
    The reasons for the precipitous decline in the number of occupied 
sites since 2005 are not known with certainty, but the near-complete 
loss of habitat outside of American Camp in some years is likely a 
principal cause. Habitat loss has been caused by road maintenance, 
mowing, cultivation of land, intentional removal of host plants, 
improperly timed restoration activities, development, landscaping, deer 
browse, and livestock grazing (Miskelly and Potter 2005, p. 6; Miskelly 
and Fleckenstein 2007, p. 6; Miskelly and Potter 2009, p. 9; Hanson et 
al. 2009, p. 18; Hanson et al. 2010, p. 21; Potter et al. 2011, p. 13).
    Transect Counts--Counts along transects can provide a measure of 
relative abundance, which can be useful in assessing changes in the 
population among sites and through time (Peterson 2010, pp. 12-13). 
From 2004 to 2008, Lambert (2009) counted adult island marble 
butterflies along transects at American Camp (14 established in 2004, 
and an additional 2 (for a total of 16) established in 2005), finding a 
consistent and significant decline in the number of adults observed: 
They counted 270 in 2004, 194 in 2005, 125 in 2006, 71 in 2007, and 63 
in 2008 (Lambert 2009, p. 5). These raw counts were also translated to 
relative encounter rates that account for differences in survey effort 
across years, and these encounter rates also showed a marked decline 
until 2016 (USFWS 2016). Four of these transects were monitored by NPS 
almost continuously from 2004 to 2016 (one transect was not monitored 
from 2009 to 2011), and relative encounter rates were calculated that 
accounted for transect length and the number of times the transect was 
surveyed each year. The relative encounter rate on these transects 
declined substantially between 2004 and 2015, from almost 2 butterflies 
per 100 meters surveyed in 2004, to approximately 0.3 butterflies per 
100 meters in 2015 (USFWS 2016). Survey results for 2016 improved 
across the three transects consistently monitored at American Camp, 
with approximately 0.6 butterflies per 100 meters. While an observation 
of 0.6 butterflies per 100 meters reflects an improvement from recent 
years, this improvement does not reverse the overall decline observed 
since monitoring began in 2004. The Service has not received updated 
transect data for the flight seasons of 2017 or 2018.
    Mark-Release-Recapture--Mark-release-recapture (MRR) studies were 
conducted at American Camp in 2008 and 2009 (and at one additional site 
on San Juan Island--the Pear Point Gravel Quarry, which is no longer 
occupied) (Peterson 2009, 2010, entire). These studies sought to 
address several demographic questions and to assess whether transect 
counts were a reliable method to estimate changes in the population 
through time (Peterson 2009, p. 3). MRR population estimates were 
generated for three focal areas at American Camp in 2009: The western 
end of American Camp (an estimated 50 individuals), American Camp below 
the Redoubt (an estimated 39 individuals), and the dunes at American 
Camp (an estimated 24 individuals). However,

[[Page 26790]]

because American Camp was not surveyed in its entirety, these areas 
represent an unquantified fraction of the occupied habitat at American 
Camp; therefore, we cannot extrapolate from this information to 
estimate the rangewide population.
    In summary, monitoring efforts have varied since 2008, but reports 
from NPS indicate an ongoing decrease in the relative abundance of the 
island marble butterfly at American Camp, suggesting that total numbers 
continue to decline (Vernon and Weaver 2012, pp. 5-6; Weaver and Vernon 
2014, p. 6). While reliable and precise rangewide population estimates 
have not been produced for this species, the available evidence 
suggests that the species has a very small population that has declined 
substantially since monitoring began in 2004.
Habitat
    The island marble butterfly has three known host plants, all in the 
mustard family (Brassicaceae). One is native, Lepidium virginicum var. 
menziesii (Menzies' pepperweed), and two are nonnative: Brassica rapa 
(no agreed-upon common name, but sometimes called field mustard; 
hereafter referred to as field mustard for the purposes of this 
document) (ITIS 2015b, entire), and Sisymbrium altissimum L. (tumble 
mustard) (Miskelly 2004, pp. 33, 38; Lambert 2011, p. 2).
    All three larval host plants occur in open grass- and forb-
dominated vegetation systems, but each species is most robust in one of 
three specific habitat types: Menzies' pepperweed at the edge of low-
lying coastal lagoon habitat; field mustard in upland prairie habitat, 
disturbed fields, and disturbed soils, including soil piles from 
construction; and tumble mustard in sand dune habitat (Miskelly 2004, 
p. 33; Lambert 2011, pp. 24, 121-123). While each larval host plant can 
occur in the other habitat types, female island marble butterflies tend 
to select specific host plants in each of the three habitat types 
referenced above, likely because certain host plants are more robust in 
each habitat type during the flight season (Miskelly 2004, p. 33; 
Lambert 2011, pp. 24, 41, 50, 54-57, 121-123; Shrum 2018, in litt.). 
Host plants that establish and grow outside of their primary habitat 
type typically are less robust, and female butterflies do not appear to 
choose them preferentially but may use them when other larval habitat 
is limited (Lambert 2011, pp. 24, 41, 50, 54-57, 121-123; Shrum 2018, 
in litt.).
    Adults primarily nectar (forage) on their larval host plants 
(Potter 2015e, pers. comm.), but use a variety of other nectar plants 
including:
     Abronia latifolia (yellow sand verbena),
     Achillea millefolium (yarrow),
     Amsinckia menziesii (small-flowered fiddleneck),
     Cakile edentula (American sea rocket),
     Cerastium arvense (field chickweed),
     Erodium cicutarium (common stork's bill),
     Geranium molle (dovefoot geranium),
     Hypochaeris radicata (hairy cat's ear),
     Lomatium utriculatum (common lomatium),
     Lupinus littoralis (seashore lupine),
     Myosotis discolor (common forget-me-not),
     Ranunculus californicus (California buttercup),
     Rubus ursinus (trailing blackberry),
     Taraxacum officinale (dandelion),
     Toxicoscordion venenosum (death camas, formerly known as 
Zigadenus venenosus), and
     Triteleia grandiflora (Howell's brodiaea, formerly 
Brodiaea howellii) (Miskelly 2004, p. 33; Pyle 2004, pp. 23-26, 33; 
Miskelly and Potter 2005, p. 6; Lambert 2011, p. 120; Vernon and Weaver 
2012, appendix 12; Lambert 2015a, p. 2, Lambert 2015b, in litt.). Of 
these additional nectar resources, island marble butterflies are most 
frequently observed feeding on yellow sand verbena, small-flowered 
fiddleneck, and field chickweed (Potter 2015e, pers. comm.). Adults 
primarily use low-statured, white flowering plants such as field 
chickweed as mating sites (Lambert 2014b, p. 17).
Biology
    The island marble butterfly life cycle comprises four distinct 
developmental phases: Egg, larva, chrysalis, and butterfly. Development 
from egg to chrysalis takes approximately 38 days and includes five 
instars (phases of larval development between molts) (Lambert 2011, p. 
7). Female island marble butterflies produce a single brood per year, 
and prefer to lay their eggs individually on the unopened terminal 
flower buds of their larval host plants (Lambert 2011, pp. 9, 48, 51). 
Gravid female butterflies appear to select plants with many tightly 
grouped flower buds over host plants with fewer buds, and they tend to 
avoid laying eggs on inflorescences (flower heads) where other island 
marble butterflies already have deposited eggs (Lambert 2011, p. 51). 
However, the number of eggs laid on a single host plant has been 
observed to vary with the density and distribution of host plants and 
may also be affected by host plant robustness as well as the age of the 
individual female butterfly (Parker and Courtney 1984, entire; Lambert 
2011, pp. 9, 53, 54).
    First instar larvae are able to feed only on tender portions of the 
host plant, such as developing flower buds and new growth, and 
initially move no more than a few centimeters from where they hatch 
before they must feed; thus, larvae that hatch from eggs located more 
than a few centimeters from a host plant's flower heads often starve 
before reaching a suitable food source (Lambert 2011, pp. 12-13). The 
limited locomotion of newly hatched larvae and their reliance on tender 
flower buds as a food resource leads to a concentration of early-instar 
larvae near the tips of their larval host plants (Lambert 2011, p. 13). 
Larvae become more mobile in later instars, and their better developed 
mouthparts allow them to consume older, tougher plant material. 
Eventually, they may move to stems of other nearby host plants to 
forage (Lambert 2011, pp. 15-17).
    The fifth (last) instar larvae ``wander'' through standing 
vegetation, never touching the ground, as they search for a suitable 
site on which to pupate (form a chrysalis) (Lambert 2011, p. 20). The 
greatest distance a fifth instar larva has been observed to move from 
its final larval host plant was 4 meters, but few observations exist 
(Lambert 2011, p. 19). Fifth instar larvae select slender dry stems in 
the lower canopy of moderately dense vegetation as sites for pupation 
and entering diapause, a state of suspended development (Lambert 2011, 
p. 21).
    Island marble butterflies spend the largest portion of their annual 
life cycle in diapause as chrysalids. They enter diapause in midsummer 
and emerge as butterflies in the spring of the following year. One 
island marble chrysalis remained in diapause for 334 days (11 months) 
(Lambert 2011, p. 22). Extremely low survivorship at early life-history 
stages has been found in recent years (e.g., of 136 and 226 individual 
eggs tracked in 2014 and 2015, respectively, zero survived to pupation; 
Lambert 2015d, p. 13).
    Adult island marble butterflies emerge from early April to mid-June 
and live as winged adults for up to 16 days (Peterson 2009, p. 7; 
Peterson 2018, in litt.; Vernon 2018, in litt.), with most persisting 
for a much shorter period; estimates range from 2 to 9 days (Lambert 
2011, pp. 50, 180; Peterson 2009, p. 7).
    Males emerge 4 to 7 days before females and patrol hillsides in 
search of

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mates (Lambert 2011, p. 47). Male island marble butterflies have been 
observed to prefer low-statured vegetation, generally avoiding flight 
over expanses of tall grasses (Miskelly 2018, in litt.). Male island 
marble butterflies are attracted to white (ultraviolet-reflecting) 
objects that may resemble females and have been observed to investigate 
white flowers (e.g., field chickweed and yarrow), white picket fences, 
and white lines painted on the surface of roads (Lambert 2011, p. 47). 
When a male locates a receptive female, mating may occur hundreds of 
meters from the nearest larval host plant, increasing the potential 
extent of adult habitat to include a varied array of plants and 
vegetative structure (Lambert 2011, p. 48). Individual adult island 
marble butterflies seldom disperse distances greater than 0.4 mi (0.6 
km), with the greatest documented dispersal distance being 1.2 mi (1.9 
km) (Peterson 2010, pp. 3, 12).
    Island marble butterflies generally exhibit weak site fidelity and 
low to intermediate dispersal capacity. When considered rangewide, the 
island marble butterfly exists as a group of spatially separated 
populations that interact when individual members move from one 
occupied location to another (Miskelly and Potter 2009, p. 14; Lambert 
2011, p. 147). For the island marble butterfly, a population is defined 
as a group of occupied sites close enough for routine genetic exchange 
between individuals. Thus, occupied areas separated by distances 
greater than 3 mi (4.8 km) with no intervening suitable habitat and a 
low likelihood of genetic exchange are considered to be separate 
populations (Miskelly and Potter 2009, p. 12). Five potential 
populations of island marble butterflies were identified and described 
in detail in the 2006 12-month finding (71 FR 66292, November 14, 2006, 
p. 66294): American Camp and vicinity, San Juan Valley, Northwest San 
Juan Island, Central Lopez Island, and West Central Lopez Island. As 
described previously, only the population at American Camp has been 
detected since 2012.

Summary of Factors Affecting the Species

    Section 4 of the Act (16 U.S.C. 1533) and its implementing 
regulations in title 50 of the Code of Federal Regulations (50 CFR part 
424) set forth the procedures for determining whether a species is an 
endangered species or threatened species. The Act defines an endangered 
species as ``in danger of extinction throughout all or a significant 
portion of its range,'' and a threatened species as ``likely to become 
an endangered species within the foreseeable future throughout all or a 
significant portion of its range.'' Section 4(a)(1) requires the 
Secretary to determine whether a species is an endangered species or 
threatened species because of any of the following five factors: (A) 
The present or threatened destruction, modification, or curtailment of 
its habitat or range; (B) overutilization for commercial, recreational, 
scientific, or educational purposes; (C) disease or predation; (D) the 
inadequacy of existing regulatory mechanisms; or (E) other natural or 
manmade factors affecting its continued existence.
    To inform the determination, we complete a status assessment in 
relation to the five factors using the best available scientific and 
commercial data. The status assessment provides a thorough description 
and analysis of the stressors, regulatory mechanisms, and conservation 
efforts affecting individuals, populations, and the species. We use the 
terms ``stressor'' and ``threat'' interchangeably, along with other 
similar terms, to describe anything that may have a negative effect on 
the island marble butterfly. In considering what factors might 
constitute threats, we must look beyond the mere exposure of the 
species to the factor to determine whether the species responds to the 
factor in a way that causes actual impacts to the species. If there is 
exposure to a factor, but no response, or only a positive response, 
that factor is not a threat. The mere identification of threats that 
could affect the island marble butterfly is not sufficient to compel a 
finding that listing is appropriate. Rather, we evaluate the effects of 
the threats in light of the exposure, timing, and scale of the threats, 
both individually and cumulatively, and any existing regulatory 
mechanisms or conservation efforts that may ameliorate or exacerbate 
the threats in order to determine if the species meets the definition 
of an endangered species or threatened species.

Factor A. The Present or Threatened Destruction, Modification, or 
Curtailment of Its Habitat or Range

    Since we first analyzed stressors to the island marble butterfly's 
habitat on San Juan and Lopez Islands in 2006, the species' 
distribution has contracted, and it is now known only from American 
Camp and the immediate vicinity on San Juan (see ``Distribution,'' 
above). Island marble butterfly larval habitat in natural landscapes, 
such as that found at American Camp, is patchy at best, making it 
difficult to estimate the acreage of larval host plants. Additionally, 
larval host plants are early successional species that thrive in 
disturbed habitats. This can result in larval habitat patches that may 
be present one year and gone the next, depending on the level of 
disturbance present on the landscape.
Development
    Residential development occurs on both San Juan and Lopez Islands, 
primarily on private lands. Habitat loss from development affects the 
island marble butterfly by reducing the availability of secure habitat 
that will persist long enough for the island marble butterfly to 
complete its life cycle. Development may also affect the known occupied 
range of the island marble butterfly by constraining the amount of 
stepping-stone habitat (patches of habitat too small to maintain an 
established population, but large enough to allow for connectivity 
between larger suitable patches) for dispersal. In addition, mowing or 
removal of host plants (e.g., for landscaping around developments) may 
also remove island marble butterfly habitat or prevent its 
establishment. Because female island marble butterflies selectively lay 
their eggs on the inflorescences (flowering head) of tall, robust 
plants (Lambert 2011, p. 55), mowing host plants reduces the 
availability of suitable oviposition (egg laying) sites for the island 
marble butterfly.
    Within American Camp, which is protected by NPS regulations (see 
Factor D discussion, below), development is not a threat to the island 
marble butterfly. However, residential development was a threat to 
island marble butterfly habitat in the Cattle Point Estate and Eagle 
Cove developments adjacent to American Camp. These areas accounted for 
199 ac (81 ha) of island marble butterfly habitat, or 18 percent of 
occupied habitat in 2006, which are now unoccupied due to habitat loss 
(Potter 2015a, in litt.) associated with development (e.g., mowing, 
landscaping, or removal of host plants) (Miskelly and Potter 2005, p. 
6; Miskelly and Fleckenstein 2007, p. 6; Hanson et al. 2009, p. 9).
    In 2006, we noted that development was occurring less rapidly in 
the areas to the north and west of American Camp and on Lopez Island 
where lands comprised small, rural farms with pastures and low-density 
residential properties. We concluded that these areas, containing about 
361 ac (146 ha), or 32 percent of the occupied habitat as of 2006, 
would be managed in a way

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that was compatible with island marble butterfly habitat. Since that 
time, the amount of farmland in San Juan County has decreased, with the 
greatest loss of farmland in San Juan County attributed to the 
subdivision of larger farms into smaller parcels, which have then been 
developed (San Juan County Agricultural Resources Committee 2011, p. 
23). While there are no estimates of the amount of potential habitat 
for the island marble butterfly lost specifically to development, 
habitat loss outside of American Camp from a variety of sources has 
been substantial (Miskelly and Potter 2005, p. 6; Miskelly and 
Fleckenstein 2007, p. 6; Miskelly and Potter 2009, p. 9; Hanson et al. 
2009, pp. 18-19; Potter et al. 2011, pp. 13-14; Potter 2015a, in 
litt.). In addition to development of former agricultural lands, 
perhaps more significant are the management practices on these lands 
that effectively preclude recolonization by island marble butterflies 
or create population sinks (habitat patches that attract dispersing 
individuals, but do not allow them to complete their life cycle and 
reproduce) (see ``Agricultural Practices,'' below). We conclude that 
development has substantively contributed to the extirpation of the 
island marble butterfly outside of American Camp and remains one of 
several factors impeding successful recolonization of previously 
occupied habitats; however, because American Camp is protected from 
development by NPS regulations and is where the species solely occurs, 
development is not a threat currently acting on the remaining extant 
population of the species.
Road Construction
    In our 2006 12-month finding (71 FR 66292; November 14, 2006), we 
evaluated the impact of a planned road relocation project (Cattle Point 
Road relocation project) through American Camp. Cattle Point Road is 
the only point of access for residents at the southeastern tip of San 
Juan Island and traverses the slope of Mount Finlayson, effectively 
bisecting occupied island marble butterfly habitat at the park. We 
estimated that the relocation would cause temporary loss of as much as 
13 ac (5 ha) of island marble butterfly habitat due to clearing and 
removal of larval host plants, although there was no known breeding 
habitat along the highway at that time. We concluded that the road 
realignment was likely to proceed with little mortality to the island 
marble butterfly.
    Since 2006, we have worked closely with NPS and the Federal Highway 
Administration (FHA) to ensure that project impacts were avoided or 
minimized. Once the project began, in 2015, the Service, NPS, and WDFW 
actively surveyed the road alignment to remove host plants before they 
could attract oviposition by female island marble butterflies and to 
rescue island marble butterfly eggs and larva from any larval host 
plants that might have been overlooked. Island marble butterfly larval 
habitat in natural landscapes, such as that found at American Camp, is 
patchy at best, making it difficult to estimate the acreage of larval 
host plants. While the area affected by road construction was estimated 
to be 13 ac (5 ha), larval host plants did not occur in dense patches 
across the construction site. As a result of these efforts, far less 
suitable habitat for island marble butterflies was temporarily lost 
than we anticipated in 2006, and impacts to the island marble butterfly 
population were significantly reduced and potentially completely 
avoided.
    Habitat restoration will continue for several years; once it is 
completed, we anticipate that the project will be a net benefit to the 
quantity and quality of island marble butterfly habitat in the project 
area due to early coordination with the FHA and the proactive 
conservation measures they implemented throughout the process. These 
conservation measures included the proactive removal of all larval host 
plants from the footprint of the project described above (so that 
butterflies do not lay eggs on plants bound to be destroyed) and the 
reseeding of larval and nectar host plant species in the disturbed 
areas. These measures will both increase the quantity and improve the 
quality of the habitat surrounding the finished project. In conclusion, 
road construction is not currently a threat to the island marble 
butterfly.
Road Maintenance
    Road maintenance that destroys or negatively affects island marble 
butterfly larval host plants has been a concern since 2005, when it was 
documented as destroying occupied larval habitat on both San Juan and 
Lopez Islands (Miskelly and Potter 2005, p. 6). For example, in 2005, 
at Fisherman's Bay tombolo (a narrow beach landform that connects the 
mainland to an island) on Lopez Island, road maintenance crews 
deposited a quantity of sand on occupied larval host plants in an 
effort to reduce the fire hazard of the vegetation in preparation for a 
Fourth of July fireworks display. In addition to the deposition of sand 
on occupied habitat, the remainder of the site was mowed by road 
maintenance crews, removing all remaining larval host plants. There 
were no detections of the island marble butterfly in 2006, a single 
detection at the tombolo in 2007, and none through 2015 (Miskelly and 
Potter 2009, p. 21; Potter et al. 2011, p. 16; Potter 2015a, in litt.).
    Roadside maintenance has resulted in the destruction of suitable 
habitat on Lopez Island and outside of American Camp on San Juan Island 
(Miskelly and Potter 2005, p. 6). Despite changes in roadside 
maintenance practices to address habitat loss, these protections were 
not implemented uniformly throughout San Juan County, nor were they 
implemented with the immediacy necessary to allow for widespread 
persistence of island marble habitat along roadsides (Potter 2016, 
pers. comm.). However, because roadside maintenance at American Camp 
will be conducted in close coordination with the Service, we conclude 
that whereas habitat loss associated with road maintenance activities 
could be one of several factors impeding successful recolonization of 
previously occupied habitats, it likely will have only minor impacts on 
the island marble butterfly, given its current distribution. We do not 
expect these impacts to change within American Camp in the future.
Vegetation Management
    The island marble butterfly is present year round and largely 
stationary while in its early developmental phases, becoming most 
visible when it becomes a winged adult. The cryptic egg, larval, and 
chrysalis forms make island marble butterflies vulnerable to land 
management and restoration practices when those practices overlap 
occupied areas. For example, in 2005, NPS conducted a prescribed fire 
intended to restore native prairie, and this fire burned through the 
occupied habitat during the butterfly's developmental stage and likely 
killed all eggs and larvae within the affected area. Similarly, the use 
of herbicides for the purpose of vegetation restoration in occupied 
island marble butterfly habitat has been documented (Potter et al. 
2011, p. 14). Although the direct effects of herbicides on island 
marble butterflies have not been studied, indiscriminate application of 
herbicides in areas occupied by eggs or larvae is likely to result in 
mortality through elimination of larval host plants and primary food 
resources.
    Since 2010, the Service, NPS, WDFW, and other partners have 
cooperated closely to achieve vegetation management and restoration 
goals while also conserving the island marble butterfly and its 
habitat, including nonnative larval host plants. As a result,

[[Page 26793]]

vegetation management has not resulted in significant harm to island 
marble butterflies since 2010. The island marble butterfly is 
vulnerable to vegetation management or restoration practices that are 
improperly timed or poorly sited. However, this vulnerability does not, 
by itself, result in impacts to the species. Currently, vegetation 
management does not have a significant impact on the species because 
the ongoing collaboration between cooperating partners has adequately 
minimized the impacts of vegetation management actions at American 
Camp.
Agricultural Practices
    Agricultural activities that include tilling of the soil have been 
identified as a stressor for the island marble butterfly (Potter et al. 
2011, p. 14). Removal or destruction of habitat by conversion from an 
agricultural condition that provides suitable habitat (e.g., old field 
pasture) for island marble butterfly to an agricultural condition that 
does not allow the island marble butterfly to complete its life cycle 
(e.g., active cropping) has likely led to the decline of occupied 
island marble butterfly habitat outside of American Camp and continues 
to contribute to the curtailment of the former range of the species. 
The species has not been detected since 2012 at any previously occupied 
agricultural sites that have been surveyed (Potter et al. 2011, pp. 15-
16; Potter 2012, unpublished data; Potter 2013, unpublished data; 
Vernon 2015b in litt., entire). In addition, no new occupied sites in 
agricultural areas have been detected during surveys conducted in 2015 
(Vernon 2015a, entire).
    Practices on San Juan and Lopez Islands that require tilling the 
soil, such as grain farming, can promote growth of field mustard (a 
host plant) during the island marble butterfly's flight period if 
tilling takes place during fall and winter months (e.g., December 
through February), allowing field mustard seeds in the seed bank to 
germinate and mature in synchrony with the needs of the island marble 
butterfly. Because cereal crops compete with field mustard, the array 
of established plants can result in a diffuse number of larval host 
plants at a density attractive to female island marble butterflies 
searching for an oviposition site. When actively cropped agricultural 
areas with larval host plants occur near occupied habitat, they can 
create an ``ecological trap'' if dispersing females lay eggs where the 
larvae do not have adequate time to complete their life cycle before 
the crop is harvested and the site is tilled for replanting the 
following spring (Hanson et al. 2009, pp. 18-19; Miskelly and Potter 
2009, p. 14).
    Similarly, grazing can produce an ecological trap if females lay 
eggs in suitable habitat that is then consumed by livestock (see 
Herbivory by livestock, below). However, since the 1980s, farming on 
San Juan Island has trended toward small market gardens, and large, 
livestock-based farms have been reduced in number (San Juan County 
Agricultural Resources Committee 2011, p. 16). Livestock grazing does 
not currently overlap any areas known to be occupied by the island 
marble butterfly; thus, livestock grazing is not currently a threat to 
the island marble butterfly, although it could become a threat in the 
future if the island marble butterfly were to become reestablished in 
areas where grazing takes place. The best available scientific and 
commercial information does not indicate that agricultural practices 
currently affect the island marble butterfly because the known 
population occurs on NPS lands that are not managed for agricultural 
use.
Plant Succession and Competition With Invasive Species
    All of the known larval host plants for the island marble butterfly 
are annual mustard species that are dependent on open, early-
successional conditions for germination (Lambert 2011, p. 149). 
Disturbance or active management maintains these conditions; otherwise, 
plant succession and invasion by weedy native and nonnative plants 
greatly inhibit germination and growth of larval host plants. These 
processes of vegetation change thus degrade and reduce the availability 
of habitat required by the island marble butterfly to complete its life 
cycle.
    Succession of open, low-statured vegetation to woody plants is a 
natural process in the absence of anthropogenic burning or other forms 
of disturbance. The cessation of Native American burning in the mid-
1800s resulted in the loss of prairie habitat in western Washington, 
including the San Juan archipelago, due to tree and shrub encroachment 
(Hamman et al. 2011, p. 317). Prairies were repeatedly burned during 
historical times by Native Americans for a variety of reasons, and 
areas used for cultivation of food plants, such as Camassia leichtlinii 
or C. quamash (great camas and common camas, respectively), may have 
been burned on an annual basis (Beckwith 2004, pp. 54-55; Boyd 1999, 
entire; Chappell and Kagan 2001, p. 42).
    Early estimates of the size of the prairie at American Camp suggest 
it may have been as large as 1,500 acres (ac) (607 hectares (ha)) when 
the first Europeans arrived (Douglas 1853, entire). Today, the prairie 
is estimated to be 695 ac (281 ha) due, in part, to succession and 
encroachment of Douglas-fir trees (Pseudotsuga menziesii) and other 
woody vegetation (Rochefort et al. 2012, p. 9). Reclaiming and 
maintaining open prairie habitat at American Camp requires active 
management to control Douglas fir trees and other woody species 
(Rochefort et al. 2012, p. 4).
    Two of the three known larval hosts for the island marble butterfly 
are introduced species that self-propagate into open, disturbed areas: 
Field mustard and tumble mustard. In the absence of active restoration 
or disturbance, other weedy plant species, as well as woody plants and 
trees, are likely to colonize the site, eventually outcompeting the 
early-successional host plants. At American Camp, where remnant prairie 
habitat persists, weedy species such as Elymus repens (quack grass), 
Holcus lanatus (velvet grass), Cirsium arvense (Canada thistle), and 
Vicia sativa (common vetch), among others, outcompete the larval host 
plants in the absence of disturbance.
    Competition with nonnative species also affects host plants in sand 
dune habitat. The sand dunes represent a unique habitat type for the 
island marble butterfly that includes open, shifting sands easily 
colonized by the larval host plant, tumble mustard (Lambert 2011, p. 
42). While Menzies' pepperweed and field mustard also occasionally 
occur in dune habitat, tumble mustard is the host plant that occurs 
there most commonly, is most robust in this habitat type, and can 
create continuous stands of larval host plants under optimal conditions 
(Lambert 2011, pp. 42, 65). When nonnative species such as Canada 
thistle, hairy cat's ear, and Rumex acetosella (sheep sorrel) colonize 
the sandy dune habitat, the dunes become increasingly stable and the 
effect is a reduction in the available germination sites for tumble 
mustard (Weaver and Vernon 2014, pp. 5, 9). Canada thistle has the 
greatest potential to negatively affect dune habitat where it is 
stabilizing the sand and facilitating establishment of grasses, which, 
in turn, displace tumble mustard (Rochefort 2010, p. 28; Weaver and 
Vernon 2014, p. 9).
    Conditions for larval host plants continue to be degraded through 
plant succession and invasion throughout the range of the island marble 
butterfly. Loss of habitat conditions favorable for larval host plants, 
and thus habitat loss for the island marble butterfly, occurs in

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at least two of three habitat types at American Camp, the only area 
where the island marble butterfly is currently known to persist (Weaver 
and Vernon 2014, pp. 5, 9). Loss of potentially suitable but not 
currently occupied habitat resulting from succession also occurs in any 
areas outside of American Camp where these processes take place. Due to 
the extremely limited numbers and range of the island marble butterfly, 
any further loss of habitat may lead to further decline of the species 
and preclude its establishment in new areas.
Herbivory
    Herbivory by deer: Black-tailed deer (Odocoileus hemionus 
columbianus) are common in the San Juan Island archipelago. At the 
single occupied site where island marble butterfly is currently known 
to exist, black-tailed deer numbers appear to be increasing (Lambert 
2014a, p. 3). Browsing deer prefer flowering plants when available, and 
tend to select stems on the tops or sides of plants over the stems that 
emerge lower on the stalk (Anderson 1994; p. 107; Lambert 2015c, in 
litt., Thomas 2015, pers. obs.). Specifically, at study sites where 
island marble butterflies exist, deer browse selectively on robust 
larval host plants with several inflorescences of compact flower buds--
the same plant characteristics preferred by female island marble 
butterflies as egg-laying sites (Lambert 2011, p. 103). The effect of 
deer browsing on larval host plants is three-fold. First, it destroys 
suitable egg-laying habitat; second, it stimulates rapid growth of 
lateral (side) stems on the plant, rendering the plant less likely to 
support an individual butterfly from egg to late-instar larva; and 
third, continual browsing of the flowering portion of the plant reduces 
seed production, resulting in fewer larval host plants over time 
(Lambert 2011, p. 10; Lambert 2014a, p. 10; Lambert 2015d, p. 17). Deer 
browsing, which stimulates rapid lateral stem growth, results in 
increased mortality when eggs are laid on the flowers of lateral stems 
on the larval host plants (Lambert 2011, p. 10). Immobile, early-instar 
larvae of island marble butterfly present on these stems are left 
behind as the stems grow away from them. When the larvae can no longer 
access the tender tissues at the developing tips of the plant that they 
require for survival, they die from starvation (Lambert 2011, p. 10, 
Lambert 2015e, in litt.).
    The destructive effects of deer browsing on larval habitat are 
common where surveys have taken place throughout the known range of the 
island marble butterfly (Miskelly and Fleckenstein 2007, p. 6; Miskelly 
and Potter 2009, pp. 11, 15; Hanson et al. 2009, pp. 4, 13, 19-20; 
Hanson et al. 2010, pp. 21-22; Potter et al. 2011, pp. 5, 13; Lambert 
2011, p. 104; Lambert 2014a, entire; Weaver and Vernon 2014, p. 10; 
Vernon and Weaver 2012, p. 9; Lambert 2015d, pp. 17-18). At American 
Camp, herbivory by deer has affected 95 percent of field mustard plants 
in some years (Lambert 2011, p. 127). Deer exclusion fencing has been 
erected to protect suitable habitat at American Camp to counteract the 
impacts of deer browsing, but the fencing has not been fully effective 
at excluding deer, and deer have continued to consume occupied larval 
host plants (see ``Habitat Conservation and Restoration,'' below).
    Habitat loss attributable to herbivory by deer is ongoing and 
extensive throughout the current and former range of the island marble 
butterfly, and may be increasing, with substantial impacts to the 
species (Lambert 2011, pp. 85-104; Lambert 2014a, p. 3; Lambert 2015d, 
pp. 14-18). The effect of habitat loss due to deer herbivory is 
compounded by the effect of inadvertent predation when the larval host 
plants are occupied by eggs or larvae (see ``Incidental Predation'' 
under the Factor C discussion, below).
    Herbivory by livestock: Livestock readily consume field mustard, 
which is often cultivated in pastures as a way to improve forage for 
cows and sheep (Smart et al. 2004, p. 1; McCartney et al. 2009, p. 
436). There is no livestock grazing at American Camp, but livestock 
pastures are present on San Juan and Lopez Islands in areas that may 
contain suitable habitat for dispersing island marble butterflies. When 
cattle or sheep are present on lands where field mustard is grown, they 
readily consume the flower heads, stems, and stalk of the plant, 
destroying suitable island marble butterfly habitat (Miskelly and 
Potter 2009, p. 15; Hanson et al. 2009, p. 20; Hanson et al. 2010, p. 
21). Like conversion of old field pastures to active cropping, 
cultivation of field mustard as a forage species for livestock 
potentially creates an ecological trap for the island marble butterfly 
when cultivation takes place within dispersal distance of an occupied 
site, and female island marble butterflies lay eggs in a patch of field 
mustard that is later consumed or trampled by livestock before any 
larvae can complete their life cycle (see ``Incidental Predation'' 
under Factor C, below, for further discussion). In conclusion, loss of 
potential habitat to livestock grazing can prevent reestablishment and 
persistence of suitable habitat for the species outside of American 
Camp. However, because livestock grazing is not allowed on American 
Camp where the species occurs, herbivory by livestock is not a threat 
currently acting on the remaining population of the species.
    Herbivory by rabbits: The European rabbit, Oryctolagus cuniculus, 
is a common invasive species in the San Juan Islands (Hall 1977, 
entire; Burke Museum 2015). At American Camp, European rabbits have 
been established for more than a century, following their introduction 
to San Juan Island during the late 1800s (Couch 1929, p. 336). Grazing 
by European rabbits, when they proliferate, affects both vegetative 
structure and composition, reducing both the number and kind of plant 
species near their warrens (network of burrows) (Eldridge and Myers 
2001, pp. 329, 335). Herbivory by European rabbits negatively affects 
the recruitment and establishment of larval host plants; where rabbits 
occur at American Camp, few larval host plants for the island marble 
butterfly persist due to the intense grazing pressure (Radmer 2015, in 
litt.). When larval host plants do germinate near European rabbit 
warrens, they are consumed before the plants are large enough for 
female island marble butterflies to recognize and use them.
    Population monitoring of European rabbits has been conducted at 
American Camp from 1985 to 2015, documenting an estimated population 
high of approximately 1,750 rabbits in 2006, and a low of fewer than 
100 in 2012. From 2009 through 2012, the population was estimated to be 
100 animals or fewer, and the condition of vegetation in the affected 
area had ``changed dramatically'' with the reduction in rabbit grazing 
pressure (West 2013, pp. 2, 4). The most recent population estimate, in 
2015, was approximately 500 animals, indicating that the rabbit 
population at American Camp is currently on the rise (West 2015, in 
litt.). If European rabbits remain uncontrolled at American Camp, their 
population is likely to fluctuate but continue expanding overall in the 
next decade, similar to the patterns documented in the past 30 years of 
monitoring data. The majority of the European rabbit population has 
been, and may continue to be, centered on a single large field near the 
middle of American Camp, surrounded by areas that include island marble 
butterfly habitat. As their population grows, we expect the impacts of 
European rabbits to expand, encroaching upon and destroying additional 
island marble butterfly habitat.

[[Page 26795]]

    Herbivory by brown garden snails: The nonnative brown garden snail 
(Cornu aspersum, formerly Helix aspersa) is a generalist herbivore that 
has been reported to occur in great numbers in some areas where island 
marble butterfly previously occurred (e.g., Pear Point Gravel Pit or 
`La Farge' and San Juan Valley), where it feeds on field mustard and 
tumble mustard, the two most common larval host plants for the island 
marble butterfly (Hanson et al. 2010, p. 18; Potter et al. 2011, p. 
13). State biologists removed hundreds of snails that were feeding on 
larval host plants at Pear Point in 2010, when the island marble 
butterfly still occupied this site (Potter et al. 2011, p. 13). The 
brown garden snail has extremely high reproductive potential; it 
matures within 2 years and can produce more than 100 eggs five or six 
times each year (Vernon 2015c, p. 1). The number of brown garden snails 
observed on San Juan Island has increased substantially between the 
years of 2009 and 2015 (Potter et al. 2011, p. 13; Vernon 2015c in 
litt., entire).
    In 2015, the brown garden snail was observed in San Juan Valley, a 
site formerly occupied by the island marble butterfly, and in 2016, the 
brown garden snail was documented in the South Beach area at American 
Camp by a Service biologist (Vernon 2015c in litt., entire; Vernon 
2015a p. 4; Reagan 2016, pers. obs.). High numbers of brown garden 
snails have been documented in highly disturbed sites previously 
occupied by island marble butterfly, and since our 2016 12-month 
finding (81 FR 19527; April 5, 2016) was published, they have been 
found invading the natural areas in American Camp currently occupied by 
the island marble butterfly and its host plants (Shrum 2017, in litt.). 
This most recent development indicates that brown garden snail is now 
well established within American Camp and the habitat currently used by 
the island marble butterfly, raising the likelihood that herbivory by 
the brown garden snail will result in habitat loss or degradation to an 
extent that can affect the butterfly's survival and reproductive 
success. While there are no documented accounts of snails directly 
consuming island marble butterfly eggs or larvae, the brown garden 
snail poses a threat to the island marble butterfly by consuming larval 
host plants, whether those plants are occupied or not. Therefore, 
herbivory by brown garden snails is detrimental to the butterfly's 
overall survival and reproductive success because it can both reduce 
the quantity of suitable host plants available and cause incidental 
mortality of individuals.
Storm Surges
    The nearshore lagoon habitat for island marble butterfly is close 
to sea level. Three intermittently occupied sites are in lagoons along 
the northeastern edge of American Camp, where they are partially 
protected from tidal surges that arrive from the west. One of these 
lagoons had the highest relative encounter rate of all monitored 
transects at American Camp in 2015, and raw counts at this site 
represented roughly 50 percent of the adult island marble butterflies 
recorded during annual monitoring for that year. Storm surges, 
attributable to the combined forces of high tides and high-wind storm 
events, inundate these low-lying lagoon areas intermittently, as 
evidenced by the deposition of driftwood logs along the shoreline. 
These events have occurred with some regularity through time, but the 
most recent episodes of inundation have been particularly destructive 
of nearshore island marble butterfly habitat. A storm surge event in 
the winter of 2006 resulted in the deposition of gravel substrate and 
driftwood over an island marble butterfly research plot where the one 
native larval host plant, Menzies' pepperweed, had been established, 
reducing the number of plants by more than 50 percent (Lambert 2011, 
pp. 145-146). This same storm surge likely destroyed any butterflies 
that were overwintering in nearshore habitat as chrysalids and had a 
local population-level impact; low numbers of individual island marble 
butterflies, eggs, and larvae were detected at the site for several 
years following the event (Lambert 2011, p. 99; Lambert 2015f, in 
litt.).
    The frequency of storm surges large enough to inundate the lagoons 
and destroy island marble butterfly habitat has previously been 
relatively low, but since 2006, at least one storm surge event (in 
2009) was strong enough to inundate the low-lying habitat (Whitman and 
MacLennan 2015, in litt.). The frequency of these events is expected to 
increase with sea-level rise associated with climate change (see Factor 
E discussion, below). In turn, we anticipate a concomitant increase in 
the potential for destruction of low-lying habitat for the island 
marble butterfly--approximately 15 to 20 percent of the species' 
habitat in American Camp (Lambert 2011, p. 145; Adeslman et al. 2012, 
pp. 79-86; Whitman and MacLennan 2015, in litt.; NOAA 2015a, entire; 
NOAA 2015b, entire).
    The Menzies' pepperweed (the native host plant) occurs almost 
exclusively in the low-lying nearshore habitat, and female island 
marble butterflies have been observed to deposit eggs on only a single 
species of larval host plant at any one site. (Despite close 
observations of ovipositing females, researchers have not observed 
females depositing eggs on more than one type of larval host plant at 
any one site.) Therefore, if this habitat type is lost, an unknown 
proportion of diversity--in habitat use or adaptive potential--in the 
island marble butterfly could be lost as well. Furthermore, low-lying 
habitat comprises an estimated 15 to 20 percent of habitat for the 
species at American Camp, a considerable proportion of the restricted 
range of the species. Due to the small size of the remaining known 
population of the island marble butterfly and the importance of this 
low-lying habitat demonstrated by high encounter rates during surveys, 
loss or degradation of this habitat will likely lead to a further 
decline of the species.
Habitat Conservation and Restoration
    San Juan Island National Historical Park has been implementing 
conservation measures for the island marble butterfly since shortly 
after its rediscovery in 1998. From 2003 through 2006, NPS created 
experimental prairie disturbances and vegetation plots to better 
understand how to manage the prairie and create island marble butterfly 
habitat. This work resulted in recommendations for the best method of 
reducing the cover of invasive grasses by using prescribed fire 
followed by herbicide treatment (Lambert 2006, p. 110). However, the 
work was not reproduced at larger scales, nor was it continued in ways 
sufficient to maintain adequate habitat on the landscape over time.
    In 2018, we renewed a conservation agreement with NPS for the 
island marble butterfly that contained several conservation actions 
that will be applied to manage habitat for the species into the future. 
The renewed agreement, which was signed in December 2018, committed NPS 
to: (1) Restore, where needed, habitat for island marble butterfly, as 
jointly agreed; and (2) avoid impacts to island marble butterflies, 
eggs, larvae, and host plants during the implementation of all NPS 
management actions by working in habitat that was not occupied by 
island marble butterflies. All vegetation treatment will be conducted 
in the fall after the island marble butterfly has entered diapause. We 
expect the history of collaborative conservation of the island marble 
butterfly by NPS and the

[[Page 26796]]

Service to continue for the foreseeable future.
    From 2007 through 2011, NPS managed encroaching plant species using 
multiple methods to open up areas where larval host plants could 
naturally germinate from the seed bank (NPS 2013, pp. 7-11). NPS also 
planted more than 100,000 native grass plugs in mechanically treated 
areas (NPS 2013, p. 7), which improved the native composition of the 
prairie grassland features but did not result in increased cover of the 
larval host plants needed to support the island marble butterfly. The 
Service continued to work collaboratively with NPS to develop annual 
work plans each year from 2013 through 2016; these work plans are 
addenda to the 2006 conservation agreement for the island marble 
butterfly. The goals and actions identified in the work plans have 
changed, sometimes annually, in response to new information, adaptive 
management needs, available funding, and other concerns. The 2013-2016 
work plans identified and enacted several conservation actions to 
address threats related to the destruction, modification, and 
curtailment of island marble butterfly habitat at American Camp. 
Prescribed fire, deer fencing of essential habitat, management of 
invasive species, and experimental habitat restoration were all 
implemented per annual work plans during this period.
    These work plans initially included the use of prescribed fire in 
small blocks (up to one acre) to disturb grassland habitat in an effort 
to encourage larval host plant patches to establish from the seed bank. 
These prescribed fire events resulted in very low germination of the 
larval host plants, leading NPS to conclude that few larval host plant 
seeds persist in the seed bank. In response, later annual work plans 
recommended seeding the larval host plant species after a prescribed 
burn. The 2016 annual work plan also included recommendations for the 
development of novel methods for creating island marble butterfly 
habitat.
    In 2013, the Service funded the installation of deer exclusion 
fencing at American Camp in an effort to reduce deer herbivory on 
larval host plants (and the incidental consumption of eggs and larvae; 
see discussion under Factor E, below) and to increase suitable 
oviposition sites. Deer fencing was included in each year's annual work 
plan since 2013, and continues to be employed as an exclusion 
technique. Approximately 23 acres have been fenced since deer exclusion 
efforts began in 2013 (Shrum 2015a, in litt.).
    The various forms of deer exclusion fencing that have been used 
have resulted in mixed success in preventing deer from consuming larval 
host plants. For example, in 2015, electrified fencing alone proved 
ineffective at excluding deer at three of five research sites at 
American Camp (Lambert 2015d, p. 17). However, electric and wire-mesh 
fencing combined have reduced deer herbivory on larval host plants when 
compared to years when exclusion fencing was not employed (Lambert 
2015d, p. 17). In one large expanse of habitat at American Camp, the 
distribution of field mustard was essentially limited to the fenced 
areas in 2015, although environmental conditions shifted substantively 
in 2016, allowing for a large flush of persistent field mustard beyond 
the fenced areas (Lambert 2014a, p. 23; Lambert 2015a, p. 5; Lambert 
2015d, p. 17; Lambert 2016a, p. 35). Despite these challenges, deer 
exclusion fencing remains an important tool for protecting island 
marble butterfly habitat, especially early in the flight season when we 
expect survivorship to be the highest (Lambert 2015d, p. 19). For 
example, in 2016 (after the publication of our 12-month finding on 
April 5, 2016 (81 FR 19527)), deer were completely excluded from 
research sites at American Camp for the first time, resulting in one-
quarter acre of restored habitat for host plants, and increased 
survival in island marble butterflies on field mustard than in previous 
years (Lambert 2016a, p. 11).
    The annual work plans have also included efforts to control weedy 
native and nonnative species and encroaching woody plants. 
Specifically, NPS has removed hundreds of Douglas fir trees and dozens 
of acres of Rubus armeniacus (Himalayan blackberry), R. laciniatus 
(blackberry), Symphoricarpos albus (snowberry), and Crataegus monogyna 
(one-seeded hawthorn) from the American Camp prairie. These actions 
have slowed the invasion of native and nonnative species and 
encroachment by woody plants and have created early-successional 
conditions that likely provided some nectaring habitat for the island 
marble butterfly. However, few larval host plants germinated from the 
seed bank in the areas cleared of encroaching plants. Another area of 
focus under the work plan for controlling invasive species is herbicide 
treatment of Canada thistle in the dunes.
    NPS, in collaboration with the Service and other partners, has 
supported experimental research into the active establishment of island 
marble butterfly habitat since 2003. In 2014, an experimental approach 
for establishing oviposition and larval habitat was proposed. The 
Service, in coordination with NPS, WDFW, and two local island 
conservation organizations (San Juan Preservation Trust (SJPT) and San 
Juan County Land Bank (SJCLB)), developed a plan to determine whether 
habitat patches for the island marble butterfly could be developed in a 
way that could be scaled up efficiently in a landscape context (Lambert 
2014b, entire). Thirty habitat patches were created on park property at 
American Camp between 2014 and 2016, and 10 more will be created in 
2017 (Lambert 2016a, p. 59). Early results from this work indicate that 
habitat can be created quickly and that island marble butterflies 
readily use these patches for egg laying and larval development if 
larval host plants germinate in time to provide oviposition sites for 
early-flying butterflies (Lambert 2015d, pp. 9-12).
    Each year since 2013, NPS has collected and reared a small number 
of eggs and larvae in a captive-rearing program (see discussion under 
Factor C, below, for more information). In 2015, the captive 
individuals emerged from diapause much later than the wild population. 
Despite the use of the experimental plots for oviposition by these 
late-flying, captive-reared females, none of the eggs and larvae 
tracked in the experimental plots survived. The high mortality was 
attributed to increased predation pressure by late-season spiders and 
wasps (Lambert 2015d, p. 14) (see ``Direct Predation'' under Factor C, 
below). Results of captive-rearing were better in 2016, when captive-
reared island marble butterflies emerged in synchrony with the wild 
population. Survivorship from egg to fifth instar larvae was also 
higher in the experimental plots in 2016; three percent of the tracked 
larvae survived to the fifth instar, which is a relatively high 
survival rate for the island marble butterfly.
    The Service, in coordination with NPS, supports habitat 
conservation efforts by funding local conservation groups to establish 
habitat patches on three conserved sites across the former range of the 
island marble butterfly. Two of these experimental habitat patches were 
established outside of American Camp in 2015 and one in 2016. Each 
experimental patch has been fully fenced to exclude herbivores 
(primarily deer) and allow the larval host plants to grow without 
herbivory pressure (also see Factor C, ``Incidental Predation,'' 
below).

[[Page 26797]]

Education and Outreach
    In 2009, the Service provided funding to WDFW for the creation of a 
species fact sheet and informational handout for the public about the 
biology and conservation needs of the island marble butterfly. This 
pamphlet provided outreach to interested parties and increased the 
awareness of the public about the decline of the island marble 
butterfly. The pamphlet provided basic information about how to protect 
and support habitat essential to the island marble butterfly. In 2011, 
the Service collaborated with NPS, WDFW, researchers from the 
University of Washington, and the Center for Natural Lands Management 
to reach out to the community in a local Island Prairie Educational 
Symposium to present information on current approaches to prairie 
management. Information gained through years of prairie conservation 
efforts in other northern and southern Puget Sound prairie landscapes 
was shared with the local island community. Information about the 
island marble butterfly and the educational materials developed were 
well distributed within the community; however, this effort did not 
lead to the protection or restoration of habitat adequate to ameliorate 
the threat of habitat loss for the island marble butterfly. Despite 
considerable advances in habitat restoration, new habitat 
establishment, captive rearing, herbivore exclusion, and outreach and 
education, the number of individual island marble butterflies remains 
small in the single remaining population.
Summary of Factor A
    Habitat supporting the remaining population at American Camp is 
protected from development and agriculture, but is exposed to the 
threats of plant succession and invasive plant species; herbivory by 
deer, rabbits, and brown garden snails; and storm surges. Habitat loss 
is likely a major factor impeding the recolonization of areas outside 
of American Camp. Outside of American Camp, removal of larval host 
plants by mowing; roadside maintenance; road, residential, or urban 
development; certain agricultural practices (such as tilling, cropping, 
and grazing); and landscaping activities has substantially reduced the 
amount of habitat available for recolonization by the island marble 
butterfly either temporarily (e.g., mowing, tilling, cropping, or 
grazing) or permanently (e.g., road, residential, and urban 
development) since the island marble butterfly was rediscovered 
(Miskelly and Fleckenstein 2007, p. 6; Miskelly and Potter 2009, p. 9; 
Hanson et al. 2009, p. 18; Vernon 2015b in litt., p. 5). This habitat 
removal is a primary factor in the loss of all the remaining 
populations of this species outside of American Camp since 2006.
    Since 2011, NPS has made substantial and sustained efforts to 
expand island marble butterfly habitat and to improve the composition 
and structure of the plant community to become more suitable for the 
island marble butterfly. Due to challenges in establishing suitable 
habitat and protecting it from the threats described above, only a few 
acres of high-quality habitat for island marble butterfly have been 
restored on the American Camp landscape. Many more acres within 
American Camp have been improved by restoration actions or protected 
from deer herbivory, but are not yet considered high quality or fully 
secure from herbivory by deer. To date, these efforts may have resulted 
in a small positive response in the island marble butterfly population, 
as evidenced by the 3 percent increase in survivorship from the fourth 
to fifth instar in 2016. However, the number of those individuals that 
will successfully pupate and emerge as winged adults in the spring 
remains to be seen. Conservation efforts by NPS have also resulted in 
significant contributions to our understanding of island marble 
butterfly habitat and threats to that habitat. Outside of American 
Camp, the only conservation efforts that specifically create habitat 
for the species are the small island marble butterfly habitat plots 
established by SJPT and SJCLB. These efforts will be crucial to 
establishing new populations of island marble butterfly in the future, 
but the achievement is too recent for their effectiveness to be 
evaluated, especially in the context of the extensive, ongoing habitat 
loss from changing land use, changing agricultural practices, and other 
factors that inhibit recolonization by island marble butterflies 
outside of American Camp.
    Despite successful habitat restoration experiments, continued use 
of deer exclusion fencing, and the removal of woody plants and 
nonnative and native weedy species, the increase in the total area of 
currently suitable habitat within American Camp has not been fully 
quantified, although it remains small (on the scale of quarters of 
acres). Despite these minor gains in habitat as a result of restoration 
since we published our 12-month finding on April 5, 2016 (81 FR 19527), 
the range of the species--the number of sites within American Camp 
where it is observed--has continued to contract, and the number of 
island marble butterflies observed each year remains low. Conservation 
measures will need to continue into the future, with monitoring to 
assess their long-term value to the island marble butterfly. Until 
measureable changes to the island marble butterfly population have been 
documented, it will be difficult to determine whether the implemented 
measures are effecting positive change in the status of the island 
marble butterfly. Based on the analysis above, we conclude that plant 
succession and competition with invasive species, herbivory by deer and 
brown garden snails, and storm surges are likely to have population-
level impacts on the island marble butterfly.

Factor B. Overutilization for Commercial, Recreational, Scientific, or 
Educational Purposes

Overutilization for Commercial or Recreational Purposes
    Under NPS regulations, collection of living or dead wildlife, fish, 
or plants, or products thereof, is prohibited on lands under the 
jurisdiction of NPS without a permit (36 CFR 2.1(a)(1)(i) and 
(a)(1)(ii)), but there are no State or County regulations that prohibit 
recreational collection of the island marble butterfly at this time.
    Rare butterflies and moths are highly prized by collectors, and an 
international trade exists in specimens for both live and decorative 
markets, as well as the specialist trade that supplies researchers 
(Collins and Morris 1985, pp. 155-179; Morris et al. 1991, pp. 332-334; 
Rieunier and Associates 2013, entire). Before the island marble 
butterfly was formally described, collectors may have exerted little 
pressure on the taxon because it was unknown and because it occurs in 
remote islands that had been little-surveyed for butterflies. Following 
formal description of the species in 2001, at least three inquiries 
about potential for collection were made to WDFW, which is responsible 
for managing fish and wildlife in the State of Washington, and one with 
NPS at American Camp, which requires a permit for the collection of any 
plant or animal from park property (Reagan 2015, in litt.). WDFW has 
discouraged collection, and NPS rejected the single permit request for 
collection it received (Reagan 2015, in litt.; Weaver 2015a, in litt.). 
In addition to these permit requests, we are aware of one specimen of 
the island marble butterfly purportedly being listed for sale on a 
website devoted to trade in butterfly species (Nagano 2015, pers. 
obs.), although the origin and authenticity of this specimen could not 
be verified.

[[Page 26798]]

    Even limited collection of butterfly species with small populations 
could have deleterious effects on the reproductive success and genetic 
variability within those populations and could thus contribute 
eventually to extinction or local extirpation (Singer and Wedlake 1981, 
entire; Gall 1984, entire). Capture and removal of females dispersing 
from a population also can reduce the probability that new populations 
will be established or that metapopulation structure will be developed 
or maintained. (A metapopulation is a group of spatially separated 
populations that interact when individual members move from one 
population to another.) Collectors pose a potential threat because they 
may not be aware of other collection activities, and are unlikely to 
know, and may not care, whether or not they are depleting numbers below 
the threshold necessary for long-term persistence of populations and 
the species (Martinez 1999, in litt.). This is especially true if 
collectors lack adequate biological training or if they visit a 
collection area for only a short period of time (Collins and Morris 
1985, p. 165). In addition, collectors often target adult individuals 
in perfect condition, including females that have not yet mated or had 
the opportunity to lay all of their eggs. Some collectors go to the 
length of collecting butterfly eggs in order to rear perfect specimens 
(USDOJ 1995, p. 2).
    Collection of the island marble butterfly, which is prohibited on 
NPS lands, could potentially occur without detection because occupied 
areas are not continuously patrolled and adult butterflies do move 
outside of protected areas onto adjoining lands where collection is not 
currently prohibited. Consequently, the potential for collection of 
adult island marble butterflies, and especially surreptitious 
collection of early stages (eggs, larvae, and pupae) exists, and such 
collection could go undetected, despite the protection provided on NPS 
lands. Taking into consideration the small remaining population, 
illegal collection could have strong detrimental effects on the known 
population, were it to occur. However, no illegal collection efforts 
for this species have been documented to date.
Scientific Overutilization
    The widespread surveys that took place in the period 2005-2012 
included capturing and releasing butterflies when necessary for 
positive identification, as specified in Miskelly and Fleckenstein 2007 
(p. 4). Although a limited number of individuals may have been injured 
or killed during handling, no data exist on the number of individuals 
captured, injured, or killed. To our knowledge, there have been three 
documented instances of island marble butterfly collection or handling 
for scientific purposes since the rediscovery of the species. In 2005, 
two male specimens were collected by WDFW surveyors as vouchers to 
document newly discovered island marble sites (Miskelly and Potter 
2005, pp. 4, 5; Potter 2016, in litt.). In 2008, a mark-release-
recapture (MRR) study of the species' demography involved the capture 
and marking of 97 individual adult island marble butterflies and 
recapture of 56 butterflies across four separate sites, and some 
individuals were recaptured more than once (Peterson 2009, entire; 
Peterson 2010, entire). A single individual butterfly was collected as 
a voucher specimen under a WDFW scientific collection permit in 2008 
for the MRR study (Potter 2016, in litt.). The other scientific use of 
the island marble butterfly of which the Service is aware took place in 
2013, when two adult butterflies were collected by WDFW for a genetic 
assessment of the island marble butterfly, the results of which were 
inconclusive (Potter 2015b, in litt.).
    The handling of adult butterflies for scientific purposes has been 
evaluated for effects on populations elsewhere in western North America 
(Singer and Wedlake 1981; Gall 1984). Murphy (1988, p. 236) reported 
that MRR work by others resulted in about 10 percent mortality to the 
endangered mission blue butterfly (Icaricia icarioides missionensis); 
however, studies by Singer and Wedlake (1981, entire) with other 
butterflies resulted in less than 2 percent of the marked butterflies 
being recaptured, suggesting that mortality from handling the 
butterflies may have been a factor.
    Peterson's 2008 MRR study may have resulted in unintended injury or 
mortality to island marble butterfly individuals, but we have no 
evidence to suggest that the study resulted in population- or species-
level effects. Surveyors were unable to recapture 38 percent of the 
handled individuals during the short duration of this research, but 
whether this research directly increased mortality for the handled 
individuals is unknown. Several outcomes could have led to this low 
recapture rate: The butterflies may have fully matured after completing 
their life cycle and died during this period; they may have been 
injured during handling and died following release; they may have 
become more susceptible to other stressors after handling (e.g., 
predation); or they may have simply eluded recapture. Based on the 
relative encounter rate for the island marble butterfly that was 
measured during subsequent years (see ``Abundance,'' above, for 
additional information), this research does not appear to have 
contributed to a constriction in the range of the species or a decline 
in the abundance of individuals.
    The probability of numerous future collections of live island 
marble butterflies for research purposes is low because all researchers 
who study the island marble butterfly work collaboratively with the 
Service, NPS, and WDFW, and are aware of the very low and declining 
number of individual butterflies. Any research proposal requiring the 
collection and removal of live island marble butterflies from the 
population is carefully reviewed to determine whether the conservation 
benefit to the species outweighs the loss of individuals.
Summary of Overutilization for Commercial, Recreational, Scientific, or 
Educational Purposes
    We continue to find that overutilization does not have a 
population-level impact on the island marble butterfly for the 
following reasons: The lack of evidence of commercial or recreational 
collection of island marble butterflies; our conclusion that handling 
of the species during the 2008 MRR study did not result in documented 
negative effects to island marble butterfly populations; and the small 
number of individuals collected for genetic evaluation.

Factor C. Disease or Predation

Disease
    There is a single report of disease affecting the island marble 
butterfly (Miskelly 2004, p. 35). We discussed this observation with 
the author and discovered that this was an isolated event and that the 
mortality was likely attributable to causes other than disease 
(Miskelly 2015a, in litt.). Therefore, there is no evidence to suggest 
that disease is currently a threat to the island marble butterfly.
Direct Predation
    Predation is a risk for island marble butterflies during all stages 
of their life cycle, although mortality is highest during the earliest 
stages of life: Egg to first instar (Lambert 2011, p. 92). A study 
conducted from 2005 through 2008 on survivorship of the island marble 
butterfly identified high levels of mortality attributable to predation 
by spiders and, to a lesser extent, paper

[[Page 26799]]

wasps (Polistes spp.) (Lambert 2011, p. 117). Two species of spider, 
Pardosa distincta and Zelotes puritanus, both native to Washington 
State, prey on adult island marble butterflies and may also account for 
a large proportion of the predation on eggs and larvae (Lambert 2011, 
p. 100; Crawford 2015, in litt.). The paper wasp common to American 
Camp is the nonnative Polistes dominula (Miskelly 2015b, in litt.), 
discovered in the State of Washington in 1998 (Landolt and Antonelli 
1999, entire).
    Direct predation of eggs and larvae was the greatest source of 
mortality in this 4-year study, affecting 47 percent of all individuals 
tracked (Lambert 2011, p. 99). Mortality levels attributable to direct 
predation varied depending on the larval host plant used, with almost 
80 percent mortality attributable to direct predation on Menzies' 
pepperweed and approximately 40 percent on field mustard (Lambert 2011, 
p. 117). These differences are likely attributable to variation in the 
structure and growth form of the larval host plants that can facilitate 
access by predators (Lambert 2011, p. 100).
    In addition, predation on island marble butterfly larvae by spiders 
and wasps increases as the season advances (Lambert 2015d, p. 14). This 
increase is likely because: (a) As spiders mature, they are more 
effective at locating and consuming the larvae; and (b) wasps increase 
in number as the season progresses (Reeve 1991, pp. 104-106), and the 
predation pressure they exert on their prey species increases with 
these increased numbers. Later emergence of island marble butterflies 
has been observed to correlate closely with increased predation 
pressure on island marble larvae; in the 2015 field season, when 
emergence was notably late, none of the 329 individuals tracked from 
egg through their larval development survived to form a chrysalis 
(Lambert 2015d, p. 14) (see Cumulative Effects, below, for additional 
discussion). Predation on adult island marble butterflies by birds and 
spiders has been observed anecdotally, although no effort has been made 
to quantify mortality attributable to predation on adults (Lambert 
2011, p. 90; Vernon and Weaver 2012, p. 10). We found no evidence to 
suggest that predation by small mammals or other vertebrate predators 
presents a threat.
    Direct predation of island marble butterfly eggs and larvae is 
ongoing where the species occurs (at American Camp) and is expected to 
continue into the future. Direct predation of eggs and larvae is a 
significant cause of mortality for the island marble butterfly, 
consistently accounting for more than 45 percent of deaths for tracked 
individuals (Lambert 2011, p. 99; Lambert 2015d, p. 14). Native spiders 
are responsible for a significant proportion of observed predation, and 
the island marble butterfly presumably coexisted for hundreds or 
thousands of years with these spiders. However, the small and declining 
numbers of island marble butterflies, under pressure from habitat loss 
and other threats, now cannot tolerate what may once have been a 
sustainable rate of natural predation. The threat of direct predation 
affects the island marble butterfly at the individual, population, and 
species levels (see Factor E discussion, below, for more information).
Incidental Predation
    Incidental predation by browsing black-tailed deer also is a common 
source of mortality for island marble butterfly eggs and larvae 
(Lambert 2011, pp. 93-97; Lambert 2015d, pp. 17-18). As discussed above 
under Factor A, female island marble butterflies select oviposition 
sites on or near the tips of the inflorescences of the larval host 
plants, which is the same portion of the plant that deer prefer to 
browse (Lambert 2015c, in litt.). Similar to rates of direct predation, 
each species of larval host plant is correlated with differing levels 
of mortality attributable to deer browse. Incidental predation by deer 
was highest on field mustard, which accounted for slightly more than 40 
percent of mortality tracked for this larval host plant over the course 
of the 4-year study (Lambert 2011, p. 117). Mortality attributable to 
deer browsing was less than 10 percent for both Menzies' pepperweed and 
tumble mustard (Lambert 2011, p. 117).
    In nearly every report provided to the Service, deer browsing has 
been identified as particularly problematic for the island marble 
butterfly at American Camp as well as throughout the species' former 
range, where browsing deer continue to degrade the butterfly's habitat 
(Miskelly and Fleckenstein 2007, p. 6; Miskelly and Potter 2009, pp. 
11, 15; Hanson et al. 2009, pp. 4, 13, 20; Hanson et al. 2010, pp. 21-
22; Potter et al. 2011, pp. 5, 13; Lambert 2011, p. 104; Lambert 2014a, 
entire; Vernon and Weaver 2012, p. 9; Weaver and Vernon 2014, p. 10; 
Lambert 2014a, p. 3; Lambert 2015d, pp. 17-18; Vernon 2015a, p. 12). 
Incidental predation by deer is a significant cause of mortality of the 
island marble butterfly at American Camp (Lambert 2014a, p. 3). 
Incidental predation by deer is a threat of increasing severity within 
American Camp, where it affects the island marble butterfly at the 
individual, population, and species level; outside American Camp, this 
source of habitat degradation is ongoing throughout the formerly 
occupied range of the species because of the apparent increase in deer 
numbers throughout the San Juan Islands (Milner 2015, in litt.; 
McCutchen 2016, in litt.).
    Although incidental predation by other herbivores has not been as 
rigorously quantified as it has been for black-tailed deer, the 
negative effects of livestock on occupied larval host plants cannot be 
discounted (Miskelly and Fleckenstein 2007, p. 5; Miskelly and Potter 
2009, pp. 9, 11, 15; Hanson et al. 2009, pp. 18, 20; Hanson et al. 
2010, pp. 5, 16, 21; Potter et al. 2011, p. 13; Vernon 2015c in litt., 
entire). Incidental predation by livestock, brown garden snails, and 
European rabbits is possible where the range of the island marble 
butterfly overlaps with these species. However, in the case of European 
rabbits, only two documented instances exist of rabbits consuming 
plants with eggs or larva on them (Lambert 2015d, p. 17). Suitable 
island marble butterfly larval habitat is closely monitored at American 
Camp, so while consumption of occupied larval host plants by European 
rabbits does occasionally take place, it is currently rare, is 
geographically circumscribed, and does not have a population-level 
impact to the species. The existing information does not indicate that 
incidental predation by livestock, brown garden snails, and European 
rabbits is occurring at a rate that currently causes population-level 
impacts to the island marble butterfly.
Conservation Efforts To Reduce Disease or Predation
    As described above under ``Habitat Conservation and Restoration,'' 
the Service and NPS installed deer exclusion fencing in American Camp 
from 2013 to 2016 to reduce browsing by black-tailed deer on the larval 
host plants field mustard and tumble mustard. The fencing was placed to 
reduce incidental predation, as well, by protecting areas where larval 
host plants are most likely to be occupied by island marble butterfly 
eggs and larvae.
    The Service has supported ongoing research into the effects of deer 
exclusion fencing on island marble butterfly survival. The first deer 
exclusion fencing was erected in three locations of American Camp in 
2013. Areas immediately adjacent to the fenced habitat with similar 
structure, quality, and connectivity as the fenced habitat were left 
unfenced as control plots. First-year monitoring of deer

[[Page 26800]]

exclusion areas showed that 74 percent of eggs tracked survived to 
first instar in the fenced area compared with 41 percent survival to 
first instar in the control plots (Lambert 2014a, p. 6). In 2014, 
additional deer exclusion fencing was installed, and different types of 
exclusion fencing were compared. Wire-mesh fencing was found to be 
effective at preventing incidental predation by deer, while electric 
fencing was determined to be largely ineffective at excluding deer, 
although mortality from deer in electric-fenced areas was lower than in 
previous years (Lambert 2015d, pp. 17-18). Deer exclusion fencing has 
emerged as an important tool for protecting eggs and early instar 
larvae from consumption by deer, especially early in the flight season 
when survivorship is expected to be the highest (Lambert 2015d, p. 19; 
Lambert 2016a, pp. 3, 27).
Summary of Disease and Predation
    The best available information does not indicate that disease is a 
threat to the island marble butterfly. However, a substantial amount of 
research completed since 2006 clearly documents the effects of 
predation. Direct and incidental predation rates, together, account for 
the vast majority of the recorded deaths of island marble butterfly 
eggs and larvae at American Camp. Although deer exclusion fencing at 
American Camp has been an important tool for reducing mortality due to 
incidental consumption since 2013, the number of island marble 
butterflies observed continues to be low. No conservation measures have 
yet been identified to address the threat of predation from paper wasps 
and spiders. Taken together, all forms of predation have pervasive, 
population-level impacts on the island marble butterfly.

Factor D. The Inadequacy of Existing Regulatory Mechanisms

    Under this factor, we examine whether existing regulatory 
mechanisms ameliorate or exacerbate the threats to the species 
discussed under the other factors. Section 4(b)(1)(A) of the Act 
requires the Service to take into account ``those efforts, if any, 
being made by any State or foreign nation, or any political subdivision 
of a State or foreign nation, to protect such species . . . .'' In 
relation to Factor D under the Act, we interpret this language to 
require the Service to consider relevant Federal, State, and tribal 
laws, regulations, and other such mechanisms that may ameliorate or 
exacerbate any of the threats we describe in threat analyses under the 
other four factors, or otherwise enhance conservation of the species. 
We give strongest weight to statutes and their implementing regulations 
and to management direction that stems from those laws and regulations. 
An example would be State governmental actions enforced under a State 
statute or constitution, or Federal action under statute.
Federal Laws and Regulations
    American Camp, as part of San Juan Island National Historical Park, 
is managed under the National Park Service's Organic Act and 
implementing regulations. The National Park Service Organic Act of 
1916, as amended (54 U.S.C. 100101 et seq.), states that the National 
Park Service ``shall promote and regulate the use of the National Park 
System . . . to conserve the scenery, natural and historic objects, and 
wild life in the System units and to provide for the enjoyment of the 
scenery, natural and historic objects, and wild life in such manner and 
by such means as will leave them unimpaired for the enjoyment of future 
generations'' (54 U.S.C. 100101(a)). Further, 36 CFR 2.1(a)(1)(i) and 
(a)(1)(ii) specifically prohibit collection of living or dead wildlife, 
fish, or plants, or parts or products thereof, on lands under NPS 
jurisdiction. This prohibition on collection extends to the island 
marble butterfly where it exists on NPS-managed lands. In addition, 
under the general management plan for San Juan Island National 
Historical Park, NPS is required to follow the elements of the 
conservation agreement (NPS 2008, p. 73). This includes restoring 
native grassland ecosystem components at American Camp, avoiding 
management actions that would destroy host plants, avoiding vegetation 
treatments in island marble butterfly habitat when early life-stages 
are likely to be present, and implementing a monitoring plan for the 
species (Pyle 2006, pp. 10-12).
    The Bureau of Land Management (BLM) owns the 27-ac (11-ha) Cattle 
Point Lighthouse property east of American Camp and Cattle Point 
Natural Resource Conservation Area. This site was formerly occupied by 
island marble butterflies, is proximal to occupied habitat on American 
Camp, and contains suitable habitat for the species. The Cattle Point 
Lighthouse property is part of the San Juan Islands National Monument 
established by Presidential proclamation on March 25, 2013, under the 
American Antiquities Act of 1906 (54 U.S.C. 320301 et seq.). This 
proclamation specifically identifies the island marble butterfly and 
states that protection of the lands in the San Juan Islands will 
maintain their historical and cultural significance and enhance their 
unique and varied natural and scientific resources, for the benefit of 
all Americans. Under this proclamation, the monument is being managed 
as part of the National Landscape Conservation System, requiring that 
the land be managed ``in a manner that protects the values for which 
the components of the system were designated'' (16 U.S.C. 7202(c)(2)). 
The first resource management plan for the National Monument is still 
in development, so specific regulatory protections for the species and 
its habitat have not yet been established. Nevertheless, anthropogenic 
threats at this site are unlikely given its current designation as a 
National Monument.
    The island marble butterfly is also listed as a sensitive species 
for the purposes of the BLM's Sensitive Species Policy (BLM 2008, p. 3; 
USFS 2015, entire). This policy directs the BLM to initiate 
conservation measures that reduce or eliminate threats and minimize the 
likelihood of listing under the Act, but until the resource management 
plan for the National Monument is complete, the BLM has not identified 
the required conservation measures. At this time, it is unclear what 
protections, if any, these existing regulatory mechanisms will confer 
to the island marble butterfly.
State Laws and Regulations
    State laws and regulations that apply across San Juan and Lopez 
Islands include provisions to limit collection of butterflies for 
scientific purposes, but no specific protections to island marble 
butterfly habitats. The island marble butterfly is currently classified 
as a candidate species by the State of Washington (WDFW 2015a, p. 2). 
Candidates are those species considered by Washington State to be 
sensitive and potentially in need of protection through the process of 
designation as endangered, following procedures established by the 
Washington Administrative Code (WAC) (220-610-110). However, candidates 
are not afforded any specific regulatory protections (Potter 2015c, in 
litt.). The island marble butterfly is afforded limited State 
regulatory protections from overcollection as the State of Washington 
requires a scientific collection permit for handling or collecting any 
fish, or wildlife, their nests, or eggs for scientific purposes (WAC 
220-200-150; Revised Code of Washington (RCW) 77.32.240).
    The island marble butterfly was identified as critically imperiled 
in the Washington State Comprehensive Wildlife Conservation Strategy 
(WDFW

[[Page 26801]]

2005, pp. 219, 314, 336-337). Since 2005, WDFW has retired the 
Comprehensive Wildlife Conservation Strategy and incorporated it into 
Washington's State Wildlife Action Plan (SWAP). Although the SWAP 
addresses the island marble butterfly's conservation status, identifies 
it as a ``species of greatest conservation need,'' and recommends 
conservation actions (WDFW 2015b, p. 3-39), the SWAP is not a 
regulatory mechanism.
    WDNR owns the Cattle Point Natural Resources Conservation Area 
consisting of 112 acres directly to the east of American Camp, a 
portion of which provides potentially suitable habitat for island 
marble butterflies. Natural resource conservation areas are managed to 
protect outstanding examples of native ecosystems; habitat for 
endangered, threatened, and sensitive plants and animals; and scenic 
landscapes. Removal of any plants or soil is prohibited unless written 
permission is obtained from WDNR (WAC 332-52-115).
Local Laws and Regulations
    American Camp is the only area known to be occupied by the island 
marble butterfly, and because the area is managed by NPS under the 
National Park Service's Organic Act and implementing regulations, local 
laws and regulations governing land use do not apply. However, the 
following local laws and regulations may provide some benefit to the 
island marble butterfly, should the species expand its range or 
recolonize suitable habitat areas outside American Camp.
    The Washington State Growth Management Act of 1990 (GMA) requires 
all jurisdictions in the State to designate and protect critical areas 
(RCW 36.70A). The State defines five broad categories of critical 
areas, including: (1) Wetlands; (2) areas with a critical recharging 
effect on aquifers used for potable water; (3) fish and wildlife 
habitat conservation areas; (4) frequently flooded areas; and (5) 
geologically hazardous areas (RCW 36.70A.030). The upland prairie 
habitat type that island marble butterflies may use, but are not 
restricted to, is considered both a fish and wildlife habitat 
conservation area and an area with a critical recharging effect on 
aquifers under the GMA. Identification as a fish and wildlife habitat 
conservation area mandates that each county within Washington State 
preserve and protect the fish and wildlife associated with each habitat 
conservation area by developing policies and regulations to protect the 
functions and values of critical areas. Within counties, the mandate to 
protect and regulate critical areas applies to all unincorporated 
areas. In addition, incorporated cities within counties are required to 
address critical areas within their ``urban growth area'' (UGA; the 
area in which urban growth is encouraged by the municipal government) 
independently. The only incorporated city within San Juan County is 
Friday Harbor, which is located outside of NPS-owned land on San Juan 
Island and outside of habitat currently occupied by the island marble 
butterfly. The Friday Harbor Comprehensive Plan provides no specific 
protections for animal species that are not listed as endangered or 
threatened under State or Federal law; however, Upland Category III may 
confer some benefits to the species based on conservation status of the 
species.
    San Juan County encompasses the range of the island marble 
butterfly. The County regulates critical areas through a Critical Areas 
Ordinance, which mandates protection for species listed under the Act 
through San Juan County Critical Areas Ordinance (section 18.30.110, 
Fish and Wildlife Habitat Conservation Areas). The Critical Areas 
Ordinance also identifies species of local importance, including the 
island marble butterfly (San Juan County 2018, p. 34), and provides 
protection for the island marble butterfly by requiring that 
development applications for areas determined to be occupied by the 
island marble butterfly develop a habitat management plan consistent 
with County recommendations for the conservation of the island marble 
butterfly prior to permitting. The San Juan County Comprehensive Plan 
recommends that property owners with occupied island marble butterfly 
habitat avoid the use of insecticides and herbicides, limit grazing and 
agricultural disturbance, and protect areas with larval host plants 
during the development process (San Juan County 2018, pp. 51, 56). 
However, the conservation recommendations are not comprehensive enough 
to prevent local extirpation of the island marble butterfly because 
they do not address all of the stressors influencing its persistence 
(e.g., landscaping, permanent landscape conversion, mowing, etc.), as 
evidenced by the complete loss of occupied island marble butterfly 
habitat within areas developed since 2006 (see ``Development,'' above, 
under Factor A).
    In addition, the San Juan County Comprehensive Plan concentrates 
urban density within UGAs in order to preserve the rural nature of the 
San Juan archipelago (San Juan County 2010, entire). We considered the 
plan in our 2006 12-month finding (71 FR 66292; November 14, 2006), 
concluding that the restriction of high-density development would lead 
to the maintenance of suitable habitat on Lopez and San Juan Islands. 
While preserving the low-density agricultural environment on San Juan 
and Lopez Islands partially prevents the direct conversion of suitable 
island marble butterfly habitat to other incompatible uses (e.g., 
impermeable surfaces, manicured lawns, residential housing), new 
evidence indicates that despite these planning efforts, island marble 
butterfly habitat has been severely curtailed rangewide since 2006, due 
to a variety of factors (e.g., mowing, landscaping, or removal of host 
plants) (Miskelly and Potter 2005, p. 6; Miskelly and Fleckenstein 
2007, p. 6; Potter 2015a, in litt.).
Summary of Existing Regulatory Mechanisms
    The island marble butterfly and its host plant are afforded 
substantial regulatory protections from anthropogenic threats at 
American Camp through NPS regulations and the current general 
management plan for San Juan Island National Historical Park. In 
addition, State- and County-level regulatory mechanisms that influence 
development and zoning on San Juan and Lopez Islands are generally 
beneficial to suitable habitat that could be occupied by the island 
marble butterfly in the future. However, this impressive suite of 
regulatory mechanisms has not prevented the extirpation of other 
populations, and the species remains in precarious shape with only one 
remaining known location. Therefore, we conclude that the existing 
Federal, State, and local regulatory mechanisms provide some benefits 
to the island marble butterfly and its habitat, but do not sufficiently 
ameliorate the threats to the species such that it does not meet the 
definition of an endangered species.

Factor E. Other Natural or Manmade Factors Affecting Its Continued 
Existence

    Under Factor E, we evaluate the island marble butterfly's small 
population size and its vulnerability to stochastic events, vehicular 
collisions, insecticide application, late emergence of adult 
butterflies, and climate change.
Small Population Size and Vulnerability to Stochastic Events
    Since its rediscovery in 1998, the island marble butterfly has been

[[Page 26802]]

documented to have a narrow distribution, which has become increasingly 
constrained as secure habitat has been reduced or destroyed throughout 
the butterfly's range (Miskelly and Potter 2005, entire; Miskelly and 
Fleckenstein 2007, entire; Miskelly and Potter 2009, entire; Hanson et 
al. 2009, entire; Hanson et al. 2010, entire; Potter et al. 2011, 
entire; Vernon and Weaver 2012, entire; Weaver and Vernon 2014, entire; 
Potter 2015a, in litt.; Vernon 2015a, entire). Declining numbers for 
the island marble butterfly have been documented during annual 
monitoring at American Camp that has taken place from 2004 through 2015 
(see ``Abundance,'' above), and the species now appears to be 
restricted to a single known population centered on American Camp.
    Compared to large populations, small populations are 
disproportionately affected by environmental, demographic, and genetic 
stochasticity, and thus face greater risk of extinction (Frankham 1996, 
p. 1506; Saccheri et al. 1998, entire; Harper et al. 2003, pp. 3349, 
3354). Environmental stochasticity is the variation in birth and death 
rates from one season to the next in response to weather, disease, 
competition, predation, or other factors external to the population 
(Shaffer 1981, p. 131). For example, drought or predation in 
combination with a low population year could result in extirpation, and 
butterflies are known to be sensitive to environmental variation, 
increasing the influence of this factor (Weiss et al. 1993, pp. 267-
269). Stochastic environmental events can be natural or human-caused.
    Demographic stochasticity refers to random variability in survival 
or reproduction among individuals within a population (Shaffer 1981, p. 
131). This random variability has a proportionately large effect on 
small populations, such that any loss of beneficial alleles (genes that 
provide for more successful reproduction and survival) may result in a 
rapid reduction in fitness, making small populations much more likely 
to go extinct than large populations (Frankham 1996, p. 1507). Genetic 
stochasticity, or genetic drift, describes random changes in the 
genetic composition of a population that are not related to systemic 
forces such as natural selection, inbreeding, or migration. In small 
populations, genetic stochasticity is more likely to result in reduced 
fitness and ultimately a lower number of individuals contributed to 
each successive generation. Small, narrowly distributed populations 
generally have lower genetic diversity than larger populations, which 
can result in less resilience to changing environmental conditions.
    Because the island marble butterfly persists in low numbers, loss 
of a portion of the remaining population could have disproportionately 
negative effects. Storm surges that destroy nearshore habitat 
containing overwintering island marble butterfly chrysalids may further 
deplete the genetic diversity of the island marble butterfly. 
Similarly, in grassland habitat, a poorly timed or uncontrolled fire 
could destroy a large portion of the remaining population. The effect 
of predation, which has always been at least a baseline limiting factor 
for the island marble butterfly, is magnified when there are so few 
individuals left. Additional stochastic events that could potentially 
be devastating include a late-spring weather abnormality, such as an 
extended hard freeze or a powerful storm during the flight season; a 
year in which predator populations were unusually high; or introduction 
of a novel predator. Given that the very small population at American 
Camp is likely the only remaining population of the species, we 
conclude that small population size makes it particularly vulnerable to 
a variety of likely stochastic events, and this constitutes a threat to 
the island marble butterfly at the individual, population, and species 
levels.
Vehicular Collisions
    Habitat occupied by the island marble butterfly within American 
Camp is bisected by Cattle Point Road, a highway that is the only point 
of access for a small residential community at the southeastern tip of 
San Juan Island (approximately 100-150 housing units) and, as such, is 
routinely driven by the residents. The highway runs along the shoulder 
of Mount Finlayson, a landscape feature that male island marble 
butterflies typically follow when patrolling for females (Lambert 
2016b, pers. comm.). While there have been no specific reports of 
island marble butterfly road kills, the presence of the highway within 
occupied habitat exposes the species to potential vehicle collisions. 
Few studies provide detail on the scale of vehicle-caused mortality for 
invertebrate species, and even fewer specifically examine butterfly 
mortality or the effects of traffic on individual butterfly species 
(Seibert and Conover 1991, p. 163; Munguira and Thomas 1992, entire; 
Rao and Girish 2007, entire).
    One peer-reviewed study that examined vehicular mortality for 
butterflies found that a species in the same family as the island 
marble butterfly, Pieris rapae, was more likely to be struck and killed 
by vehicles in comparison to the other more sedentary species in the 
study, with 7 percent of a local population killed by cars in a 44-day 
period (Munguira and Thomas 1992, p. 325). The study was conducted 
along ``main roads'' in the United Kingdom that connected relatively 
large cities (Munguira and Thomas 1992, p. 317); thus, it is likely 
they had more traffic than the highway at American Camp. While the 
authors of the study did not find the percentage of the population 
killed by vehicles to be significant in comparison to mortality caused 
by other natural factors affecting their survival (Munguira and Thomas 
1992, p. 316), the loss of individual island marble butterflies could 
have disproportionately large negative effects on the species as a 
whole because of its restricted range and small population size.
    Male island marble butterflies are attracted to white (ultraviolet-
reflecting) objects that may resemble females and have been observed to 
investigate white flowers (e.g., field chickweed and yarrow), white 
picket fences, and white lines painted on the surface of roads (Lambert 
2011, p. 47). The highway through American Camp has fog lines that are 
painted white that could be attractive to adult butterflies, thereby 
increasing their risk of being killed by vehicles. The centerlines on 
the highway are painted yellow.
    Given the presence of a highway within the single remaining site 
occupied by island marble butterflies, and their attraction to white 
road stripes that are present along the Cattle Point Road edges, we 
expect that some vehicular mortality is likely. However, we cannot 
estimate the severity of this stressor, as vehicular mortality has not 
been specifically studied for the island marble butterfly or documented 
at American Camp. Therefore, while there is the potential for mortality 
resulting from vehicular collisions, the best available information 
does not indicate that vehicular collision currently has an individual-
, population-, or species-level impact to the island marble butterfly.
Insecticide Application
    The best available information does not indicate any insecticide 
use in proximity to areas that are currently known to be occupied by 
the island marble butterfly at American Camp. However, remnant patches 
of potentially suitable habitat for the species are located within a 
matrix of rural agricultural lands and low-density residential 
development, where

[[Page 26803]]

insecticides may be used. One such insecticide that has the potential 
to adversely affect the island marble butterfly if applied during its 
larval phase is Bacillus thuringiensis var. kurstaki (Btk). This 
insecticide, derived from a common soil bacterium, is used in a wide 
range of settings, including organic agriculture, for the control of 
lepidopteran (butterfly and moth) pest species (National Pesticide 
Information Center 2015, p. 1; Oregon Health Authority 2015, p. 1). In 
forestry, it is used broadly for the control of the Asian and European 
gypsy moth species (Lymantria dispar, and L. dispar dispar, 
respectively) (see WSDA 2015, entire). Btk is also more generally 
applied for other lepidopteran pest species, such as tent caterpillars 
(Malacosoma spp.).
    Btk has the potential to kill the island marble butterfly larvae if 
applied in close proximity and upwind of an occupied site. Spraying of 
Btk has had adverse effects to nontarget butterfly and moth species 
(Severns 2002, p. 169; Wagner and Miller 1995, p. 19), with butterfly 
diversity, richness, and abundance (density) reduced for up to 2 years 
following the application of Btk (Severns 2002, p. 168). One study 
demonstrated that most nontarget lepidopteran species may be more 
susceptible to Btk than target species such as Asian and European gypsy 
moths or western tent caterpillars (Haas and Scriber 1998). For 
nontarget lepidopterans, the early instar stages of larvae are the most 
susceptible stage (Wagner and Miller 1995, p. 21).
    Large-scale application of Btk in Washington State is done in a 
targeted fashion in response to positive trapping of pest species. In 
most years, Btk application is conducted at the scale of hundreds of 
acres per year, although in years when detection of pest species are 
high, such as in 2015, application of Btk may be scaled up to thousands 
of acres in response (WSDA 2015, p. 1). Large-scale application of Btk 
does not normally overlap with areas where the island marble butterfly 
is known to occur within American Camp, although if pest species were 
detected in close proximity and if the target species is active at the 
same time as larvae of the island marble butterfly, the effect of Btk 
treatment could be detrimental. Because the island marble butterfly 
produces a single brood per year, has a spring flight season, and has 
developing larvae during the summer insecticide application period, 
this species is more likely to be susceptible to the adverse effects of 
Btk than butterfly species with later flight and developmental periods 
or those that produce multiple broods per year. Btk is commonly used to 
control tent caterpillars and is likely to have been used on San Juan 
Island (Potter 2015d, in litt.), although the effect on the island 
marble butterfly at American Camp is not documented. At this time, the 
best available information does not indicate that Btk has been applied 
at or adjacent to any location where island marble butterflies are 
known to occur.
    We recognize that the use of insecticides could have a negative 
impact on larvae of the island marble butterfly if applied in such a 
way that individuals were exposed. However, there is no documented 
exposure to insecticide use in the island marble butterfly at this 
time. While there is the potential for high levels of mortality 
resulting from insecticide exposure, we conclude that insecticide use 
is not having a known impact on the island marble butterfly, 
principally because of the low likelihood of exposure at American Camp.
Late Emergence of Adult Butterflies
    Since regular transect surveys for the island marble butterfly 
began in 2004, the first date of the flight period has shifted an 
average of approximately 9 days later in the year (USFWS 2016, 
unpublished data). The reason for this change is unclear, and the 
existing time-series is too brief to ascertain whether this change is a 
trend or part of natural variability on a longer time scale. For 
example, no clear correlation exists between average winter 
temperatures and the beginning of the island marble flight season and 
the shift toward later emergence between 2004 and 2016. Later emergence 
cannot currently be attributed to climate change, although temperature 
may play a role. When conditions inside the captive-rearing lab for 
island marble butterflies were cooler than the ambient temperature in 
2015, butterflies emerged later than the wild population (Shrum 2015b, 
in litt.). The temperature was increased inside in 2016, and the 
captive and wild adults emerged at the same time (Weaver 2015b, in 
litt.; Shrum 2016, in litt.). Other environmental conditions, including 
moisture, likely influence emergence time as well (Tauber et al. 1998, 
entire).
    Ongoing research has recently detected a steep increase in 
mortality for late-season eggs and larvae compared to the mortality of 
early-season eggs, with none of the larvae observed in study plots 
surviving to the fifth instar in 2015 (Lambert 2015d, p. 14). Only a 
portion of the mortality documented was attributable to starvation (25 
percent); the greatest cause of mortality was attributable to direct 
predation (60 percent) (Lambert 2015d, p. 14; see discussion above 
under Factor C). The single, small population of island marble 
butterflies likely cannot sustain the increased late-season predation 
pressure, and probable survival of fewer offspring, over multiple 
years.
Climate Change
    Our analyses under the Act include consideration of ongoing and 
projected changes in climate. The majority of climate models for the 
Pacific Northwest region predict wetter winters, with an increase in 
the proportion of precipitation falling as rain rather than snow due to 
increasing ambient temperature, and drier summers as a result of 
reduced snowpack and ensuing hydrologic drought (Mote and 
Salath[eacute] 2010, p. 48). No downscaled climate models specific to 
the San Juan Island archipelago are available, and San Juan Island is 
not reliant on snowpack for its water. The portion of San Juan Island 
where the known population of the island marble butterfly occurs is in 
the rain shadow of mountain ranges on Vancouver Island, Canada, and in 
Washington State, resulting in weather patterns commonly drier than 
much of the rest of the Pacific Northwest (Mass 2009, entire). While 
the San Juan Island archipelago may be subject to the increasing 
average annual temperatures associated with climate change, it is 
unclear how changing temperatures will affect the island marble 
butterfly.
    One predicted stressor associated with climate change for 
herbivorous (plant-eating) insect species is the potential for the 
development of phenological asynchrony (a mismatch in timing) between 
insects and their larval host plants (Bale et al. 2002, p. 8). If an 
herbivorous insect emerges earlier or later than the optimal stage of 
its larval host plant, the insect may not be able to find plants at the 
right stage for egg laying, or the insect's larvae may not have 
adequate food resources. If the insect emerges earlier than its larval 
host plant, the plants may not be detectable, leaving the animal with 
no place to lay her eggs, or the plants may be too small to provide 
enough forage for larvae, leading to starvation. Conversely, if the 
insect emerges when the plant is at a later phenological stage, eggs 
may be laid on a larval host plant that has matured to the point that 
plant tissues are too tough for the larvae to consume, or the plant may 
die before the insect has acquired enough resources to survive to the 
pupation stage. The island marble butterfly is an early-flying species, 
generally emerging in April and immediately mating and laying eggs on 
the larval host plants that

[[Page 26804]]

are available. This strategy ensures that the host plants are young 
enough to provide tender plant tissue for first instar larvae, which 
have mouthparts incapable of consuming anything but the high-moisture 
flower buds. In the absence of access to tender buds, early instar 
larvae die from desiccation (Lambert 2011, p. 12). Although evidence 
exists that some larvae of late-emerging island marble butterflies have 
suffered starvation (Lambert 2015d, p. 14), perhaps as a result of 
mismatch between butterfly and food-plant phenology, no recurring 
pattern in such mismatch exists now that can be associated with climate 
change. However, monitoring of phenology and survival in the island 
marble butterfly is ongoing and may shed light on this relationship in 
the future.
    Sea-level rise associated with climate change is expected to 
continue as polar ice melts, leading to an increase in ocean volume 
(Adelsman et al. 2012, p. 82). The warming climate is also expected to 
lead to rising ocean temperatures resulting in thermal expansion of the 
water, which will also increase the volume of the ocean (Dalton et al. 
2013, p. 70). Both of these effects of climate change are expected to 
lead to rising sea level, which will have the direct effect of 
increasing the impacts of storm surges and flooding events in low-lying 
areas, such as the nearshore lagoon habitat of the island marble 
butterfly (MacLennan et al. 2013, pp. 4-5; Vose et al. 2014, p. 381; 
Friends of the San Juans 2014, p. 7; Whitman and MacLennan 2015, in 
litt.; NOAA 2015a, entire; NOAA 2015b, entire). Because the nearshore 
habitat is barely above sea level, rise in sea level increases the risk 
of inundation and direct mortality for island marble butterflies 
overwintering as chrysalids in low-lying nearshore habitat. Powerful 
storm surges have historically deposited large amounts of coarse 
sediment and driftwood in areas occupied by Menzies' pepperweed (an 
estimated 5 to 8 percent of habitat occupied in 2006) and where a 
number of island marble butterflies were overwintering as chrysalids, 
leading to low numbers of individuals detected in nearshore habitat in 
years following a storm surge event (Lambert 2011, pp. 99, 145-146; 
Lambert 2015f, in litt.). Due to the small number of individuals 
remaining, mortality and habitat loss resulting from storm surges 
likely has a population-level impact on the island marble butterfly, 
and we expect these impacts to increase over time as an effect of 
global climate change.
    While some effects of global climate change, such as sea-level rise 
and storm intensity, are expected to be nearly universal, warming 
associated with climate change is expected to be variable or even 
patchy, depending on localized weather patterns (e.g., patterns 
influenced by oceanographic phenomena such as El Ni[ntilde]o and La 
Ni[ntilde]a) (Adelsman et al. 2012, p. 37). The Pacific Northwest 
region of the United States abuts the eastern edge of the Pacific 
Ocean, which warms and cools in sync with the Pacific Decadal 
Oscillation (Mantua and Hare 2002, entire). Given the unclear direction 
of climate trends in the San Juan archipelago, we cannot conclude that 
the island marble butterfly is exhibiting phenological changes such as 
later emergence as a result of climate change, or that the species will 
do so in the future.
    Climate conditions that affect phenology in a given year can have 
important impacts to the species, however. Cooler temperatures are 
associated with later emergence of butterflies reared in captivity 
(Weaver 2015b, in litt.), and late emergence leads to a spike in late-
season predation on island butterfly larvae, when spider and wasp 
populations are greatest (see discussions above under Factor C, and 
above under ``Late Emergence of Adult Butterflies''). Compared with an 
abundant species with numerous, well-distributed populations, the 
island marble butterfly's small remaining population is far more 
vulnerable to such fluctuations in mortality.
Conservation Efforts To Reduce Other Natural or Manmade Factors 
Affecting Its Continued Existence
    The Service, NPS, and other partners have been implementing 
multiple conservation efforts in an attempt to ameliorate the threats 
posed by small population size, vulnerability to stochastic events, and 
insecticide applications. No conservation efforts currently address 
collisions with vehicles or the effects of climate change. Below we 
summarize the conservation measures that have been implemented by NPS, 
WDFW, University of Washington researchers, and conservation partners 
on San Juan Island to address the threats to the island marble 
butterfly described above under Factor E.
    The Service, NPS, and other partners have conducted conservation 
efforts to address the effects of small population size and 
vulnerability to stochastic events on the island marble butterfly since 
2008. Specifically, NPS and other partners began exploring methods for 
captive-rearing island marble butterflies in 2008. In 2009, 16 island 
marble butterfly individuals were rescued from a construction site, 
reared to emergence as adult butterflies, and released in the spring of 
2010 (Vernon 2015d, p. 2). In 2010, more individuals were reared as 
part of a food preference experiment (Trapp and Weaver 2010, entire), 
and 32 adults were released in 2011 (Vernon 2015d, p. 5). These 
opportunistic events demonstrated that rescue, rearing, and releasing 
of island marble butterflies could be successful. A handbook based on 
these captive-rearing events and more recent efforts was developed to 
guide captive-rearing and release efforts for the island marble 
butterfly (Vernon 2015d, entire).
    In 2013, continued decline in the number of island marble 
butterflies observed in the wild led to the rescue, captive-rearing, 
and release of the species in an effort to improve survivorship and 
reverse the trend of declining numbers, and provide a safety net 
against stochastic events. Forty-seven individuals successfully formed 
chrysalids, and 40 adult island marble butterflies emerged in the 
spring of 2014, and were released at American Camp (85 percent 
survival) (Vernon 2015d, p. 3). NPS has scaled up and streamlined the 
captive-rearing program. In 2014, NPS converted an outbuilding into a 
rearing facility, and 89 eggs and larvae were brought in for captive-
rearing. Of those, 75 adult island marble butterflies emerged (84 
percent survival) in the spring of 2015, and were released at American 
Camp (Silahua 2015, in litt.). In 2015, 126 eggs and larvae were 
brought in for captive-rearing, 114 of which survived to become 
chrysalids (Silahua 2015, in litt.). The productivity of the captive 
rearing facility has continued to increase in subsequent years; in 
2016, 111 adult island marble butterflies were released; in 2017, 136; 
and in 2018, 158 adults were released (SJINHP 2018, in litt.). In 
total, more than 500 adult island marble butterflies have been released 
back into the wild through this program (SJINHP 2018, in litt.).
    Although the number of adult island marble butterflies recorded 
during annual surveys remains small (fewer than 30 butterflies were 
observed each year during monitoring for the 2014 and 2015 flight 
seasons), the captive-rearing effort has likely provided crucial 
support to the population remaining in the wild and will remain 
necessary in the future. We note, that there is no data available 
allowing a precise characterization of the success released individuals 
have in contributing to the overall population of the species. However, 
this ongoing conservation effort to address small population size

[[Page 26805]]

and vulnerability to stochastic events is not without risk and does not 
ameliorate other threats to the species in the long term. For example, 
in 2015, individuals reared in captivity emerged late in the flight 
season (on or around May 13) (Weaver 2015b, in litt.), and available 
data suggest that the majority of the offspring of these captive-reared 
individuals died as a result of high late-season predation rates 
(Lambert 2015d, p. 14; see discussion under Factor C, above). In 2016, 
the date of emergence in the captive-rearing facility was better 
calibrated to ambient environmental temperatures by adjusting the 
temperature in the facility to match those of the surrounding outdoor 
area, but there are likely to be other unforeseen challenges to 
successful captive-rearing.
    Conservation efforts to reduce natural or manmade factors include 
efforts to reduce the application of the insecticide Btk in close 
proximity to sites occupied by the island marble butterfly. The final 
decision over the use of insecticide for control of invasive moths and 
butterflies has been, and will continue to be, made by the Washington 
State Department of Agriculture after coordination with the Service and 
WDFW. All pesticide used by the State of Washington is applied in 
compliance with label instructions, which are designed to reduce 
overspray, drift, and other negative impacts to nontarget organisms and 
areas.
Summary of Other Natural or Manmade Factors Affecting Its Continued 
Existence
    The small population size of the island marble butterfly makes the 
species highly vulnerable to stochastic events (such as storm surges 
and climate anomalies) that directly or indirectly affect survival and 
reproductive success or the extent of habitat. Storm surges, which can 
cause direct mortality of island marble butterflies and habitat loss, 
are likely to increase with climate change. Although successful 
captive-rearing and release of island marble butterflies is an 
important achievement that has supplemented numbers at American Camp 
since 2013, threats to the species and its habitat continue. The range 
of the island marble butterfly has continued to contract at American 
Camp, and the number of island marble butterflies observed annually has 
continued to decline. These conservation efforts will need to be 
continued into the future and be monitored to assess their long-term 
conservation value to the island marble butterfly before we can 
determine their efficacy.

Cumulative Effects

    In our analysis of the five factors, we found that the island 
marble butterfly is likely to be affected by loss and degradation of 
habitat, direct and incidental predation, and vulnerabilities 
associated with small population size. Multiple stressors acting in 
combination have greater potential to affect the island marble 
butterfly than each factor alone. For example, increased sea level 
resulting from climate change may enhance the impacts of storm surges 
and flooding on low-lying coastal habitat where the one native larval 
host plant for the species occurs. The combined effects of 
environmental and demographic stochasticity, especially on a small 
population, can lead to a decline that is unrecoverable and results in 
extinction (Brook et al. 2008, pp. 457-458). The impacts of the 
stressors described above, which might be sustained by a larger, more 
resilient population, have the potential in combination to rapidly 
affect the size, growth rate, and genetic integrity of a species that 
persists as a small, isolated population. Thus, factors that, by 
themselves, may not have a significant effect on the island marble 
butterfly, may affect the species when considered in combination.

Determination of Island Marble Butterfly

    Section 4 of the Act (16 U.S.C. 1533) and its implementing 
regulations (50 CFR part 424) set forth the procedures for determining 
whether a species meets the definition of ``endangered species'' or 
``threatened species.'' The Act defines an ``endangered species'' as a 
species that is ``in danger of extinction throughout all or a 
significant portion of its range,'' and a ``threatened species'' as a 
species that is ``likely to become an endangered species within the 
foreseeable future throughout all or a significant portion of its 
range.'' The Act requires that we determine whether a species meets the 
definition of ``endangered species'' or ``threatened species'' because 
of any of the following factors: (A) The present or threatened 
destruction, modification, or curtailment of its habitat or range; (B) 
Overutilization for commercial, recreational, scientific, or 
educational purposes; (C) Disease or predation; (D) The inadequacy of 
existing regulatory mechanisms; or (E) Other natural or manmade factors 
affecting its continued existence.

Status Throughout All of Its Range

    As required by the Act, we have carefully assessed the best 
scientific and commercial information available regarding the past, 
present, and future threats to the island marble butterfly. Since the 
species was discovered in the San Juan Islands in 1998, the species' 
range has contracted from five populations on two islands (San Juan and 
Lopez) to a single population, at American Camp on San Juan Island, 
today. The causes of these extirpations are not well understood, but 
likely include habitat loss outside American Camp from a combination of 
sources. Within the single remaining population at American Camp, the 
number of sites where island marble butterflies are detected during 
surveys declined from 25 in 2007, to 4 in 2015. Encounter rates for 
adult butterflies calculated from survey data have declined each year, 
from almost 2 per 100 meters in 2004, to about 0.3 per 100 meters in 
2015. The slight increase in this rate in 2016, to 0.6 per 100 meters, 
does not reverse the overall trend of decline. Captive rearing and 
release of the island marble butterfly shows promise for bolstering the 
remaining population of the species. However, the potential for this 
species to recolonize areas within its historical range is uncertain 
due to ongoing, pervasive habitat degradation that results from 
herbivory by deer and other animals on larval host plants, from plant 
succession and invasion by nonnative plants that render habitat 
unsuitable for larval host plants, and potentially from cultivation and 
other land uses. The widespread occurrence of native (spiders) and 
nonnative (wasps) predators of eggs and larvae is also an ongoing 
threat that may hamper or prevent potential recolonizations. 
Furthermore, the source for any recolonizations consists of a single, 
small population already vulnerable to these threats and to stochastic 
sources of mortality, such as severe storms and other climate 
anomalies.
    In summary, we have identified the following threats to the island 
marble butterfly: (1) Habitat loss and degradation from plant 
succession and competition with invasive species that displace larval 
host plants; herbivory by deer, European rabbits, and brown garden 
snails; and storm surges (Factor A); (2) direct predation by spiders 
and wasps, and incidental predation by deer (Factor C); (3) small 
population size and vulnerability to stochastic events (Factor E); and 
(4) the cumulative effects of small population size and the restricted 
range combined with any stressor that removes individuals from the 
population or decreases the species' reproductive success (Factor E). 
These threats affect the island marble butterfly

[[Page 26806]]

throughout the entirety of its range and are ongoing and likely to 
persist into the foreseeable future. These factors pose threats to the 
island marble butterfly whether considered individually or 
cumulatively. The existing regulatory mechanisms (Factor D) and ongoing 
conservation efforts are not currently sufficient to ameliorate the 
impact of these threats; despite intense focused efforts to conserve 
the species, population numbers continue to decline.
    The ongoing threats of habitat loss and degradation, predation, the 
effects of small population size, and stochastic events that cause 
mortality or reduce reproductive success render this species in its 
entirety presently in danger of extinction throughout all of its range.
    The Act defines an endangered species as any species that is ``in 
danger of extinction throughout all or a significant portion of its 
range'' and a threatened species as any species ``that is likely to 
become an endangered species within the foreseeable future throughout 
all or a significant portion of its range.'' The ongoing threats of 
habitat loss and degradation, predation, the effects of small 
population size, and stochastic events that cause mortality or reduce 
reproductive success render this species in its entirety presently in 
danger of extinction. Therefore, on the basis of the best available 
scientific and commercial information, we are listing the island marble 
butterfly as endangered in accordance with sections 3(6) and 4(a)(1) of 
the Act. We find that threatened species status is not appropriate for 
the island marble butterfly because of its already contracted range and 
single remaining population, because the threats are ongoing and 
affecting the entirety of the species, and because these threats are 
expected to continue into the future.

Status Throughout a Significant Portion of Its Range

    Under the Act and our implementing regulations, a species may 
warrant listing if it is in danger of extinction or likely to become so 
in the foreseeable future throughout all or a significant portion of 
its range. We have determined that the island marble butterfly is in 
danger of extinction throughout all of its range, and accordingly, did 
not undertake an analysis of any significant portion of its range. 
Because we have determined that the island marble butterfly warrants 
listing as endangered throughout all of its range, our determination is 
consistent with the decision in Center for Biological Diversity v. 
Everson, 2020 WL 437289 (D.D.C. Jan. 28, 2020), in which the court 
vacated the aspect of the 2014 Significant Portion of its Range Policy 
that provided the Services do not undertake an analysis of significant 
portions of a species' range if the species warrants listing as 
threatened throughout all of its range.

Determination of Status

    Our review of the best available scientific and commercial 
information indicates that the island marble butterfly meets the 
definition of an endangered species. Therefore, we are listing the 
island marble butterfly as an endangered species in accordance with 
sections 3(6) and 4(a)(1) of the Act.

Available Conservation Measures

    Conservation measures provided to species listed as endangered or 
threatened species under the Act include recognition, recovery actions, 
requirements for Federal protection, and prohibitions against certain 
practices. Recognition through listing results in public awareness, and 
conservation by Federal, State, Tribal, and local agencies, private 
organizations, and individuals. The Act encourages cooperation with the 
States and requires that recovery actions be carried out for all listed 
species. The protection required by Federal agencies and the 
prohibitions against certain activities are discussed, in part, below.
    The primary purpose of the Act is the conservation of endangered 
and threatened species and the ecosystems upon which they depend. The 
ultimate goal of such conservation efforts is the recovery of these 
listed species, so that they no longer need the protective measures of 
the Act. Subsection 4(f) of the Act requires the Service to develop and 
implement recovery plans for the conservation of endangered and 
threatened species. The recovery planning process involves the 
identification of actions that are necessary to halt or reverse the 
species' decline by addressing the threats to its survival and 
recovery. The goal of this process is to restore listed species to a 
point where they are secure, self-sustaining, and functioning 
components of their ecosystems.
    Recovery planning includes the development of a recovery outline 
shortly after a species is listed and preparation of a draft and final 
recovery plan. The recovery outline guides the immediate implementation 
of urgent recovery actions and describes the process to be used to 
develop a recovery plan. Revisions of the plan may be done to address 
continuing or new threats to the species, as new substantive 
information becomes available. The recovery plan identifies site-
specific management actions that set a trigger for review of the five 
factors that control whether a species remains endangered or may be 
reclassified from endangered to threatened (``downlisted'') or removed 
from listed status (``delisted''), and methods for monitoring recovery 
progress. Recovery plans also establish a framework for agencies to 
coordinate their recovery efforts and provide estimates of the cost of 
implementing recovery tasks. Recovery teams (composed of species 
experts, Federal and State agencies, nongovernmental organizations, and 
stakeholders) are often established to develop recovery plans. When 
completed, the recovery outline, draft recovery plan, and the final 
recovery plan will be available on our website (http://www.fws.gov/endangered) or from our Washington Fish and Wildlife Office (see FOR 
FURTHER INFORMATION CONTACT).
    Implementation of recovery actions generally requires the 
participation of a broad range of partners, including other Federal 
agencies, States, Tribes, nongovernmental organizations, businesses, 
and private landowners. Examples of recovery actions include habitat 
restoration (e.g., restoration of native vegetation), research, captive 
propagation and reintroduction, and outreach and education. The 
recovery of many listed species cannot be accomplished solely on 
Federal lands because their range may occur primarily or solely on non-
Federal lands. To achieve recovery of these species requires 
cooperative conservation efforts on private, State, and Tribal lands.
    Following publication of this final rule, funding for recovery 
actions will be available from a variety of sources, including Federal 
budgets, State programs, and cost share grants for non-Federal 
landowners, the academic community, and nongovernmental organizations. 
In addition, pursuant to section 6 of the Act, the State of Washington 
will be eligible for Federal funds to implement management actions that 
promote the protection or recovery of the island marble butterfly. 
Information on our grant programs that are available to aid species 
recovery can be found at: http://www.fws.gov/grants.
    Please let us know if you are interested in participating in 
recovery efforts for the island marble butterfly. Additionally, we 
invite you to submit any new information on this species whenever it 
becomes available and any information you may have for recovery 
planning purposes (see FOR FURTHER INFORMATION CONTACT).
    Section 7(a) of the Act requires Federal agencies to evaluate their

[[Page 26807]]

actions with respect to any species that is listed as an endangered or 
threatened species and with respect to its critical habitat, if any is 
designated. Regulations implementing this interagency cooperation 
provision of the Act are codified at 50 CFR part 402. Section 7(a)(2) 
of the Act requires Federal agencies to ensure that activities they 
authorize, fund, or carry out are not likely to jeopardize the 
continued existence of any endangered or threatened species or destroy 
or adversely modify its critical habitat. If a Federal action may 
affect a listed species or its critical habitat, the responsible 
Federal agency must enter into consultation with the Service.
    Federal agency actions within the species' habitat that may require 
conference or consultation or both as described in the preceding 
paragraph include management and any other landscape-altering 
activities on Federal lands administered by the Bureau of Land 
Management, Farm Service Agency, Federal Highway Administration, 
National Park Service, U.S Army Corps of Engineers, U.S. Fish and 
Wildlife Service, U.S. Department of Agriculture, and the U.S. Coast 
Guard.
    The Act and its implementing regulations set forth a series of 
general prohibitions and exceptions that apply to endangered wildlife. 
The prohibitions of section 9(a)(1) of the Act, codified at 50 CFR 
17.21, make it illegal for any person subject to the jurisdiction of 
the United States to take (which includes harass, harm, pursue, hunt, 
shoot, wound, kill, trap, capture, or collect; or to attempt any of 
these) endangered wildlife within the United States or on the high 
seas. In addition, it is unlawful to import; export; deliver, receive, 
carry, transport, or ship in interstate or foreign commerce in the 
course of commercial activity; or sell or offer for sale in interstate 
or foreign commerce any listed species. It is also illegal to possess, 
sell, deliver, carry, transport, or ship any such wildlife that has 
been taken illegally. Certain exceptions apply to employees of the 
Service, the National Marine Fisheries Service, other Federal land 
management agencies, and State conservation agencies.
    We may issue permits to carry out otherwise prohibited activities 
involving endangered wildlife under certain circumstances. Regulations 
governing permits are codified at 50 CFR 17.22. With regard to 
endangered wildlife, a permit may be issued for the following purposes: 
For scientific purposes, to enhance the propagation or survival of the 
species, and for incidental take in connection with otherwise lawful 
activities. There are also certain statutory exemptions from the 
prohibitions, which are found in sections 9 and 10 of the Act.
    It is our policy, as published in the Federal Register on July 1, 
1994 (59 FR 34272), to identify to the maximum extent practicable at 
the time a species is listed, those activities that would or would not 
constitute a violation of section 9 of the Act. The intent of this 
policy is to increase public awareness of the effect of a final listing 
on proposed and ongoing activities within the range of a listed 
species. Due to the cryptic nature of this species throughout a large 
portion of the year, we are unable, at this time, to identify specific 
activities within the known range of the species that wouldnot result 
in unauthorized take under section 9 of the Act.
    Based on the best available information, the following activities 
may potentially result in a violation of section 9 the Act; this list 
is not comprehensive:
    (1) Unauthorized collecting, handling, possessing, selling, 
delivering, carrying, or transporting of island marble butterflies, 
including import or export across State lines and international 
boundaries, except for properly documented antique specimens at least 
100 years old, as defined by section 10(h)(1) of the Act;
    (2) Introduction of nonnative species that compete with or prey 
upon the island marble butterfly or its host and nectar plants--for 
example, the introduction of competing, nonnative plants or animals to 
the State of Washington, and in particular the San Juan Islands;
    (3) The unauthorized release of biological control agents that 
attack any life stage of the island marble butterfly--for example, Btk 
release in the range of the species;
    (4) Unauthorized modification of the soil profiles or the 
vegetation components on sites known to be occupied by island marble 
butterflies; or
    (5) Intentional disturbance of butterflies (or any life stage 
thereof), especially mowing or burning of areas where butterflies are 
known to occur during the breeding season.
    Questions regarding whether specific activities would constitute a 
violation of section 9 of the Act should be directed to the Washington 
Fish and Wildlife Office (see FOR FURTHER INFORMATION CONTACT).

Critical Habitat

Background

    Critical habitat is defined in section 3 of the Act as:
    (1) The specific areas within the geographical area occupied by the 
species, at the time it is listed in accordance with the Act, on which 
are found those physical or biological features
    (a) Essential to the conservation of the species, and
    (b) Which may require special management considerations or 
protection; and
    (2) Specific areas outside the geographical area occupied by the 
species at the time it is listed, upon a determination that such areas 
are essential for the conservation of the species.
    Our regulations at 50 CFR 424.02 define the geographical area 
occupied by the species as an area that may generally be delineated 
around species' occurrences, as determined by the Secretary (i.e., 
range). Such areas may include those areas used throughout all or part 
of the species' life cycle, even if not used on a regular basis (e.g., 
migratory corridors, seasonal habitats, and habitats used periodically, 
but not solely by vagrant individuals).
    Conservation, as defined under section 3 of the Act, means to use 
and the use of all methods and procedures that are necessary to bring 
an endangered or threatened species to the point at which the measures 
provided pursuant to the Act are no longer necessary. Such methods and 
procedures include, but are not limited to, all activities associated 
with scientific resources management such as research, census, law 
enforcement, habitat acquisition and maintenance, propagation, live 
trapping, and transplantation, and, in the extraordinary case where 
population pressures within a given ecosystem cannot be otherwise 
relieved, may include regulated taking.
    Critical habitat receives protection under section 7 of the Act 
through the requirement that Federal agencies ensure, in consultation 
with the Service, that any action they authorize, fund, or carry out is 
not likely to result in the destruction or adverse modification of 
critical habitat. The designation of critical habitat does not affect 
land ownership or establish a refuge, wilderness, reserve, preserve, or 
other conservation area. Such designation does not allow the government 
or public to access private lands. Such designation does not require 
implementation of restoration, recovery, or enhancement measures by 
non-Federal landowners. Where a landowner requests Federal agency 
funding or authorization for an action that may affect a listed species 
or critical habitat,

[[Page 26808]]

the consultation requirements of section 7(a)(2) of the Act would 
apply, but even in the event of a destruction or adverse modification 
finding, the obligation of the Federal action agency and the landowner 
is not to restore or recover the species, but to implement reasonable 
and prudent alternatives to avoid destruction or adverse modification 
of critical habitat.
    Under the first prong of the Act's definition of critical habitat, 
areas within the geographical area occupied by the species at the time 
it was listed are included in a critical habitat designation if they 
contain physical or biological features (1) which are essential to the 
conservation of the species and (2) which may require special 
management considerations or protection. For these areas, critical 
habitat designations identify, to the extent known using the best 
scientific and commercial data available, those physical or biological 
features that are essential to the conservation of the species (such as 
space, food, cover, and protected habitat). In identifying those 
physical or biological features within an area, we focus on the 
specific features that support the life-history needs of the species, 
including, but not limited to, water characteristics, soil type, 
geological features, prey, vegetation, symbiotic species, or other 
features. A feature may be a single habitat characteristic, or a more 
complex combination of habitat characteristics. Features may include 
habitat characteristics that support ephemeral or dynamic habitat 
conditions. Features may also be expressed in terms relating to 
principles of conservation biology, such as patch size, distribution 
distances, and connectivity.
    Under the second prong of the Act's definition of critical habitat, 
we can designate critical habitat in areas outside the geographical 
area occupied by the species at the time it is listed, upon a 
determination that such areas are essential for the conservation of the 
species. For example, an area currently occupied by the species but 
that was not occupied at the time of listing may be essential to the 
conservation of the species and may be included in the critical habitat 
designation.
    Section 4 of the Act requires that we designate critical habitat on 
the basis of the best scientific data available. Further, our Policy on 
Information Standards Under the Endangered Species Act (published in 
the Federal Register on July 1, 1994 (59 FR 34271)), the Information 
Quality Act (section 515 of the Treasury and General Government 
Appropriations Act for Fiscal Year 2001 (Pub. L. 106-554; H.R. 5658)), 
and our associated Information Quality Guidelines provide criteria, 
establish procedures, and provide guidance to ensure that our decisions 
are based on the best scientific data available. They require our 
biologists, to the extent consistent with the Act and with the use of 
the best scientific data available, to use primary and original sources 
of information as the basis for recommendations to designate critical 
habitat.
    When we are determining which areas should be designated as 
critical habitat, our primary source of information is generally the 
information from the species status assessment (SSA) document and 
information developed during the listing process for the species. 
Additional information sources may include any generalized conservation 
strategy, criteria, or outline that may have been developed for the 
species; the recovery plan for the species; articles in peer-reviewed 
journals; conservation plans developed by States and counties; 
scientific status surveys and studies; biological assessments; other 
unpublished materials; or experts' opinions or personal knowledge.
    Habitat is dynamic, and species may move from one area to another 
over time. We recognize that critical habitat designated at a 
particular point in time may not include all of the habitat areas that 
we may later determine are necessary for the recovery of the species. 
For these reasons, a critical habitat designation does not signal that 
habitat outside the designated area is unimportant or may not be needed 
for recovery of the species. Areas that are important to the 
conservation of the species, both inside and outside the critical 
habitat designation, will continue to be subject to: (1) Conservation 
actions implemented under section 7(a)(1) of the Act; (2) regulatory 
protections afforded by the requirement in section 7(a)(2) of the Act 
for Federal agencies to ensure their actions are not likely to 
jeopardize the continued existence of any endangered or threatened 
species; and (3) section 9 of the Act's prohibitions on taking any 
individual of the species, including taking caused by actions that 
affect habitat. Federally funded or permitted projects affecting listed 
species outside their designated critical habitat areas may still 
result in jeopardy findings in some cases. These protections and 
conservation tools will continue to contribute to recovery of this 
species. Similarly, critical habitat designations made on the basis of 
the best available information at the time of designation will not 
control the direction and substance of future recovery plans, habitat 
conservation plans (HCPs), or other species conservation planning 
efforts if new information available at the time of these planning 
efforts calls for a different outcome.
    On August 27, 2019, we published a final rule in the Federal 
Register (84 FR 45020) to revise our regulations concerning the 
procedures and criteria used for listing or removing species from the 
Lists of Endangered and Threatened Wildlife and Plants and designating 
critical habitat. That rule became effective on September 26, 2019, but 
as stated in that rule, the revisions it sets forth apply to 
classification and critical habitat rules for which a proposed rule was 
published after September 26, 2019. Since the proposed rule for the 
Island marble butterfly critical habitat was published on April 12, 
2018 (83 FR 15900), this final rule follows the version of Sec.  424.12 
that was in effect prior to September 26, 2019.

Physical or Biological Features

    In accordance with section 3(5)(A)(i) of the Act and regulations at 
50 CFR 424.12(b), in determining which areas within the geographical 
area occupied by the species at the time of listing to designate as 
critical habitat, we consider the physical or biological features that 
are essential to the conservation of the species and which may require 
special management considerations or protection. For example, physical 
features might include gravel of a particular size required for 
spawning, alkali soil for seed germination, protective cover for 
migration, or susceptibility to flooding or fire that maintains 
necessary early-successional habitat characteristics. Biological 
features might include prey species, forage grasses, specific kinds or 
ages of trees for roosting or nesting, symbiotic fungi, or a particular 
level of nonnative species consistent with conservation needs of the 
listed species. The features may also be combinations of habitat 
characteristics and may encompass the relationship between 
characteristics or the necessary amount of a characteristic needed to 
support the life history of the species. In considering whether 
features are essential to the conservation of the species, the Service 
may consider an appropriate quality, quantity, and spatial and temporal 
arrangement of habitat characteristics in the context of the life-
history needs, condition, and status of the species. These 
characteristics include, but are not limited to, space for individual 
and population growth and for normal behavior; food, water, air, light, 
minerals, or other nutritional or

[[Page 26809]]

physiological requirements; cover or shelter; sites for breeding, 
reproduction, or rearing (or development) of offspring; and habitats 
that are protected from disturbance.
    We derive the specific physical or biological features essential to 
the conservation of the island marble butterfly from studies of this 
species' habitat, ecology, and life history as described below. We have 
determined that the following physical or biological features are 
essential to the conservation of the island marble butterfly:
Space for Individual and Population Growth and for Normal Behavior
    The island marble butterfly has previously been documented as 
having as many as five core populations across San Juan and Lopez 
Islands in the San Juan archipelago, but of those five, there is only 
one location where it has been consistently detected on an annual basis 
since its rediscovery in 1998 at American Camp, part of San Juan Island 
National Historical Park. The long-term occupancy of American Camp 
indicates that one or more aspects of this site provide the combination 
of habitat factors needed by the species. American Camp encompasses 
multiple small populations within large expanses of diverse habitat, 
including open south-facing slopes, varied broad-scale topographic 
features, and low-statured plant communities (Lambert 2011, pp. 151-
152; Lambert 2016a, p. 4). Surface topography (slope and aspect) and 
landscape features that have topographic relief (slopes, bluffs, sand 
banks, or driftwood berms) are critical to the movement and dispersal 
of the island marble butterfly (Lambert 2011, p. 152).
    The portion of the park where the island marble butterfly persists 
contains an open expanse of prairie and dune habitat greater than 700 
ac (283 ha) and is bounded on two sides by marine shoreline. The island 
marble butterfly uses landscape features to fly low across the land, 
following shallow ridgelines associated with sand dunes, road cuts, and 
coastal bluffs. We surmise that island marble butterflies use the lee 
of rolling hills or hollows in broader expanses of prairie and dune 
habitats to facilitate their movements. Therefore, we determine habitat 
areas large enough to include broad topographic features (e.g., 
ridgelines, hills, and bluffs) to be physical or biological features 
for the island marble butterfly.
    At a rangewide scale, the island marble butterfly exhibits 
metapopulation dynamics, while on a local scale, ``patchy'' population 
dynamics best describes the movement of individuals between suitable 
habitat patches (Lambert 2011, pp. 147-148). Specifically, the island 
marble butterfly tends to occupy multiple habitat patches within a 
larger, heterogeneous area, with some small amount of movement between 
suitable habitat patches. Individual butterflies rarely move distances 
greater than 0.4 mi (600 m) (Peterson 2010, p. 3). Marked individuals 
are nearly always recaptured at the sites where they were marked, with 
a single exception when a marked individual was recaptured 1.2 mi (1.9 
km) from its site of origin (Peterson 2010, p. 3). Within the last 
known occupied site, smaller occupied patches have been observed to 
undergo local extirpation events, but the close proximity of nearby 
populations within the larger contiguous area has allowed for 
recolonization (Lambert 2011, p. 155). Areas large enough to contain 
multiple small populations of island marble butterfly that allow for 
population connectivity and re-establishment are essential to the 
conservation of the species. Therefore, we conclude that areas large 
enough to support multiple small populations of the species are a 
physical or biological feature essential to the island marble 
butterfly.
    Island marble butterflies tend to fly close to the ground, along 
the edges of treed areas or along marine shorelines. Therefore, forest 
and open water create natural barriers to movement (Lambert 2011, pp. 
49, 50). Male island marble butterflies fly low (approximately 5 ft 
(1.5 m) above the ground) and follow ridgelines, bluffs, road-cuts, 
trail edges, fence lines, and shrub or forest edges in search of mates 
(Lambert 2011, pp. 47-48). Female island marble butterflies have been 
observed to fly in low (approximately 3 ft (1 m) above the ground), 
wide (330-980 ft (100-500 m)) circles above the ground searching for 
suitable host plants upon which to lay their eggs (Lambert 2011, p. 
49). We conclude that large open areas with few trees are a physical or 
biological feature for the island marble butterfly.
    Based on the best information available, we estimate that the 
conservation of the island marble butterfly is best supported by open, 
primarily treeless areas with short-statured forb- and grass-dominated 
vegetation. Areas should be large enough to allow for the inclusion of 
diverse topographic features and habitat types, including sites for 
mating, egg laying, feeding, refugia (places to safely harbor), and 
diapause locations, and should support multiple discrete occupied 
habitat patches, which increases the likelihood of recolonization if 
local extinction takes place. Therefore, we conclude that open, 
primarily treeless habitat areas that are large enough to support 
multiple, small populations and that include broad topographic features 
such as ridgelines, hills, and bluffs are physical or biological 
features essential to the conservation of the island marble butterfly.
Food, Water, Air, Light, Minerals, or Other Nutritional or 
Physiological Requirements
    The island marble butterfly needs larval and adult food resources 
in order to complete its life cycle: larval host plants (food plants 
required by the immature stages of the butterfly) and nectar plants for 
the adults. The island marble butterfly has three known larval host 
plants, all in the mustard family (Brassicaceae). One is native, 
Menzies' pepperweed, and two are nonnative, field mustard and tumble 
mustard (Miskelly 2004, pp. 33, 38; Lambert 2011, p. 2). These three 
larval host plants are essential components of habitat for the island 
marble butterfly.
    All three larval host plants occur in open grass- and forb-
dominated plant communities, but each species is most robust in one of 
three specific habitat types, with little overlap: Menzies' pepperweed 
at the edge of low-lying coastal lagoon habitat; field mustard in 
upland prairie habitat, disturbed fields, and disturbed soils, 
including soil piles from construction; and tumble mustard in sand dune 
habitat (Miskelly 2004, p. 33; Miskelly and Potter 2009, p. 9; Lambert 
2011, pp. 24, 121-123). While each larval host plant can occur in each 
of the three habitat types referenced above, female island marble 
butterflies typically lay eggs on only the most robust host plants in 
each aforementioned habitat type (Miskelly 2004, p. 33; Lambert 2011, 
pp. 24, 41, 50, 55-57, 121-123).
    We conclude that the presence of Menzies' pepperweed, field 
mustard, or tumble mustard is a physical or biological feature upon 
which the island marble butterfly depends.
    Adults primarily forage for nectar on their larval host plants 
(Potter 2015e, pers. comm.). They also use a variety of other nectar 
plants that flower during the island marble butterfly's flight period, 
which is generally from mid-April to mid- to late-June. Adults have 
been observed to nectar on yellow sand verbena, yarrow, small-flowered 
fiddleneck, American sea rocket, field chickweed, common stork's bill, 
dovefoot geranium, hairy cat's ear, common lomatium, seashore lupine, 
common forget-me-not, California

[[Page 26810]]

buttercup, trailing blackberry, dandelion, death camas, and Howell's 
brodiaea (Miskelly 2004, p. 33; Pyle 2004, pp. 23-26, 33; Miskelly and 
Potter 2005, p. 6; Lambert 2011, p. 120; Vernon and Weaver 2012, 
appendix 12; Lambert 2015a, p. 2; Lambert 2015b, in litt.). Of these 
additional nectar resources, island marble butterflies are most 
frequently observed feeding on yellow sand verbena, small-flowered 
fiddleneck, and field chickweed (Potter 2015e, pers. comm.). We 
conclude that adult nectar resources, including, but not limited to, 
those listed here, are a physical or biological feature upon which the 
island marble butterfly depends.
    Like many animals that rely on external sources of body heat 
(ectotherms), the island marble butterfly is more active at warmer 
temperatures; for this species, this generally means temperatures that 
are higher than 55 degrees Fahrenheit ([deg]F) (13 degrees Celsius 
([deg]C)). This leads to adult (winged) island marble butterflies being 
most active between the hours of 10 a.m. and 4 p.m. The island marble 
butterfly relies upon solar radiation for the warmth that drives their 
development, mate-finding, and reproduction. We conclude that exposure 
to the sun provided by open, primarily treeless areas with some south-
facing slopes and short-statured vegetation is a physical or biological 
feature upon which the island marble butterfly depends.
    We consider open sunlit areas containing at least one species of 
larval host plant, Menzies' pepperweed, field mustard, and/or tumble 
mustard, with both flower buds and blooms between the months of May 
through July to be physical or biological features of island marble 
butterfly habitat. We additionally consider the presence of adult 
nectar plants in flower to be a physical or biological feature of 
island marble butterfly habitat.
Sites for Breeding, Reproduction, or Rearing (or Development) of 
Offspring
    Male island marble butterflies are attracted to white and may 
investigate white picket fences, white lines on surface roads, or other 
white objects while searching for a mate (Lambert 2011, p. 47). The 
island marble butterfly primarily uses short-statured, white-flowering 
plants such as field chickweed as sites for mate attraction and mating 
(Lambert 2014b, p. 17). We conclude that the presence of short-
statured, white-flowering plants during the flight period (generally 
from mid-April to mid- to late-June) for the island marble butterfly to 
be a physical or biological feature of the island marble butterfly 
habitat.
    Once mated, gravid female island marble butterflies seek out larval 
host plants at an optimal growth stage for egg laying (recently hatched 
caterpillars require tender plant parts, such as immature flower buds, 
because their mouthparts are not developed enough to eat hardened plant 
matter) (Lambert 2011, pp. 9-10). Larval host plant flowering phenology 
(timing of flower opening) is important for island marble butterflies. 
If the plants emerge too early, there may not be enough tissue at the 
right stage available for the larvae to go through their developmental 
phases. If the plants emerge too late, female butterflies may not 
recognize the larval host plants as suitable sites to lay eggs.
    Female island marble butterflies carefully gauge the suitability of 
each larval host plant, preferentially selecting plants that possess 
both flowers and buds to lay eggs on. Plants with greater than 50 
percent of their flowers in bloom are more likely to be selected than 
plants in an earlier (less than 50 percent of flowers in bloom) or 
later developmental stage (Lambert 2011, pp. 59-60). Female island 
marble butterflies tend to lay eggs singly on the immature buds of the 
flowers of their larval host plants, rarely laying eggs on 
inflorescences that are already occupied by island marble butterfly 
eggs or larvae (Lambert 2011, pp. 51-57). Female island marble 
butterflies prefer larval host plants growing in low-density patches 
with less than one plant per meter square and tend to choose plants 
that are along the outer edge of a patch of larval host plants rather 
than in areas with a high density of host plants (Lambert 2011, pp. 53, 
68-69; Lambert 2015d, p. 9). Additionally, host plant phenology (timing 
of development) plays a significant role in determining where females 
lay eggs. Low- to medium-density larval host plants, with both flower 
buds and blooms on them between the months of May through July, for 
egg-laying and larval development are a physical or biological feature 
of island marble butterfly habitat.
    After hatching, larvae of the island marble butterfly rapidly 
progress through five instars (larval growth stages) and have been 
documented to then move up to 13 ft (4 m) from their larval host plant 
to nearby standing vegetation (usually tall grasses) to pupate (Lambert 
2011, p. 19). Island marble butterfly larvae use nearby vegetation as 
bridges to other plants and appear to avoid being close to the ground 
while searching for a safe site on which to form a chrysalis (pupal 
casing) (Lambert 2011, pp. 20-21). Therefore, we find that the presence 
of larval host plants, in complement with tall, standing vegetation 
that provides the structure necessary to allow mature larvae to cross 
to a safe pupation site, is a physical or biological feature of island 
marble butterfly habitat.
Habitats That Are Protected From Disturbance or Are Representative of 
the Historical, Geographical, and Ecological Distributions of a Species
    The island marble butterfly spends approximately 300 days in 
diapause (a form of dormancy) as a chrysalis (pupa) before undergoing 
metamorphosis to emerge as a winged adult the following spring. Unlike 
other butterfly species that may diapause underground or, 
alternatively, rapidly advance from egg to winged adult and overwinter 
in an adult phase, the island marble butterfly enters diapause 
aboveground and very close to where it hatched. During diapause, the 
island marble butterfly is vulnerable to any activity such as 
trampling, mowing, harvesting, grazing, or plowing that may disturb or 
destroy the vegetative structure to which a larva has attached its 
pupal casing. The larval host plants for the island marble butterfly 
are annual (or biennial), and habitat patches for the island marble 
butterfly do not tend to persist in the same area continuously over 
time. Leaving the vegetation near where larval host plants established 
in the spring until mid-summer the following year provides a safe place 
for the island marble butterfly chrysalids to harbor until they emerge. 
Therefore, we find that sufficient areas of undisturbed vegetation 
surrounding larval host plants that are left standing for a sufficient 
period of time in order for the island marble butterfly to complete its 
life cycle is a physical or biological feature of island marble 
butterfly habitat.
Summary of Essential Physical or Biological Features
    We have determined that the following physical or biological 
features of the areas on San Juan Island, Washington, that are 
essential to the conservation of the island marble butterfly are:
    (a) Open, primarily treeless areas with short-statured forb- and 
grass-dominated vegetation that include diverse topographic features 
such as ridgelines, hills, and bluffs for patrolling, dispersal 
corridors between habitat patches, and some south-facing terrain. Areas 
must be large enough to allow for the development of patchy-population

[[Page 26811]]

dynamics, allowing for multiple small populations to establish within 
the area.
    (b) Low- to medium-density larval host plants, with both flower 
buds and blooms on them between the months of May through July, for 
egg-laying and larval development. Larval host plants may be any of the 
following: Brassica rapa, Sisymbrium altissimum, or Lepidium 
virginicum.
    (c) Adult nectar resources in flower and short-statured, white-
flowering plants in bloom used for mate-finding, which may include, but 
are not limited to, Abronia latifolia (yellow sand verbena), Achillea 
millefolium (yarrow), Amsinckia menziesii (small-flowered fiddleneck), 
Cakile edentula (American sea rocket), Cerastium arvense (field 
chickweed), Erodium cicutarium (common stork's bill), Geranium molle 
(dovefoot geranium), Hypochaeris radicata (hairy cat's ear), Lomatium 
utriculatum (common lomatium), Lupinus littoralis (seashore lupine), 
Myosotis discolor (common forget-me-not), Ranunculus californicus 
(California buttercup), Rubus ursinus (trailing blackberry), Taraxacum 
officinale (dandelion), Toxicoscordion venenosum (death camas, formerly 
known as Zigadenus venenosus), and Triteleia grandiflora (Howell's 
brodiaea, formerly Brodiaea howellii).
    (d) Areas of undisturbed vegetation surrounding larval host plants 
sufficient to provide secure sites for diapause and pupation. The 
vegetation surrounding larval host plants must be left standing for a 
sufficient period of time for the island marble butterfly to complete 
its life cycle.
Special Management Considerations or Protection
    When designating critical habitat, we assess whether the specific 
areas within the geographical area occupied by the species at the time 
of listing contain features that are essential to the conservation of 
the species and which may require special management considerations or 
protection. Because the island marble butterfly depends on vegetation 
that requires disturbance and open areas to establish, special 
management may be necessary to both maintain low-level disturbance and 
to prevent the invasion of weedy native and nonnative plant species, 
such as Douglas fir, Mediterranean pasture grasses, and thistle. 
Beneficial special management activities could include prescribed 
burning to remove standing vegetation and seedlings and to reduce seed 
set of nonnative plant species. Additionally, the application of 
selective herbicides to combat specific invasive plants may also prove 
useful in vegetation management. For some weedy species, hand-pulling 
can be an effective vegetation management tool, if staffing and 
resources allow.
    Special management considerations within the critical habitat unit 
may include protection of larval host plants from herbivory by browsing 
deer, European rabbits, and brown garden snails. These herbivores 
constitute the primary threat to the larval host plants upon which the 
island marble butterfly depends. Special management actions that could 
ameliorate the threat of herbivory by deer, European rabbits, and brown 
garden snails could include lethal control methods, such as targeted 
hunting or professional removal. For deer, exclusion fencing increases 
the survivorship of both larval host plants and the island marble 
butterfly in the fenced areas, but the fences are difficult to erect 
and maintain and provide a host of other challenges for the land 
management agencies. Additionally, exclusion fencing does nothing to 
reduce the number of deer, which is the primary cause of the intense 
browsing pressure on the larval host plants for the island marble 
butterfly (Lambert 2011, pp. 85-104, 127; Lambert 2014a, p. 3; Lambert 
2015d, pp. 14-18). Fencing is not effective against European rabbits 
and brown garden snails.

Criteria Used To Identify Critical Habitat

    As required by section 4(b)(2) of the Act, we use the best 
scientific data available to designate critical habitat. In accordance 
with the Act and our implementing regulations at 50 CFR 424.12(b), we 
review available information pertaining to the habitat requirements of 
the species and identify specific areas within the geographical area 
occupied by the species at the time of listing and any specific areas 
outside the geographical area occupied by the species to be considered 
for designation as critical habitat. In this case, we are not 
designating any areas outside the geographical area occupied by the 
species.
    When we are determining which areas should be designated as 
critical habitat, our primary source of information is generally the 
information developed during the listing process for the species. 
Additional information sources may include the recovery plan for the 
species, articles in peer-reviewed journals, conservation plans 
developed by States and counties, scientific status surveys and 
studies, biological assessments, other unpublished materials, or 
experts' opinions or personal knowledge. In this case, we used existing 
occurrence data for the island marble butterfly and information on the 
habitat and ecosystems upon which it depends. These sources of 
information included, but were not limited to:
    (1) Data used to prepare the rule to list the species;
    (2) Information from biological surveys;
    (3) Various agency reports and databases;
    (4) Information from NPS and other cooperators;
    (5) Information from species experts;
    (6) Data and information presented in academic research theses; and
    (7) Regional Geographic Information System (GIS) data (such as 
species occurrence data, land use, topography, aerial imagery, soil 
data, and land ownership maps) for area calculations and mapping.
Areas Occupied at the Time of Listing
    In accordance with the Act and our implementing regulations at 50 
CFR 424.12(b), we reviewed available information pertaining to the 
habitat requirements of the species, identified specific areas within 
the geographical area occupied by the species at the time of listing, 
and examined whether we could identify any specific areas outside the 
geographical area occupied by the species to be considered for 
designation as critical habitat. In this case, as we are listing the 
island marble butterfly concurrently with the designation of critical 
habitat, all areas presently occupied by the island marble butterfly 
constitute those areas occupied at the time of listing.
    We plotted the known locations of the island marble butterfly where 
they occur in Washington using 2015 National Agriculture Imagery 
Program (NAIP) digital imagery in ArcGIS, version 10.4 (Environmental 
Systems Research Institute, Inc.), a computer geographic information 
system program, and determined that the currently occupied areas 
contain the physical or biological features needing special management, 
as discussed above. We also analyzed the appropriate quantity and 
spatial arrangement of these features in the context of the life 
history, status, and conservation needs of the species.
    We note that limitations in available GIS data and the scale of 
designations can affect our precision in mapping critical habitat 
boundaries. We strive to use clearly recognizable geographic or legal 
features in designating critical habitat boundaries; however, in those 
instances where we think critical habitat maps may cause uncertainty 
over the precise extent of mapped critical

[[Page 26812]]

habitat, we have attempted to clarify with supplemental narrative 
descriptions.
    Survey effort for the island marble butterfly has not been 
consistent spatially or temporally. Island-wide surveys of San Juan and 
Lopez Islands were discontinued by WDFW in 2012, due to decreased 
detections and the lack of larval host plants in previously occupied 
areas across both islands. In 2015, the Service funded an island-wide 
survey of San Juan, and no occurrences were documented outside of the 
known occupied area centered on American Camp at the southern end of 
San Juan Island. The last survey of Lopez Island was conducted in 2012, 
and a single larva was observed. There have been no reports of island 
marble butterflies from Lopez Island since 2012.
    Therefore, the Service considers areas to be occupied at the time 
of listing if there are occurrence records within those areas within 
the last 5 years, or if areas adjacent to known occupied areas have the 
physical or biological features upon which the island marble butterfly 
depends and there are no barriers to dispersal. It is reasonable to 
conclude that the species regularly occurs in such areas because of the 
species' population dynamics and frequent movement between habitat 
patches, as discussed above. Occurrence records are deemed credible if 
recorded by a Federal, State, or contract biologist, or a qualified 
surveyor for the island marble butterfly.
    We have also determined that all of these occupied areas (areas 
with documented occurrences as well as adjacent areas containing 
suitable habitat and where there are no barriers to dispersal) contain 
one or more of the essential physical or biological features. For these 
reasons and due to the restricted range of the island marble butterfly, 
we determined that all known occupied areas should be designated as 
critical habitat. The only known occupied area is centered on American 
Camp at San Juan Island National Historical Park and includes adjacent 
lands to the east and west of the National Park that are owned and/or 
managed by BLM, WDNR, San Juan County, Washington State Parks and 
Recreation, and private individuals.
    The critical habitat designated on the private parcels along Eagle 
Cove only includes the area of steep coastal bluff between the marine 
shoreline and the upland edge at the top of the bluff. It does not 
include areas landward of the top of the bluff, which are typically 
mowed and maintained as yard.
    When determining critical habitat boundaries within this final 
rule, we made every effort to avoid including developed areas such as 
lands covered by buildings, pavement, and other structures because such 
lands lack physical or biological features for the island marble 
butterfly. The scale of the maps we prepared under the parameters for 
publication within the Code of Federal Regulations may not reflect the 
exclusion of such developed lands. Any such lands inadvertently left 
inside critical habitat boundaries shown on the maps of this final rule 
have been excluded by text in the rule and are not designated as 
critical habitat. Therefore, a Federal action involving these lands 
will not trigger section 7 consultation with respect to critical 
habitat and the requirement of no adverse modification unless the 
specific action would affect the physical or biological features in the 
adjacent critical habitat. Please note that we specifically include 
road margins and shoulders in the critical habitat designation, as the 
island marble butterfly larval host plants often establish in these 
disturbed areas and may be used by the island marble butterfly for egg-
laying and development. Special management considerations for road 
margins and shoulders may apply.
    We are not designating any areas as critical habitat outside the 
geographical area occupied by the species at the time of listing. While 
we know the conservation of the species will depend on increasing the 
number and distribution of populations of the island marble butterfly, 
not all of its historical range will be essential to the conservation 
of the species, and we are unable to delineate any specific unoccupied 
areas that are essential at this time. Sites both within and outside of 
the central valleys of San Juan and Lopez Islands were previously 
occupied by the island marble butterfly. A number of areas within and 
outside of these valleys continue to contain some or could develop many 
of the physical and biological features upon which the species depends, 
although the best available scientific data indicate all these areas 
are currently unoccupied. The areas of the central valleys with the 
potential to support the physical and biological features continue to 
be important to the overall conservation strategy for the island marble 
butterfly. However, due to the ephemeral and patchy nature of island 
marble butterfly habitat, only some of these areas within these larger 
central valley landscapes will likely be essential to the species' 
long-term persistence and conservation because of the ease with which 
field mustard recruits and the uncertainty associated with habitat 
patch longevity at any one site.
    Any specific areas essential to the species' conservation within 
these broader landscapes are not currently identifiable due to our 
limited understanding regarding the ideal configuration for the 
development of future habitat patches to support the island marble 
butterfly's persistence, the ideal size and number of these habitat 
patches, and how these habitat patches may naturally evolve within and 
persist on the landscape. Finally, the specific areas needed for 
conservation will depend in part on landowner willingness to restore 
and maintain the species' habitat in these areas.
    Consequently, the Service is considering proposing the future 
establishment of one or more experimental populations (such as, but not 
limited to, those provided for under section 10(j) of the Act) within 
these broad geographic areas after we list the island marble butterfly 
under the Act. Section 10(j) of the Act authorizes the Service, by 
rulemaking, to establish new populations of listed species that are 
within the species' historical range but outside its current natural 
range. If we designate a nonessential population, we can adopt a rule 
to minimize restrictions on landowners. Any such rule would, to the 
maximum extent practicable, represent an agreement between the Service 
and affected landowners and government agencies (50 CFR 17.81(d)).
    The critical habitat unit was designated based on one or more of 
the elements of physical or biological features being present to 
support island marble butterfly life processes. The critical habitat 
unit contains all of the identified elements of physical or biological 
features and supports multiple life processes. Some segments contain 
only some elements of the physical or biological features necessary to 
support the island marble butterfly's particular use of that habitat.
    The critical habitat designation is defined by the map or maps, as 
modified by any accompanying regulatory text, presented at the end of 
this document under Regulation Promulgation. We include more detailed 
information on the boundaries of the critical habitat designation in 
the preamble of this document. We will make the coordinates or plot 
points or both on which each map is based available to the public on 
http://www.regulations.gov at Docket No. FWS-R1-ES-2016-0145, on our 
internet site at https://www.fws.gov/wafwo/, and at the field office 
responsible for the designation (see FOR FURTHER INFORMATION CONTACT, 
above).

[[Page 26813]]

Final Critical Habitat Designation

    We are designating one unit as critical habitat for the island 
marble butterfly. The critical habitat area described below constitutes 
our best assessment at this time of areas that meet the definition of 
critical habitat. Table 1 shows the unit, which is occupied.

  Table 1--Designated Critical Habitat for the Island Marble Butterfly
------------------------------------------------------------------------
                                                           Size of  unit
       Critical habitat unit          Land ownership by      in acres
                                            type            (hectares)
------------------------------------------------------------------------
Island marble butterfly critical    NPS.................       718 (291)
 habitat.                           BLM.................          19 (8)
                                    DHS.................           5 (2)
                                    WDNR and SJCLB......         1 (0.4)
                                    WDNR................         37 (15)
                                    SJCPD...............         30 (12)
                                    Private.............         2 (0.8)
                                   -------------------------------------
    Total:........................  ....................       812 (329)
------------------------------------------------------------------------
Note: Area sizes may not sum due to rounding. NPS = National Park
  Service, BLM = Bureau of Land Management, DHS = Department of Homeland
  Security (Coast Guard), WDNR = Washington Department of Fish and
  Wildlife, SJCLB = San Juan County Land Bank, SJCPD = San Juan County
  Parks Department.

    The critical habitat designation consists of 812 ac (329 ha) of 
land at the southern end of San Juan Island, with San Juan Island 
National Historical Park (NPS) being the largest landholder of 718 ac 
(291 ha). The Bureau of Land Management (BLM) owns and manages 19 ac (8 
ha), Washington Department of Natural Resources (WDNR) owns and manages 
37 ac (15 ha) at Cattle Point, the Department of Homeland Security owns 
5 ac (2 ha), WDNR and the San Juan County Land Bank (SJCLB) jointly own 
1 ac (0.4 ha), San Juan County Parks Department owns 30 ac (12 ha), and 
approximately 2 ac (0.8 ha) is in private ownership. The critical 
habitat designation is centered on the American Camp portion of San 
Juan Island National Historical Park, which is owned and managed by the 
National Park Service, but includes adjacent lands both to the east and 
the west of National Park Service lands. Boundaries for the critical 
habitat unit follow the open, generally treeless habitat that the 
island marble butterfly relies upon during its flight period for mate-
finding, reproduction, feeding, and dispersal.
    The entirety of the critical habitat unit is within the 
geographical area occupied at the time of listing. The designation 
contains all of the physical or biological features required to support 
the island marble butterfly. The critical habitat designation is almost 
entirely conserved for use by or for the benefit of the public and is 
heavily used for recreation, primarily in the form of day hiking on 
easy trails. NPS has maintained a conservation agreement for the island 
marble butterfly with the Service since 2006, with the most recent 
renewal signed in December of 2018. As the largest landholder within 
the critical habitat unit, NPS continues to support and participate in 
ongoing research integral to the conservation of the island marble 
butterfly. BLM, DHS, WDNR, SJCLB, and San Juan County Parks are all 
engaged in the conservation of the island marble butterfly and meet 
with the Service multiple times annually to coordinate conservation 
efforts.
    Within the critical habitat designation, all of the current threats 
to the island marble butterfly are present. Please see Determination, 
above, for a summary of the threats and ``Special Management 
Considerations or Protection'' for additional recommendations.

Effects of Critical Habitat Designation

Section 7 Consultation
    Section 7(a)(2) of the Act requires Federal agencies, including the 
Service, to ensure that any action they fund, authorize, or carry out 
is not likely to jeopardize the continued existence of any endangered 
species or threatened species or result in the destruction or adverse 
modification of designated critical habitat of such species. In 
addition, section 7(a)(4) of the Act requires Federal agencies to 
confer with the Service on any agency action which is likely to 
jeopardize the continued existence of any species proposed to be listed 
under the Act or result in the destruction or adverse modification of 
proposed critical habitat.
    We published a final rule with a new definition of destruction or 
adverse modification on February 11, 2016 (81 FR 7214). Destruction or 
adverse modification means a direct or indirect alteration that 
appreciably diminishes the value of critical habitat for the 
conservation of a listed species. Such alterations may include, but are 
not limited to, those that alter the physical or biological features 
essential to the conservation of a species or that preclude or 
significantly delay development of such features.
    If a Federal action may affect a listed species or its critical 
habitat, the responsible Federal agency (action agency) must enter into 
consultation with us. Examples of actions that are subject to the 
section 7 consultation process are actions on State, tribal, local, or 
private lands that require a Federal permit (such as a permit from the 
U.S. Army Corps of Engineers under section 404 of the Clean Water Act 
(33 U.S.C. 1251 et seq.) or a permit from the Service under section 10 
of the Act) or that involve some other Federal action (such as funding 
from the Federal Highway Administration, Federal Aviation 
Administration, or the Federal Emergency Management Agency). Federal 
actions not affecting listed species or critical habitat, and actions 
on State, tribal, local, or private lands that are not federally funded 
or authorized, do not require section 7 consultation.
    As a result of section 7 consultation, we document compliance with 
the requirements of section 7(a)(2) through our issuance of:
    (1) A concurrence letter for Federal actions that may affect, but 
are not likely to adversely affect, listed species or critical habitat; 
or
    (2) A biological opinion for Federal actions that may affect and 
are likely to adversely affect, listed species or critical habitat.
    When we issue a biological opinion concluding that a project is 
likely to jeopardize the continued existence of a listed species and/or 
destroy or adversely modify critical habitat, we provide reasonable and 
prudent

[[Page 26814]]

alternatives to the project, if any are identifiable, that would avoid 
the likelihood of jeopardy and/or destruction or adverse modification 
of critical habitat. We define ``reasonable and prudent alternatives'' 
(at 50 CFR 402.02) as alternative actions identified during 
consultation that:
    (1) Can be implemented in a manner consistent with the intended 
purpose of the action,
    (2) Can be implemented consistent with the scope of the Federal 
agency's legal authority and jurisdiction,
    (3) Are economically and technologically feasible, and
    (4) Would, in the Service Director's opinion, avoid the likelihood 
of jeopardizing the continued existence of the listed species and/or 
avoid the likelihood of destroying or adversely modifying critical 
habitat.
    Reasonable and prudent alternatives can vary from slight project 
modifications to extensive redesign or relocation of the project. Costs 
associated with implementing a reasonable and prudent alternative are 
similarly variable.
    Regulations at 50 CFR 402.16 require Federal agencies to reinitiate 
consultation on previously reviewed actions in instances where we have 
listed a new species or subsequently designated critical habitat that 
may be affected and the Federal agency has retained discretionary 
involvement or control over the action (or the agency's discretionary 
involvement or control is authorized by law). Consequently, Federal 
agencies sometimes may need to request reinitiation of consultation 
with us on actions for which formal consultation has been completed, if 
those actions with discretionary involvement or control may affect 
subsequently listed species or designated critical habitat.
Application of the ``Adverse Modification'' Standard
    The key factor related to the adverse modification determination is 
whether, with implementation of the Federal action, the affected 
critical habitat would continue to serve its intended conservation role 
for the species. Activities that may destroy or adversely modify 
critical habitat are those that result in a direct or indirect 
alteration that appreciably diminishes the value of critical habitat 
for the conservation of the island marble butterfly. Such alterations 
may include, but are not limited to, those that alter the physical or 
biological features essential to the conservation of these species or 
that preclude or significantly delay development of such features. As 
discussed above, the role of critical habitat is to support physical or 
biological features essential to the conservation of a listed species 
and provide for the conservation of the species.
    Section 4(b)(8) of the Act requires us to briefly evaluate and 
describe, in any proposed or final regulation that designates critical 
habitat, activities involving a Federal action that may destroy or 
adversely modify such habitat, or that may be affected by such 
designation.
    Activities that may affect critical habitat, when carried out, 
funded, or authorized by a Federal agency, should result in 
consultation for the island marble butterfly. These activities include, 
but are not limited to:
    (1) Actions that destroy the habitat within the critical habitat 
unit. Such activities could include, but are not limited to, new 
infrastructure developments, planting forests in historical prairie, or 
large paving projects. These activities could disrupt dispersal, mate 
finding, and patchy population dynamics, as well as prevent the 
recruitment of future habitat.
    (2) Actions that would temporarily or permanently remove host 
plants from areas within the critical habitat unit that were otherwise 
phenologically and spatially available for use by the species. Such 
activities could include, but are not limited to, mowing, burning, or 
applying herbicide to host plants leading up to or during the flight 
season. These activities could reduce the quantity or distribution of 
oviposition sites available to the species.
    (3) Actions that would temporarily or permanently remove nectar 
resources or plants used for mate finding from areas within the 
critical habitat unit that were otherwise phenologically and spatially 
available for use by the species. Such activities could include, but 
are not limited to, mowing, burning, or applying herbicide to nectar or 
mate-finding plants leading up to or during the flight season. These 
activities could reduce nectaring opportunities or disrupt mate 
finding, both of which could reduce fecundity.
    (4) Actions that would physically disturb appropriate areas for 
diapause and pupation. Such activities could include, but are not 
limited to, mowing, trampling, grazing, or burning between flight 
seasons. These activities could also kill island marble butterflies in 
diapause as pupae.

Exemptions

Application of Section 4(a)(3) of the Act
    Section 4(a)(3)(B)(i) of the Act (16 U.S.C. 1533(a)(3)(B)(i)) 
provides that: ``The Secretary shall not designate as critical habitat 
any lands or other geographical areas owned or controlled by the 
Department of Defense, or designated for its use, that are subject to 
an integrated natural resources management plan [INRMP] prepared under 
section 101 of the Sikes Act (16 U.S.C. 670a), if the Secretary 
determines in writing that such plan provides a benefit to the species 
for which critical habitat is proposed for designation.'' There are no 
Department of Defense (DoD) lands with a completed INRMP within the 
final critical habitat designation.

Consideration of Impacts Under Section 4(b)(2) of the Act

    Section 4(b)(2) of the Act states that the Secretary shall 
designate and make revisions to critical habitat on the basis of the 
best available scientific data after taking into consideration the 
economic impact, national security impact, and any other relevant 
impact of specifying any particular area as critical habitat. The 
Secretary may exclude an area from critical habitat if he determines 
that the benefits of such exclusion outweigh the benefits of specifying 
such area as part of the critical habitat, unless he determines, based 
on the best scientific data available, that the failure to designate 
such area as critical habitat will result in the extinction of the 
species. In making that determination, the statute on its face, as well 
as the legislative history are clear that the Secretary has broad 
discretion regarding which factor(s) to use and how much weight to give 
to any factor.

Consideration of Economic Impacts

    Section 4(b)(2) of the Act and its implementing regulations require 
that we consider the economic impact that may result from a designation 
of critical habitat. In order to consider economic impacts, we prepared 
an incremental effects memorandum (IEM) and screening analysis, which, 
together with our narrative and interpretation of effects, we consider 
our draft economic analysis (DEA) of the proposed critical habitat 
designation and related factors. The DEA was made available for public 
review and comment concurrently with the April 12, 2018, proposed rule 
(Industrial Economics, Incorporated 2017). The DEA addresses probable 
economic impacts of the critical habitat designation for island marble 
butterfly. No additional information was

[[Page 26815]]

submitted during the comment period that pertained to our consideration 
of the probable incremental economic impacts of this critical habitat 
designation. Additional information relevant to the probable 
incremental economic impacts of critical habitat designation for the 
island marble butterfly is summarized below and available in the 
screening analysis for the island marble butterfly (Industrial 
Economics, Incorporated 2017), available at http://www.regulations.gov.
    The critical habitat designation for the island marble butterfly is 
comprised of a single unit and is considered occupied. The critical 
habitat designation consists of 812 ac (329 ha) and is owned and 
managed by NPS, BLM, DHS, WDNR, San Juan County, and private 
landowners. In these areas, any actions that may affect the species or 
its habitat would also affect designated critical habitat, and it is 
unlikely that any additional conservation efforts will be recommended 
to address the adverse modification standard over and above those 
recommended as necessary to avoid jeopardizing the continued existence 
of the island marble butterfly. Therefore, the potential incremental 
economic impacts of the island marble butterfly critical habitat 
designation are expected to be limited to administrative costs. We 
anticipate that the incremental administrative costs of addressing 
adverse modification of the island marble butterfly critical habitat in 
a section 7 consultation will be minor.
    Total annualized incremental costs of critical habitat designation 
for the island marble butterfly are anticipated to be less than 
$150,000 over the next 20 years, or approximately $10,000 annually. The 
incremental administrative burden resulting from the designation of 
critical habitat for the island marble butterfly is not anticipated to 
reach $100 million in any given year based on the anticipated annual 
number of consultations and associated consultation costs, which are 
not expected to exceed $10,000 in most years.

Exclusions

Exclusions Based on Economic Impacts
    The Service considered the economic impacts of the critical habitat 
designation and the Secretary is not exercising his discretion to 
exclude any areas from this designation of critical habitat for the 
island marble butterfly based on economic impacts.
    A copy of the IEM and screening analysis with supporting documents 
may be obtained by contacting the Washington Fish and Wildlife Office 
(see FOR FURTHER INFORMATION CONTACT) or by downloading from the 
internet at http://www.regulations.gov.
Exclusions Based on Impacts on National Security and Homeland Security
    Section 4(a)(3)(B)(i) of the Act may not cover all DoD lands or 
areas that pose potential national-security concerns (e.g., a DoD 
installation that is in the process of revising its INRMP for a newly 
listed species or a species previously not covered). If a particular 
area is not covered under section 4(a)(3)(B)(i) of the Act, national-
security or homeland-security concerns are not a factor in the process 
of determining what areas meet the definition of ``critical habitat.'' 
Nevertheless, when designating critical habitat under section 4(b)(2), 
the Service must consider impacts on national security, including 
homeland security, on lands or areas not covered by section 
4(a)(3)(B)(i) of the Act. Accordingly, we will always consider for 
exclusion from the designation areas for which DoD, Department of 
Homeland Security (DHS), or another Federal agency has requested 
exclusion based on an assertion of national-security or homeland-
security concerns.
    We cannot, however, automatically exclude requested areas. When 
DoD, DHS, or another Federal agency requests exclusion from critical 
habitat on the basis of national-security or homeland-security impacts, 
it must provide a reasonably specific justification of an incremental 
impact on national security that would result from the designation of 
that specific area as critical habitat. That justification could 
include demonstration of probable impacts, such as impacts to ongoing 
border-security patrols and surveillance activities, or a delay in 
training or facility construction, as a result of compliance with 
section 7(a)(2) of the Act. If the agency requesting the exclusion does 
not provide us with a reasonably specific justification, we will 
contact the agency to recommend that it provide a specific 
justification or clarification of its concerns relative to the probable 
incremental impact that could result from the designation. If the 
agency provides a reasonably specific justification, we will defer to 
the expert judgment of DoD, DHS, another Federal agency as to: (1) 
Whether activities on its lands or waters, or its activities on other 
lands or waters, have national-security or homeland-security 
implications; (2) the importance of those implications; and (3) the 
degree to which the cited implications would be adversely affected in 
the absence of an exclusion. In that circumstance, in conducting a 
discretionary 4(b)(2) exclusion analysis, we will give great weight to 
national-security and homeland-security concerns in analyzing the 
benefits of exclusion.
    Department of Homeland Security currently owns 5 ac (2 ha) of land 
that is surrounded by land owned and managed by BLM and lies within the 
critical habitat boundary. Specifically, these lands include a 
lighthouse facility that is managed by the U.S. Coast Guard. The U.S. 
Coast Guard is in the process of transferring ownership of these lands 
to BLM; therefore, we anticipate no impact on national security from 
the inclusion of these lands in the critical habitat designation. 
Consequently, the Secretary is not intending to exercise his discretion 
to exclude any areas from the final designation based on impacts on 
national security.
Exclusions Based on Other Relevant Impacts
    Under section 4(b)(2) of the Act, we consider any other relevant 
impacts, in addition to economic impacts and impacts on national 
security. We consider a number of factors including whether there are 
permitted conservation plans covering the species in the area such as 
HCPs, safe harbor agreements, or candidate conservation agreements with 
assurances (CCAA), or whether there are non-permitted conservation 
agreements and partnerships that would be encouraged by designation of, 
or exclusion from, critical habitat. In addition, we look at the 
existence of tribal conservation plans and partnerships and consider 
the government-to-government relationship of the United States with 
tribal entities. We also consider any social impacts that might occur 
because of the designation.
    In preparing this final rule, we have determined that there are 
currently no non-permitted conservation agreements or partnerships for 
the island marble butterfly. There is a CCAA which is designed to 
provide non-federal landowners with the opportunity to create and 
maintain habitat for the island marble butterfly while providing 
incidental take coverage and regulatory certainty. The final 
designation does not include any tribal lands or tribal trust 
resources. We anticipate no impact on tribal lands, partnerships, 
permitted or non-permitted plans or agreements from this critical 
habitat designation. Accordingly, the Secretary is not exercising his 
discretion to exclude any areas from this final designation based on 
other relevant impacts.

[[Page 26816]]

Required Determinations

Regulatory Planning and Review (Executive Orders 12866 and 13563)

    Executive Order 12866 provides that the Office of Information and 
Regulatory Affairs (OIRA) will review all significant rules. The Office 
of Information and Regulatory Affairs has determined that this rule is 
not significant.
    Executive Order 13563 reaffirms the principles of E.O. 12866 while 
calling for improvements in the nation's regulatory system to promote 
predictability, to reduce uncertainty, and to use the best, most 
innovative, and least burdensome tools for achieving regulatory ends. 
The executive order directs agencies to consider regulatory approaches 
that reduce burdens and maintain flexibility and freedom of choice for 
the public where these approaches are relevant, feasible, and 
consistent with regulatory objectives. E.O. 13563 emphasizes further 
that regulations must be based on the best available science and that 
the rulemaking process must allow for public participation and an open 
exchange of ideas. We have developed this rule in a manner consistent 
with these requirements.

Executive Order 13771

    This rule is not an E.O. 13771 (``Reducing Regulation and 
Controlling Regulatory Costs'') (82 FR 9339, February 3, 2017) 
regulatory action because this rule is not significant under E.O. 
12866.

Regulatory Flexibility Act (5 U.S.C. 601 et seq.)

    Under the Regulatory Flexibility Act (RFA; 5 U.S.C. 601 et seq.), 
as amended by the Small Business Regulatory Enforcement Fairness Act of 
1996 (SBREFA; 5 U.S.C. 801 et seq.), whenever an agency is required to 
publish a notice of rulemaking for any proposed or final rule, it must 
prepare and make available for public comment a regulatory flexibility 
analysis that describes the effects of the rule on small entities 
(i.e., small businesses, small organizations, and small government 
jurisdictions). However, no regulatory flexibility analysis is required 
if the head of the agency certifies the rule will not have a 
significant economic impact on a substantial number of small entities. 
The SBREFA amended the RFA to require Federal agencies to provide a 
certification statement of the factual basis for certifying that the 
rule will not have a significant economic impact on a substantial 
number of small entities.
    According to the Small Business Administration, small entities 
include small organizations such as independent nonprofit 
organizations; small governmental jurisdictions, including school 
boards and city and town governments that serve fewer than 50,000 
residents; and small businesses (13 CFR 121.201). Small businesses 
include manufacturing and mining concerns with fewer than 500 
employees, wholesale trade entities with fewer than 100 employees, 
retail and service businesses with less than $5 million in annual 
sales, general and heavy construction businesses with less than $27.5 
million in annual business, special trade contractors doing less than 
$11.5 million in annual business, and agricultural businesses with 
annual sales less than $750,000. To determine if potential economic 
impacts to these small entities are significant, we considered the 
types of activities that might trigger regulatory impacts under this 
designation as well as types of project modifications that may result. 
In general, the term ``significant economic impact'' is meant to apply 
to a typical small business firm's business operations.
    The Service's current understanding of the requirements under the 
RFA, as amended, and following recent court decisions, is that Federal 
agencies are only required to evaluate the potential incremental 
impacts of rulemaking on those entities directly regulated by the 
rulemaking itself, and are, therefore, not required to evaluate the 
potential impacts to indirectly regulated entities. The regulatory 
mechanism through which critical habitat protections are realized is 
section 7 of the Act, which requires Federal agencies, in consultation 
with the Service, to ensure that any action authorized, funded, or 
carried out by the agency is not likely to destroy or adversely modify 
critical habitat. Therefore, under section 7, only Federal action 
agencies are directly subject to the specific regulatory requirement 
(avoiding destruction and adverse modification) imposed by critical 
habitat designation. Consequently, it is our position that only Federal 
action agencies will be directly regulated by this designation. There 
is no requirement under the RFA to evaluate the potential impacts to 
entities not directly regulated. Moreover, Federal agencies are not 
small entities. Therefore, because no small entities are directly 
regulated by this rulemaking, the Service certifies that the final 
critical habitat designation will not have a significant economic 
impact on a substantial number of small entities.
    During the development of this final rule, we reviewed and 
evaluated all information submitted during the comment period that may 
pertain to our consideration of the probable incremental economic 
impacts of this critical habitat designation. Based on this 
information, we affirm our certification that this final critical 
habitat designation will not have a significant economic impact on a 
substantial number of small entities, and a regulatory flexibility 
analysis is not required.

Energy Supply, Distribution, or Use--Executive Order 13211

    Executive Order 13211 (Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use) requires 
agencies to prepare Statements of Energy Effects when undertaking 
certain actions. OMB has provided guidance for implementing this 
Executive Order that outlines nine outcomes that may constitute ``a 
significant adverse effect'' when compared to not taking the regulatory 
action under consideration. The economic analysis finds that none of 
these criteria is relevant to this analysis. Thus, based on information 
in the economic analysis, energy-related impacts associated with island 
marble butterfly conservation activities within critical habitat are 
not expected. As such, the designation of critical habitat is not 
expected to significantly affect energy supplies, distribution, or use. 
Therefore, this action is not a significant energy action, and no 
Statement of Energy Effects is required.

Unfunded Mandates Reform Act (2 U.S.C. 1501 et seq.)

    In accordance with the Unfunded Mandates Reform Act (2 U.S.C. 1501 
et seq.), we make the following findings:
    (1) This rule will not produce a Federal mandate. In general, a 
Federal mandate is a provision in legislation, statute, or regulation 
that would impose an enforceable duty upon State, local, or tribal 
governments, or the private sector, and includes both ``Federal 
intergovernmental mandates'' and ``Federal private sector mandates.'' 
These terms are defined in 2 U.S.C. 658(5)-(7). ``Federal 
intergovernmental mandate'' includes a regulation that ``would impose 
an enforceable duty upon State, local, or tribal governments'' with two 
exceptions. It excludes ``a condition of Federal assistance.'' It also 
excludes ``a duty arising from participation in a voluntary Federal 
program,'' unless the regulation ``relates to a then-existing Federal 
program under which $500,000,000 or more is provided annually to State, 
local, and tribal governments under entitlement

[[Page 26817]]

authority,'' if the provision would ``increase the stringency of 
conditions of assistance'' or ``place caps upon, or otherwise decrease, 
the Federal Government's responsibility to provide funding,'' and the 
State, local, or tribal governments ``lack authority'' to adjust 
accordingly. At the time of enactment, these entitlement programs were: 
Medicaid; Aid to Families with Dependent Children work programs; Child 
Nutrition; Food Stamps; Social Services Block Grants; Vocational 
Rehabilitation State Grants; Foster Care, Adoption Assistance, and 
Independent Living; Family Support Welfare Services; and Child Support 
Enforcement. ``Federal private sector mandate'' includes a regulation 
that ``would impose an enforceable duty upon the private sector, except 
(i) a condition of Federal assistance or (ii) a duty arising from 
participation in a voluntary Federal program.''
    The designation of critical habitat does not impose a legally 
binding duty on non-Federal Government entities or private parties. 
Under the Act, the only regulatory effect is that Federal agencies must 
ensure that their actions do not destroy or adversely modify critical 
habitat under section 7. While non-Federal entities that receive 
Federal funding, assistance, or permits, or that otherwise require 
approval or authorization from a Federal agency for an action, may be 
indirectly impacted by the designation of critical habitat, the legally 
binding duty to avoid destruction or adverse modification of critical 
habitat rests squarely on the Federal agency. Furthermore, to the 
extent that non-Federal entities are indirectly impacted because they 
receive Federal assistance or participate in a voluntary Federal aid 
program, the Unfunded Mandates Reform Act would not apply, nor would 
critical habitat shift the costs of the large entitlement programs 
listed above onto State governments.
    (2) We do not believe that this rule will significantly or uniquely 
affect small governments because the area included in the critical 
habitat designation is largely owned by Federal and State agencies 
(greater than 95 percent). None of these government entities fits the 
definition of ``small government jurisdiction.'' Consequently, we do 
not believe that the critical habitat designation would significantly 
or uniquely affect small government entities. As such, a Small 
Government Agency Plan is not required.

Takings--Executive Order 12630

    In accordance with E.O. 12630 (Government Actions and Interference 
with Constitutionally Protected Private Property Rights), we have 
analyzed the potential takings implications of designating critical 
habitat for the island marble butterfly in a takings implications 
assessment. The Act does not authorize the Service to regulate private 
actions on private lands or confiscate private property as a result of 
critical habitat designation. Designation of critical habitat does not 
affect land ownership, or establish any closures or restrictions on use 
of or access to the designated areas. Furthermore, the designation of 
critical habitat does not affect landowner actions that do not require 
Federal funding or permits, nor does it preclude development of habitat 
conservation programs or issuance of incidental take permits to permit 
actions that do require Federal funding or permits to go forward. 
However, Federal agencies are prohibited from carrying out, funding, or 
authorizing actions that would destroy or adversely modify critical 
habitat. A takings implications assessment has been completed and 
concludes that this designation of critical habitat for the island 
marble butterfly does not pose significant takings implications for 
lands within or affected by the designation.

Federalism--Executive Order 13132

    In accordance with E.O. 13132 (Federalism), this rule does not have 
significant federalism effects. A federalism summary impact statement 
is not required. In keeping with Department of the Interior and 
Department of Commerce policy, we requested information from, and 
coordinated development of this critical habitat designation with, 
appropriate State resource agencies in Washington. We did not receive 
comments from Washington Department of Fish and Wildlife. From a 
federalism perspective, the designation of critical habitat directly 
affects only the responsibilities of Federal agencies. The Act imposes 
no other duties with respect to critical habitat, either for States and 
local governments, or for anyone else. As a result, the rule does not 
have substantial direct effects either on the States, or on the 
relationship between the national government and the States, or on the 
distribution of powers and responsibilities among the various levels of 
government. The designation may have some benefit to these governments 
because the areas that contain the features essential to the 
conservation of the species are more clearly defined, and the physical 
and biological features of the habitat necessary to the conservation of 
the species are specifically identified. This information does not 
alter where and what federally sponsored activities may occur. However, 
it may assist these local governments in long-range planning (because 
these local governments no longer have to wait for case-by-case section 
7 consultations to occur).
    Where State and local governments require approval or authorization 
from a Federal agency for actions that may affect critical habitat, 
consultation under section 7(a)(2) will be required. While non-Federal 
entities that receive Federal funding, assistance, or permits, or that 
otherwise require approval or authorization from a Federal agency for 
an action, may be indirectly impacted by the designation of critical 
habitat, the legally binding duty to avoid destruction or adverse 
modification of critical habitat rests squarely on the Federal agency.

Civil Justice Reform--Executive Order 12988

    In accordance with Executive Order 12988 (Civil Justice Reform), 
the Office of the Solicitor has determined that the rule does not 
unduly burden the judicial system and that it meets the applicable 
standards set forth in sections 3(a) and 3(b)(2) of the Order. We are 
designating critical habitat in accordance with the provisions of the 
Act. To assist the public in understanding the habitat needs of the 
species, the rule identifies the elements of physical or biological 
features essential to the conservation of the island marble butterfly. 
The designated areas of critical habitat are presented on maps, and the 
rule provides several options for the interested public to obtain more 
detailed location information, if desired.

Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq.)

    This rule does not contain any new collections of information that 
require approval by the Office of Management and Budget (OMB) under the 
Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq.). An agency may 
not conduct or sponsor, and a person is not required to respond to, a 
collection of information unless it displays a currently valid OMB 
control number.

National Environmental Policy Act (42 U.S.C. 4321 et seq.)

    We have determined that environmental assessments and environmental 
impact statements, as defined under the authority of the National 
Environmental Policy Act

[[Page 26818]]

(NEPA; 42 U.S.C. 4321 et seq.), need not be prepared in connection with 
listing a species as an endangered or threatened species under the 
Endangered Species Act. We published a notice outlining our reasons for 
this determination in the Federal Register on October 25, 1983 (48 FR 
49244).
    It is our position that, outside the jurisdiction of the U.S. Court 
of Appeals for the Tenth Circuit, we do not need to prepare 
environmental analyses pursuant to NEPA in connection with designating 
critical habitat under the Act. We published a notice outlining our 
reasons for this determination in the Federal Register on October 25, 
1983 (48 FR 49244). This position was upheld by the U.S. Court of 
Appeals for the Ninth Circuit (Douglas County v. Babbitt, 48 F.3d 1495 
(9th Cir. 1995), cert. denied 516 U.S. 1042 (1996)).

Government-to-Government Relationship With Tribes

    In accordance with the President's memorandum of April 29, 1994 
(Government-to-Government Relations with Native American Tribal 
Governments; 59 FR 22951), Executive Order 13175 (Consultation and 
Coordination with Indian Tribal Governments), and the Department of the 
Interior's manual at 512 DM 2, we readily acknowledge our 
responsibility to communicate meaningfully with recognized Federal 
Tribes on a government-to-government basis. In accordance with 
Secretarial Order 3206 of June 5, 1997 (American Indian Tribal Rights, 
Federal-Tribal Trust Responsibilities, and the Endangered Species Act), 
we readily acknowledge our responsibilities to work directly with 
tribes in developing programs for healthy ecosystems, to acknowledge 
that tribal lands are not subject to the same controls as Federal 
public lands, to remain sensitive to Indian culture, and to make 
information available to tribes. We determined that there are no tribal 
lands occupied by the island marble butterfly at the time of listing 
that contain the physical or biological features essential to 
conservation of the species, and no tribal lands unoccupied by the 
island marble butterfly that are essential for the conservation of the 
species. Therefore, we are not designating critical habitat for the 
island marble butterfly on tribal lands.

References Cited

    A complete list of references cited in this rulemaking is available 
on the internet at http://www.regulations.gov and upon request from the 
Washington Fish and Wildlife Office (see FOR FURTHER INFORMATION 
CONTACT).

Authors

    The primary authors of this final rule are the staff members of the 
Washington Fish and Wildlife Office.

List of Subjects in 50 CFR Part 17

    Endangered and threatened species, Exports, Imports, Reporting and 
recordkeeping requirements, Transportation.

Regulation Promulgation

    Accordingly, we amend part 17, subchapter B of chapter I, title 50 
of the Code of Federal Regulations, as set forth below:

PART 17--ENDANGERED AND THREATENED WILDLIFE AND PLANTS

0
1. The authority citation for part 17 continues to read as follows:

    Authority: 16 U.S.C. 1361-1407; 1531-1544; and 4201-4245, unless 
otherwise noted.


0
2. Amend Sec.  17.11(h) by adding an entry for ``Butterfly, island 
marble'' to the List of Endangered and Threatened Wildlife in 
alphabetical order under ``INSECTS'' to read as follows:


Sec.  17.11  Endangered and threatened wildlife.

* * * * *
    (h) * * *

----------------------------------------------------------------------------------------------------------------
                                                                                          Listing citations and
           Common name              Scientific name      Where listed         Status         applicable rules
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------
                                                     INSECTS
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
Butterfly, island marble........  Euchloe ausonides   Wherever found....  E              85 FR [insert Federal
                                   insulanus.                                             Register page where
                                                                                          the document begins],
                                                                                          5/5/2020; 50 CFR
                                                                                          17.95(i).CH
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------


0
3. In Sec.  17.95, amend paragraph (i) by adding an entry for ``Island 
Marble Butterfly (Euchloe ausonides insulanus)'' in the same 
alphabetical order that the species appears in the table at Sec.  
17.11(h), to read as follows:


Sec.  17.95   Critical habitat--fish and wildlife.

* * * * *
    (i) Insects.
* * * * *
Island Marble Butterfly (Euchloe ausonides insulanus)
    (1) The critical habitat unit is depicted for San Juan County, 
Washington, on the map below.
    (2) Within the critical habitat area on San Juan Island, 
Washington, the physical or biological features essential to the 
conservation of the island marble butterfly consist of the following 
components:
    (i) Open, primarily treeless areas with short-statured forb- and 
grass-dominated vegetation that include diverse topographic features 
such as ridgelines, hills, and bluffs for patrolling, dispersal 
corridors between habitat patches, and some south-facing terrain. Areas 
must be large enough to allow for the development of patchy-population 
dynamics, allowing for multiple small populations to establish within 
the area.
    (ii) Low- to medium-density larval host plants, with both flower 
buds and blooms on them between the months of May through July, for 
egg-laying and larval development. Larval host plants may be any of the 
following: Brassica rapa, Sisymbrium altissimum, or Lepidium 
virginicum.
    (iii) Adult nectar resources in flower and short-statured, white-
flowering plants in bloom used for mate-finding, which may include, but 
are not limited to, Abronia latifolia (yellow sand verbena), Achillea 
millefolium (yarrow), Amsinckia menziesii (small-flowered fiddleneck), 
Cakile edentula (American sea rocket), Cerastium arvense (field 
chickweed), Erodium cicutarium

[[Page 26819]]

(common stork's bill), Geranium molle (dovefoot geranium), Hypochaeris 
radicata (hairy cat's ear), Lomatium utriculatum (common lomatium), 
Lupinus littoralis (seashore lupine), Myosotis discolor (common forget-
me-not), Ranunculus californicus (California buttercup), Rubus ursinus 
(trailing blackberry), Taraxacum officinale (dandelion), Toxicoscordion 
venenosum (death camas, formerly known as Zigadenus venenosus), and 
Triteleia grandiflora (Howell's brodiaea, formerly Brodiaea howellii).
    (iv) Areas of undisturbed vegetation surrounding larval host plants 
sufficient to provide secure sites for diapause and pupation. The 
vegetation surrounding larval host plants must be left standing for a 
sufficient period of time for the island marble butterfly to complete 
its life cycle.
    (3) Critical habitat includes road shoulders and road margins, but 
does not include other manmade structures (such as buildings, 
aqueducts, runways, paved portions of roads, and other paved areas) and 
the land on which they are located existing within the legal boundaries 
on June 4, 2020.
    (4) Critical habitat map unit. Data layers defining the map were 
created using 2015 National Agriculture Imagery Program (NAIP) digital 
imagery in ArcGIS, version 10.4 (Environmental Systems Research 
Institute, Inc.), a computer geographic information system program. The 
map in this entry, as modified by any accompanying regulatory text, 
establishes the boundaries of the critical habitat designation. The 
coordinates or plot points or both on which the map is based are 
available to the public at the Service's internet site at https://www.fws.gov/wafwo/, at http://www.regulations.gov at Docket No. FWS-R1-
ES-2016-0145, and at the field office responsible for this designation. 
You may obtain field office location information by contacting one of 
the Service regional offices, the addresses of which are listed at 50 
CFR 2.2.
    (5) Island marble butterfly critical habitat, San Juan County, 
Washington.
    (i) Island marble butterfly critical habitat consists of 812 acres 
(ac) (329 hectares (ha)) on San Juan Island in San Juan County, 
Washington, and is composed of lands in Federal (742 ac (301 ha)), 
State (37 ac (15 ha)), State/County joint (1 ac (0.4 ha)), County (30 
ac (12 ha)), and private (2 ac (0.8 ha)) ownership. The critical 
habitat designated on private parcels along Eagle Cove only includes 
the area of steep coastal bluff between the marine shoreline and the 
upland edge at the top of the bluff; it does not include areas landward 
of the top of the bluff, which are typically mowed and maintained as 
yard.
    (ii) Map of island marble butterfly critical habitat follows:
BILLING CODE 433-15-P

[[Page 26820]]

[GRAPHIC] [TIFF OMITTED] TR05MY20.000

* * * * *

    Signed:
Aurelia Skipwith,
Director, U.S. Fish and Wildlife Service.
[FR Doc. 2020-07856 Filed 5-4-20; 8:45 am]
BILLING CODE 4333-15-C