[Federal Register Volume 77, Number 171 (Tuesday, September 4, 2012)]
[Proposed Rules]
[Pages 54332-54352]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2012-21344]



[[Page 54331]]

Vol. 77

Tuesday,

No. 171

September 4, 2012

Part IV





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; 12-Month Finding on a 
Petition To List the Mardon Skipper as Threatened or Endangered; 
Proposed Rule

  Federal Register / Vol. 77 , No. 171 / Tuesday, September 4, 2012 / 
Proposed Rules  

[[Page 54332]]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R1-ES-2012-0060; 4500030113]


Endangered and Threatened Wildlife and Plants; 12-Month Finding 
on a Petition To List the Mardon Skipper as Threatened or Endangered

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of 12-month petition finding.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a 
12-month finding on a petition to list the mardon skipper (Polites 
mardon) as a threatened or endangered species under the Endangered 
Species Act of 1973, as amended (Act). After review of the best 
available scientific and commercial information, we find that listing 
the mardon skipper is not warranted at this time. However, we ask the 
public to submit to us any new information that becomes available 
concerning the threats to the mardon skipper or its habitat at any 
time. At our discretion, after additional review of the subspecies 
Polites mardon mardon and Polites mardon klamathensis, we find that 
listing for these subspecies is also not warranted at this time.

DATES: The finding announced in this document was made on September 4, 
2012.

ADDRESSES: This finding is available on the Internet at http://www.regulations.gov at Docket Number FWS-R1-ES-2012-0060. Supporting 
documentation we used in preparing this finding is available for public 
inspection, by appointment, during normal business hours at the U.S. 
Fish and Wildlife Service, Washington Fish and Wildlife Office, 510 
Desmond Drive SE., Suite 102, Lacey, WA 98503. Please submit any new 
information, materials, comments, or questions concerning this finding 
to the above address.

FOR FURTHER INFORMATION CONTACT: Ken Berg, Field Supervisor, Washington 
Fish and Wildlife Office (see ADDRESSES); by telephone at 360-753-9440; 
facsimile at 360-753-9008; or Paul Henson, Field Supervisor, Oregon 
Fish and Wildlife Office, 2600 SE 98th Avenue, Suite 100, Portland, OR 
97266; by telephone at 503-231-6179; facsimile at 503-231-6195 mailto:. 
If you use a telecommunications device for the deaf (TDD), please call 
the Federal Information Relay Service (FIRS) at 800-877-8339.

SUPPLEMENTARY INFORMATION:

Background

    Section 4(b)(3)(B) of the Act (16 U.S.C. 1531 et seq.), requires 
that, for any petition to revise the Federal Lists of Endangered and 
Threatened Wildlife and Plants that contains substantial scientific or 
commercial information that listing the species may be warranted, we 
make a finding within 12 months of the date of receipt of the petition. 
In this finding, we will determine that the petitioned action is: (1) 
Not warranted, (2) warranted, or (3) warranted, but the immediate 
proposal of a regulation implementing the petitioned action is 
precluded by other pending proposals to determine whether species are 
threatened or endangered species, and expeditious progress is being 
made to add or remove qualified species from the Federal Lists of 
Endangered and Threatened Wildlife and Plants. Section 4(b)(3)(C) of 
the Act requires that we treat a petition for which the requested 
action is found to be warranted but precluded as though resubmitted on 
the date of such finding, that is, requiring a subsequent finding to be 
made within 12 months. We must publish these 12-month findings in the 
Federal Register.

Previous Federal Actions

    On October 25, 1999, the Service identified the mardon skipper 
(Polites mardon) as a candidate species for listing under the Act (64 
FR 57539). The identification of the mardon skipper as a candidate 
species was based on information compiled in the Washington State 
Status Report for the Mardon Skipper (Potter et al. 1999, entire).
    On December 11, 2002, we received a petition dated December 10, 
2002, from The Xerces Society, Gifford Pinchot Task Force, The 
Northwest Environmental Defense Center, Center for Biological 
Diversity, Oregon Natural Resources Council, Friends of the San Juans, 
and Northwest Ecosystem Alliance (petitioners), requesting that the 
mardon skipper be listed as an endangered species, and that critical 
habitat be designated under the Act (Black et al. 2002, entire). 
Included in the petition was supporting information regarding the 
species' taxonomy and ecology, historical and current distribution, 
present status, and actual and potential causes of decline. We 
acknowledged the receipt of the petition in a letter to the 
petitioners, dated January 22, 2003. In that letter we also stated that 
the Service considered the mardon skipper as having been subject to 
both a positive 90-day finding and a ``warranted but precluded'' 12-
month finding, with the Candidate Notice of Review constituting 
publication of these required findings. The Service's ``warranted but 
precluded'' finding was based on limited funding that was dedicated to 
court-ordered or other higher-priority listings.
    From 2003 to 2011, the Service continued to work with Federal, 
State, and private parties to compile information on the status and 
distribution of the mardon skipper, which is documented in the 
Service's candidate species assessment forms for those years. 
Substantial new information was collected regarding mardon skipper 
populations, distribution, and habitat requirements. In 2009, we 
changed the listing priority number for the mardon skipper from 5 to 8 
(lower priority) due to the documentation of many new populations and 
increased protections for the species and its habitat provided by State 
and Federal special status species programs.
    In a settlement agreement with plaintiff WildEarth Guardians, on 
May 10, 2011, the Service submitted a workplan to the U.S. District 
Court for the District of Columbia in re Endangered Species Act Section 
4 Deadline Litigation, No. 10-377 (EGS), MDL Docket No. 2165 (D. DC May 
10, 2011), and obtained the court's approval to systematically, over a 
period of 6 years, review and address the needs of more than 250 
candidate species to determine if they should be added to the Federal 
Lists of Endangered and Threatened Wildlife and Plants. The mardon 
skipper is one of 251 candidate species identified in the May 2011 
workplan. On October 26, 2011, the Service published the intent to 
develop a proposed listing for several candidate species in the Puget 
Sound prairie region (including the mardon skipper) with funding 
allocated in Fiscal Year 2011 (76 FR 66830). We have since determined 
that, as the distribution of the mardon skipper includes additional 
habitat other than prairie, the public would be better served 
evaluating this information and the species, separately.
    This notice constitutes our 12-month finding on the mardon skipper. 
Substantial new information regarding the mardon skipper has been 
compiled since we originally advanced the species to candidacy. 
Therefore, this finding considers information presented in the 2002 
petition, as well as new information compiled over the past decade.

[[Page 54333]]

Species Information

    The mardon skipper is a small (20 to 24 millimeters; less than 1 
inch), tawny-orange butterfly with a stout, hairy body. The upper 
surface of the forewings and hindwings is orange with broad dark-brown 
borders, and the ventral hindwings have a distinctive pattern of light 
yellow to white rectangular spots (Pyle 2002, p. 88). Males are smaller 
than females, and have a small, dark-brown, slender and branched streak 
(stigma) on the upper surface of the forewing. Females have a more 
distinct ventral hindwing pattern. The mardon skipper is differentiated 
from other closely related Polites species by its short, rounded wings, 
reduced stigmal elements, and other distinctive morphological features 
(MacNeill 1993, p. 179). Like most Hesperiinae butterflies, mardon 
skippers have bent antennae clubs and a characteristic basking posture 
in which the forewings are held at a 45-degree angle and the hind wings 
are fully spread (Potter et al. 1999, p. 1).

Taxonomy and Species Description

    The mardon skipper is a butterfly in the Order Lepidoptera 
(butterflies and moths), superfamily Hesperioidae, and family 
Hesperiidae (skippers), subfamily Hesperiinae (grass skippers). It was 
originally described by W. H. Edwards (1881, pp. 47-48) as Pamphila 
mardon from three males and three females collected by H.K. Morrison in 
1880. The original type locality, stated by W.H. Edwards as Mount Hood, 
Oregon, was later correctly designated as small prairies near Puget 
Sound, Washington (Morrison 1883, p. 43). This type location was 
further defined as ``Tenino Prairie, Thurston County, Washington'' by 
Brown and Miller (1980, p. 53). The mardon skipper is a rare species 
that occurs in four disjunct areas that include locations near the 
coast in northwestern California and southwestern Oregon, the southern 
Oregon Cascades, the southern Washington Cascades, and prairies in the 
south Puget Sound region (James and Nunallee 2011, p. 388).
    In 1998, Mattoon et al. (p. 768) proposed that the Oregon Cascade 
populations be given subspecies status as Polites mardon klamathensis, 
and the Washington and northern California populations be given 
subspecies status as Polites mardon mardon. Adults of P.m. klamathensis 
are described as having a consistently tawnier dorsal and ventral 
coloration when compared to adults from other populations (Mattoon et 
al. 1998, pp.771-772).
    The distinction between Polites mardon klamathensis and P.m. mardon 
was based largely on comparisons between specimens collected in 
northwestern California and the southern Oregon Cascades. According to 
Warren (2005, p. 49), the use of the name P.m. mardon for California 
populations should be considered tentative because the series of P.m. 
mardon from the northwestern California (and coastal southwestern 
Oregon) populations have not yet been carefully compared to the series 
of P.m. mardon from Washington due to the small number of specimens 
available for evaluation (Mattoon et al. 1998, p. 771). The Catalogue 
of the Butterflies of the United States and Canada (Pelham 2008, p. 78) 
lists the full species followed by both subspecies. However, in the 
introduction of his Catalogue, Pelham (2008, p. VII) notes that the 
subspecies category is used without regard to its validity. No 
additional taxonomic work or genetic analyses have been done to clarify 
the subspecific designations described above (Kerwin 2011, p. 10). 
Polites mardon is recognized as a valid species by the Integrated 
Taxonomic Information System (ITIS) while P.m. klamathensis and P.m. 
mardon are recognized as valid subspecies (ITIS 2011, P. mardon, 
entire). For the purposes of this finding, we first analyzed the 
threats to the species Polites mardon as a whole. We then, at our 
initiative, further considered the threats to each of the currently 
recognized subspecies: P.m. mardon and P.m. klamathensis.

Distribution

    The mardon skipper is a rare northwestern butterfly with a 
remarkably disjunct range. The species' current range is known from 
four widely separated locations: the south Puget Sound region of 
Washington, the southern Washington Cascades, the Cascade Mountains of 
southern Oregon, and coastal hills in northwestern California and 
southwestern Oregon (Kerwin 2011, pp. 8-9). The historical range and 
abundance of mardon skippers are unknown. The species was originally 
described from specimens collected at a south Puget Sound prairie site 
in 1880 (Morrison 1883, p. 43), but there are few historical records or 
museum collections of this species (Potter et al. 1999, p. 3). No 
estimates of abundance are available from any site prior to 1980 
(Potter et al. 1999, p. 5).
    The mardon skipper's disjunct distribution and strong association 
with early-seral, semi-mesic grassland habitats in the Pacific 
Northwest suggest a relict distribution that was likely much more 
widespread in the past. Both Pyle (2002, p. 89) and Runquist (2004a, p. 
6) suggest that the mardon skipper is an ancient species. The species' 
short, rounded wing morphology is not adapted to long-distance 
dispersal. The apparent lack of intervening populations between the 
distinct geographic areas suggests the species probably evolved under 
more open, contiguous environmental conditions (Runquist 2004a, p. 6). 
Populations in each disjunct geographic region have likely become 
isolated over long geologic time scales, as evidenced by the subspecies 
distinction between Polites mardon mardon and P. m. klamathensis. It is 
likely that mardon skippers were historically more widespread within 
each disjunct geographic region prior to the widespread loss of 
grassland and montane meadow habitats due to fire suppression, invasive 
species, and development over the past century (Potter et al. 1999, p. 
5, Beyer and Schultz 2010, p. 863; Schultz et al. 2011, p. 370).
    In this assessment we use the term ``site'' to indicate a specific 
location with species presence. Sites are usually mapped as distinct 
habitat patches, such as individual meadows in summary reports (e.g., 
Black et al. 2010, p. 25). Sites may include locations with a single 
mardon skipper observation, or locations that support many mardon 
skippers observed over multiple years. Sites are variable, and not all 
reports define sites the same way. For purposes of estimating the 
number of populations, occupied meadows can be considered to belong to 
the same population if the sites are within the annual dispersal 
distance for the species, generally assumed to be 0.5 mi (0.8 km) or 
less (Potter and Fleckenstein 2001, p.6). In this assessment we use the 
term ``populations'' to represent local clusters of sites that we 
assume are likely to be associated and function as a local population.

Summary of Mardon Skipper Current Range and Distribution

    In 1999, the mardon skipper was known from approximately 14 extant 
sites located in four distinct geographic areas (Potter et al. 1999, 
p.5). Targeted surveys from 2000 through 2011 have documented a total 
of 165 sites with mardon skipper presence representing approximately 66 
populations (Table 1). New sites or populations have been documented in 
each year that surveys have been completed. For example, five new sites 
were documented in 2011, including four sites in the Washington 
Cascades, and one site in the southern

[[Page 54334]]

Oregon Cascades. It is very likely that additional undocumented sites 
exist, particularly in the Washington Cascades and possibly in 
southwestern Oregon or northwestern California, because not all of the 
potential habitat areas have been surveyed. The increase in known 
populations since 1999 is due to increased survey effort in areas not 
previously surveyed, rather than to increased habitat or expanding 
populations (Kerwin 2011, p. 18). The majority (76 percent) of the 
sites throughout the species' range occur on Federal lands managed by 
the Forest Service, Bureau of Land Management (BLM), National Park 
Service, Fish and Wildlife Service, and the Department of Defense, as 
well as Tribal lands owned by the Yakama Indian Reservation (17 
percent). Due to the species' disjunct distribution, the populations in 
different geographic regions are relatively isolated, with two 
recognized subspecies Polites mardon mardon and P.m. klamathensis, 
occurring within the species' range.

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                                                                                    Approximate
                                                                                     number of      Approximate
                                                                                    documented       number of
             Geographic region                          Site ownership              sites with      populations
                                                                                      species         (local
                                                                                     presence       clusters of
                                                                                    (2000-2011)       sites)
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                                              Polites mardon mardon
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Washington--South Puget Sound Prairies       Joint Base Lewis McChord--Dept. of                4               1
 (Pierce and Thurston Counties).              Defense.
                                             Washington Dept. of Fish & Wildlife               2               2
Washington--South Cascades (Yakima,          Wenatchee National Forest..........              36              15
 Klickitat, and Skamania Counties).          Gifford Pinchot National Forest....              43              13
                                             Conboy Lake National Wildlife                     3               3
                                              Refuge.                                         23              11
                                             Yakama Indian Reservation..........               6               4
                                             Private ownership..................
Southwest Oregon--Curry County.............  BLM--Coos Bay District.............               2               1
                                             Rogue River Siskiyou National                     3               1
                                              Forest.
                                             Oregon State Parks.................               1
Northwest California--Del Norte County.....  Six Rivers National Forest.........               8               2
                                             Redwood National Park..............               9               1
                                             Private ownership..................               3               1
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                                           Polites mardon klamathensis
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Oregon--South Cascades Jackson County......  BLM Medford District...............              15               9
                                             Rogue River Siskiyou National                     4               2
                                              Forest.
                                             Private ownership..................               3  ..............
                                            --------------------------------------------------------------------
    Totals.................................  ...................................             165             66
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Note: In this assessment we use the term ``sites'' for specific locations with documented species presence (some
  of which are single observations) and ``populations'' to represent local clusters of sites that we assume are
  likely to be closely associated and function as a local population.

Summary of Mardon Skipper Population Estimates and Trends

    Estimates of population sizes or population trends over time for 
mardon skippers are generally not available. Surveys to estimate 
relative abundance of mardon skippers are conducted by systematically 
walking transects through a site and counting the number of adult 
mardon skippers encountered (Seitz et al. 2007, p. 11). The majority of 
survey efforts have been 1-day counts, so it is not known if they were 
conducted early or late in the adult flight period. Multiple surveys 
during the flight season and across a number of years are required to 
assess population sizes because the timing and length of adult flight 
periods can vary widely from year to year (Kerwin 2011, p. 19).
    A few surveyors have used line-transect distance-sampling methods 
to estimate mardon skipper populations, but these techniques have 
generally failed to provide statistically reliable estimates at sites 
with small populations (Runquist 2004b, p. 4, Arnold 2006, p. 6). 
Runquist (2004a, pp. 4-5) used both line-transect sampling and mark-
recapture sampling techniques to estimate a mardon skipper population 
in a small complex of three meadows in the Oregon Cascades. Researchers 
counted a total of 172 mardon skippers on all line-transects over all 
days, compared with a total of 238 mardon skippers that were captured 
and marked in the same meadows during the same period (Runquist 2004a, 
p. 5). No statistically reliable estimates of the actual population 
size were derived from this effort, but the author opines that a total 
population estimate of 350-400 individuals would be reasonable at this 
site based on his observations (Runquist 2004a, p. 5).
    Line-transect distance sampling was used to census mardon skippers 
across approximately 800 acres (ac) (324 hectares (ha)) of Puget 
prairie habitat in 2009, and provided the first statistically reliable 
estimates of the mardon skipper populations at these sites (Potter 
2010, p. 4). At the Scatter Creek Wildlife Area in 2009, the population 
estimate during the peak of the adult flight period was 801 mardon 
skippers at the South Unit (95 percent confidence interval = 399-1,286 
skippers) and 204 at the North Unit (95 percent confidence interval = 
84-360) (Potter 2010, p. 4). These estimates were derived from actual 
counts of 312 skippers on the South Unit and 93 skippers on the North 
Unit (Potter 2009, p. 1). This was the most comprehensive survey effort 
at this site to date, so the results of the survey are not directly 
comparable to previous monitoring efforts at this site (Potter 2009, p. 
2), but this population appears to be relatively stable based on counts 
conducted between 1997 and 2009 (Potter et al. 1999, p. 6; Harke 2001, 
p. 12; Potter 2009, p. 1).
    Only one site (in Washington) has had a full spectrum of censuses 
that have covered the entire adult flight period (Beyer and Black 2007, 
p. 8). In 2006, the counts at this site (Grapefern Meadow) went from 0 
mardon skippers counted on July 6, to 135 on July 9; 345

[[Page 54335]]

on July 16; 128 on July 23; and 2 on August 4 (Beyer and Black 2007, p. 
8). These counts demonstrate that the number of mardon skippers present 
at a site can fluctuate significantly over a few days. The observed 
mardon skipper population at this site has fluctuated greatly over the 
past decade, with peak counts ranging from 420 butterflies in 2004 to 
34 in 2011. Although there have been high counts of butterflies from 
time to time, overall the populations on the Wenatchee National Forest 
and Gifford Pinchot National Forest appear to be relatively stable. 
Data from the Wenatchee National Forest show some evidence of trends 
related to elevation, with lower elevation population sites (less than 
3,300 feet (ft) [1,000 meters (m)]) appearing to be stable, and mid-
elevation sites (3,500-4000 ft [1,067-1,220 m]) showing some local 
declines, likely associated with cool, wet summer conditions (St. 
Hilaire et al. 2010, p. 2).
    In the Oregon Cascades, limited population information for Polites 
mardon klamathensis is available, as few multiple-day surveys have been 
conducted here. Black et al. (2010, Appendix 1) report single-day 
counts for multiple P.m. klamathensis sites over a 5-year period, 
spanning 2005-2010 (there were no counts for most sites in 2008). In 
2011, one new P.m. klamathensis site was located on Bureau of 
Reclamation Lands managed by BLM (Black 2012, pers. comm.). Although 
several of the P.m. klamathensis sites appear to be small in size 
(fewer than 20 individuals), only a handful of these sites had counts 
on more than a single day in a year, and even in these few cases there 
were never more than 2 days of counts in any single year (Black et al. 
2010, Appendix 1). Furthermore, the dates for these counts range quite 
widely from one year to the next, from early or mid-June through the 
first week of July, so whether these counts occurred within the peak 
flight period is unclear. For example, as described above for Grapefern 
Meadow in Washington, the only site where we have data from mardon 
skipper counts over the entire adult flight period, the numbers of 
skippers counted on any single day ranged anywhere from 0 to 345 over a 
10-day period (Beyer and Black 2007, p. 8). This high variability in 
potential counts shows why single-day counts are not a credible means 
of determining population abundance or trend. Of the known sites for 
the subspecies, most have had relatively few individuals counted on any 
single day over the period 2005 through 2010, but it is not known 
whether the observed numbers may represent an increase or decrease over 
historical levels. One site, Pumpchance 125 Meadow, has generally had 
relatively high numbers of P.m. klamathensis over 5 years of single-day 
counts (up to 304 individuals counted in 2009); historical abundance of 
mardon skippers is not known at this site. On the other hand, the three 
sites that make up the Hobart Peak complex, the one site where 
historical abundance information is available, appear to have lower 
numbers of P. m. klamathensis than observed in the past (Black et al. 
2010, Appendix 1). In general, however, based on the lack of historical 
abundance information and the uncertainty accompanying individual day 
counts, we are unable to determine population trends for P.m. 
klamathensis.
    Recent monitoring at Coon Mountain in California found lower 
numbers of mardon skippers in areas treated with prescribed burning 
compared to unburned areas in 2008. Three years after the burn event, 
mardon skipper numbers were still lower in burned areas than in 
unburned areas, but the overall population at this site appears to be 
stable (Black et al. 2011, p. 13). Monitoring efforts at other sites in 
California have been inconsistent, but the limited data for the 
historical sites at High Divide Ridge indicate this population is 
potentially stable within the limited suitable habitat areas present at 
these sites.
    Mardon skippers can be locally abundant where the species is 
present (Pyle 1989, p. 28) with day counts of greater than 100 
individuals documented at several sites across the species' geographic 
range (Black et al. 2010, pp. 70-71; St. Hilaire et al. 2010, pp. 10-
12; Black et al. 2011, p. 13). Conversely, populations at many 
locations within the species' range are apparently persisting at very 
low levels with consistent peak counts of fewer than 20 individuals.
    Documented extirpations occurred at five Puget Prairies sites from 
1985 through 1999, resulting in a local contraction of the species' 
range in that region (Potter et al. 1999, p. 6). Extirpation at one 
historical site in the Washington Cascades has been documented (Potter 
et al. 1999, p. 4), but there are at least three other extant 
populations in the vicinity of this historical site at the Conboy Lake 
National Wildlife Refuge, including a newly documented population in 
2011 (USFWS unpublished data). Black et al. (2010, p. 7) state that 
some Polites mardon klamathensis sites in the Oregon Cascades may 
possibly be extirpated; however, they also stress that more monitoring 
is needed to confirm this supposition. No historical data is available 
at these sites prior to 2005, and many of these sites appear to have 
always had very low numbers of individuals according to single-day 
counts (Black et al. 2010, pp. 70-72). Black et al. (2010, p. 7) 
additionally note that there are cases where one individual mardon 
skipper may have been found in past years but not in subsequent 
surveys, but such instances may represent errant findings and are not 
indicative of sites or popultions that have become extirpated.
    With the apparent exception of a few Polites mardon klamathensis 
populations where more monitoring is needed, and a few higher-elevation 
P. m. mardon sites in the Washington Cascades, most mardon skipper 
populations now appear to be stable across the species' range.

Habitat

    Mardon skippers are grass skippers in the subfamily Hesperiinae, 
meaning the larvae feed strictly on graminoids (grasses and sedges) 
(Scott 1986, p. 424). The mardon skipper's habitat requirements include 
food resources for adults (flower nectar), larval host plants (grasses 
and sedges), and site-specific environmental and structural conditions 
that support successful reproduction and survival. This includes 
patches of early-seral open grassland habitat that are dominated by 
short-statured grasses or sedges and forbs that are generally free of 
overstory trees and shrubs. Mardon skippers generally avoid areas with 
tall grasses, shrubs, or trees (Henry 2010, p. 44). Grassland patches 
that are as small as 0.5 ac [0.2 ha] are capable of supporting small 
populations of mardon skippers. However, most areas that support 
populations of mardon skippers consist of mixed forest-grassland 
complexes that support multiple occupied ``sites'' with some 
connectivity between habitat patches for successful dispersal and 
movement of individuals among sites.
    The species' larval development is prolonged, lasting for 3 months 
or more prior to diapause (Newcomer 1966a, p. 246; Henry 2010, p. 5). 
During this time the larvae require succulent grasses for successful 
development. Occupied sites retain sufficient moisture to maintain host 
plant palatability (green leaves) for larval development (Beyer and 
Black 2007, p. 18; Kerwin 2011, p. 21). Meadows that are too wet or too 
dry do not support mardon skippers. Site conditions and host plants 
selected by mardon skippers vary across sites, indicating the species 
is capable of using multiple graminoids as larval food (Beyer and 
Schultz 2010, p. 867).

[[Page 54336]]

Although mardon skippers are not selective for a specific grass 
species, they do exhibit host plant specificity within some localities 
(Beyer and Schultz 2010, p. 869; Henry 2010, p. 15).

South Puget Sound Prairies

    In the south Puget Sound region of Washington, mardon skippers are 
found in low-elevation (200-300 ft [60-90 m]), glacial outwash 
grasslands (prairies) with abundant Festuca roemeri (Roemer's fescue) 
interspersed with Viola adunca (early blue violet) (Potter et al. 1999, 
p. 5). Occupied prairies range in size from 300 to greater than 1,000 
ac [120 to more than 400 ha]. Mardon skippers oviposit (lay eggs) on 
Roemer's fescue almost exclusively at Puget prairie sites, indicating a 
very strong association with this grass species (Henry 2010, p. 13). 
Roemer's fescue is a perennial bunchgrass native to the Pacific 
Northwest. Although Roemer's fescue accounted for 50 percent of the 
total grass cover at the sampled locations, mardon skippers selected 
this species in 86 out of 88 observed ovipositions (Henry 2010, p. 
13.). In addition to the presence of the host plants, the structure of 
the surrounding plant community is also important for oviposition 
selection (Henry 2010, p. 16). Mardon skippers selected small, green 
(live) fescue tufts in areas with at least 50 percent open moss cover 
on the surrounding ground (Henry 2010, p. 16). Mardon skippers avoid 
areas that are heavily invaded with Arrhenatherum elatius (tall 
oatgrass) and Cytisus scoparius (Scot's broom) (Henry 2010, p. 44). The 
oviposition habitat requirements of mardon skippers in Puget prairies 
are distinct from those of populations in the southern Washington 
Cascades (Henry 2010, p. 19).
    At Puget prairie sites, early blue violet and Vicia sativa (common 
vetch) are strongly preferred as nectar sources, and Scot's broom is 
strongly avoided (Hays et al. 2000, p. 14). Nectaring was also observed 
on Camassia quamash (common camas), Lomatium utriculatum (fine-leaved 
desert parsley), Teesdalia nudicaulis (barestem teesdalia), and 
Ranunculus occidentalis (western buttercup) (Hays et al. 2000, p. 24).

Southern Washington Cascades

    In the southern Washington Cascades, the mardon skipper is found in 
open grasslands and small montane meadows within Abies grandis (Grand 
fir), Psuedotsuga menziesii (Douglas-fir), or Pinus contorta (lodgepole 
pine)/mixed-conifer woodlands at mid to high elevations (1,800 to 5,600 
ft [549 to 1,707 m]) (Potter et al. 2002, p. 12). Occupied sites in the 
Washington Cascades vary in size from small (0.5 ac [0.2 ha]) meadows 
to large forest/meadow complexes encompassing hundreds of acres. Site 
conditions range from relatively dry, ridgetop meadows to small montane 
meadows associated with wetlands, springs, or riparian habitat (Potter 
et al. 2002, p. 13). Wetland areas that are perennially submerged do 
not support mardon skippers, but the species is often found in dry 
transitional zones along the margins of wetlands. Water features such 
as small streams or wetlands are common at many Washington Cascades 
sites (Kerwin 2011, p. 20). Alpine meadows (more than approximately 
6,000 ft [1,829 m] elevation) apparently do not support this species, 
perhaps due to the relatively short season these areas are free from 
snow cover. Sites with grassland vegetation, including grassy forest 
openings, roadside meadows, and young, grass-dominated tree plantations 
support mardon skipper populations (Potter et al. 2002, pp. 12-13).
    In the Washington Cascades, oviposition has been documented on 23 
different graminoid species (Beyer and Schultz 2010, p. 866). However, 
this analysis indicated that mardon skippers are selective for certain 
grass species within different meadows. The most frequently used 
oviposition plants include Festuca idahoensis (Idaho fescue), Poa 
pratensis (Kentucky bluegrass), Danthonia intermedia (timber oatgrass), 
Carex inops (long-stolen sedge), and Festuca rubra (red fescue) (Beyer 
and Schultz 2010, p. 866). Danthonia unispecta (one-spiked oatgrass) 
appears to be an important grass species at sites on the Wenatchee 
National Forest. Females have been observed ovipositing on this species 
(Jepsen et al. 2008, p. 3), and higher densities of adult butterflies 
are commonly associated with patches of D. unispecta (St. Hilaire et 
al. 2009, p. 7). The variety of identified oviposition plants suggests 
that females may not always oviposit on specific host plants, but 
within a community of possible species that can be used by the larvae 
(Beyer and Black 2007, p. 5). These findings are significantly 
different from the observations at Puget prairies sites, which 
indicated mardon skippers were strongly associated with a single grass 
species (Henry 2010, p. 19).
    Due to the range of plant communities present at Washington 
Cascades sites, there were no common habitat features across all study 
sites other than the presence of short-statured grasses and sedges 
(Beyer and Schultz 2010, pp. 869-870). Mardon skippers selected for 
larger graminoids with greater total cover and less bare ground 
selection was also negatively influenced by the presence of trees, 
indicating a preference for selecting oviposition sites away from trees 
and forest edges (Beyer and Schultz, p. 869). Studies of mardon skipper 
densities within individual meadows also demonstrated that mardon 
skippers are patchily distributed within occupied sites, with the 
highest densities tending to occur near the center of a meadow away 
from forested edges (Beyer and Black 2007, p. 18).
    In the Washington Cascades, adults have most frequently been 
observed nectaring on vetch, Fragaria spp. (strawberry), and Trifolium 
spp. (clover) (Beyer and Black 2007, p. 15). Erysimum asperum 
(wallflower), Erigeron peregrinus (fleabane), Calochortus spp. (sego 
lily), and Achillea millefolium (yarrow) are also reported as nectar 
sources from this region (Beyer and Black 2007, p. 15; Potter and 
Fleckenstein 2001, p. 6).

Southern Oregon Cascades

    Populations of Polites mardon klamathensis in southern Oregon 
occupy small (0.5 to10 ac [0.25 to 4 ha]), high-elevation (4,500 to 
5,100 ft [1,372 to 1,555 m]) grassy meadows within mixed-conifer 
forests that are associated with an ephemeral or permanent water source 
such as a stream or wetland (Black et al. 2010, pp. 6-7). As seen at 
many sites in Washington, mardon skippers in the Oregon Cascades are 
typically found along the margins of forest wetlands in the narrow 
transitional zone along the edge of a water feature and the adjacent 
dry uplands (Kerwin 2011, p. 21).
    Occupied sites are dominated by short-statured grass/sedge 
communities. In the Oregon Cascades, the most common oviposition plant 
was Danthonia californica (California oatgrass) (Beyer and Black 2007, 
p. 6). Other species selected for oviposition were red fescue, Roemer's 
fescue, Kentucky bluegrass, Deschampsia cespitosa (tufted hairgrass), 
and Carex spp. (sedges) (Beyer and Black 2007, p. 6). The primary 
nectar plants being utilized are Potentilla diversifolia (diverse-
leaved cinquefoil), Wyethia angustifolia (narrow-leaved mule's ears), 
Penstemon procerus (small-flowered penstemon), and Plectritis congesta 
(sea blush) (Beyer and Black 2007, p. 16).

[[Page 54337]]

Coastal Northwest California/Southwest Oregon

    The coastal populations of Polites mardon mardon are found in small 
meadows (0.5-5 ac [0.2-2 ha]) dominated by Idaho fescue in sparse Pinus 
jeffreyi (Jeffrey pine) forests in extreme northwestern California and 
southwestern Oregon. Sites are located in coastal hills approximately 7 
to 15 miles (11 to 24 km) inland from the Pacific coast, at elevations 
ranging from approximately 1,500 to 3,000 ft (427 to 854 m). These 
sites are within the coastal fog belt (Mattoon et al. 1998, p. 771). 
Meadow habitats at these sites are associated with the western extent 
of serpentine-based soils in the region (Imper 2003, p. 4), and are 
more mesic (moist) than typical serpentine grasslands found in 
northwestern California (Imper 2003, p. 4). Ross (2010, p. 1) notes 
that the coastal Oregon mardon skipper sites are associated with 
serpentine-based soils supporting moist-to-dry transitional meadow 
habitats with abundant bunchgrasses.
    The most detailed description of vegetation for sites in this area 
is for the High Divide Ridge sites (Imper 2003, pp. 4-5). Both Idaho 
fescue and California oatgrass are common at these sites (Imper 2003, 
p. 5) and are likely used as host plants for oviposition and larval 
food. No oviposition or habitat selection studies have been completed 
for these populations, but Runquist (2004b, p. 2) observed females 
ovipositing on Festuca spp. at High Divide sites. The most commonly 
selected nectar plants at California sites are Phlox diffusa (spreading 
phlox) and Viola adunca (early blue violet; Arnold 2006, pp. 6-7). 
Detailed observations of mardon skipper behavior including oviposition, 
plant selection, and adult nectar species have not been reported for 
the coastal Oregon sites. Ross (2008, p. 9) noted observing mardon 
skippers nectaring on Viola spp. and Calochortus spp. at a coastal 
Oregon site.

Biology

    Mardon skippers are univoltine, completing one life cycle annually 
(i.e., egg-larva-pupa-adult). Adults typically emerge between May and 
July, depending upon location and elevation of the site, with adults in 
higher elevation sites emerging later. Adults do not all emerge on the 
same date, so flight period duration at any given site depends in part 
on the number of skippers present. In 2007, at one Washington site, 
Beyer and Black (2007, p. 8) note that adult emergence went from 0 
adults on July 6 to 135 adults on July 9. In large populations the 
flight period may extend for over a month, while small populations may 
have adults present for only 10 or fewer days (Potter et al. 2002, p. 
11). Within the same geographic area, emergence dates vary with 
elevation, with emergence occurring earlier at lower elevations. 
Weather influences emergence and flight period duration. Wet or cold 
conditions delay emergence; conversely, warm, dry conditions promote 
earlier emergence, and both may affect the duration of the adult flight 
period (Potter et al. 2002, p. 11).
    Mark-recapture experiments indicate adults can live up to 3 weeks 
(Runquist 2004a, p. 5), but most adults live only 7 to 9 days (Scott 
1986, p. 25). During their brief life as adult butterflies, mardon 
skippers feed on flower nectar, mate, and lay eggs on grasses or sedges 
(see Habitat Requirements for details). As with many butterfly species, 
males are often observed ``puddling'' or congregating on wet soils 
(Scott 1986, p. 68). During periods of adverse weather, mardon skippers 
seek shelter low in the vegetation, under grass or forbs. Mardon 
skippers generally fly low to the ground, often hovering over low 
grasses and forbs, or darting from place to place with a fast skipping 
flight. Mardon skippers are non-migratory. Adults generally disperse 
distances of up to 0.25 mile (mi) (0.4 kilometers [km]) over relatively 
short periods, but there appears to be very little dispersal beyond 
their natal meadow complexes (Runquist 2004a, p. 5). On occasion, 
individual males have been detected up to 1 mi (1.6 km) away from their 
original location (Runquist 2004a, p. 5). Mardon skippers have not been 
observed flying through closed-canopy forest, but they have been 
observed along open corridors such as powerlines or roads with nectar 
sources (Potter and Fleckenstein 2001, p. 6).
    After mating, females deposit their eggs (oviposit) singly into 
tufts of low-growing grasses or sedges (host plants) (James and 
Nunnalle 2011, p. 388). The total number of eggs laid in the wild is 
unknown, but Newcomer (1966a, p. 243) observed about 25 eggs per female 
for captive Polites, and James and Nunnallee (2011, p. 388) note that 
two captive females produced 21 eggs total. Eggs hatch in 7 to 10 days 
(Newcomer 1966a, p. 244; Henry 2010, p. 5). After hatching, the larvae 
feed on host grasses or sedges throughout the summer and into the fall 
months (Beyer and Black 2007, p. 19, Henry 2010, p. 14). Larvae use 
silk to construct a grass ``nest'' and emerge from this shelter to feed 
on the tender edges or leaf tips of host grasses (James and Nunallee 
2011, p. 388). These nests are tube-like structures up to 0.78 inches 
(in) (2 centimeters [cm]) long that are oriented either vertically or 
horizontally at the base of the host plant (Beyer and Black 2007, p. 
17). It does not appear that the larvae disperse away from the oviposit 
location (Beyer and Black 2007, p. 17). Henry (2010, p. 14) found six 
larvae at a Puget prairie site in September 2009, confirming that 
larvae feed on the same plants that the females had selected during 
oviposition (Henry 2010, p. 14). There are five instars (stages) of 
larval development, followed by the formation of a pupa and emergence 
as an adult butterfly (James and Nunallee 2011, p. 388).
    Captive-rearing efforts suggest that mardon skipper larvae 
overwinter as pupae (Newcomer 1966a, p. 246; James and Nunalle 2011, p. 
388), but field observations indicate that the larvae overwinter in 
diapause, and feed again in the spring before pupating (Henry 2009, p. 
2; Henry 2010, p. 5). Beyer and Black (2007, p. 19) found larvae 
present at a Washington Cascades site as late as October 21, and Henry 
(2009, p. 2) found larvae at a Puget prairie site in November and 
February. This aspect of mardon skipper life history is not well 
understood. Some captive-reared larvae developed quickly, forming a 
pupa and eclosing (emerging) as adults in the fall (which is not known 
to occur in the wild), while other captive-reared larvae overwintered 
as pupa (James and Nunallee 2011, p. 388). Other Polites species have 
been recorded as overwintering as larvae (P. mystic), pupae (P. 
sabuleti), or both (P. peckius) (Scott, 1986, pp. 443-445).

Conservation Measures

    When the mardon skipper was first identified as a Federal candidate 
for listing in 1999 (64 FR 57539; October 25, 1999), the species was 
known from approximately 14 extant sites located in 4 distinct 
geographic areas--south Puget Sound prairies, the southern Washington 
Cascades, the southern Oregon Cascades, and northwestern California 
(Potter et al. 1999, p. 5). At that time, the species was not afforded 
any special status or protections from existing regulatory mechanisms 
(Potter et al. 1999, p. 15). However, the subsequent designation of the 
mardon skipper as a State-listed endangered species in Washington and 
as a Federal candidate species has raised awareness of the need for the 
species' conservation. The species is now designated as a Sensitive 
Species or Special Status Species on Federal lands within its range 
(discussed below), and State natural resource agencies have

[[Page 54338]]

identified mardon skippers as a priority species for conservation.

State Laws and Conservation Plans

    The mardon skipper is listed as an endangered species in the State 
of Washington by the Washington Fish and Wildlife Commission 
(Washington Administrative Codes 232-12-014, Endangered Species; 232-
12-011, Threatened Species, Appendix D). The Washington Department of 
Fish and Wildlife (WDFW) has prepared a Comprehensive Wildlife 
Conservation Strategy (CWCS) (WDFW 2005). The CWCS identifies the 
mardon skipper as a ``species of greatest conservation need'' and 
identifies specific conservation actions for the species, including the 
protection of known sites and potential habitats and the investigation 
of limiting factors, and identifies development of a recovery plan for 
the species as a priority (WDFW 2005, p. 326). The conservation plan 
provides recommended management actions that have contributed to the 
amelioration of threats to the mardon skipper where they are found on 
State lands. Ongoing management for mardon skipper habitat on State 
lands in the Puget Prairie region is occurring through partnerships 
between the Department of Defense, The Nature Conservancy (now Center 
for Natural Lands Management), Washington State Department of Natural 
Resources, Washington Department of Fish and Wildlife, and U.S. Fish 
and Wildlife Service among others. These treatments have been effective 
for restoring or maintaining mardon skipper habitat at managed sites. 
Mardon skippers have been documented using many areas that were 
previously unsuitable due to the presence of invasive weeds after the 
habitat was restored with herbicides to eliminate tall oat grass, 
followed by management (mowing, pulling) to control Scot's broom (Hays 
2008, pp 1-2).
    There are also a number of small Prairie sites in the region that 
are currently in protected status and are actively being managed to 
maintain butterfly habitats that may serve as potential future 
reintroduction sites for mardon skippers (Anderson 2008, p. 2, Henry 
2010, pp.3-4). Beginning in 2007, the Fort Lewis Army Compatible Use 
Buffer (ACUB) initiative has supported the convening of a cooperative, 
interdisciplinary and interagency Butterfly Habitat Enhancement Team to 
develop and implement habitat improvements for mardon skipper and other 
rare butterflies on formerly occupied sites off of the Fort Lewis 
reservation (Anderson 2008, p. 1). This interagency team is a source of 
funding for mardon skipper habitat management, population assessments, 
and mardon skipper life history research at Puget prairie sites. These 
projects continue to maintain habitat and mardon skipper populations at 
the Scatter Creek Wildlife Area through prescribed fire, direct seeding 
of native species, mowing, and herbicide control of Scotch broom 
(Cytisus scoparius) and exotic grasses and forbs (WDFW 2011, p.79). The 
ongoing management to maintain mardon skipper populations and habitat 
at Puget prairie sites afford the species a high level of protection 
against further losses of habitat or populations.
    Oregon has a State Endangered Species Act, but the law does not 
cover invertebrate species. The Oregon Department of Fish and Wildlife 
(ODFW) has prepared a Comprehensive Conservation Strategy (ODFW 2006). 
The strategy identifies the mardon skipper as a ``strategy species.'' 
Strategy species are found in low numbers at few locations and are 
considered to be at-risk species. The plan targets conservation actions 
for the most at-risk species. The strategy generally identifies special 
habitat needs, limiting factors, and data gaps for the mardon skipper 
(ODFW 2006, p. 351).
    California has a State Endangered Species Act, but the law does not 
apply to insects. The State Comprehensive Wildlife Action Plan (CDFG 
2006) does not specifically address the conservation needs of the 
mardon skipper, but the plan emphasizes conservation of invertebrate 
species listed on the State ``special animal'' list.

Special Status Species Policies on National Forest and BLM Lands

    The mardon skipper is listed as a Sensitive Species by the U.S. 
Forest Service in Washington and Oregon (Forest Service Region 6), and 
in California (Forest Service Region 5), and as a Special Status 
Species by the Bureau of Land Management (BLM) in Oregon and 
Washington. For Oregon and Washington BLM-administered lands, Special 
Status Species policy (BLM 6840) details the need to conserve those 
species and the ecosystems on which they depend. Conservation is 
defined as the use of all methods and procedures which are necessary to 
improve the condition of Special Status Species and their habitats to a 
point where their Special Status recognition is no longer warranted. 
Policy objectives also state that actions authorized or approved by the 
BLM do not contribute to the need to list Special Status Species under 
the Endangered Species Act (Interagency Special Status/Sensitive 
Species Program [ISSSSP] 2011, entire).
    On National Forest lands, Sensitive Species are defined as those 
plant and animal species identified by a Regional Forester for which 
population viability is a concern, as evidenced by significant current 
or predicted downward trends in population numbers or density and 
habitat capability that would reduce a species' existing distribution 
(Forest Service Manual [FSM] 2670.5). Management of Sensitive Species 
``must not result in a loss of species viability or create significant 
trends toward federal listing'' (FSM 2670.32). The Regional Forester is 
responsible for identifying Sensitive Species and is directed by policy 
to coordinate with Federal and State agencies and other sources, as 
appropriate, in order to focus conservation management strategies and 
to avert the need for Federal or State listing as a result of National 
Forest management activities (ISSSSP 2011, entire).
    The Pacific Northwest Regional Office of the Forest Service and 
Oregon/Washington State Office of the BLM established the Interagency 
Special Status/Sensitive Species Program (ISSSSP) to facilitate the 
conservation and management of rare species on Federal lands. This 
interagency collaboration focuses on regional-level conservation 
approaches for Sensitive and Special Status Species lists (ISSSSP 2011, 
entire).
    With dedicated funding from the ISSSSP, the Forest Service/BLM 
have:
    (1) Formed the inter agency Mardon Skipper Work Group, which meets 
semi annually to share information and ideas and to plan future 
conservation work for mardon skippers;
    (2) Developed a mardon skipper survey protocol (Seitz et al. 2007, 
entire);
    (3) Funded multiple seasons of mardon skipper surveys across Forest 
Service, BLM, and other lands in Oregon and Washington;
    (4) Funded an oviposition habitat study in cooperation with the 
Xerces Society and Washington State University to determine plants that 
mardon skippers choose for egg laying and larval hosts (Beyer 2009, 
entire);
    (5) Contracted with the Xerces Society to develop site-specific 
management plans for all mardon skipper sites on BLM lands in the 
southern Oregon Cascades (Black et al. 2010, entire);
    (6) Completed a Conservation Assessment for the mardon skipper in 
2007 (Kerwin and Huff 2007, entire); and

[[Page 54339]]

    (7) Revised and updated the Conservation Assessment in 2011 (Kerwin 
2011, entire).
    Additional site-management plans are currently under development in 
2012 with dedicated funding from the ISSSSP for Forest Service mardon 
skipper sites on the Wenatchee, Gifford Pinchot, and Rogue River--
Siskiyou National Forests, as well as additional sites on the Coos Bay 
BLM District.
    The Forest Service/BLM Conservation Assessment is a comprehensive 
review of the mardon skipper's status, threats, and conservation needs, 
and provides specific management guidance and recommendations for 
protecting and maintaining the species' habitat on Federal lands 
(Kerwin 2011, pp. 30-35). The management considerations in the 
Conservation Assessment provide general guidance to Forest Service/BLM 
administrative units for managing mardon skipper sites and addressing 
potential threats such as conifer encroachment, invasive weeds, 
livestock grazing, and off-road vehicles (Kerwin 2011, pp. 31-33). The 
listing of the mardon skipper as a Forest Service Sensitive/BLM Special 
Status species ensures that the species is considered and addressed 
during the planning and implementation of Forest Service and BLM land 
management activities. The Sensitive/Special Species status has 
resulted in direct protection or restoration of mardon skipper habitat 
at many sites on Federal lands across the species range. Examples 
include conifer removal projects and placement of boulders to block 
off-road vehicle access (Kogut 2008, pp. 4-9), building grazing 
exclosures to exclude cattle from mardon skipper habitat (e.g., USFS 
2003, p. 185); or eliminating grazing impacts by closing grazing 
allotments or reducing use (e.g., BLM 2008, p. 6). In California, both 
the Forest Service and the National Park Service have included mardon 
skipper habitat protections in the planning and implementation of 
prescribed burn projects (e.g., Black et al. 2011, p. 3; NPS 2010, pp. 
26-27).
    In summary, the majority of the known occurrences of the mardon 
skipper throughout its range are located on Federal or State lands 
where the species is assured a high level of protection through 
existing regulations or conservation management associated with special 
status species programs. Federal and State agencies have been proactive 
in implementing effective conservation measures for the mardon skipper 
throughout its range. These protective measures are currently in place 
and are not dependent upon the species being listed under the Act.

Summary of Factors Affecting the Species

    Section 4 of the Act (16 U.S.C. 1533) and implementing regulations 
(50 CFR 424) set forth procedures for adding species to, removing 
species from, or reclassifying species on the Federal Lists of 
Endangered and Threatened Wildlife and Plants. Under section 4(a)(1) of 
the Act, a species may be determined to be an endangered or threatened 
species based on 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.
    In making this finding, information pertaining to the mardon 
skipper in relation to the five factors provided in section 4(a)(1) of 
the Act is discussed below. 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. If there is exposure and the species 
responds negatively, the factor may be a threat and we then attempt to 
determine how significant a threat it is. If the threat is significant, 
it may drive or contribute to the risk of extinction of the species 
such that the species warrants listing as a threatened or endangered 
species as those terms are defined by the Act. This does not 
necessarily require empirical proof of a threat. The combination of 
exposure and some corroborating evidence of how the species is likely 
impacted could suffice. The mere identification of factors that could 
impact a species negatively is not sufficient to compel a finding that 
listing is appropriate; we require evidence that these factors are 
operative threats that act on the species to the point that the species 
meets the definition of a threatened or endangered species under the 
Act.
    In making our 12-month finding on the petition, we considered and 
evaluated the best available scientific and commercial information. 
Here we evaluate the factors affecting the petitioned species Polites 
mardon. In addition, the Service has elected, at our own discretion, to 
additionally evaluate the two subspecies Polites mardon mardon and 
Polites mardon klamathensis. For the sake of brevity, we analyze the 
subspecies separately from the species rangewide only in those cases 
where the factors affecting the subspecies are unique, or where 
potential threats to the subspecies differ in severity or scope of 
impact from those affecting the species in the remainder of its range. 
The evaluation of the five factors, below, should thus be interpreted 
as applying equally to the species as a whole as well as to its 
constituent subspecies, unless indicated otherwise.

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

    Pyle (1989, p. 28) characterized threats to the mardon skipper as 
any factor that degrades its obligate grassland habitats, including 
development or land conversion, overgrazing, the use of herbicides and 
pesticides, encroachment by native and invasive nonnative vegetation, 
and succession from grassland to forest. In addition to the threats 
listed above, Black and others (2010, p. 12) identify climate change, 
stochastic weather events, and small, isolated populations as threats 
for Polites mardon klamathensis. Here we discuss the potential threats 
associated with habitat loss or degradation; the additional threats 
identified by Black et al. (2010, p. 12) are discussed under Factor E, 
below.

Habitat Loss Associated With Land Conversion

    Prairies, which historically covered over 145,000 ac (60,000 ha) of 
the south Puget Sound region, have largely been lost over the past 150 
years (Crawford and Hall 1997, p. 11). The primary causes of historical 
prairie habitat loss in the region are attributed to the conversion of 
prairie habitat to urban development and agricultural uses (over 60 
percent of losses), and succession to Douglas-fir forest (32 percent) 
(Crawford and Hall 1997, p. 11). Today approximately 8 percent of the 
original prairies in the south Puget Sound area remain, but only about 
3 percent contain native prairie vegetation (Crawford and Hall 1997, p. 
11). Today approximately 8 percent of the original prairies in the 
south Puget Sound area remain, but only about 3 percent contain native 
prairie vegetation.
    Puget prairie sites with extant populations of mardon skippers are 
protected from further development through either State or Federal 
ownership. Habitats at these sites have

[[Page 54340]]

been degraded by invasive species and competing uses such as recreation 
or military training (Schultz et al. 2011, pp. 370-371), but these 
threats are now being addressed through active management, as 
referenced above under ``Conservation Measures'' and as discussed 
further below.
    Remaining prairie habitats in the south Puget Sound region are 
relatively small, isolated patches with little potential connectivity 
between patches (Schultz et al. 2011, p. 371). Because of this, 
historical prairie sites where mardon skippers have been extirpated are 
unlikely to be re colonized naturally due to isolation from extant 
populations (Schultz et al. 2011, p. 371). However, there are a number 
of small prairie sites in the region that are currently in protected 
status and are actively managed to maintain butterfly habitats that may 
serve as potential future reintroduction sites for mardon skippers 
(Anderson 2008, p. 2; Henry 2010, pp. 3-4).
    In other portions of the mardon skipper's range, outside of the 
south Puget prairie region, habitat loss due to urban development or 
land conversion has not been a significant threat due to their 
locations primarily on Federal or Tribal lands, in remote areas that 
have historically been managed for grazing, timber production, or 
recreation. There have been minor historical losses of mardon skipper 
habitat from the placement of roads, trails, or buildings in occupied 
meadow sites (Potter et al. 1999, p. 12), but these losses have not 
been quantified and are relatively small. There are no reported 
examples of recent habitat loss from new road construction or 
developments in mardon skipper habitats on Federal lands. Because of 
the protections the mardon skipper receives as a Federal special 
status/sensitive species (described above under ``Conservation 
Measures'') the threat of additional habitat loss due to land 
conversion on Forest Service or BLM lands is very low. Twelve out of 
the 165 sites known for mardon skipper are found on private lands; the 
potential for future development at these privately owned sites is 
unknown. However, most of these sites on private lands are located near 
other extant populations on neighboring Federal lands, indicating that 
private lands sites are likely subpopulations of these larger 
populations on Federal lands. It is therefore unlikely that any of the 
few mardon skipper sites on private lands support source populations of 
the species.
    Summary: The historical loss of native prairie habitats to urban 
development and agriculture in the south Puget Sound region has likely 
resulted in a contraction of the species' distribution within that 
portion of the species' range. However, Puget prairie sites currently 
occupied by mardon skippers are protected from further loss due to 
development by State or Federal ownership. Land conversion for roads 
and other uses has historically resulted in only minor losses of mardon 
skipper habitat on Federal lands in all other portions of the species' 
range. Additional habitat losses due to land conversion or development 
on Federal lands that support populations of Polites mardon mardon and 
Polite mardon klamathensis are not anticipated. Very few of the known 
mardon skipper sites are found on private lands, and most of these 
sites are believed to be subpopulations of larger populations found on 
Federal lands that are protected from conversion or development. 
Therefore, continued habitat loss due to land conversion is not a 
significant threat to the mardon skipper at the species or subspecies 
levels.

Habitat Loss and Fragmentation Associated With Forest Succession

    Throughout the Pacific Northwest the invasion of meadow or 
grassland habitats by conifers represents a recent and widespread 
phenomenon potentially triggered by changes in climate, the cessation 
of intensive grazing, and wildfire suppression (Haugo and Halpern 2007, 
pp. 285-286). In Redwood National Park in California, meadow habitats 
have declined due to forest encroachment over the past century (NPS 
2010, pp. 44-45). At Joint Base Lewis-McChord in Washington, 
approximately 39 percent (over 16,200 ac [6,560 ha]) of the original 
prairie habitat has transitioned to Douglas-fir forest, and only a 
fraction of the original prairie habitat remains as small, isolated 
prairies (Tveten 1997, p. 124)
    The loss of meadow habitats in the Cascades is also well 
documented. At one study site in the Oregon Cascades, the area 
associated with mesic meadows declined from 328 ac (133 ha) to 163 ac 
(66 ha) during the period from 1946 to 2000 (Takaoka and Swanson 2008, 
p. 521). This represents a loss of approximately 50 percent of the 
mesic meadow habitat over a period of 54 years. Most xeric (dry) 
meadows were fairly stable over the study period, indicating that 
patterns of forest succession in montane meadows are complex and that 
diverse factors influence these processes (Takaoka and Swanson 2008, p. 
521). The contraction of mesic meadow habitats was strongly associated 
with a lack of fire disturbance over the past half century (Takaoka and 
Swanson 2008, p. 538).
    Aerial photographs taken on the Gifford Pinchot National Forest in 
the southern Washington Cascades indicate that the mardon skipper sites 
located within a historical (1918-1919) burn area were larger with much 
greater potential for connectivity between sites than exists today 
(Foster 2010, p. 3). Forest succession over the past 60 years has 
reduced the meadow habitats in this landscape to a few isolated patches 
ranging in size from 2 to 8 ac (0.8 to 3.2 ha) (Foster 2010, p. 2).
    The loss of meadow habitats from forest succession not only reduces 
the amount of suitable grassland habitat available for mardon skippers, 
it also closes off potential dispersal corridors between meadows, 
potentially resulting in remnant, isolated populations (Beyer and 
Schultz 2010, p. 870). In addition to natural meadow habitats, many 
mardon skipper sites in the Washington Cascades are located in areas 
that were clearcut for timber harvest in 1960s through 1980s (Price and 
Mendez-Treneman 2000, p. 6; St. Hilaire et al. 2008, p. 5), and 
subsequently were colonized by mardon skippers. Open grass habitats in 
many of these old clearcuts are now rapidly declining. Because the 
mardon skipper requires early seral habitats, conifer encroachment is a 
potential threat at all mardon skipper sites located on National Forest 
or BLM lands in Washington, Oregon, and California. However, actual 
habitat degradation as a result of this threat is ranked as high at 
only a few mardon skipper sites, primarily on the Wenatchee National 
Forest, and a few in the range of P.m. klamathensis (Kerwin 2011, pp. 
49-60).
    Land managers across the range of the mardon skipper recognize 
conifer encroachment as impacting meadow habitats, and many local 
districts have undertaken projects to reduce conifer encroachment at 
mardon skipper meadows. For example, Kerwin (2011, p. 31) notes the 
implementation of ``considerable meadow restoration efforts for mardon 
skippers'' on the Gifford-Pinchot National Forest. Examples of 
restoration activities range from hand-cutting and removal of small 
conifers on the Gifford Pinchot National Forest in Washington (Kogut 
2008, pp. 4-7) to prescribed burning projects on the Six Rivers 
National Forest in California (Black et al. 2011, p. 3). Some level of 
grazing is also recognized as a potential management tool for reducing 
conifer encroachment (Kerwin 2011, p. 27). Habitat management 
activities can be beneficial to the species, although

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site disturbance from these actions can result in negative impacts to 
mardon skipper populations if they are not carefully planned and 
implemented (Black 2011, p. 385).
    Although conifer encroachment has the potential to negatively 
impact meadow habitats required by the mardon skipper, Federal land 
managers are actively managing sites to reduce conifer encroachment and 
maintain meadows to improve habitat for the mardon skipper throughout 
its range, as outlined in the management provisions in the revised 
Forest Service/BLM Conservation Assessment for the Mardon Skipper 
(Kerwin 2011, pp. 30-33), and in Management Plans for all Southern 
Oregon Cascades Mardon Skipper (Polites mardon klamathensis) Sites on 
BLM Lands (Black et al. 2010, pp. 15-17). Therefore, the impacts of 
conifer encroachment do not presently represent a threat to the mardon 
skipper across its range, and continued active management is expected 
to control this threat in the future.
    Discussion Specific to Polites mardon klamathensis
    Little information exists about vegetation change over time in the 
grasslands, shrublands, and woodlands of southwestern Oregon (Hosten et 
al. 2007b, p. 1). A comparison of historical and current photos shows a 
general loss of high-elevation grassland to woody shrub and tree 
domination, and transition from shrubland and woodland to conifer 
domination (Hosten et al. 2007b, p. 31). The encroachment of shade-
tolerant conifers into non-conifer vegetation, reduced reproduction by 
pine, and the loss of meadows support the generally accepted belief 
that fire suppression has negatively impacted historically open 
vegetation types in the southern Oregon Cascades (Hosten et al. 2007b, 
p. 1). Historical anecdotes also identify livestock grazing as playing 
a role in the depletion of native perennial bunchgrasses and subsequent 
invasion of woody species (Hosten et al. 2007b, p. 31).
    The loss of open grassland habitats from conifer succession has the 
potential to impact populations of Polites mardon klamathensis through 
the gradual reduction and loss of suitable habitat patches and by 
closing off corridors between meadows, reducing the potential for 
successful dispersal to suitable habitat patches. Studies with other 
butterfly species have demonstrated that conifer encroachment reduces 
dispersal between populations and reduces gene flow, resulting in 
small, isolated populations with a greater risk of local extirpation 
(Roland and Matter 2007, p. 13702). Although identified as a potential 
threat at some sites, conifer encroachment within meadows is currently 
being addressed through management plans developed for P.m. 
klamathensis sites on BLM lands (Black et al. 2010, pp. 21-61). In 
2011, the BLM staff at the Medford District implemented small conifer 
removal projects at most of the sites identified for this work, which 
has reduced the imminency of continued habitat loss within meadows 
(Mardon Skipper Work Group [MSWG] 2011, in litt.). Present management 
of these areas to reduce conifer encroachment and enhance meadow 
habitats appears to have ameliorated this threat for P.m. klamathensis.
    Summary: The potential loss of meadow habitats due to forest 
succession is a concern at most mardon skipper sites across the 
species' range. However, habitat loss due to succession is a gradual 
process that occurs on a scale of decades and can be checked with 
appropriate low-impact management methods, which is presently occurring 
at many key sites across the species' and subspecies' range. Because 
Federal managers have implemented actions to substantially ameliorate 
this threat, forest succession, while still affecting habitat, is no 
longer considered to be a threat to the mardon skipper at the species 
or subspecies levels.

Habitat Modifications Associated With Fire

    Fire is an important source of disturbance that reduces conifer 
encroachment and maintains meadow and grassland habitats. Prescribed 
fire is a tool that is often used by land managers to maintain meadows 
or other fire-adapted habitats (e.g., NPS 2010, p. 4). Although mardon 
skippers occur in landscapes that have historically burned, mardon 
skipper populations may be vulnerable to local extirpation if a fire 
burns all of the occupied habitats at a population site (Black 2011, p. 
384). The use of prescribed fire is implicated in the extirpation of 
mardon skippers from one historical Puget Prairie site in 1992 (Stinson 
2005, p. 10).
    In California, the Coon Mountain mardon skipper site on the Six 
Rivers National Forest is being managed with prescribed fire to 
maintain the meadow habitat at the site and, consequently, mardon 
skipper habitat. Working in cooperation with the Xerces Society, the 
Forest Service modified their original plans to burn the entire site, 
and established four experimental burn plots with corresponding 
unburned areas. The experimental plots were burned in the fall of 2008 
(Black et al. 2011, pp. 3-4). Monitoring at the site in 2009 indicated 
mardon skippers were 3-27 times more abundant in unburned areas 
compared to burned areas (Black 2011, p. 384). Continued monitoring at 
the site in 2010 and 2011 indicate that mardon skipper densities in 
unburned patches were consistently higher than in burned patches (Black 
et al. 2011, p. 14); however, mardon skippers are gradually 
recolonizing the burned patches from the adjacent unburned areas at the 
site as their preferred habitat increases (Black 2011, p. 384). 
Although peak counts of mardon skippers in subsequent years after the 
burn have not been as high as they were prior to burning in 2008, the 
authors note that the overall population appears to be stable, and is 
still considered the largest known population in California (Black et 
al. 2011, p. 13). As their preferred habitat increases at these sites, 
the mardon skipper population may expand into the burned areas and 
increase over time. Continued monitoring is needed to fully assess the 
population response at Coon Mountain.
    A large wildfire burned over 8,000 ac (3,238 ha) at Mt. Adams in 
Washington in 2008, including burning the forest around at least one 
known mardon skipper site (Eureka Meadow). Although the fire burned the 
surrounding forest, the meadow itself did not burn (likely because it 
was still snow-covered at the time of the fire), and 135 mardon 
skippers were counted at the site in 2010 (Wainwright 2010, p. 1). The 
Windy Valley site on the Rogue River-Siskiyou National Forest in 
southwestern Oregon is another example of a mardon skipper population 
surviving a recent wildfire event. Much of the forest around this 
meadow/wetland complex burned as part of the Biscuit Fire in 2002, but 
the site continues to support a large population of mardon skippers 
that was discovered in 2010 (Kerwin 2011, p. 51). Wildfires are likely 
to have beneficial effects for mardon skippers due to resultant 
increases in early seral habitat, although large wildfires also pose a 
risk to mardon skippers if all occupied habitat in a local area is 
burned. Because wildfires typically result in a mosaic of burned and 
unburned areas, it is unlikely that wildfires would result in the loss 
of multiple populations across large areas within the species' or 
subspecies' range.
    Assessing whether wildfires or prescribed fire used to manage 
mardon skipper habitats poses a threat to the species is a complex 
undertaking. Fire disturbance is an integral process in

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natural ecosystems (Agee 1993, p. 3), and has certainly played a 
pivotal role in maintaining mardon skipper habitats. Conservation 
scientists as well as Federal land managers recognize that the habitat 
benefits gained from using prescribed fire to maintain mardon skipper 
habitat must balance the lethal effects fire can pose to mardon 
skippers (Black 2011, p. 384; Kerwin 2011, p. 33). The Coon Mountain 
experiment demonstrates that prescribed fire can be used to restore 
mardon skipper meadow habitat and maintain a population at the site, 
but the fire must be carefully managed so that only a portion of the 
occupied areas at a site is burned (Black 2011, p. 384).
    Summary: Wildfires or prescribed fires that maintain and restore 
meadow habitats can be either beneficial or lethal to mardon skippers, 
depending on the timing and severity of the fire and the condition of 
the habitat. Fire is an important disturbance agent for maintaining the 
early-seral habitats mardon skippers require. Managers using fire to 
restore habitat can and have modified burn plans to meet both fire 
objectives and protect mardon skippers, which greatly reduces the 
potential threat associated with prescribed fires. Therefore, the use 
of prescribed fires for habitat management is not considered to be a 
threat to mardon skippers at either the species or subspecies level. 
Wildfires are also a potential threat on a local scale, but it is 
unlikely that wildfires would result in the loss of multiple 
populations across large areas within the species' or subspecies' 
range; therefore, we do not consider it to be a threat to mardon 
skippers at the species or subspecies level.

Habitat Loss Associated With Invasive, Nonnative Plants

    The invasion and subsequent dominance of nonnative plant species in 
native grassland habitats is common and has occurred rapidly at several 
current and historical mardon skipper locations associated with Puget 
prairies (Potter et al. 1999, p. 10). Invasive grasses such as tall 
oatgrass and the invasive shrub Scot's broom drastically alter the 
short-grass/forb habitat structure that mardon skippers select for 
oviposition or nectaring sites (Hays et al. 2000, p. 28; Schultz et al. 
2011, p. 371). Habitat utilization studies have demonstrated that 
mardon skippers actively avoid areas invaded by these species (Hays et 
al. 2000, p. 28; Henry 2010, p. 44), but will recolonize sites where 
these invasive species have been removed (Hays et al. 2000, p. 16). 
Scot's broom and tall oatgrass are present at south Puget Sound prairie 
sites occupied by mardon skippers, but significant portions of these 
sites are managed annually to control these species (Hays 2010, p. 1). 
The Washington State Department of Natural Resources, for example, 
recommends restoration techniques including mowing, hand pulling, 
herbicide application, and prescribed burning to restore or maintain 
prairie habitats for the mardon skipper (Potter et al. 1999, p. 8) . 
Mardon skippers have been documented using many areas that were 
previously unsuitable due to the presence of invasive weeds after the 
habitat was restored with herbicides to eliminate tall oatgrass, 
followed by management (mowing, pulling) to control Scot's broom (Hays 
2008, pp. 1-2).
    Continued site management is required to maintain mardon skipper 
habitat and populations at south Puget prairie sites (Schultz et al. 
2011, p. 375). Ongoing management for mardon skipper habitat is 
occurring through partnerships between the Department of Defense, The 
Nature Conservancy (now Center for Natural Lands Management), 
Washington State Department of Natural Resources, Washington Department 
of Fish and Wildlife, and U.S. Fish and Wildlife Service among others. 
The prairie sites with extant populations of mardon skippers also 
support a number of other high-priority prairie species, including 
Taylor's checkerspot butterfly (Euphydryas editha taylorii), a 
candidate for listing under the Act (Stinson 2005, p. 6). Based on the 
importance of these sites for multiple prairie-associated species, we 
expect that State, Federal, and nongovernmental organizations will 
continue to place a high priority on maintaining prairie habitats at 
these sites for the benefit of mardon skippers and other prairie 
species.
    Not all mardon skipper sites have been evaluated for the presence 
of invasive, nonnative plants; however, the problem is increasingly 
common (Potter et al. 1999, p. 10). At least two sites (Cave Creek and 
Lost Meadows) on the Gifford Pinchot National Forest are being actively 
managed to reduce invasive Cirsium arvense (Canada thistle) which has 
formed dense patches and has been spreading throughout the mardon 
skipper habitat (Kogut 2008, p. 9). Managing for invasive species is 
required at a number of sites to maintain mardon skipper habitat, but, 
as with managing for conifer removal, the management must be carefully 
planned to avoid negative impacts to local butterfly populations 
(Schultz et al. 2011, p. 373). We expect that Federal land managers 
will continue to manage sites to control invasive weeds and will do so 
in a way that improves habitat for the mardon skipper, while minimizing 
impacts to local populations as outlined in the revised Forest Service/
BLM Conservation Assessment for the Mardon Skipper (Kerwin 2011, pp. 
30-33), and in site-specific plans such as those developed on the 
Gifford Pinchot National Forest (USFS 2008, p. 57).
    Summary: Invasive nonnative plants have historically resulted in 
habitat loss and degradation at a number of mardon skipper sites, 
primarily in the Puget prairies. Federal, State, and private land 
managers have been actively managing invasive weeds at the most 
degraded sites to restore and maintain mardon skipper habitat, and are 
likely to continue to do so under their current management plans, which 
substantially reduces this potential threat. Based on the ongoing 
partnership and commitment of private, State, and Federal entities to 
manage invasive nonnative plants and restore prairie habitats, the 
impact of invasive nonnative plants appears to have been sufficiently 
ameliorated throughout the range of the mardon skipper such that it 
does not pose a threat to the species or either subspecies.

Habitat Modifications Associated With Livestock Grazing

    Current or historical livestock grazing has occurred at essentially 
all mardon skipper sites in the Washington and Oregon Cascades. 
Historically (1900-1930s), many areas in the Cascades were intensively 
grazed by sheep (Miller and Halpern 1998, p. 267), including several 
known mardon skipper sites on the Gifford Pinchot National Forest (USFS 
2007a, p. 30; Foster 2010, p. 2). Sheep grazing was largely replaced by 
cattle grazing after the 1930s. Grazing allotments at Mt. Adams in 
Washington have been grazed for over 100 years (USFS 2007a, pp. 30-31).
    Long-term grazing can alter both the structure and composition of 
plant communities, rendering them unsuitable to some butterfly species 
(Dana 1991, p. 54; Ellis 2003, p. 292), while benefiting other species, 
depending on the specific habitat requirements of each species (Kruess 
and Tshcharntke 2002, p. 1575; Poyry et al. 2005, p. 469; Vogel et al. 
2007, pp. 81-82). Grazing can impact mardon skipper populations by (1) 
direct trampling of eggs, larvae, pupae, and adults (Potter et al. 
1999, p. 13; Black et al. 2010, pp. 13-14); (2) removal of both larval 
and adult food sources, and (3) disturbing the soil, which allows weeds 
to invade (Ellis 2003, pp. 292-293; Schtickzelle et al. 2007, p. 657). 
One grazing study found that both the

[[Page 54343]]

abundance and recruitment of the bog fritillary butterfly (Proclossiana 
eunomia) were reduced by as much as 74 percent in grazed areas compared 
to ungrazed sites (Schtickzelle et al. 2007, p. 657). Dana (1991, p. 
54) notes that both the Dakota skipper (Hesperia dacotae) and the ottoe 
skipper (Hesperia ottoe) apparently decline or can be extirpated in 
response to intensive grazing, likely due to changes in the composition 
and structure of the plant communities at intensively grazed sites.
    Although intensive livestock grazing can be detrimental to many 
butterfly species, moderate to light grazing can be a useful method for 
halting succession and maintaining butterfly habitats where other 
habitat management methods are impractical (Schtickzelle et al. 2007, 
p. 658; Ellis 2003, p. 293). The silver-spotted skipper (Hesperia 
comma) is one species that has shown a positive response to moderate 
grazing, and depends on continued grazing to maintain the short-
statured grassland habitats the species requires (Thomas and Jones 
1993, p. 473).
    The impact of cattle grazing to mardon skipper populations is 
likely relative to the timing, duration, and magnitude of the grazing 
at the site (Black et al. 2010, p. 13). Large mardon skipper 
populations are able to persist in some heavily grazed habitats. Conrad 
Meadows on the Wenatchee National Forest is subjected to native 
ungulate (deer and elk) grazing in the spring, and then intensive 
cattle grazing during the summer months. Conrad Meadows is a large 
system of interconnected meadows, wetlands, and forested areas with 
complex vegetative structure and site conditions. The meadow complex 
supports the largest known population of mardon skippers, with minimum 
population counts of over 1,000 mardon skippers in some years (St. 
Hilaire et al. 2010, p. 11). Conrad Meadows has been in an active 
cattle grazing allotment for 80 years, and there continues to be a 
robust population of mardon skippers at this site (St. Hilaire et al. 
2008, p. 15). Because the timing of the onset of livestock grazing 
tends to occur towards the end or after the adult flight period at 
Conrad Meadows, the grazing at this site may not affect mardon skipper 
populations to the same degree as sites that are grazed throughout the 
flight period (St. Hilaire et al. 2008, p. 14).
    Ongoing monitoring at grazing exclosures (2007-2010) on the 
Wenatchee National Forest has shown no clear pattern between mardon 
skipper populations in grazed versus ungrazed areas (St. Hilaire et al. 
2010, p. 7). The authors note that there are a number of confounding 
variables associated with this monitoring project and more research at 
these sites is recommended. Anecdotal observations within grazing 
exclosures indicate a much higher abundance and diversity of flowering 
forbs (adult nectar sources) compared to outside the exclosures (Jepsen 
et al. 2007, p. 17), but there appears to be no clear pattern in the 
number of mardon skippers within exclosures versus outside exclosures 
(St. Hilaire et al. 2010, p. 7). Mardon skipper densities at sites 
grazed by cattle on the Wenatchee National Forest are comparable or 
higher than densities observed at sites on the adjacent Gifford Pinchot 
National Forest that are subjected only to light native ungulate 
grazing.
    Because mardon skippers have specific habitat requirements related 
to graminoid cover, composition, and structure (Beyer and Schultz 2010, 
pp. 867-868), it appears likely that intensive livestock grazing that 
occurs before or during the adult flight period would have a negative 
effect on mardon skipper reproductive success and larval survival due 
to the loss of adult nectar sources and larval host plants, and the 
introduction of nonnative grasses, forbs, or shrubs that do not meet 
the structural requirements of mardon skippers. The grasses most 
commonly used by mardon skippers for oviposition and larval food (e.g., 
Roemer's fescue, California oatgrass, Kentucky bluegrass (nonnative), 
and sedges) (Beyer and Black 2007, p. 6) are also some of the most 
preferred forage species used by cattle (Hosten et al. 2007, p. 20). 
These effects are likely to be most profound at sites where grazing 
impacts are intensified due to the presence of surface water or wet 
soils that attract livestock (Hosten and Whitridge 2007, p. 1), and the 
grazing use entirely overlaps the adult flight period (Black et al. 
2010, p. 13). However, the removal of livestock from sites that have 
historically been grazed for decades does not automatically restore 
degraded habitats or improve mardon skipper populations.
    There are a number of sites that are no longer in active grazing 
allotments that continue to have chronically low or declining 
populations of mardon skippers, most likely due to degraded habitat 
conditions associated with the plant community composition (Black et 
al. 2010, pp. 60-63; USFWS unpublished data). The short-grass/forb 
habitats preferred by mardon skippers can become quickly degraded in 
the absence of livestock grazing due to presence of tall-structured 
nonnative grasses and shrubs (Black et al. 2010, p. 61). The use of 
short-duration, low-intensity grazing may prove to be beneficial or 
necessary for maintaining mardon skipper habitat in some situations 
(e.g., Black et al. 2010, p. 38).
    Over the past 5 years, a number of grazing allotments on both 
Forest Service and BLM lands in both Oregon and Washington have been 
retired. Grazing allotments at most of the southern Oregon Cascades BLM 
mardon skipper sites for Polites mardon klamathensis were retired in 
2009 (Black et al. 2011, pp. 14-15). A major grazing allotment (Ice 
Caves) on the Gifford Pinchot National Forest was discontinued in 2009, 
and was officially closed in 2011. On the Wenatchee National Forest, 
the Forest Service has installed a number of grazing exclosures to 
reduce grazing impacts and protect key mardon skipper habitat areas 
(St. Hilaire et al. 2010, p. 5). In general, grazing impacts on Federal 
lands are decreasing, with fewer animals being allowed onto grazing 
allotments, with shorter grazing periods, and placement of exclosures 
in key locations to protect sensitive habitats (e.g., USFS 2007b, p. 
2). Active grazing allotments are still present at several mardon 
skipper sites within the range of the species, and continued monitoring 
is needed to assess the impact that grazing has on these populations. 
Under current management conditions, light to moderate grazing can be 
potentially beneficial in maintaining the habitat structure preferred 
by mardon skippers, and based on the most recent conservation 
assessment for the mardon skipper, intensive grazing does not appear to 
be a significant factor in habitat degradation for the species across 
its range (Kerwin 2011, Appendix A).
    Summary: Cattle grazing can have either negative or beneficial 
effects to mardon skippers depending upon the timing, duration, and 
intensity of the grazing. Robust mardon skipper populations are able to 
persist in some heavily grazed habitats, while other areas that have 
been heavily grazed have generally poor habitat conditions and support 
only low numbers of mardon skippers. Grazing is likely to be beneficial 
for maintaining mardon skipper habitat at sites that are vegetated with 
tall-statured nonnative grasses and shrubs. Potential negative impacts 
from grazing on Federal lands have been substantially reduced due to 
the closure of a number of grazing allotments in key areas, as well as 
changes in management practices to reduce grazing intensity and protect 
key habitat areas. Therefore, livestock grazing does not represent a 
threat to the mardon skipper at the species level at this time, nor is 
it likely

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to be so in the future due to current management efforts. We have no 
information to indicate that it is a threat to the subspecies Polites 
mardon mardon.
    Discussion specific to Polites mardon klamathensis:
    Current or historical livestock grazing has occurred at all Polites 
mardon klamathensis sites in the Oregon Cascades for over 100 years 
(Hosten et al. 2007, p. 13), and habitat conditions at some sites have 
been excessively degraded by grazing (Black et al. 2010, pp. 22-23). 
Until recently all of the occupied sites were located in active grazing 
allotments. With the recent designation of the Cascades-Siskiyou 
National Monument (Monument) in 2000, the BLM initiated a review of 
grazing impacts on Federal lands within the Monument. This review 
determined that four grazing allotments within the Monument failed to 
meet BLM standards for maintaining populations of threatened and 
endangered and other locally important species (BLM 2008, p. 6). The 
major reasons for not meeting this standard included the threat to 
special status species including the mardon skipper, the favoring of 
noxious weeds (e.g., Canada thistle at high elevations) over native 
plants; and the invasion of the nonnative Poa bulbosa (bulbous 
bluegrass) (BLM 2008, p. 6). Although overgrazing is considered to have 
had negative impacts on several P.m. klamathensis sites in the past 
(Black. 2010, p. 14), some of these sites have now been retired from 
grazing, and others are now being managed in accordance with a 
management plan developed by The Xerces Society for Invertebrate 
Conservation for all P.m. klamathensis sites on BLM lands in southern 
Oregon, including provisions specific to grazing, such as avoiding 
grazing during the flight period of adults and keeping grazing periods 
short and interspersed with long recovery period for the habitat (Black 
et al. 2010, entire).
    In 2009, grazing allotments at 10 mardon skipper sites located on 
BLM lands within the Monument were retired (Black et al. 2010, pp. 14). 
The remaining sites on BLM lands that are still within active grazing 
allotments have existing or planned grazing exclosures to protect core 
mardon skipper habitat areas (Black et al. 2010, pp. 23-61). Four 
Polites mardon klamathensis sites located on the Rogue River-Siskiyou 
National Forest are in active grazing allotments, and Jepsen et al. 
(2007b, pp. 24-25) reported that grazing had degraded habitat at three 
of these sites. However, more recently Kerwin (2011, pp. 49-60) 
reviewed the P.m. klamathensis sites in his conservation assessment and 
found that none faced a serious threat from grazing (with exception of 
Hobart Peak, where effects from grazing were considered ``unknown''), 
and additionally noting that several of the grazed sites are in 
excellent condition. Remaining sites in active grazing allotments on 
Federal lands are expected to continue to exhibit reduced grazing 
impacts due to the placement of existing or planned grazing exclosures 
around core habitat areas (Black et al. 2010, pp. 23-61; Kerwin 2011, 
p. 32).
    Summary: The threats from active livestock grazing have been 
substantially reduced from all Federal lands sites within the range of 
Polites mardon klamathensis. Planned or existing grazing exclosures are 
likely to protect core habitat areas at some key sites, but the 
effectiveness of grazing exclosures for maintaining mardon skipper 
habitat structure and populations remains unknown. We expect that 
mardon skipper habitat conditions within exclosures will generally 
improve with the removal of livestock grazing, but these areas will 
require monitoring and possible management actions to insure that 
invasive weeds or tall-statured nonnative grasses do not become a 
secondary threat in the absence of grazing, as recommended in the 
revised Forest Service/BLM Conservation Assessment for the Mardon 
Skipper (Kerwin 2011, pp. 30-33), and in Management Plans for all 
Southern Oregon Cascades Mardon Skipper (Polites mardon klamathensis) 
Sites on BLM Lands (Black et al. 2010, pp. 15-17). The potential 
negative impacts of grazing on Federal lands within the range of 
P.m.klamathensis have been substantially reduced due to the closure of 
a number of grazing allotments in key areas, as well as changes in 
management practices to reduce grazing intensity and protect key 
habitat areas. Therefore, we do not consider the effects of livestock 
grazing to be a threat to P.m. klamathensis.

Habitat Loss Associated With Off-Road Vehicles and Recreation

    Recreational activities, including off-trail walking, off-trail 
horseback riding, and off-road vehicle use, may directly kill some 
mardon skippers by trampling and crushing larvae (Potter et al. 1999, 
p. 12). Off-road vehicle use has the greatest impact on mardon skipper 
habitat because vehicle tires can destroy native plants and disturb 
soils, leading to invasion by weeds. Small, roadside meadows are 
vulnerable to damage or destruction associated with off-road vehicle 
use. Currently, this threat applies to a few locations across the range 
of the species (Kerwin 2011, pp. 37-41). In 2008, a mardon skipper site 
located on private lands in Del Norte County, California, was partially 
destroyed when the site was used as a dump for logging slash and debris 
(Ross 2008a, p. 5; Devlin 2009, pers. comm.). At least one historical 
locale in the southern Washington Cascades was destroyed by this 
practice in 1997 or 1998 (Potter et al. 1999, p. 11). Military training 
activities at Joint Base Lewis-McChord have also resulted in damage to 
mardon skipper habitat (Potter et al. 1999, p. 12), but the majority of 
the prairie habitat at this site is protected from vehicle damage due 
to the presence of unexploded ordnance (Stinson 2005, p. 12). Over the 
past 10 years, Federal land managers have installed access barriers 
(e.g., placement of road-side boulders, gates, or exclosures) and 
posted educational signs in attempts to reduce illegal off-road 
vehicles and other recreational uses at almost all mardon skipper sites 
where these problems have been noted (Kogut 2008, p. 8). These measures 
have substantially reduced these threats on Federal lands, which 
constitutes the majority of the range occupied by the species. 
Therefore, habitat loss associated with off-road vehicles and 
recreation is not a significant concern for the mardon skipper at the 
species level at this time, nor is it likely to become so. In addition, 
we have no information to indicate that it has a significant impact on 
the subspecies Polites mardon mardon.
    Discussion specific to Polites mardon klamathensis:
    Management plans developed for Polites mardon klamathensis sites on 
BLM lands identified off-road vehicle use and recreation (camping) 
within meadows as a potential threat at several sites (Black et al. 
2010, pp. 21-61). In 2011, both BLM staff at Medford District and 
Forest Service staff on the Rogue River-Siskiyou National Forest 
implemented a number of projects to reduce these impacts at P.m. 
klamathensis sites through the strategic placement of boulders to block 
vehicle access, and by posting signs at most of the sites identified 
for this work (MSWG 2011, in litt.). These measures are expected to 
substantially reduce any potential impacts from off-road vehicles and 
other recreational uses.
    Summary: Off-road vehicles and other recreational activities have 
historically resulted in minor habitat losses and degradation at a 
number of sites across the range of the mardon skipper. However, this 
threat has been substantially reduced on Federal lands

[[Page 54345]]

where the majority of these activities occur through the placement of 
access barriers and signs. Because private lands comprise an 
insubstantial portion of the species' range, we do not consider any 
such activities on private lands, if they should occur, to pose a 
threat to the mardon skipper. Therefore, habitat loss or degradation as 
a consequence of off-road vehicles and other recreational uses is not 
considered to be a threat at either the species or subspecies levels.

Summary of Factor A

    In summary, the potential negative impacts to mardon skipper 
habitat associated with forest succession, fire, invasive nonnative 
plants, livestock grazing, and off-road vehicle use have been 
substantially reduced or eliminated on Federal and State lands through 
the development and implementation of conservation plans and habitat 
restoration projects. Habitat degradation associated with intensive 
livestock grazing continues to occur at a few sites, but grazing 
impacts have been substantially reduced or eliminated at many key sites 
across the species' range with recent closures of Federal grazing 
allotments and the implementation of site-specific conservation plans 
for the benefit of the mardon skipper. Habitat degradation from off-
road vehicle use has been reduced or eliminated at many sites by 
installing vehicle barriers or closing roads. Meadow habitat 
restoration activities (prescribed burning, herbicide treatments) can 
be lethal to mardon skippers, but careful planning and implementation 
of habitat restoration projects designed with these concerns in mind 
have minimized the risks associated with these positive efforts for 
skipper conservation. Because the vast majority of mardon skipper sites 
are found on Federal or State lands, and most of the sites that are 
found on private lands are subpopulations of larger populations on 
Federal lands, we do not consider habitat degradation that may occur on 
private lands to pose a threat to the mardon skipper. Based on these 
ongoing conservation actions on Federal and State lands, we do not 
consider Factor A, the present or threatened destruction, modification, 
or curtailment of its habitat or range, to pose a threat to the mardon 
skipper as a species now or in the future, nor do we have any 
information to indicate that it is a threat to either subspecies 
Polites mardon mardon or Polites mardon klamathensis, now or in the 
future.

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

    Insect collecting is a valuable component of research, including 
systematics work, and is often necessary for documenting the existence 
of populations (Potter et al. 1999, p. 14). Rare butterflies, such as 
the mardon skipper, could be potentially desirable. Most mardon skipper 
populations are easily accessible and could be vulnerable to collectors 
(Potter et al. 1999, p.14). However, we currently have no information 
indicating that mardon skipper populations at either the species or 
subspecies level have been negatively affected by collection or 
scientific research activities (Kerwin 2011, p. 26), and therefore have 
determined that overutilization for commercial, recreational, 
scientific, or educational purposes is not a threat to the mardon 
skipper at the species or subspecies level now or in the future.

Factor C. Disease or Predation

    Disease and predation are usually naturally occurring factors that 
may pose a heightened threat to populations that are vulnerable due to 
other factors, but no specific examples are known for the mardon 
skipper. Predatory insects (ants, wasps, spiders, etc.) commonly prey 
on butterfly eggs, larvae, and pupae (Scott, 1986, p. 70), but no 
studies have specifically researched this aspect of mardon skipper 
ecology. At Puget Prairie sites, mardon skipper larvae were found only 
in the smallest tufts of bunchgrass, while potential larval predators 
(spiders, ants) were commonly observed in larger clumps of bunchgrass 
(Henry 2010, p. 18). The author suggests that larval survival rates 
from predation are likely influenced by the fine-scale structure of 
individual host plants and the density of vegetation surrounding host 
plants, but acknowledged that more research is needed to understand how 
these factors influence mardon skipper survival rates (Henry 2010, p. 
18). We currently have no information indicating mardon skipper 
populations have been negatively affected by disease or predation 
outside the normal range of variability; therefore, we do not consider 
disease or predation to pose a threat to the mardon skipper at the 
species or subspecies levels.

Factor D. The Inadequacy of Existing Regulatory Mechanisms

State Laws

    The mardon skipper is listed as an endangered species in the State 
of Washington by the Washington Fish and Wildlife Commission 
(Washington Administrative Codes 232-12-014, Endangered Species; 232-
12-011, Threatened Species, Appendix D). This designation provides 
protection from directly harming the species (e.g., collecting) (Black 
et al. 2002, p. 19).
    State regulatory mechanisms in the States of Oregon and California 
do not apply to the mardon skipper, as Oregon`s State Endangered 
Species Act does not cover invertebrate species, and California's State 
Endangered Species Act does not apply to insects.
    We have no information to indicate that the inadequacy of existing 
State regulatory mechanisms may pose a threat to the mardon skipper, 
rangewide or at the subspecies level.

Special Status Species Policies on National Forest and BLM Lands

    As discussed above under ``Conservation Measures,'' the mardon 
skipper is listed as a Sensitive Species by the U.S. Forest Service in 
Washington, Oregon (Forest Service Region 6), and California (Forest 
Service Region 5) and as a Special Status Species by the Bureau of Land 
Management (BLM) in Oregon and Washington. We have no information to 
indicate that the inadequacy of existing Federal regulatory mechanisms 
may pose a threat to the mardon skipper, rangewide or at the subspecies 
level.

Summary of the Inadequacy of Existing Regulatory Mechanisms

    When the mardon skipper was originally identified as a Federal 
candidate in 1999, the species had no protection mechanisms under the 
auspices of either State or Federal agencies. Since that time, both 
Federal and State land managers have developed conservation plans and 
policies that provide a high level of protection for the species. 
Existing laws and regulations do not protect mardon skipper habitats 
where they occur on private land. However, there are few mardon skipper 
populations known to occur on private lands. The majority of the 
species' occurrences are on Federal or State lands where the species is 
assured a high level of protection through its recognition as a 
Sensitive Species or Special Status Species (Federal lands) or through 
State Conservation Plans (California, Oregon, and Washington). We did 
not identify any threats to the mardon skipper at either the species or 
subspecies levels that existing regulatory mechanisms have failed to 
address. Therefore, we have no information to indicate that the 
inadequacy of existing regulatory mechanisms is a threat to the mardon

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skipper at either the species or subspecies levels.

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

Application of Pesticides and Herbicides

    Aerial applications of pesticide pose a potential threat to mardon 
skippers. The lepidopteran-specific insecticide, Bacillus thuringiensis 
var. kurstaki (Btk), has been aerially applied to control the Asian 
gypsy moth (Lymantria dispar) in the Puget Sound region, and in the 
Washington Cascades to control spruce budworm (Choristoneura 
occidentalis) (Potter et al. 1999, p. 13). Although grasslands are not 
targeted for application, small meadows may receive aerial applications 
due to the location of these habitats within the wooded target area or 
from aerial drift. Drift from aerial applications can be lethal to non 
target butterflies up to 1.8 miles (3 km) away from the target area in 
steep, mountainous terrain (Whaley et al. 1998, p. 539). Lepidoptera, 
such as the mardon skipper, that are single-brooded, spring-active 
species with caterpillars actively feeding during the application 
period of Btk are especially vulnerable (Wagner and Miller 1995, p. 
21).
    Several of the southern Washington Cascade mardon skipper sites are 
located in areas where widespread applications of Btk were used on 
State, tribal, and private lands to control spruce budworm outbreaks in 
the late 1990s (Potter et al. 1999, p. 13). Btk application is 
implicated in the local decline of at least one mardon skipper 
population on non-Federal lands from 1998 to 2000 (Potter and 
Fleckenstein 2001, pp. 7-8). The use of Btk has diminished in the 
southern Cascades over the past decade as spruce budworm populations 
have declined. There have been no reported applications of Btk on 
Federal lands in close proximity to mardon skipper sites. The risks 
associated with Btk application can be greatly reduced with adequate 
buffers to avoid pesticide drift into sensitive habitats (Black et al. 
2010, p. 19). Although Btk application poses a potential threat to 
mardon skipper populations, we are not aware of any Btk applications 
over the past 10 years that would have had the potential to affect 
mardon skipper populations. The aerial application of pesticides 
remains a potential threat, but any local application of lepidopteran-
specific pesticides on Federal lands will be subject to environmental 
review consistent with National Environmental Policy Act procedures, 
and existing special status/sensitive species policies of the Forest 
Service and BLM are likely to provide for a high level of protection.
    Herbicides are commonly used to manage mardon skipper habitat and 
control invasive nonnative plants in south Puget Sound prairies 
(Schultz et al. 2011, p. 373); and have been used at mardon skipper 
sites on the Gifford Pinchot National Forest. Herbicide use may affect 
mardon skippers by damaging larval or adult food sources, or through 
the direct ingestion of a toxic substance. Loss of non target plants 
can be avoided by using grass-specific herbicides, such as sethoxydim, 
which has been used effectively to control invasive grasses such as 
tall oatgrass, while having minimal impacts on native bunchgrasses and 
forbs (Schultz et al. 2011, p. 373).
    There are currently dozens of herbicide formulations that are 
available for general use. The toxicity of an herbicide to butterflies 
varies from non toxic to potentially lethal depending upon the 
compounds used. All herbicides are required to be tested on honeybees 
(Apis spp.) as part of registration requirements (USFS 2005, p. 252), 
but there are relatively few studies that evaluate the effects of 
herbicides on butterflies (Russell and Schultz 2010, p. 53). One study 
with the Karner blue butterfly (Lycaeides melissa samuelis) found that 
direct applications of some herbicide compounds with glyphosate had no 
apparent effect on egg survival and larval development (Sucoff et al. 
2001, p. 18). However, treatments with a glyphosate-triclopyr mix did 
significantly lower egg hatching rates (Sucoff, et al. 2001, p. 18). 
Use of the grass-specific herbicide compounds sethoxydim or fluazifop-
p-butyl with the non-ionic surfactant Preference can stress 
butterflies, resulting in reduced survival and increased rates of 
development from larvae to adult, as well as decreased wing area in 
some species of butterflies (Russell and Schultz 2010, p. 53). Stark 
and others (2012, pp. 26-27) found that Behr's metalmark butterfly 
(Apodemia virgulti) exposed to field rates of triclopyr, sethoxydim, 
and imazapyr reduced the number of adults that emerged from pupation, 
perhaps due to effects from inert ingredients or indirect effects on 
food plant quality. These studies indicate that direct applications of 
herbicides can result in reduced survival in some butterfly species, 
emphasizing the need for careful management using selective 
applications in habitats occupied by mardon skippers.
    Herbicides are recognized as an important tool for managing 
invasive plants and maintaining habitat for butterflies. Potential 
adverse effects of herbicides to mardon skippers can be minimized 
through selective applications. Federal and State land managers 
currently using herbicides to manage invasive plants at mardon skipper 
sites are using best management practices to minimize effects to non 
target plant species and to butterflies (Hays 2010, p. 1; USFS 2008, p. 
57). These methods include using selective herbicide treatments and 
only treating a small portion of the habitat area within the site in 
any given year (USFS 2008, p. 57; Schultz et al. 2011, p. 373). We 
expect Federal and State land managers will continue to manage sites to 
control invasive weeds and to do so in a way that improves habitat for 
the mardon skipper, while minimizing impacts to local populations as 
outlined in the revised Forest Service/BLM Conservation Assessment for 
the Mardon Skipper (Kerwin 2011, pp. 30-33), and in site-specific plans 
such as those developed on the Gifford Pinchot National Forest (USFS 
2008, p. 57). Based on this information, we do not consider the use of 
herbicides to be a threat to mardon skipper at either the species level 
or subspecies levels.
    Summary: The widespread application of pesticides and herbicides 
may affect the mardon skipper and its habitat. However, there are no 
documented instances of Btk applications occurring on Federal lands in 
close proximity to mardon skipper sites. Further, Federal and State 
land managers have successfully used herbicides to restore and maintain 
mardon skipper habitat at a number of sites in Washington. Based on 
this information, we do not consider the use of pesticides or 
herbicides to be a threat to the species or either subspecies.

Climate Change

    Over the next century, climate change at global and regional scales 
is predicted to result in changes in butterfly species distributions 
and altered life histories (McLaughlin et al. 2002, p. 6074; Hill et 
al. 2002, p. 2163; Singer and Parmesan 2010, p. 3161). Rare 
butterflies, including the mardon skipper, may be vulnerable to climate 
change, as their populations are often fragmented due to habitat losses 
that restrict the species' ability to adapt to changing environmental 
conditions (Schultz et al. 2011, p. 375). Likewise, butterflies with 
limited dispersal capability, such as the mardon skipper, may be 
vulnerable to climate change if suitable alternative

[[Page 54347]]

habitats are not located within the dispersal distance for the species.
    Changes in regional climate can benefit some butterfly species. The 
habitat-generalist Sachem skipper (Atalopedes campestris) has expanded 
its range more than 435 mi (700 km) northward from California into 
central Washington in the last 50 years (Crozier 2004, p. 231). 
Crozier's (2004, p. 231) study suggested that the range expansion has 
been due to a warming trend, and each step in the range expansion 
coincided with warmer winters (which affects larval survival rates). 
Similarly, populations of the silver-spotted skipper (Hesperia comma) 
in southern England have increased over the past 20 years, due in part 
to warmer summer temperatures, which have increased the availability of 
thermally suitable habitats for the species (Davies et al. 2006, p. 
247). Recent butterfly range expansions linked to climate change are 
generally limited to highly mobile, habitat-generalist species, while 
many habitat-specialist butterfly species have declined due to complex 
interactions of climate, habitat loss, and fragmentation (Warren et al. 
2001, p. 65; Hill et al. 2002, p. 2170).
    In the Pacific Northwest, mean annual temperatures rose 0.8 
[deg]Celsius ([deg] C) (1.5 [deg]Fahrenheit ([deg] F)) in the 20th 
century and are expected to continue to warm from 0.1 to 0.6 [deg]C 
(0.2 to 1 [deg]F) per decade (Mote and Salathe 2010, p. 29). Global 
climate models project an increase of 1 to 2 percent in annual average 
precipitation, with some models predicting wetter autumns and winters 
with drier summers (Mote and Salathe 2010, p. 29). Regional models of 
potential climate changes are much more variable, but the models 
generally indicate a warming trend in mean annual temperature, reduced 
snowpack, and increased frequency of extreme weather events (Salathe et 
al. 2010, pp. 72-73). Downscaled regional climate models, such as those 
presented by http://www.climatewizard.org have tremendous variation in 
projections for annual changes in temperature or precipitation 
depending upon the climate model or scenario. Averaged values across 
large areas generally indicate a general warming trend in mean annual 
temperature consistent with the climate projections reported by Salathe 
and others (2010, pp. 72-73).
    Predicted climate changes in the Pacific Northwest have 
implications for forest disturbances that are important for maintaining 
montane meadow habitats. Both the frequency and intensity of wildfires 
and mountain pine beetle (Dendroctonus ponderosae) outbreaks are 
expected to increase over the next century in the Pacific Northwest 
(Littell et al. 2010, p. 130). The gradual loss of montane meadow 
habitats over the past century is linked to fire suppression and lack 
of disturbance. One study in the Cascades found that the majority of 
mesic meadow habitats that were historically burned (1880-1946) have 
contracted over the past half century (Takaoka and Swanson 2008, p. 
539). Increased fires over the next century are likely to result in 
increased meadow habitat and improved connectivity between meadows 
occupied by mardon skippers. Similarly, mountain pine beetle outbreaks 
can result in the widespread mortality of lodgepole pine trees, a 
common tree species that is invading meadow habitats at many mardon 
skipper sites. Where invading trees are killed, marginal areas along 
the edges of existing meadows are likely to revert rapidly back to 
dominance by meadow species (Haugo et al. 2011, p. 17).
    Climate change is also likely to affect the rate of conifer 
succession in montane meadow habitats. A decrease in summer 
precipitation and soil moisture may reduce the rate of conifer 
encroachment in montane meadows at mesic sites (Haugo et al. 2011, p. 
17), which may prove beneficial to mardon skippers by increasing 
available meadow habitats. Increased wildfire or insect disturbances 
associated with climate change are likely to have beneficial effects 
for mardon skippers due to increases in early seral habitat, although 
large wildfires also pose a risk to mardon skippers if all occupied 
habitat in a local area is burned. Because wildfires typically result 
in a mosaic of burned and unburned areas, it is unlikely that increased 
incidence of wildfires associated with climate change would result in 
the loss of multiple populations across large areas within the species' 
or subspecies' range.
    How mardon skipper populations will respond to future climate 
change is unknown. There are no retrospective studies for the species 
that have examined how annual weather patterns such as annual or 
seasonal precipitation, snowpack, and temperature have influenced 
mardon skipper populations from year to year. We do know that prolonged 
periods of cool, wet weather during the spring or summer months can 
delay adult emergence and reduce the abundance of mardon skippers. 
Because the mardon skipper at the species level is distributed across a 
broad range of elevations and habitat types, and has documented use of 
several host-plant species, it may not be as vulnerable to climate 
change as some other narrowly distributed butterfly species. In the 
Washington Cascades the majority of mardon skipper sites occur in the 
mid-elevation montane zone, where there is a potential for upslope 
movement and colonization of higher elevation habitats in response to 
climate change over time. Based on the above information, we do not 
have data to suggest that climate change poses a threat to the species 
Polites mardon, or the subspecies Polites mardon mardon.
    Discussion specific to Polites mardon klamathensis
    Populations of Polites mardon klamathensis may be vulnerable to the 
effects of climate change due to the subspecies' limited distribution, 
apparently smaller populations, and limited dispersal capability. All 
P.m. klamathensis sites are located in the high-elevation montane zone 
of the southern Oregon Cascades, where there is little potential for 
upslope movement or colonization of higher elevation habitats in 
response to climate change over time. Regional models of potential 
climate changes in the Pacific Northwest are variable, but the models 
generally indicate a warming trend in mean temperature, reduced 
snowpack, and increased frequency of extreme weather events (Salathe et 
al. 2010, pp. 72-73). All P.m. klamathensis sites are associated with 
mesic soils and permanent or ephemeral water sources (Black et al. 
2010, p. 12).
    Black et al. (2010, p. 60) notes that habitat within portions of 
the meadow complex are marginal for P.m. klamathensis because the sites 
are currently too dry, but the habitat may have been wetter in the 
past. Runquist (2004a, p. 5) observed over 200 skippers at this complex 
in 2002. Although multi day surveys have not been completed here, the 
population at this meadow complex appears to have declined (Black et 
al. 2010, pp. 60-61).
    Given the restricted distribution of P.m. klamathensis, and the 
strong association of the subspecies with mesic sites, a projected 
warming trend in regional climate is a potential concern for P.m. 
klamathensis, depending on the changes in the environment that may 
manifest as a result. We acknowledge this concern and the need for 
monitoring of these populations in the face of climate change. However, 
at the present time, due to the multiple uncertainties associated with 
regional climate models, the actual changes that may be realized and 
how they would impact the species, the timeframes involved, and the 
questions surrounding P.m. klamathensis abundance information, we can 
not conclude that

[[Page 54348]]

climate change is a threat to P.m. klamathensis or likely to become so.
    Summary: Because the mardon skipper is distributed across a range 
of elevations and habitat types, and has documented use of several 
host-plant species, it may not be as vulnerable to climate change as 
some other narrowly distributed species. Despite the potential for 
future climate change in the Pacific Northwest as discussed above, we 
have not identified, nor are we aware of, any data on an appropriate 
scale to evaluate habitat or population trends for the mardon skipper 
or to make reliable predictions about future trends and whether the 
species will be significantly impacted. Due to the uncertainty 
associated with regional climate models and how any potential 
environmental changes may possibly impact the species, we conclude that 
climate change is not a threat to mardon skippers at the species or 
subspecies levels or likely to become so.

Stochastic Weather Events and Small, Isolated Populations

    Adverse weather (freezing temperatures, heavy rain events, or 
prolonged drought) can extirpate local butterfly populations by killing 
adults, larvae, or larval food plants (Guppy and Shephard 2001, p. 59). 
Even large populations of butterflies (greater than 5,000 individuals) 
can rapidly decline in response to successive seasons of unfavorable 
weather conditions during reproduction and larval development (Ehrlich 
et al. 1980, pp. 102-103). The decline in mardon skipper numbers at 
some Washington Cascades sites in 2009 is an example of how variations 
in seasonal weather can have a profound effect on local mardon skipper 
populations. The exact weather event that caused the decline is 
unknown, but unseasonably warm weather in May and June caused a rapid 
snowmelt to occur in these high-elevation meadows, followed by at least 
4 days of freezing temperatures in late June during the period when 
mardon skipper adults typically emerge (Kogut 2009, p. 1). The adult 
flight period in 2009 occurred later, in mid-July, and was very brief, 
and the total numbers of adults were approximately 80 to 95 percent 
less than what had typically been counted at these sites during the 
previous 6 years (Kogut 2009, p. 1).
    The weather effect was not limited to mardon skippers; other 
butterfly species were also affected, including the closely related 
Sonora skipper (Polites sonora), which was apparently absent from all 
sites where the species commonly co-occurs with mardon skippers at 
Cowlitz Valley (Kogut 2009, p. 1). The apparent weather-related effect 
was also noted at sites on the adjacent Wenatchee-Okanogan National 
Forest, where the emergence of adults occurred later, and the adult 
flight period was shorter than in previous years (St. Hilaire et al. 
2009, p. 2), although the effect to the populations was not as severe 
as that seen on the Gifford Pinchot National Forest. Populations at 
lower elevation sites did not appear to be affected by these same 
weather events (St. Hilaire et al. 2009, p. 3). Subsequent years (2010 
and 2011) have generally been cool and wet during the mardon skipper 
flight season, so the populations at the Cowlitz Valley sites have not 
recovered and have continued to gradually decline since 2009, but 
populations at other locations in the Washington Cascades have not 
shown a similar pattern of decline and are apparently stable. It is 
evident that adverse weather conditions can profoundly impact local 
mardon skipper populations. Because the species occurs across a broad 
range of elevations and habitat types, it is unlikely that a stochastic 
weather event is likely to affect all populations simultaneously.
    Butterfly populations with very low numbers of individuals (e.g., 
fewer than 20 butterflies) are vulnerable to extirpation from random 
events such as inclement weather, wildfire, or other potential threats 
identified above (e.g., Schtickzelle et al. 2005, p. 578). There are a 
number of studies that demonstrate that habitat patch size, local 
population size, and proximity to adjacent populations have important 
implications for the long-term persistence of butterfly populations 
with limited dispersal capabilities (e.g., Thomas and Jones, 1993, p. 
472; Hanski et al. 1995, p. 618; Saccheri et al. 1998, p. 492; Maes et 
al. 2004, pp. 234-235). Studies that examined butterfly population 
dynamics generally define ``small'' populations as having fewer than 
500 adults and ``very small'' as having fewer than 100 adults at peak 
emergence (e.g., Maes et al. 2004, p. 232; Davies et al. 2005, p. 192). 
(As described below, for mardon skippers, counts of at least 100 
individuals are generally considered to be large). Extremely small 
butterfly populations (fewer than 20 individuals) are not only highly 
vulnerable to environmental factors such as adverse weather conditions 
(Schtickzelle et al. 2005, p. 578), but such small populations are also 
at increased risk of extinction due to genetic effects associated with 
inbreeding (Saccheri et al. 1998, p. 491; Nieminen et al. 2001, p. 
243). Inbreeding in small populations of the Glanville fritillary 
butterfly (Melitaea cinxia) resulted in reduced egg hatching rates, 
larval survival, and adult longevity (Nieminen et al. 2001, p. 243).
    Long-term studies of the silver-spotted skipper (Hesperia comma) in 
England have documented a series of local population extinctions and 
colonizations over a 20-year period (Thomas and Jones 1993, p. 472; 
Davies et al. 2005, p. 189). These studies found that large habitat 
patches tended to support large populations of skippers, and that no 
extinctions occurred in habitat patches that supported populations of 
greater than 225 individuals; sites with 10 populations of fewer than 
225 skippers, however, went extinct and the probability of extinction 
increased with isolation from the nearest population (Thomas and Jones 
1993, pp. 476-478). Populations of silver-spotted skipper have expanded 
in recent years, and most of the sites that had documented extinctions 
in 1991 have subsequently been recolonized by dispersing individuals 
from adjacent sites (Davies et al. 2005, p. 195).
    Most populations of mardon skippers consist of a series of one or 
more occupied meadows located within close proximity to each other. 
These populations or local ``clusters'' of sites likely function as 
small metapopulations with some dispersal of individuals between local 
sites (Kerwin 2011, pp. 21-23). Mardon skipper ``metapopulations'' 
likely experience local site-scale extinctions and recolonizations as 
local populations expand and contract in response to changing climate 
or habitat conditions, such as with the silver-spotted skipper in 
England (Davies et al. 2005, p. 195), although on a smaller scale, as 
silver-spotted skippers likely have greater dispersal capability than 
mardon skippers (Kerwin 2011, p. 23). However, there is strong evidence 
that mardon skippers exhibit similar metapopulation dynamics. The large 
number of mardon skipper sites in the Washington Cascades that are 
located in young clearcuts or roadside areas that were previously 
forested demonstrate that the species is capable of dispersing away 
from their core habitats and colonizing adjacent early-seral habitats 
that support host grasses and forbs (e.g., Kerwin 2011, p. 14).
    Mardon skippers can be locally abundant where the species is 
present (Pyle 1989, p. 28) with single-day counts of greater than 100 
individuals documented at many sites across the species' entire 
geographic range (for the mardon skipper, populations in the hundreds 
are relatively large) (Black et al. 2010, pp. 70-71; St. Hilaire et al.

[[Page 54349]]

2010, pp.10-12; Black et al. 2011, p. 13). Conversely, there are a 
number of apparently very small populations within the species' range 
with peak counts of fewer than 20 individuals. Because the number of 
mardon skippers present at a site can vary tremendously over the course 
of a few days (Beyer and Black 2007, p. 8), and the timing of the 
flight period can vary due to a variety of conditions, including 
elevation and weather conditions, there is little certainty of actual 
population sizes associated with these individual day counts. A single 
day, peak count of 100 skippers potentially represents a total 
population of more than 200 skippers based on observations during an 
experimental mark-recapture study (Runquist 2004a, p. 5), because not 
all butterflies emerge on the same date, and not all butterflies 
present at a site are likely to be counted during a survey.
    Since 1999, mardon skippers have been documented at approximately 
165 sites across the species' range. Considering that local clusters of 
sites likely function as small metapopulations, there are approximately 
66 populations of mardon skippers currently known, and, with the 
exception of the Puget prairies, it is likely that there are additional 
undocumented populations present in all portions of the species' range 
because not all suitable habitats have been searched for mardon 
skippers (Kerwin 2011, p. 18). Each region within the species' range 
supports one or more ``large'' populations of mardon skippers (in the 
case of the mardon skipper, ``large'' is defined as single-day counts 
of more than 100 individuals, which likely represents a much larger 
total population).
    All extant Puget prairie sites likely support total populations 
from more than 100 up to 1,000 individuals (Schultz et al. 2011, p. 
370). The largest mardon skipper populations occur in the Washington 
Cascades, with at least 2 populations of greater than 1,000 
individuals, and at least 11 other populations that have supported 
populations from 100 to 400 skippers over the past decade (unpublished 
data). In the Oregon Cascades, there are 2 populations that number from 
100 to 300 individuals, and in the coastal areas of northwest 
California/southwestern Oregon, there are at least 3 populations with 
more than 100 individuals. In total, at least 22 of the approximately 
66 populations rangewide support large populations of mardon skippers, 
and these sites represent the majority of the species' total 
populations.
    Conversely, there are many individual ``sites'' with single-day 
counts of fewer than 20 individuals. Most of these sites are closely 
associated with larger local populations. A few sites may represent 
small, isolated populations that are vulnerable to local extirpation 
associated with stochastic weather events, but these generally 
represent only a small portion of the total species' populations. 
Because the mardon skipper has presumably limited dispersal 
capabilities, if an isolated population were to become extirpated, some 
isolated sites are unlikely to be reestablished due to long distances 
or physical barriers (e.g., extensive forested areas) between extant 
populations (Kerwin 2011, p. 23).
    The mardon skipper is a naturally rare species across its disjunct 
range. Given the limited information concerning mardon skipper 
population trends rangewide, and the presence of multiple ``large'' 
populations in each distinct region within the species range, the 
majority of the species' total populations appear to be relatively 
secure from threats associated with small populations.
    Discussion specific to Polites mardon klamathensis:
    The distribution of Polites mardon klamathensis appears to be 
restricted to 22 sites likely representing approximately 11 populations 
in the southern Oregon Cascades. Surveys in recent years have searched 
over 200 sites in the vicinity of these known populations and have 
failed to detect the species, indicating the subspecies is highly 
restricted in its distribution to a few small meadow complexes within a 
small geographic area (Black et al. 2010, p. 7). However, one small 
site was documented on Bureau of Reclamation lands managed by BLM in 
2011 (Black 2012, pers. comm.), indicating it is possible that 
additional undocumented P.m. klamathensis sites may exist in the area. 
Although populations of P.m. klamathensis appear to be relatively 
small, it is difficult to draw any reliable conclusions on population 
sizes based on the limited data available, since the majority of sites 
have only been visited once during the flight season in recent years 
(Black et al. 2010, pp. 70-72). Additional multiple-day surveys are 
needed to confirm if populations are as small as they appear based on 
the limited survey data collected thus far, or whether past single-day 
counts may have just missed the peak flight period. As discussed 
earlier, due to the variability of mardon flight periods between sites 
and years, as well as extreme fluctuations in numbers of individuals 
that may be present from day to day, a single-day survey in a year is 
insufficient to indicate trends or abundance.
    In summary, total population sizes at all Polites mardon 
klamathensis sites are unknown due to limited surveys, although counts 
at most sites indicate that populations of this subspecies may be 
relatively small. Unfortunately the high variability in potential 
counts from day to day for this subspecies undermines the credibility 
of any single-day counts for the purpose of determining population 
status or trend, and raises questions as to whether counts of zero or 
few individuals on any one day accurately reflect population numbers or 
abundance. Based on the lack of historical abundance information and 
the uncertainty accompanying the numbers of individuals associated with 
individual day counts, we do not have reliable information to suggest 
that P.m. klamathensis is such a small isolated population that 
stochastic weather events would pose a significant threat to the 
subspecies as a whole.
    Summary: Prolonged periods of cool wet weather during the spring 
and summer months are known to negatively affect mardon skipper 
populations. Small butterfly populations are particularly vulnerable to 
these effects. Given the limited information concerning mardon skipper 
population trends rangewide, and the presence of multiple ``large'' 
populations in each distinct region within the species' range, the 
majority of the species' total populations and those of the subspecies 
Polites mardon mardon appear to be relatively secure from threats 
associated with small populations. Additionally, due to the limited 
population and abundance information we have for the the subspecies 
Polites mardon klamathensis, we conclude that we do not have reliable 
information to indicate that populations of this subspecies are so 
small or isolated as to represent a threat to P.m. klamathensis as a 
whole.

Finding

    As required by the Act, we considered the five factors in assessing 
whether the mardon skipper is a threatened or endangered species 
throughout all of its range. We additionally considered whether either 
of the two recognized subspecies comprising the species mardon skipper 
may be a threatened or endangered species throughout all or a 
significant portion of their ranges. We examined the best scientific 
and commercial information available regarding the past, present, and 
future threats faced by the mardon skipper and its subspecies. We 
reviewed the petition, information available in our

[[Page 54350]]

files, other available published and unpublished information, and 
consulted with recognized mardon skipper experts and other Federal, 
State, and tribal agencies.

The Species Mardon Skipper (Polites mardon)

    The mardon skipper is a little-studied species; however, the 
species has received considerable attention and funding for surveys 
since becoming a Federal candidate species in 1999. The number of 
documented locations of mardon skippers has expanded from fewer than 10 
in 1998 to 165 in 2011; this increase in known occurrences of the 
species is largely due to increased survey effort. Since 1999, new site 
locations have been documented each year that targeted surveys have 
been conducted. In the past 5 years, significant new populations have 
been located in the Washington Cascades and in coastal areas of Oregon 
and California, with local sites supporting populations of hundreds of 
mardon skippers. It is likely that there are additional, undocumented 
populations, particularly in the Washington Cascades, and possibly in 
southwestern Oregon and northern California because not all available 
habitat for the species has yet been surveyed. The majority of the 
sites throughout the species' range occur on Federal lands managed by 
the Forest Service, Bureau of Land Management, National Park Service, 
Fish and Wildlife Service, and the Department of Defense (76 percent).
    Current management actions, policies, and protections associated 
with State and Federal special-status-species programs now afford the 
species a high level of security from habitat loss or destruction 
across the species' range. Potential threats to mardon skipper habitat 
associated with forest succession, fire, invasive nonnative plants, 
livestock grazing, and off-road vehicle use have been substantially 
reduced or eliminated on State and Federal lands through the 
development of conservations plans and implementation of habitat 
restoration projects. Habitat degradation associated with intensive 
livestock grazing continues to occur at some sites, but grazing impacts 
have been substantially reduced or eliminated at many key sites across 
the species' range with recent closures of Federal grazing allotments. 
Habitat degradation from off-road vehicle use has been reduced or 
eliminated at many sites by installing vehicle barriers or closing 
roads. Meadow habitat restoration activities (prescribed burning, 
herbicide treatments) can be lethal to mardon skippers if not conducted 
properly, but these risks have been minimized through careful planning 
and implementation of habitat restoration projects. Ongoing threats 
that are not currently addressed by existing conservation plans include 
potential habitat loss on private lands, but there are relatively few 
known mardon skipper sites on private lands. Climate change may affect 
the mardon skipper and its habitat. Because the mardon skipper is 
distributed across a range of elevations and habitat types, and has 
documented use of multiple host-plant species, it may not be as 
vulnerable to climate change as some other more narrowly distributed 
specialist species.
    Based on our review of the best available scientific and commercial 
information pertaining to the five factors, we find that the threats 
are not so severe or broad in scope as to indicate that the mardon 
skipper is in danger of extinction (endangered), or likely to become 
endangered within the foreseeable future (threatened), throughout all 
of its range. Therefore, we find that the mardon skipper does not meet 
the definition of an endangered or threatened species throughout its 
range.
    The mardon skipper is listed as endangered by the State of 
Washington. Washington's listing of the mardon skipper was based on a 
status assessment of the species conducted in 1999 (Potter 1999), and 
relied on much of the same information that the Service considered in 
placing the mardon skipper on the candidate list that same year. A 
substantial amount of new information has become available since that 
time, however, which we have evaluated in making the present finding. 
Although the State of Washington has updated information on new 
population data and conservation efforts for the mardon skipper in 
their annual reports, they have not reconsidered the listed status of 
the species based on this information. Our analysis of the best 
available information considers the many positive conservation measures 
that have been implemented by both Federal and State agencies 
throughout the range of the mardon skipper, including actions by the 
State of Washington, to recover the species and ameliorate the threats 
that initially led to its State listing and Federal candidacy 13 years 
ago. In addition, we considered the numerous additional populations of 
the species (and subspecies) that have been documented since the mardon 
skipper first became a Federal candidate and was listed by the State. 
Our current evaluation of the best available information according to 
the Federal Endangered Species Act, as detailed in this finding, does 
not lead us to conclude that the mardon skipper meets the definition of 
an endangered species or threatened species throughout all or a 
significant portion of its range.
    The Subspecies Polites mardon mardon and Polites mardon 
klamathensis

Polites mardon mardon

    Polites mardon mardon faces the same threats as discussed in the 
rangewide evaluation previously, and we consider all conclusions 
reached regarding the degree of threat for the species as a whole to 
apply equally to the subspecies P. m. mardon. As a result, we find that 
this subspecies does not meet the definition of an endangered or 
threatened species throughout its range.

Polites mardon klamathensis

    Polites mardon klamathensis faces the same threats as discussed in 
the rangewide evaluation previously; however, where relevant we have 
assessed threats specific or unique to the subspecies Polites mardon 
klamathensis separately throughout the rangewide evaluation. In 
general, we consider all conclusions reached regarding the degree of 
threat for the species as a whole to apply equally to the subspecies P. 
m klamathensis. As a result, we find that this subspecies does not meet 
the definition of an endangered or threatened species throughout its 
range.

Significant Portion of the Range

    Having determined that the species Polites mardon and the 
subspecies Polites mardon. mardon and Polites mardon klamathensis do 
not meet the definition of a threatened or endangered species, we next 
consider whether there are any significant portions of the range where 
the mardon skipper is in danger of extinction or is likely to become in 
danger of extinction in the foreseeable future.
    In determining whether a species is a threatened or endangered 
species in a significant portion of its range, we first identify any 
portions of the range of the species that warrant further 
consideration. The range of a species can theoretically be divided into 
portions an infinite number of ways. However, there is no purpose to 
analyzing portions of the range that are not reasonably likely to be 
both (1) significant and (2) meeting the definition of a threatened or 
endangered species. To identify only those portions that warrant 
further consideration, we

[[Page 54351]]

determine whether there is substantial information indicating that: (1) 
The portions may be significant, and (2) the species may be in danger 
of extinction there or likely to become so within the foreseeable 
future. In practice, a key part of this analysis is whether the threats 
are geographically concentrated in some way. If the threats to the 
species are essentially uniform throughout its range, no portion is 
likely to warrant further consideration. Moreover, if any concentration 
of threats applies only to portions of the species' range that are not 
significant, such portions will not warrant further consideration.
    If we identify portions that warrant further consideration, we then 
determine whether the species is threatened or endangered in these 
portions of its range. Depending on the biology of the species, its 
range, and the threats it faces, the Service may address either the 
significance question or the status question first. Thus, if the 
Service considers significance first and determines that a portion of 
the range is not significant, the Service need not determine whether 
the species is threatened or endangered there. Likewise, if the Service 
considers status first and determines that the species is not 
threatened or endangered in a portion of its range, the Service need 
not determine if that portion is significant.
    Applying the process described above for determining whether a 
species is threatened or endangered in a significant portion of its 
range, we considered the status question first to determine if any 
threats or potential threats acting individually or collectively 
threaten or endanger the species in some portion of its range. In 
analyzing the status of the mardon skipper across its range, the only 
area we identified where threats may be concentrated is the Puget 
prairies. We therefore considered whether the threats to the Puget 
prairie populations of Polites mardon or Polites mardon mardon are such 
that the species may be in danger of extinction there, now or within 
the foreseeable future, such that the Puget prairie populations may 
warrant further consideration as a potential significant portion of the 
range.
    Although the rangewide mardon skipper population is relatively 
secure under current conditions, the Puget prairies represent the only 
portion of the species' historical and current distribution where there 
are confirmed extirpations of historical populations, and we can 
reasonably infer that the species' range has contracted due to the 
historical loss of Puget prairie habitat over the past century. We 
therefore considered the likely future condition of the Puget prairie 
populations under the presently observed rates of population change. 
Historically, mardon skippers were known to be present at eight Puget 
prairie sites, and are currently restricted to three known populations. 
The trends of the remaining populations are unknown due to limited and 
inconsistent monitoring data, but appear to have been relatively stable 
over the past decade, with 2 populations estimated to consist of 
hundreds of mardon skippers, and 1 population with likely over 1,000 
skippers (Schultz et al. 2011, p. 370). Puget prairie sites with extant 
populations of mardon skippers are protected from further development 
through either State or Federal ownership. Mardon skipper habitat at 
these sites is: (1) Actively being managed to restore and maintain 
mardon skippers and other prairie species; or (2) at Joint Base Lewis-
McChord being maintained by regular wildfires, and large areas of 
habitat are protected from development, off-road vehicle use, and 
military training due to the presence of unexploded ordnance. In 
addition, Joint Base Lewis-McChord is cooperating in an interagency 
effort to restore and maintain prairie habitats for the mardon skipper 
and other prairie species, discussed below.
    Remaining prairie habitats in the south Puget Sound region are 
relatively small, isolated patches with little potential connectivity 
between patches (Schultz et al. 2011, p. 371). Because of this, 
historical prairie sites where mardon skippers have been extirpated are 
unlikely to be recolonized due to isolation from extant populations 
(Schultz et al. 2011, p. 371). There are a number of small prairie 
sites in the region that are currently in protected status and are 
actively being managed to maintain butterfly habitats that may serve as 
potential future reintroduction sites for mardon skippers (Anderson 
2008, p. 2; Henry 2010, pp. 3-4). Beginning in 2007, the Joint Base 
Lewis-McChord Army Compatible Use Buffer (ACUB) initiative has 
supported the convening of a cooperative, interdisciplinary and 
interagency Butterfly Habitat Enhancement Team to develop and implement 
habitat improvements for mardon skipper and other rare butterflies on 
formerly occupied sites off the military reservation (Anderson 2008, p. 
1). This interagency team is a source of funding for mardon skipper 
habitat management, population assessments, and mardon skipper life-
history research at Puget prairie sites. These projects continue to 
maintain habitat and mardon skipper populations at the Scatter Creek 
Wildlife Area. The ongoing management to maintain mardon skipper 
populations and habitat at Puget prairie sites afford the species a 
high level of protection against further losses of habitat or 
populations. Because these conservation efforts have been implemented, 
are effective, and are expected to continue, we consider the Puget 
prairie population of the mardon skipper as not likely to become in 
danger of extinction within the foreseeable future.
    As the best available information indicates that the Puget prairie 
population of mardon skipper at either the species or subspecies level 
is not likely to become in danger of extinction within the foreseeable 
future, we conclude that Puget prairie does not warrant further 
consideration as a potential significant portion of the range at this 
point in time. We did not identify any other potential significant 
portions of the range of the mardon skipper (Polites mardon, Polites 
mardon mardon, or Polites mardon klamathensis) that may meet the 
definition of a threatened or endangered species.
    In Defenders of Wildlife v. Norton, 258 F.3d 1136, 1145 (9th Cir. 
2001), the court ruled that a species may be an endangered species in a 
significant portion of its range ``if there are major geographical 
areas in which it is no longer viable but once was.'' Where the area in 
which the species is expected to survive is ``much smaller than its 
historical range,'' the determination of whether the species warrants 
listing turns on whether the lost portion of the range would be 
significant. As discussed above, the Puget Prairie population of the 
mardon skipper is the only portion of the species' range that is known 
to have contracted from the historical distribution. We conclude that 
current and future conservation efforts are expected to maintain mardon 
skippers and restore the species to additional Puget prairie habitats. 
Therefore, we have determined that neither the full species mardon 
skipper, nor the subspecies Polites mardon mardon or Polites mardon 
klamathensis, is an endangered or threatened species in a significant 
portion of its range.
    We do not find that the mardon skipper, or the subspecies Polites 
mardon mardon or Polites mardon klamathensis, are in danger of 
extinction now, nor are they likely to become in danger of extinction 
within the foreseeable future throughout all or a significant portion 
of their range. Therefore, listing the mardon skipper Polites mardon, 
the subspecies P. m.

[[Page 54352]]

mardon, or the subspecies Polites mardon klamathensis, as a threatened 
or endangered species under the Act is not warranted at this time.
    We request that you submit any new information concerning the 
status of, or threats to, the mardon skipper to our Washington Fish and 
Wildlife Office (see ADDRESSES section) whenever it becomes available. 
New information will help us monitor the mardon skipper and encourage 
its conservation. If an emergency situation develops for the mardon 
skipper or any other species, we will act to provide immediate 
protection.
    We will continue to monitor the condition of the mardon skipper 
throughout its range. In the event that conditions or threats change 
and the species becomes imperiled, we could again consider whether it 
is appropriate to list the species as endangered or threatened under 
the Act. We will continue to provide technical assistance to Federal, 
State, and other entities and encourage them to address the 
conservation needs of the mardon skipper. We will continue to work with 
these agencies and entities to collect additional biological 
information, monitor the status of the mardon skipper, and monitor the 
progress of its conservation efforts.

References Cited

    A complete list of references cited is available on the Internet at 
http://www.regulations.gov and upon request from the Washington Fish 
and Wildlife Office (see ADDRESSES section).

Author(s)

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

Authority

    The authority for this section is section 4 of the Endangered 
Species Act of 1973, as amended (16 U.S.C. 1531 et seq.).

    Dated: August 20, 2012.
Benjamin N. Tuggle,
Acting Director, Fish and Wildlife Service.
[FR Doc. 2012-21344 Filed 8-31-12; 8:45 am]
BILLING CODE 4310-55-P