[Federal Register Volume 87, Number 196 (Wednesday, October 12, 2022)]
[Proposed Rules]
[Pages 61834-61868]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-21659]
[[Page 61833]]
Vol. 87
Wednesday,
No. 196
October 12, 2022
Part III
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; Finding for the Gopher
Tortoise Eastern and Western Distinct Population Segments; Proposed
Rule
Federal Register / Vol. 87, No. 196 / Wednesday, October 12, 2022 /
Proposed Rules
[[Page 61834]]
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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS-R4-ES-2009-0029; FF09E21000 FXES1111090FEDR 223]
Endangered and Threatened Wildlife and Plants; Finding for the
Gopher Tortoise Eastern and Western Distinct Population Segments
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Notification of findings.
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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce
findings on the status of the gopher tortoise (Gopherus polyphemus)
rangewide and in the eastern (east of the Mobile and Tombigbee Rivers)
and western (west of the Mobile and Tombigbee Rivers) portions of the
range under the Endangered Species Act of 1973, as amended (Act). After
a review of the best available scientific and commercial information,
we find that listing the gopher tortoise as an endangered or a
threatened species rangewide is not warranted. We find that the gopher
tortoise in the eastern portion of its range and the gopher tortoise in
the western portion of its range meet the criteria of separate distinct
population segments (DPS), as defined by our Policy Regarding the
Recognition of Distinct Vertebrate Population Segments Under the
Endangered Species Act. We determine the Eastern DPS of the gopher
tortoise is not warranted for listing at this time. Further, we confirm
that the Western DPS of the gopher tortoise meets the definition of a
threatened species. Additionally, this notice serves as our completed
5-year review of the Western DPS of the gopher tortoise. We ask the
public to submit to us any new information that becomes available
concerning the threats to the gopher tortoise or its habitat at any
time.
DATES: The finding announced in this document was made on October 12,
2022.
ADDRESSES: This finding is available on the internet at https://www.regulations.gov at Docket No. FWS-R4-ES-2009-0029. Supporting
information that we developed for this finding including the species
status assessment report, peer review, and future condition modeling,
are found in the decision file available at https://www.regulations.gov
at Docket No. FWS-R4-ES-2009-0029 and on the Service's website at
https://www.fws.gov/office/florida-ecological-services/library, and is
available for public inspection, by appointment, during normal business
hours at the U.S. Fish and Wildlife Service, Florida Field Office, 7915
Baymeadows Way, Suite 200, Jacksonville, FL 32256. Please submit any
new information or materials concerning this finding to the above
address.
FOR FURTHER INFORMATION CONTACT: Lourdes Mena, Division Manager,
Florida Classification and Recovery, U.S. Fish and Wildlife Service,
Florida Ecological Services Field Office, 7915 Baymeadows Way, Suite
200, Jacksonville, FL 32256-7517; telephone 904-731-3134; or James
Austin, Acting Field Supervisor, Mississippi Ecological Services Field
Office, 6578 Dogwood View Parkway, Jackson, MS 39213; telephone 601-
321-1129. Individuals in the United States who are deaf, deafblind,
hard of hearing, or have a speech disability may dial 711 (TTY, TTDD,
or TeleBraille) to access telecommunications relay services.
Individuals outside the United States should use the relay services
offered within their country to make international calls to the point-
of-contact in the United States.
SUPPLEMENTARY INFORMATION:
Previous Federal Actions
On July 7, 1987, the gopher tortoise (Gopherus polyphemus) was
listed under the Act as a threatened species (52 FR 25376) in the
western portion of its range, from the Tombigbee and Mobile Rivers in
Alabama west to southeastern Louisiana on the lower Gulf Coastal Plain.
On January 18, 2006, we received a petition dated January 13, 2006,
from Save Our Big Scrub, Inc. and Wild South requesting that the
population of the gopher tortoise in the eastern portion of its range
be listed as a threatened species under the Act and critical habitat be
designated. On September 9, 2009, we published a 90-day finding (74 FR
46401) that the petition contained substantial information indicating
that listing may be warranted for the eastern population of the gopher
tortoise. On July 27, 2011, we published a 12-month finding (76 FR
45130) on the petition to list the gopher tortoise in the eastern
portion of its range, and, in that finding, we evaluated the status of
the gopher tortoise in the western portion of its range. We reaffirmed
that the gopher tortoise warranted listing as a threatened species in
the western portion of its range. We found the gopher tortoise in the
eastern portion of its range was warranted for listing but precluded by
higher priority listing actions (warranted but precluded finding).
The species was placed on the candidate list (our list of species
that have been found to warrant listing, but which are precluded by
higher priority listing actions) and received a listing priority number
of 8 based on the magnitude and immediacy of the threats. The eastern
population of gopher tortoise was included in subsequent annual
candidate notices of review (CNORs) (76 FR 66370, October 26, 2011; 77
FR 69994, November 21, 2012; 78 FR 70104, November 22, 2013; 79 FR
72450, December 5, 2014; 80 FR 80584, December 24, 2015; 81 FR 87246,
December 2, 2016; 84 FR 54732, October 10, 2019; 85 FR 73164, November
16, 2020; 87 FR 26152, May 3, 2022).
On April 1, 2021, the Center for Biological Diversity (CBD) filed a
complaint alleging our ``warranted but precluded'' finding for the
eastern population of the gopher tortoise violated the Act because we
were not making ``expeditious progress'' in adding qualified species to
the lists of endangered or threatened species and because we had not
shown that the immediate proposal of the eastern population of the
gopher tortoise was precluded by higher priority actions consistent
with 16 U.S.C. 1533(b)(3)(B)(iii). On April 26, 2022, the Service
entered into a court-approved settlement agreement with CBD requiring
the Service to submit either a warranted or a not warranted finding for
the eastern population of gopher tortoise to the Federal Register by
September 30, 2022.
On June 20, 2019, we initiated a 5-year review for the western
population of the gopher tortoise (84 FR 28850), and this document
completes our status review under section 4(c)(2) of the Act. See
https://ecos.fws.gov/ecp/species/C044 for the species profile for the
gopher tortoise.
Supporting Documents
A species status assessment (SSA) team prepared an SSA report for
the gopher tortoise. The SSA team was composed of Service biologists,
in consultation with other species experts. The SSA report represents
compilations of the best scientific and commercial data available
concerning the status of the species, including the impacts of past,
present, and future factors (both negative and beneficial) affecting
the species. In accordance with our joint policy on peer review
published in the Federal Register on July 1, 1994 (59 FR 34270), and
our August 22, 2016, memorandum updating and clarifying the role of
peer review of listing actions
[[Page 61835]]
under the Act, we sought the expert opinions of seven appropriate
specialists regarding the gopher tortoise SSA. We received responses
from two peer reviewers. We coordinated with the nine Tribal nations in
the range of the species early in the SSA process for the gopher
tortoise, including the Catawba Nation, the Jena Band of Choctaw
Indians, the Tunica-Biloxi Indian Tribe, the Miccosukee Tribe of
Indians, the Seminole Tribe of Florida, the Chitimacha Tribe of
Louisiana, the Coushatta Tribe of Louisiana, the Mississippi Band of
Choctaw Indians, and the Poarch Band of Creek Indians. We sent the
draft SSA report for review to 10 Tribes (with the addition of the
Cherokee Nation).
Background
Species Information
In this section, we present an overview of the biological
information for gopher tortoise. A more thorough review of the
taxonomy, species description, life history, species needs, and ecology
of the gopher tortoise is presented in detail in the SSA report
(Service 2022, pp. 24-45).
Taxonomy and Species Description
The gopher tortoise is the only tortoise (family Testudinidae) east
of the Mississippi River; one of six species in the genus Gopherus in
North America (Ernst and Lovich 2009, p. 581; Edwards et al. 2016, p.
131). The scientific name, Gopherus polyphemus, has remained unchanged
since it was first described by F.M. Daudin in 1802. There is no
taxonomic distinction between the gopher tortoise in the western and
eastern portions of its range or at any level of geographic
subdivision. However, genetic differences do occur in populations
across the range of the species. Genetic variation across the range is
best explained by the geographic features of the Apalachicola-
Chattahoochee River system and the Mobile and Tombigbee Rivers in
Alabama (Osentoski and Lamb 1995, p. 709; Clostio et al. 2012, pp. 613-
625; Ennen et al. 2012, pp. 110-122; Gaillard et al. 2017, p. 497) (see
Genetics section below for more information).
The gopher tortoise is larger than any other terrestrial turtle in
the Southeast and is characterized by a domed, dark brown to grayish-
black carapace (upper shell) and a yellowish plastron (lower shell).
Adult gopher tortoises are typically 10 to 12 inches (in) (25.4 to 30.5
centimeters (cm)) long and weigh 9 to 13 pounds (4 to 6 kilograms)
(Ernst et al. 1994, p. 466; Ashton and Ashton 2008, p. 17; Bramble and
Hutchison 2014, p. 4). Hatchlings are up to 2 in (5 cm) in length, with
a somewhat soft, yellow-orange shell. When young, female gopher
tortoises may be smaller than males, but, as adults, female tortoises
are generally larger than males. Females have a flat plastron, while
that of males is more concave. Male gopher tortoises can also be
distinguished by a larger gland under the chin and a longer throat
projection. As a fossorial species, its hind feet are elephantine or
stumpy, and the forelimbs are shovel-like, with claws used for digging.
Range and Distribution
The gopher tortoise occurs in the Southeastern Atlantic and Gulf
Coastal Plains from southern South Carolina, west through Georgia, the
Florida panhandle, Alabama, and Mississippi to eastern Louisiana, and
south through peninsular Florida (Auffenberg and Franz 1982, p. 95).
The current range of the gopher tortoise generally aligns with the
species' historical range and the historical range of the longleaf pine
ecosystem (Auffenberg and Franz 1982, pp. 99-120). The eastern portion
of the gopher tortoise's range includes Alabama (east of the Tombigbee
and Mobile Rivers), Florida, Georgia, and southern South Carolina. The
western portion of the range includes areas west of the Tombigbee River
in Alabama, Mississippi, and Louisiana.
The gopher tortoise is more widespread and abundant in the eastern
portion of its range, particularly in central and north Florida and
eastern and southern Georgia. These areas in Florida and Georgia make
up the core of the species' distribution (Tuberville et al. 2009, p.
12). The best available information indicates gopher tortoises occur on
approximately 844,812 acres (ac) (341,883 hectares (ha)) across the
species' range (areal extent of populations as delineated for our
analysis below in Analysis Unit and Population Delineation). An
additional 16,338,932 ac (6,612,131 ha) of potential habitat has been
identified by a species-specific habitat suitability model (Crawford et
al. 2020, entire; Service 2022, pp. 122-126). For the SSA assessment,
potential habitat is described as suitable habitat with unknown gopher
tortoise presence outside delineated local gopher tortoise populations
but within the species' current range. Rangewide, approximately 80
percent of potential gopher tortoise habitat occurs in private
ownership, with the remainder owned or managed by local, State,
Federal, or private conservation entities (Wear and Greis 2013, p. 103;
Natural Resources Conservation Service (NRCS) 2018, p. 2).
Life History
The gopher tortoise's life history is characterized by a late age
of reproductive maturity, low reproductive output (fecundity), and long
lifespan, which make this long-lived species more vulnerable to
demographic perturbations and slower to rebound from impacts to
populations (Lohoefener and Lohmeier 1984, p. 2; Service 2013, p. 21;
Tuberville et al. 2014, p. 1151). Gopher tortoises reach reproductive
maturity between 9 and 20 years of age, although reproductive maturity
is determined by size rather than age. Growth rates and sizes at sexual
maturity vary among populations and habitat quality (Landers et al.
1982, pp. 104-105; Mushinsky et al. 1994, pp. 123-125).
Gopher tortoises generally breed from May through October; however,
the gopher tortoise populations in south Florida have an extended
reproductive season (Landers et al. 1980, p. 355; McRae et al. 1981,
pp. 172-173; Taylor 1982, entire; Diemer 1992a, pp. 282-283; Ott-
Eubanks et al. 2003, p. 317; Moore et al. 2009, p. 391). The warmer
weather in south Florida is associated with year-round courtship
behavior, greater site productivity, and larger clutches leading to
production of young over a much longer time period than populations
farther north (Ashton et al. 2007, p. 359; Moore et al. 2009, p. 391).
Female gopher tortoises usually lay eggs from mid-May through mid-July,
and incubation lasts 80-110 days (Diemer 1986, p. 127). Rangewide,
average clutch size varies from 4-8 eggs per clutch, with clutches in
the western portion of the range averaging lower with 4.8-5.6 eggs per
clutch (Seigel and Hurley 1993, p. 6; Seigel and Smith 1996, pp. 10-11;
Tuma 1996, pp. 22-23; Epperson and Heise 2003, pp. 318-321; Ashton et
al. 2007, p. 357). Sex determination is temperature dependent for
gopher tortoises, with lower temperatures producing more males and
higher temperatures producing more females. The pivotal temperature for
a 1:1 sex ratio has been observed to be 29.3 degrees Celsius ([deg]C)
(84.7 degrees Fahrenheit ([deg]F)) (DeMuth 2001, pp. 1612-1613). The
lifespan of gopher tortoises is generally estimated at 50-80 years.
The gopher tortoise's diet reflects that of a generalist herbivore
(e.g., eating mainly grasses, plants, fallen flowers, fruits, and
leaves) and may also include insects and carrion (Auffenberg and
Iverson 1979, p. 558; Landers 1980, p. 9; Garner and Landers 1981, p.
123;
[[Page 61836]]
Wright 1982, p. 25; Macdonald and Mushinsky 1988, pp. 349-351; Birkhead
et al. 2005, pp. 146, 155; Mushinsky et al. 2006, p. 480; Richardson
and Stiling 2019, pp. 387-388). Gopher tortoises prefer grassy, open-
canopy microhabitats, and their population density directly relates to
the density and diversity of herbaceous biomass and a lack of canopy
(Auffenberg and Iverson 1979, p. 558; Landers and Speake 1980, p. 522;
Wright 1982, p. 22; Stewart et al. 1993, p. 79; Breininger et al. 1994,
p. 63; Boglioli et al. 2000, p. 703; Ashton and Ashton 2008, p. 78).
Habitat
Gopher tortoise habitat comprises well-drained, sandy soils (needed
for burrowing, sheltering, and nest construction/breeding), with an
open canopy, sparsely vegetated midstory, and abundant herbaceous
groundcover (for feeding). Soil characteristics are an important
component of gopher tortoise habitat and affect burrow density and
extent. The soils in the eastern portion of the range are characterized
by a higher sand content, although the percentage of sand varies by
habitat type (i.e., coastal soils often contain more sand than more
inland upland soils) (Auffenberg and Franz 1982, pp. 98-105, 113-118,
120-121). In the western portion of the range, soils are loamy and
contain more clay, and xeric (dry) conditions are less common west of
the Florida panhandle (Lohoefener and Lohmeier 1981, p. 240; Auffenberg
and Franz 1982, pp. 114-115; Mann 1995, pp. 10-11; Craul et al. 2005,
pp. 11-13). Higher clay content in soils may contribute to lower
abundance and density of tortoises (Means 1982, p. 524; Wright 1982, p.
21; Ultsch and Anderson 1986, p. 790; Estes and Mann 1996, p. 24; Smith
et al. 1997, p. 599; Jones and Dorr 2004, p. 461).
Historically, gopher tortoise's habitats were open pine forests,
savannahs, and xeric grasslands. Today, upland natural vegetative
communities, including longleaf pine (Pinus palustris) and other open
pine systems, sandhill, xeric (dry) oak (Quercus spp.) uplands, xeric
hammock, xeric Florida scrub, and maritime scrub coastal habitats, most
often provide the conditions necessary (e.g., open canopy and abundant
herbaceous groundcover) to support gopher tortoises (Auffenberg and
Franz 1982, p. 99; Diemer 1986, p. 126; Diemer 1987, pp. 73-74;
Breininger et al. 1994, p. 60). In addition to the upland natural
communities, some ruderal (disturbed) habitat may also provide the open
canopy or sunny conditions and herbaceous groundcover needed by gopher
tortoises (Auffenberg and Franz 1982, p. 99; Howell et al. 2020, p. 1).
An open canopy allows sunlight to reach the forest floor to stimulate
the growth and development of herbaceous groundcover and provide warmth
for basking and egg incubation (Landers 1980, pp. 6, 8; Landers and
Speake 1980, p. 522; Lohoefener and Lohmeier 1981, entire; Auffenberg
and Franz 1982, pp. 98-99, 104-107, 111, 120; Boglioli et al. 2000, p.
703; Rostal and Jones 2002, p. 485; Jones and Dorr 2004, p. 461;
McDearman 2006, p. 2; McIntyre et al. 2019, p. 287). When canopies
become too dense in an area, gopher tortoises move into ruderal
habitats such as roadsides with more herbaceous ground cover, lower
tree cover, and sun exposure (Garner and Landers 1981, p. 122; McCoy et
al. 1993, p. 38; Baskaran et al. 2006, p. 346). Ruderal habitats may
also include utility rights-of-way, edges, fencerows, pasturelands, and
planted pine stands.
Historically, open-canopied southern pine forests were maintained
by frequent, lightning-generated fires. Currently, a variety of land
management practices including prescribed fire, grazing, mowing, roller
chopping, timber harvesting, and selective herbicide application, are
used in the restoration, enhancement, and maintenance of gopher
tortoise habitats (Cox et al. 2004, p. 10; Ashton and Ashton 2008, p.
78; Georgia Department of Natural Resources (GDNR) 2014, unpaginated;
Rautsaw et al. 2018, p. 141). These habitat management activities
implemented singularly or in combination (e.g., roller chopping
followed by prescribed fire) are used to restore and maintain the open
canopy, sparsely vegetated midstory, and abundant herbaceous
groundcover conditions needed by gopher tortoises.
Gopher tortoise burrows are central to normal feeding, breeding,
and sheltering activity. Gopher tortoises can excavate many burrows
over their lifetime and often use several each year. Burrows typically
extend 15 to 25 feet (ft; 4.6 to 7.6 meters (m)), can be up to 12 ft
(3.7 m) deep, and provide shelter from predators, winter cold, fire,
and summer heat (Hansen 1963, p. 359; Landers 1980, p. 6; Wright 1982,
p. 50; Diemer 1986, p. 127; Boglioli 2000, p. 699). Tortoises spend
most of their time within burrows and emerge during the day to bask,
feed, and reproduce (Service 2022, p. 28). During the cool weather
dormant season, gopher tortoises throughout most of the range shelter
within their burrows, become torpid, do not eat, and rarely emerge,
except on warm days to bask in sunlight at the burrow entrance (Service
2013, p. 21).
As a keystone species (which is a species that has a
disproportionately large effect on its natural environment relative to
its abundance), gopher tortoise burrow systems provide benefits to the
landscape and return leached nutrients to the soil surface; increase
habitat heterogeneity; shelter seeds from fires; and provide resources
and refugia for other species (Auffenberg and Weaver 1969, p. 191;
Landers 1980, pp. 2, 515; Kaczor and Hartnett 1990, pp. 107-108). An
estimated 60 vertebrates and 302 invertebrates, including the
threatened Eastern indigo snake, the gopher mouse, the six-lined
roadrunner, the gopher frog, the cave cricket, and casual visitants,
such as the tiger beetle, skunk, opossum, and rattlesnakes, share
tortoise burrows (Jackson and Milstrey 1989, p. 87).
Genetics
Genetic flow in gopher tortoise populations is known to be
influenced by distance, geographic features, and human influence by
transporting tortoises across the range. Several studies show genetic
assemblages across the geographic range, but these studies have not
been entirely congruent in their delineations of western and eastern
genetic assemblages (Osentoski and Lamb 1995, p. 713; Clostio et al.
2012, pp. 617-620; Ennen et al. 2012, pp. 113-120; Gaillard et al.
2017, pp. 501-503). Recent microsatellite analysis suggests there are
five main genetic groups delineated by the Tombigbee and Mobile Rivers,
Apalachicola and Chattahoochee Rivers, and the transitional areas
between several physiographic province sections of the Coastal Plains
(i.e., Eastern Gulf, Sea Island, and Floridian) (figure 1) (Gaillard et
al. 2017, pp. 505-507).
[[Page 61837]]
[GRAPHIC] [TIFF OMITTED] TP12OC22.000
The last decade of genetic research has shown that genetic
diversity exists among individuals in a population, among populations,
and across the range (Ennen et al. 2010, entire; Clostio et al. 2012,
entire; Gaillard et al. 2017, entire). The most recent rangewide
genetic analysis confirmed that the edges (periphery) of the range have
lower levels of genetic diversity relative to the core but also showed
genetic mixing at the borders between units (Gaillard et al. 2017, p.
507). Evidence of tortoises with ancestry from different genetic sites
is most likely due to the decades of tortoises being moved by humans as
part of various formal and informal translocation and population
augmentation efforts as well as non-conservation, human-mediated
movements (see Translocation and Headstarting, below) (Gaillard et al.
2017, pp. 504-505). In addition, contemporary gene flow is asymmetric
across the gopher tortoise range as a result of recent migrations
affecting changes in genetic diversity. For example, gene flow is
higher from the Central to Western genetic regions and from the Florida
panhandle to the East Georgia genetic region, while the Florida
panhandle area has low genetic flow with the West Georgia genetic
region (Gaillard et al. 2017, pp. 504-509). In general, migration rates
between genetic regions were low, with the highest proportion of
movements and genetic exchange from within the same genetic unit
(Gaillard et al. 2017, pp. 505-506).
Home Range and Movement
As mentioned previously, gopher tortoises often use several burrows
per year. The burrows of a gopher tortoise represent the general
boundaries of a home range, which is the area used for feeding,
breeding, and sheltering (McRae et al. 1981, p. 176). Gopher tortoise
home ranges tend to vary in size depending on habitat quality, with
larger areas in lower quality habitat (Auffenberg and Iverson 1979, pp.
559-561; Castellon et al. 2012, p. 159; Guyer et al. 2012, p. 130).
Home ranges are larger in the western portion of the gopher tortoise
range than those typically observed for tortoises in Alabama (east of
the Tombigbee and Mobile Rivers), Georgia, South Carolina, and Florida,
and this variation is most likely due to habitat quality differences
(Lohoefener and Lohmeier 1984, pp. 1-25; Epperson and Heise 2003, p.
315; Tuberville et al. 2005, p. 356; Richter et al. 2011, p. 408).
Males typically have larger home ranges and tend to travel farther
distances than females; this is primarily for breeding opportunities
and related to burrow density and social hierarchical behaviors (McRae
et al. 1981, p. 175; Guyer et al. 2012, pp. 129-
[[Page 61838]]
132; Castellon et al. 2018, pp. 11-12). For example, average home
ranges in Mississippi, Alabama, Florida, and Georgia have varied from
0.1 to 39.8 ac (0.04 to 16.1 hectares ha) (McRae et al. 1981, pp. 175-
176; Diemer 1992b, pp. 160-161; Tuma 1996, pp. 28-43; Ott-Eubanks et
al. 2003, pp. 315-316; Guyer et al. 2012, pp. 128-129; Castellon et al.
2018, p. 17).
Just as gopher tortoise home ranges are larger in lower quality
habitat, gopher tortoise movements also increase as herbaceous biomass
and habitat quality decrease and tortoises must search farther for
adequate resources (Auffenberg and Iverson 1979, p. 558; Auffenberg and
Franz 1982, p. 121; Castellon et al. 2018, p. 18). As distances
increase between gopher tortoise burrows, isolation among gopher
tortoises also increases due to the decreasing rate of visitation and
breeding by males to females (Boglioli et al. 2003, p. 848; Guyer et
al. 2012, p. 131). Most breeding populations have been found to consist
of burrows no greater than about 549 ft (167 m) apart, although males
may move up to 1,640 ft (500 m) for mating opportunities (Guyer and
Johnson 2002, pp. 6-8; Ott-Eubanks et al. 2003, p. 320; Guyer et al.
2012, p. 131).
Population Dynamics
At the landscape scale, the gopher tortoise requires large swaths
of interconnected, high-quality habitat patches to support healthy
populations. Large swaths of high-quality habitat provide habitat
connectivity for gopher tortoise life-history needs of dispersal
(immigration and emigration), breeding, and foraging. Interconnected,
high-quality habitat that supports gopher tortoise requirements
influences population dynamics and demographics through the carrying
capacity of the area and opportunities for genetic exchange.
As long-lived animals, gopher tortoises naturally experience
delayed sexual maturity, low reproductive rates, high mortality at
young ages and small size-classes, and relatively low adult mortality.
Factors affecting population growth, decline, and dynamics include the
number or proportion of annually breeding and egg-laying females
(breeding population size), clutch size, nest depredation rates, egg
hatching success, mortality (hatchling-yearling, juvenile-subadult,
adult), the age or size at first reproduction, age- or stage-class
population structure, maximum age of reproduction, and immigration and
emigration rates.
Gopher tortoise population dynamics are sensitive to demographic
changes in adult, hatchling, and juvenile survival (Gibbons 1987,
entire; Congdon et al. 1993, entire; Heppell 1998, entire; Epperson and
Heise 2001, entire; Miller 2001, entire; Wester 2005, entire; McDearman
2006, p. 7). Hatchling survivorship is the most critical life history
stage due to the high mortality in this life stage (Tuberville et al.
2009, p. 33). For example, a simulated 5 percent decrease in hatchling
mortality shifted the population growth rate from slowly declining (1.5
percent decrease) to slowly increasing (1.1 percent increase) and
eliminated the probability of extinction within 200 years (Tuberville
et al. 2009, p. 33). Changes in other vital parameters, including age
of first reproduction and average clutch size, also affect population
growth, although generally not to the extent of hatchling and juvenile
mortality (McDearman 2006, pp. 7, 20).
Demographic factors have been evaluated in population viability
analysis (PVA) studies to estimate the probabilities of gopher tortoise
population extinction over time and the important factors affecting the
species' viability (Cox et al. 1987, pp. 24-34; Lohoefener and Lohmeier
1984, entire; Cox 1989, p. 10; Epperson and Heise 2001, pp. 37-39;
Miller 2001, entire; Wester 2005, pp. 16-20; McDearman 2006, entire;
Tuberville et al. 2009, entire; Folt et al. 2022, entire). The number
of gopher tortoises required for a population to remain on the
landscape for 200 years varies from 50 to 200 individuals depending on
habitat and management conditions (Cox et al. 1987, pp. 27-29; Cox et
al. 1994, p. 29). Although populations as small as 50 tortoises have
exhibited positive growth rates and are projected to remain on the
landscape in the future in some PVA models, the inclusion of threats
such as upper respiratory tract disease (URTD) or fire ant (Conomyrma
spp., Solenopsis invicta) predation led to population decline and
eventual extirpation of these smaller populations in these models
(Miller 2001, pp. 13, 26-27; McDearman 2006, pp. 6-7). In models that
resulted in projected gopher tortoise population declines of 1 to 3
percent per year, the factors that affected gopher tortoise population
growth rates included the geographic location of the population and
habitat quality (Tuberville et al. 2009, pp. 17-22). Populations of at
least 100 gopher tortoises were found to be reasonably resilient to
variations in habitat quality; however, larger populations of at least
250 tortoises were needed to remain on the landscape in lower quality
habitat (Tuberville et al. 2009, p. 19).
A minimum viable population (MVP) in terms of acceptable benchmarks
for the purpose of conservation and recovery efforts of gopher tortoise
has been established by the Gopher Tortoise Council (GTC; GTC 2013,
entire). Viability, as defined in the MVP, is valuable for conservation
planning purposes and differs from the definition of viability used in
the SSA (Service 2022, p. 20). The GTC adopted the definition of a
viable tortoise population as consisting of at least 250 adult
tortoises, at a density of at least 0.4 tortoises per ha, with an even
sex ratio, and evidence of all age classes present, on a property with
at least 247 ac (100 ha) of high-quality habitat managed for the
benefit of the gopher tortoise (GTC 2013, pp. 2-3). Within our SSA
report and this document, we use the GTC's definition of a ``viable
population.'' A primary support population was defined as consisting of
50-250 adult gopher tortoises. Primary support populations may improve
viability through habitat restoration, natural recruitment increases,
or population augmentation. A secondary support population was defined
as fewer than 50 tortoises that have more constraints to reach
sufficient viability, but are important for education, community
interest, and augmentation, and can maintain sufficient viability to
remain on the landscape in the long term with rigorous habitat
management and/or connectivity with other populations (GTC 2014, p. 4).
It should be noted that smaller support populations may remain on the
landscape for a long period of time under high-quality habitat
conditions but are more vulnerable to stochastic events than
populations that meet the MVP threshold (Miller 2001, p. 28; GTC 2014,
p. 4; Folt et al. 2021, entire). We rely on these defined population
benchmarks in our assessment of gopher tortoise viability, as described
below in Current Condition.
Regulatory and Analytical Framework
Regulatory Framework
Section 4 of the Act (16 U.S.C. 1533) and the implementing
regulations in title 50 of the Code of Federal Regulations set forth
the procedures for determining whether a species is an endangered
species or a threatened species, issuing protective regulations for
threatened species, and designating critical habitat for threatened and
endangered species. In 2019, jointly with the National Marine Fisheries
Service, the Service issued final rules that revised the regulations in
50 CFR parts 17 and 424 regarding how we add, remove, and reclassify
threatened and endangered species and the criteria for designating
listed species' critical
[[Page 61839]]
habitat (84 FR 45020 and 84 FR 44752; August 27, 2019). At the same
time the Service also issued final regulations that, for species listed
as threatened species after September 26, 2019, eliminated the
Service's general protective regulations automatically applying to
threatened species the prohibitions that section 9 of the Act applies
to endangered species (collectively, the 2019 regulations).
However, on July 5, 2022, the U.S. District Court for the Northern
District of California vacated the 2019 regulations (Center for
Biological Diversity v. Haaland, No. 4:19-cv-05206-JST, Doc. 168 (N.D.
Cal. July 5, 2022) (CBD v. Haaland)), reinstating the regulations that
were in effect before the effective date of the 2019 regulations as the
law governing species classification and critical-habitat decisions.
Accordingly, in developing the analysis contained in this finding, we
applied the pre-2019 regulations, which may be reviewed in the 2018
edition of the Code of Federal Regulations at 50 CFR 424.11(d). Those
pre-2019 regulations did not include provisions clarifying the meaning
of ``foreseeable future,'' so we applied a 2009 Department of the
Interior Solicitor's opinion (M-37021, ``The Meaning of `Foreseeable
Future' in Section 3(2) of the Endangered Species Act'' (Jan. 16, 2009)
(M-37021). Because of the ongoing litigation regarding the court's
vacatur of the 2019 regulations, and the resulting uncertainty
surrounding the legal status of the regulations, we also undertook an
analysis of whether the finding would be different if we were to apply
the 2019 regulations. That analysis, which we described in a separate
memo in the decisional file and posted on https://www.regulations.gov,
concluded that we would have reached the same finding if we had applied
the 2019 regulations because, based on the modeling and scenarios
evaluated, we considered our ability to make reliable predictions in
the future and the uncertainty in how and to what degree the gopher
tortoise could respond to those risk factors in this timeframe. We
determined that this timeframe represents a period of time for which we
can reliably predict both the threats to the species and the species'
response to those threats under the 2019 regulations. We also find this
determination to be ``rooted in the best available data that allow
predictions into the future'' and extend as far as those predictions
are ``sufficiently reliable to provide a reasonable degree of
confidence in the prediction, in light of the conservation purposes of
the Act'' in accordance with the 2009 Solicitor's Opinion.
On September 21, 2022, the U.S. Circuit Court of Appeals for the
Ninth Circuit stayed the district court's July 5, 2022, order vacating
the 2019 regulations until a pending motion for reconsideration before
the district court is resolved (In re: Cattlemen's Ass'n, No. 22-
70194). The effect of the stay is that the 2019 regulations are
currently the governing law. Because a court order requires us to
submit this finding to the Federal Register by September 30, 2022, it
is not feasible for us to revise the finding in response to the Ninth
Circuit's decision. Instead, we hereby adopt the analysis in the
separate memo that applied the 2019 regulations as our primary
justification for the finding. However, due to the continued
uncertainty resulting from the ongoing litigation, we also retain the
analysis in this preamble that applies the pre-2019 regulations and we
conclude that, for the reasons stated in our separate memo analyzing
the 2019 regulations, this finding would have been the same if we had
applied the pre-2019 regulations.
The Act defines an ``endangered species'' as a species that is in
danger of extinction throughout all or a significant portion of its
range, and a ``threatened species'' as a species that is likely to
become an endangered species within the foreseeable future throughout
all or a significant portion of its range. The Act requires that we
determine whether any species is an endangered species or a threatened
species because of any of the following factors:
(A) The present or threatened destruction, modification, or
curtailment of its habitat or range;
(B) Overutilization for commercial, recreational, scientific, or
educational purposes;
(C) Disease or predation;
(D) The inadequacy of existing regulatory mechanisms; or
(E) Other natural or manmade factors affecting its continued
existence.
These factors represent broad categories of natural or human-caused
actions or conditions that could have an effect on a species' continued
existence. In evaluating these actions and conditions, we look for
those that may have a negative effect on individuals of the species, as
well as other actions or conditions that may ameliorate any negative
effects or may have positive effects.
We use the term ``threat'' to refer in general to actions or
conditions that are known to or are reasonably likely to negatively
affect individuals of a species. The term ``threat'' includes actions
or conditions that have a direct impact on individuals (direct
impacts), as well as those that affect individuals through alteration
of their habitat or required resources (stressors). The term ``threat''
may encompass--either together or separately--the source of the action
or condition or the action or condition itself.
However, the mere identification of any threat(s) does not
necessarily mean that the species meets the statutory definition of an
``endangered species'' or a ``threatened species.'' In determining
whether a species meets either definition, we must evaluate all
identified threats by considering the species' expected response and
the effects of the threats--in light of those actions and conditions
that will ameliorate the threats--on an individual, population, and
species level. We evaluate each threat and its expected effects on the
species, then analyze the cumulative effect of all of the threats on
the species as a whole. We also consider the cumulative effect of the
threats in light of those actions and conditions that will have
positive effects on the species, such as any existing regulatory
mechanisms or conservation efforts. The Secretary determines whether
the species meets the definition of an ``endangered species'' or a
``threatened species'' only after conducting this cumulative analysis
and describing the expected effect on the species now and in the
foreseeable future.
The Act does not define the term ``foreseeable future,'' which
appears in the statutory definition of ``threatened species.'' Because
the decision in CBD v. Haaland vacated our 2019 regulations regarding
the foreseeable future, we refer to a 2009 Department of the Interior
Solicitor's opinion entitled ``The Meaning of `Foreseeable Future' in
Section 3(20) of the Endangered Species Act'' (M-37021). That
Solicitor's opinion states that the foreseeable future ``must be rooted
in the best available data that allow predictions into the future'' and
extends as far as those predictions are ``sufficiently reliable to
provide a reasonable degree of confidence in the prediction, in light
of the conservation purposes of the Act.'' Id. at 13.
It is not always possible or necessary to define the foreseeable
future as a particular number of years. Analysis of the foreseeable
future uses the best scientific and commercial data available and
should consider the timeframes applicable to the relevant threats and
to the species' likely responses to those threats in view of its life-
history characteristics. Data that are typically relevant to assessing
the species'
[[Page 61840]]
biological response include species-specific factors such as lifespan,
reproductive rates or productivity, certain behaviors, and other
demographic factors.
Analytical Framework
The SSA report documents the results of our comprehensive
biological review of the best scientific and commercial data regarding
the status of the species, including an assessment of the potential
threats to the species. The SSA report does not represent our decision
on whether the species should be proposed for listing as an endangered
or threatened species under the Act. However, it does provide the
scientific basis that informs our regulatory decisions, which involve
the further application of standards within the Act and its
implementing regulations and policies. The following is a summary of
the key results and conclusions from the SSA report; the full SSA
report can be found at Docket FWS-R4-ES-2009-0029 on https://www.regulations.gov and at https://www.fws.gov/office/florida-ecological-services/library.
To assess gopher tortoise viability, we used the three conservation
biology principles of resiliency, redundancy, and representation
(Shaffer and Stein 2000, pp. 306-310). Briefly, resiliency supports the
ability of the species to withstand environmental and demographic
stochasticity (for example, wet or dry, warm or cold years), redundancy
supports the ability of the species to withstand catastrophic events
(for example, droughts, large pollution events), and representation
supports the ability of the species to adapt over time to long-term
changes in the environment (for example, climate changes). In general,
the more resilient and redundant a species is and the more
representation it has, the more likely it is to sustain populations
over time, even under changing environmental conditions. Using these
principles, we identified the species' ecological requirements for
survival and reproduction at the individual, population, and species
levels, and described the beneficial and risk factors influencing the
species' viability.
The SSA process can be categorized into three sequential stages.
During the first stage, we evaluated the individual species' life-
history needs. The next stage involved an assessment of the historical
and current condition of the species' demographics and habitat
characteristics, including an explanation of how the species arrived at
its current condition. The final stage of the SSA involved making
predictions about the species' responses to positive and negative
environmental and anthropogenic influences. Throughout all of these
stages, we used the best available information to characterize
viability as the ability of a species to sustain populations in the
wild over time. We use this information to inform our regulatory
decision.
Summary of Biological Status and Threats
In this discussion, we review the biological condition of the
species and its resources, and the threats that influence the species'
current and future condition, in order to assess the species' overall
viability and the risks to that viability. The following discussions
include evaluations of the following threats and associated sources
influencing the gopher tortoise and its habitat: (1) Habitat loss,
degradation, and fragmentation, (2) climate change, and (3)
insufficient and/or incompatible habitat management. Other factors
influencing gopher tortoise viability include road mortality, disease,
harvest and rattlesnake roundups, predation, nonnative invasive
species, and conservation measures, including relocation,
translocation, and headstarting programs. Conservation of habitat
through land acquisition and conservation actions on public and private
lands and the retention of private forest lands reduces the severity of
some of these threats by providing protection of habitat across the
landscape, maintaining connectivity between habitat patches, and
increasing the opportunity for beneficial habitat management actions.
In this section, we describe the threats that influence the species'
current and future conditions and conservation measures that may
mitigate those threats. Additional information may be found in the SSA
report (Service 2022, pp. 46-102).
Habitat Loss, Degradation, and Fragmentation
Habitat loss, degradation, and fragmentation have affected the
gopher tortoise and its habitat. The gopher tortoise was historically
associated with fire-dependent longleaf pine ecosystems. Longleaf pine
communities declined to less than 3 million ac (1.2 million ha) by the
20th century from a historical estimate of 92 million ac (37 million
ha) due to forest clearing and conversion for agriculture, conversion
from longleaf to other pine species, and development (Frost 1993, p.
20; Ware et al. 1993, p. 447; Landers et al. 1995, p. 39). As a result
of fire suppression and exclusion in many areas, approximately two to
three percent of longleaf pine ecosystems remain in relatively natural
condition (Frost 1993, p. 17; Simberloff 1993, p. 3; Jose et al. 2007,
p. ix; Jensen et al. 2008, p. 16; Oswalt et al. 2012, p. 7). Although
historically associated with longleaf pine communities, the species
currently occurs in open canopy stands of several southern pine
species.
Currently, habitat loss, degradation, and fragmentation caused by a
variety of sources across the species' range continue to negatively
affect gopher tortoise viability. Urbanization and development, major
road construction, incompatible and/or insufficient habitat management,
and certain types of agriculture negatively impact the gopher tortoise
and its habitat (Auffenberg and Franz 1982, pp. 105, 112; Lohoefener
and Lohmeier 1984, pp. 2-6; Diemer 1986, p. 128; Diemer 1987, pp. 74-
75; Hermann et al. 2002, pp. 294-295; Enge et al. 2006, p. 4). While
large-scale development of solar farms may impact the gopher tortoise
and its habitat in connection with other threats, we have determined
that solar energy development is not a key factor influencing the
species' viability at this time (Ong et al. 2013, p. iv; Service 2022,
p. 52). Invasive species introduced as a result of habitat
fragmentation or urbanization can influence gopher tortoises either
through predation or alterations to habitat structure and function
(Mann 1995, p. 24; Lippincott 1997, pp. 48-65; Basiotis 2007, p. 24;
Engeman et al. 2009, p. 84; Engeman et al. 2011, p. 607; Dziadzio et
al. 2016, p. 531; Bartoszek et al. 2018, pp. 353-354). Climate change
has the potential to negatively impact habitat through the loss of
habitat due to sea level rise, limitations on number of suitable burn
days due to changes in temperature, precipitation, increased flooding
due to predicted increases in the severity of hurricanes, and human
migration from inundated coastal areas to inland areas, with subsequent
impacts to gopher tortoises (Ruppert et al. 2008, p. 127; Castellon et
al. 2018, pp. 11-14; Hayhoe et al. 2018, entire; Kupfer et al. 2020,
entire). Although habitat management and climate change influence
gopher tortoise habitat and contribute to habitat loss, fragmentation,
and degradation, they are discussed as separate factors, below. In this
section, we discuss below the primary sources (Urbanization and
Development, Road Effects and Mortality) for habitat loss,
fragmentation, and degradation.
Urbanization and Development
At a landscape scale, the gopher tortoise needs large swaths of
interconnected, high-quality habitat patches to support viable
populations.
[[Page 61841]]
Within these large swaths of high-quality habitat on the landscape,
gopher tortoises require habitat connectivity for dispersal
(immigration and emigration), breeding, and foraging. Urbanization and
development of the landscape fragments and replaces natural areas with
artificial structures, impervious surfaces, and lawns and gardens
containing nonnative plant species; this activity impacts gopher
tortoise populations that rely on a mosaic of interconnected uplands
(Sutherland 2009, p. 35). Development and urbanization can also impact
gopher tortoise populations on conservation lands (lands in public or
private ownership managed for conservation under a management plan) by
disrupting habitat connectivity across the landscape and disrupting
habitat management activities on conservation lands, particularly
through the reduction of prescribed fire activities. Urbanization and
development impacts to individuals, populations, and habitats have been
documented, although not specifically quantified in terms of survival,
recruitment, and health of gopher tortoises prior to our SSA. Our
modeling for the future condition analysis in the SSA includes
urbanization projected by the SLEUTH model as part of the threats
scenarios as described in Future Condition (Service 2022, pp. 144-175;
Folt et al. 2022, entire).
Human population growth is a primary driver of urbanization and
subsequent habitat fragmentation that is impacting gopher tortoises
rangewide. Rangewide, Alabama, Florida, Georgia, Louisiana, and South
Carolina have experienced population growth from 3 to 15 percent since
2010, while Mississippi has experienced a 6 percent decrease in human
population. Population growth from 2 to 13.4 percent is projected to
occur in each State rangewide from 2020 to 2030 (Blanchard 2007, p. 7;
FEDR 2021, unpaginated; Culverhouse College of Business 2021,
unpaginated; Georgia Census 2021, unpaginated; Population Projections
2005, unpaginated; U.S. Census Bureau 2021, unpaginated). As the human
population continues to grow in the Southeast, development is expected
to increase demand for forest resources and lead to habitat
fragmentation and degradation of forests through the conversion of
high-quality gopher tortoise habitat to lands in forest production that
may not be managed in a way compatible with gopher tortoise needs.
Forest loss and fragmentation reduce the ecological function and
connectivity essential for the dispersal of gopher tortoises across the
landscape (Guyer et al. 2012, p. 131; Jones and Dorr 2004, p. 461).
Gopher tortoises can occur in residential areas despite the fact
that these areas are typically of lower habitat quality. However,
conversion of gopher tortoise habitat to residential areas results in
mortality of gopher tortoises when individuals are entombed in burrows
during construction activities. In the western portion of the range
where the species is federally listed, individual gopher tortoises are
translocated from development sites to avoid mortality from land
development activities. Since 2007, the Florida Fish and Wildlife
Conservation Commission (FWC) requires developers to relocate tortoises
out of harm's way, either onsite or at an approved recipient site (FWC
2007, p. 10). Other States (Georgia, Alabama, and South Carolina) have
some measure of legal protection for gopher tortoises, though gopher
tortoise burrows are not protected uniformly across the range. When
notified, these States work with developers to minimize impacts when
tortoises occur on development sites.
Human development of the landscape (i.e., urbanization) affects
terrestrial wildlife communities in the Southeastern United States,
including gopher tortoise populations that often rely on upland
habitats that are popular sites for urban development or agriculture.
Gopher tortoise populations on protected and managed lands are somewhat
buffered from habitat loss as a result of urbanization, but landscape-
level connectivity is negatively affected. Urbanization and development
have influenced the gopher tortoise and its habitat historically, and
we expect these effects to continue in the future. This threat is
present across the range of the species, although populations near
already urbanized areas and areas of projected development are more
affected. For example, in Florida, urban growth and development is
identified as one of the primary threats to gopher tortoises
(Auffenberg and Franz 1982, p. 112; Diemer 1986, p. 128; Diemer 1987,
pp. 74-75; Enge et al. 2006, p. 4). Georgia is also anticipated to
experience dramatic human population increases (Georgia Census 2021,
unpaginated), leading to subsequent development and potential loss of
gopher tortoise habitat.
Road Effects and Mortality
Roads pose a barrier to gopher tortoise movement, fragment habitat,
isolate areas of habitat, and increase mortality of gopher tortoises
(Andrews and Gibbons 2005, p. 772; Hughson and Darby 2013, pp. 227-
228). Roads that bisect habitat pose a hazard to gopher tortoises by
forcing individuals into unsuitable areas and onto highways (Diemer
1987, p. 75; Mushinsky et al. 2006, p. 38). Roads occurring within or
adjacent to tortoise habitat impact gopher tortoises, because tortoises
are attracted to road shoulders where open-canopy, grassy areas are
maintained (Steen and Gibbs 2004, entire; Steen et al. 2006, p. 271).
Gopher tortoises appear to use roadsides independently of larger
habitat patches, treating them as areas for residency as opposed to
travel corridors among other habitat patches (Rautsaw et al. 2018, p.
141). Gopher tortoise nests in roadsides are more susceptible to
predators, such as raccoons (Procyon lotor), which are common in
ecological edges and fragmented, suburban landscapes (Hoffman and
Gottschang 1977, p. 633; Wilcove 1985, pp. 1213-1214). The installation
of wildlife barrier fences along roadways has the potential to minimize
gopher tortoise road mortality. While barrier fencing along roads may
reduce road mortality, fencing may also further limit the movement of
gopher tortoises.
While road mortality occurs in gopher tortoise populations, the
extent to which it affects populations or the species is not well
documented. There are no current rangewide monitoring efforts for
gopher tortoise road mortality. Florida is the only state that has a
database for reporting sick, injured, or dead tortoises; of tortoises
reported to the Florida FWC as sick, injured, or dead, 41 percent were
found injured or dead on roads (CCA 2018, p. 95).
As development and subsequent habitat loss and fragmentation
occurs, gopher tortoises will disperse to find better quality habitat,
putting individual gopher tortoises at risk of road mortality. Impacts
to habitat and road mortality are expected to increase as road
densities and traffic volumes increase and habitat patches become more
isolated and more difficult to manage (Enge et al. 2006, p. 10).
Highway mortality of gopher tortoises will be highest where there are
improved roads adjacent to gopher tortoise populations. Increased
traffic on new or expanded roads adjacent to a gopher tortoise
population will expose individuals to direct mortality from vehicles
and potentially to increased predation. In addition, gopher tortoises
in the vicinity of urban areas will be particularly vulnerable
(Mushinsky et al. 2006, p. 362), especially in areas with heavy traffic
patterns or high speed limits. The threat posed by roads is ongoing and
is expected to continue, particularly in peninsular Florida and
[[Page 61842]]
urban centers in coastal portions of Georgia, Alabama, and Mississippi,
where human populations are likely to increase as seen in urban
modeling projections using SLEUTH (Terando et al. 2014, entire).
Agricultural Lands
Agricultural lands are an important component of land use
activities in the gopher tortoise range. Agricultural lands on suitable
soils are 6 times less likely to have burrows and contain 20 times
fewer gopher tortoise burrows than open pine sites (Hermann et al.
2002, pp. 294-295). Gopher tortoises do not use the poor-quality
habitat in annually tilled fields that do not provide necessary forage
(Auffenberg and Franz 1982, p. 105). However, adult tortoises will
return to abandoned agricultural fields in a few years when the land is
dominated by perennial herbaceous species and remain until succession
results in closed canopy conditions that do not provide the species'
requirements (Auffenberg and Franz 1982, pp. 105, 107-108).
Accordingly, habitat that is normally suitable for gopher tortoise but
that is cleared for agricultural activities is not suitable for gopher
tortoise use while it is in production or until forage and soil
conditions provide gopher tortoise requirements for feeding, nesting,
and sheltering.
Cropland (i.e., agriculture) in the gopher tortoise range is
projected to decline by 19 percent from 1997 to 2060 (Wear and Greis
2013, p. 45). Restoration of abandoned agricultural fields with
appropriate soils into potential gopher tortoise habitat is feasible
and has been accomplished through the U.S. Department of Agriculture
Conservation Reserve Program (CRP). For example, in the eastern portion
of the gopher tortoise range, over 10.5 million acres were reported as
enrolled in CRP from 2000 to 2019 in counties with gopher tortoise
occurrences (USDA 2020, unpaginated). Although not all of these lands
are expected to support gopher tortoise or fall into potential habitat,
we expect these restoration actions will improve gopher tortoise
habitat. However, at this time, we cannot project the extent to which
abandoned agricultural fields will be restored to a level of
suitability necessary to support gopher tortoise populations.
Solar Farms
As interest in renewable energy increases, the development of solar
farms across the gopher tortoise's range in the Southeast is also
increasing, particularly in Florida and South Carolina (EIA 2021,
unpaginated). A primary concern regarding large-scale deployment of
solar energy is the potentially significant land use requirements,
habitat fragmentation, possible exclusion of gopher tortoises as a
result of fencing, and the need to relocate tortoises from solar farm
sites prior to construction (Ong et al. 2013, p. iv). Some solar
utility developers and companies recognize the potential to impact the
gopher tortoise and its habitats and work with conservation
organizations to avoid and minimize impacts via strategic siting
assessments (NASA Develop 2018, unpaginated). The best available
science indicates it is not a key factor in species viability, although
information quantifying the extent and magnitude of the impact of solar
farms on the gopher tortoise is limited.
Climate Change
The effects of changing climate conditions have influenced and are
expected to continue to influence gopher tortoises and their habitat.
In the Southeastern United States, the impacts of climate change are
currently occurring in the form of sea level rise and extreme weather
events (Carter et al. 2018, p. 749). Changes in temperatures are
projected to result in more frequent drought, more extreme heat
(increases in air and water temperatures), increased heavy
precipitation events (e.g., flooding), more intense storms (e.g.,
frequency of major hurricanes increases), and rising sea level and
accompanying storm surge (Intergovernmental Panel on Climate Change
(IPCC) 2022, entire). Higher temperatures and an increase in the
duration and frequency of droughts are projected to increase the
occurrence of wildfires and reduce the effectiveness of prescribed
fires (Carter et al. 2018, pp. 773-774).
Predicted increases in temperature across the gopher tortoise's
range due to climate change are expected to affect the species' life
history characteristics and demography through skewed sex ratios,
larger clutch sizes, increased hatchling success, and larger hatchling
size (DeMuth 2001, p. 1614; Ashton et al. 2007, pp. 355-362; Hunter et
al. 2021, pp. 215, 221-224). Although these life history and
demographic effects may not initially appear to have negative impacts,
we do not have available modeling to project the effects of these
changes on gopher tortoise demography in terms of forage availability,
carrying capacity of areas where the gopher tortoise occurs, or other
life history and demographic changes. However, the gopher tortoise may
ameliorate these effects by selection of cooler nest sites and altering
timing of nesting to earlier in the season (Czaja et al. 2020, entire).
Some populations of gopher tortoises already exhibit both of these
behaviors (Ashton and Ashton 2008, entire; Moore et al. 2009, entire;
Craft 2021, pp. 42-45).
Frequency of severe hurricanes is predicted to increase in the
future (IPCC 2022, entire; Carter et al. 2018, entire). Gopher tortoise
burrows, particularly those in coastal ecosystems, will be impacted by
flooding after a hurricane, causing abandonment, though the burrow may
become usable again (Waddle et al. 2006, pp. 281-283; Castellon et al.
2018, pp. 11-14; Falk 2018, entire). In addition, overwash of coastal
dunes may result in ``salt burn'' and loss of coastal vegetation,
temporarily reducing forage availability in coastal natural communities
used by gopher tortoises.
Predicted changes in rangewide temperature and precipitation due to
climate change will reduce the number of days with suitable conditions
for prescribed burns needed to manage gopher tortoise habitat in the
future compared to current conditions (Kupfer et al. 2020, entire).
This reduction in prescribed fire, combined with the effects of
urbanization, will further restrict the ability to manage gopher
tortoise habitat with prescribed fire. In addition to the constrained
ability to implement prescribed fire in the future, modeling for the
Southeastern United States projects an increased wildfire risk and a
longer fire season, with at least a 30 percent increase in lightning-
ignited wildfire from 2011 to 2060 (Vose et al. 2018, p. 239).
Sea level rise associated with climate change is expected to affect
coastal populations of gopher tortoises through subsequent inundation
and loss of habitat in coastal areas. As sea levels continue to rise,
coastal water levels--from the mean to the extreme--are growing deeper
and reaching farther inland along most U.S. coastlines (Sweet et al.
2022, p. 28). Global mean sea level has risen 7 to 8 in (16 to 21 cm)
since 1900, with about half of that rise occurring since 1993 (Hayhoe
et al. 2018, p. 85). In areas of the Southeastern United States, tide
gauge analysis reveals as much as 1 to 3 ft (0.30 to 0.91 m) of local
relative sea level rise in the past 100 years (Carter et al. 2018, p.
757). The future estimated amount that sea level will rise varies based
on the responses of the climate system to warming and human-caused
emissions (Hayhoe et al. 2018, p. 85). The amount of gopher tortoise
habitat predicted to be lost within a given population due to
[[Page 61843]]
sea level rise depends on the location of the population and site-
specific characteristics. Populations affected by habitat loss and
degradation due to saltwater inundation and vegetation changes are
expected to experience reduced abundance and resiliency. In addition,
impacts to gopher tortoises and their habitat are expected due to the
relocation of people from flood-prone coastal areas to inland areas,
including the relocation of millions of people to currently undeveloped
interior natural areas (Stanton and Ackerman 2007, p. 15; Ruppert et
al. 2008, p. 127).
The effects of climate change are projected to impact the gopher
tortoise and its habitat. These impacts will be direct through loss of
individuals and indirect through the loss of habitat due to sea level
rise, lack of habitat management due to reduction in burn days,
increased flooding, and human migration from inundated coastal areas to
inland areas (Ruppert et al. 2008, p. 127; Castellon et al. 2018, pp.
11-14; Hayhoe et al. 2018, entire; Kupfer et al. 2020, entire). Despite
the recognition of climate effects on ecosystem processes, there is
some uncertainty about the timing of these effects for the Southeastern
United States and how the gopher tortoise will respond to these
changes. Factors associated with a changing climate may act as risk
multipliers by increasing the risk and severity of other threats, as
described in Synergistic and Cumulative Effects, below.
Habitat Management
As mentioned previously, the gopher tortoise needs large swaths of
interconnected, high-quality habitat patches with open canopy and
abundant herbaceous groundcover to support viable populations, and a
variety of land management practices are used in the restoration,
enhancement, and maintenance of gopher tortoise habitats. Insufficient
habitat management (e.g., no prescribed fire program) has been
identified as a major threat to the gopher tortoise (Smith et al. 2006,
pp. 326-327). High-quality gopher tortoise habitat will require
prescribed fire only at regular intervals, while areas of degraded or
low-quality gopher tortoise habitat will require more active habitat
management (e.g., multiple habitat management tools including
mechanical and chemical treatments in conjunction with the
reintroduction of prescribed fire to restore natural conditions).
However, not all habitat management activities are uniformly beneficial
to the gopher tortoise. In general, management actions that minimize
soil disturbance, protect burrows, and maintain a diversity of
groundcover plants, to ensure that sufficient sunlight reaches the
ground, are beneficial to the gopher tortoise. Conversely, actions that
cause significant soil disturbances or result in the loss of diverse
groundcover are detrimental to the species. A variety of habitat
management methods are implemented rangewide at varying degrees across
land ownership and use types (e.g., conservation land, commercial
forestry, family-owned lands, etc.). Prescribed fire, selective use of
herbicide, mechanical vegetation management (e.g., roller chopping and
mowing), and timber harvest are valuable management techniques in the
restoration, management, and maintenance of gopher tortoise habitat and
are frequently used in combination to achieve habitat condition goals.
The regular application of prescribed fire is important for the
maintenance of habitat conditions required by the gopher tortoise. When
applied at appropriate intervals, prescribed fire reduces shrub and
hardwood encroachment, and stimulates growth of forage plants such as
grasses, forbs, and legumes, particularly when applied during the
growing season (Thaxton and Platt 2006, p. 1336; FWC 2007, p. 32; Iglay
et al. 2014, pp. 39-40; Fill et al. 2017, pp. 156-157). In addition, a
more open canopy and midstory created with the use of prescribed fire
allows for proper incubation of eggs and thermal regulation (basking)
of tortoises. Without habitat management including fire management,
gopher tortoises may abandon an area of previously suitable habitat
after as little as 20 years of fire exclusion (Ashton et al. 2008, p.
528). In the future, reduced habitat management is expected to result
in habitat degradation or loss, negatively impacting the gopher
tortoise.
Mechanical or chemical (herbicide) management techniques may be
needed to reduce hardwood competition to levels where prescribed fire
can be effective and are increasingly important for areas where
prescribed fire use is not a viable option, such as habitat in
urbanized areas (Ashton and Ashton 2008, p. 78; Miller and Chamberlain
2008, pp. 776-777; Jones et al. 2009, p. 1168; Iglay et al. 2014, p.
40; Platt et al. 2015, p. 913; Greene et al. 2020, p. 50). Habitat
management using mechanical means can be effective in reducing shrub
and tree density to promote conditions favorable to herbaceous
vegetation. Mechanical treatments are used in habitat restoration, site
preparation to promote pine seedling survival and growth, maintenance,
and in other agricultural and forestry endeavors. Mechanical vegetation
management examples include mulching/chipping, subsoiling, shearing,
stumping, root raking into piles or windrows, roller chopping, discing,
and bedding. Depending on management objectives and treatment type,
mechanical site preparation may result in substantial soil disturbance
affecting soil structure and chemistry and may increase invasive
species on a site (Hobbs and Huenneke 1992, pp. 324-325; Jack and
McIntyre 2017, p. 189). Heavy equipment used to manage gopher tortoise
habitat may also cause impacts to gopher tortoise through crushing or
damage to burrows (Landers and Buckner 1981, pp. 1-7; Greene et al.
2020, p. 54). Some land managers incorporate best management practices
for gopher tortoise habitat into their management plans, including a
buffer distance around burrows to minimize disturbance and hazards
(Smith et al. 2015, pp. 459-460).
Mechanical vegetation management followed by herbicide application
is used as a short-term option to maintain habitat in areas where fire
use is restricted. Herbicide can reduce midstory vegetation growth
resulting in more sunlight reaching the ground. Although mechanical
vegetation management is effective in reducing the vertical structure
and overgrowth in the mid- and overstories, mechanical treatments alone
do not replicate the stimulation of plant growth, flowering, and seed
release, and soil nutrient cycling provided by fire (Dean et al. 2015,
pp. 55-56). Best conservation practices for mechanical and herbicide
management practices in gopher tortoise habitat are available for
landowners and managers and are increasingly implemented (FWC 2013,
entire; Service 2013, entire; GDNR 2014, entire; Florida Department of
Agriculture and Consumer Services (FDACS) 2014, entire; FDACS 2015,
entire; Jack and McIntyre 2017, p. 200).
Forest (Timber) Management
Management of forests, either public or private, influences habitat
where gopher tortoises occur or habitat that may be suitable for gopher
tortoises. Although specific forest or timber management techniques
vary by site, management goals, and ownership, we summarize the
influence of forest or timber management in general on gopher tortoise
below. More details and information on this influence may be found in
the SSA section 3.8.4 Timber Management (Service 2022, pp. 76-79).
Not all forested lands provide appropriate conditions for gopher
tortoises. However, forests on lands with suitable soils and compatible
forest
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management objectives in the gopher tortoise range can be managed in
such a way as to provide the open canopy and the dense herbaceous
groundcover conditions needed for gopher tortoise viability. Some types
of timber and gopher tortoise habitat management include the reduction
of hardwood competition. This activity results in reduced tree density
and increased sunlight, promoting herbaceous forage proliferation and
suitable conditions for gopher tortoise basking and egg incubation
(NRCS 2020, entire). Several management practices associated with
working forests, such as planting densities, rotation length, and time
until first and subsequent thinning(s), have a direct influence on
whether these lands provide and maintain habitat for the species.
Gopher tortoises occur in production pine forests with suitable
conditions, although at lower densities than reported in other cover
types, and densities may be below the threshold necessary to sustain a
viable population (Diemer-Berish et al. 2012, pp. 51-52; Wigley et al.
2012, p. 42; Greene et al. 2019, p. 51). In pine forests managed for
timber or pulp (typically slash or loblolly pine) where suitable
conditions are not maintained, gopher tortoises more frequently
abandoned burrows and emigrated from low-quality habitat conditions
associated with closed canopy pine plantations (Diemer 1992a, p. 288;
Aresco and Guyer 1999, p. 32). Most modern forests managed more
intensely for traditional wood products (i.e., timber, pulp)
incorporate management strategies to maintain open canopy conditions
for much of the life of a commercial stand (Weatherford et al. 2020, p.
4). For private lands, programs such as forest certifications (e.g.,
Sustainable Forestry Initiative (SFI) or Forest Stewardship Council)
and the development of diversified markets for forest products have
increased forest management practices that benefit gopher tortoises
(Greene et al. 2019, p. 201; Greene et al. 2020, p. 55).
Public lands managed for multiple use or conservation objectives
that include timber production employ some of the same habitat
management techniques and additionally may be guided by land management
plans or forest plans. The Forest and Rangeland Renewable Resources
Planning Act (16 U.S.C. 36), as amended by the National Forest
Management Act of 1976 (16 U.S.C. 1600-1614), requires that each
National Forest (NF) be managed under a forest plan that is revised
every 10 years. Forest plans provide an integrated framework for
analyzing and approving projects and programs, including conservation
of listed species. Several National Forests (e.g., Ocala NF, Desoto NF,
Conecuh NF, Apalachicola NF, etc.) occur within the current range of
the gopher tortoise, providing important habitat conservation for the
species. Identification and implementation of land management and
conservation measures to benefit gopher tortoises vary among National
Forests, but generally include habitat restoration and management
objectives and maintaining buffers around gopher tortoise burrows
during various forest management activities.
However, not all public or private lands are managed to these
standards, and incompatible practices and insufficient management
continue to affect gopher tortoise habitat and influence gopher
tortoise viability. Reductions in required groundcover forage may be
caused by nearly complete groundcover weed control, high seedling
stocking rates, or short timber rotations with a minimal proportion of
the rotation being open canopied. In addition, exclusion of prescribed
fire and dense hardwood midstory encroachment within open canopied
forests degrade habitat through suppression of groundcover and loss of
open areas for burrowing and movement.
Historical declines of longleaf forests are well established, with
estimates of 95 percent loss from the historical estimate of 88 million
ac (35.6 million ha) (Oswalt et al. 2012, p. 13). However, the
magnitude and extent of insufficient and incompatible forestry and
timber management currently occurring on the landscape and impacting
gopher tortoise populations and habitat has not been quantified.
Rangewide, approximately 80 percent of potential gopher tortoise
habitat occurs in private ownership, with the remainder owned or
managed by local, State, Federal, or private conservation entities
(Wear and Greis 2013, p. 103; Natural Resources Conservation Service
(NRCS) 2018, p. 2). Private landowners hold more than 86 percent of
forests in the South and produce nearly all of the forest investment
and timber harvesting in the region (Most of the potential gopher
tortoise habitat is privately held, and much of this is in
silviculture. Rangewide conservation and management efforts between
private landowners and conservation agencies, such as best conservation
practices for gopher tortoises developed by States and conservation
incentive programs and partnerships, promote compatibility between
timber and gopher tortoise management; these are further described in
Conservation Efforts and Regulatory Mechanisms, below. We have included
the best available information regarding gopher tortoises in timber
production pine forests in our SSA; however, to date, systematic
surveys in pine forests intensively managed for timber and pulp
products across the range of the gopher tortoise have not been
conducted.
Other Factors--Disease, Predation, Harvest and Roundups, Nonnative
Invasive Species
Disease
A number of diseases, including fungal, viral, bacterial, and
parasitic diseases, have been documented in gopher tortoises (Ashton
and Ashton 2008, pp. 39-41; Johnson et al. 2008, entire; Myers et al.
2009, p. 582; Desiderio et al. 2021, entire). Upper Respiratory Tract
Disease (URTD) resulting from two bacterial species (Mycoplasma
agassizii and M. testudineum) has been documented throughout much of
the tortoise's range (McLaughlin 1997, p. 6; Gates et al. 2002, entire;
Rabatsky and Blihovde 2002, entire; Dziadzio et al. 2018, entire;
Goessling et al. 2019, pp. 5-6). While large-scale die-offs due to URTD
appear to be rare, correlations between exposure to Mycoplasma spp. and
population declines are variable among populations (McCoy et al. 2007,
p. 173). URTD has been linked to several large mortality events
(defined as the loss of greater than 3 percent of adults in 1 year) in
Florida with an estimated loss of 25-50 percent of the adult population
in one event and 35 to 125 adults in other events (McLaughlin 1997, p.
6; Gates et al. 2002, entire; Rabatsky and Blihovde 2002, entire;
Dziadzio et al. 2018, entire). However, tortoises have natural
antibodies to Mycoplasma spp., and these natural immune mechanisms may
explain why die-offs are less prevalent rangewide than may be expected
from the degree of seroprevalence in gopher tortoise populations
(Hunter et al. 2008, p. 464; Gonynor and Yabsley 2009, pp. 1-2;
Sandmeier et al. 2009, pp. 1261-1262). In addition, URTD may result in
altered movement (e.g., increased dispersal) and behavior (e.g.,
changes to basking) among gopher tortoises (McGuire et al. 2014, pp.
750-754; Goessling et al. 2017, p. 488). Tortoises dispersing long
distances increase their likelihood of encountering a road (i.e., a
barrier), potentially limiting spread of disease but increasing risk of
road mortality. The magnitude of threat that URTD poses to gopher
tortoise populations and tortoise demographics is currently
[[Page 61845]]
unknown, but the best available science indicates it is not a key
factor in species viability (Karlin 2008, p. 145).
Predation
Gopher tortoise nest predation varies annually and across sites,
ranging from approximately 45 to 90 percent in a given year (Landers et
al. 1980, p. 358; Wright 1982, p. 59; Marshall 1987, pp. 29-32). Gopher
tortoises are most susceptible to predation within their first year of
life, primarily within 30 days of hatching (Pike and Seigel 2006, p.
128; Smith et al. 2013, pp. 4-5). Overall annual hatchling survival has
been estimated to be approximately 13 percent (Perez-Heydrich et al.
2012, p. 342). Raccoons (P. lotor) are the most frequently reported
predator of nests and juvenile gopher tortoises (Landers et al. 1980,
p. 358; Butler and Sowell 1996, p. 456). However, 25 species--12
mammals, 5 birds, 6 reptiles, and 2 invertebrates--are known to be
predators of eggs, emerging neonates, hatchlings, and older tortoises
(Ashton and Ashton 2008, p. 27). Adult gopher tortoises are less likely
to experience predation compared to hatchlings and eggs, but predation
by canines (e.g., domestic dogs, coyotes, foxes) and humans has
occurred (Causey and Cude 1978, pp. 94-95; Taylor 1982, p. 79; Hawkins
and Burke 1989, p. 99, Mann 1995, p. 24). Some predation can be
attributed to habitat fragmentation and edge effects, roads and
infrastructure, increased availability of food for predators in
proximity to human-inhabited areas, reduction or elimination of top
canid carnivores, ecological perturbations allowing predator range
expansion, and domestic animals associated with humans (Stiles and
Jones 1998, p. 343; Crooks and Soule 1999, entire; Wetterer and Moore
2005, pp. 352-353).
As mentioned previously, the gopher tortoise is a long-lived
species that naturally experiences high levels of mortality in early
life stages. However, as urbanization increases in the future, we
expect that higher levels of hatchling and juvenile mortality
associated with increased predation near anthropogenic sites will have
a negative impact on gopher tortoise recruitment in affected
populations.
Harvest and Rattlesnake Roundups
Historical harvest of gopher tortoises for consumption has
influenced gopher tortoise populations in the past, particularly in
portions of the Florida panhandle (Lohoefener and Lohmeier 1984, pp. 1-
30; Mann 1995, p. 18; Estes and Mann 1996, p. 21; Tuma and Sanford
2014, pp. 145-146). Although this practice is now uncommon, localized
harvest still occurs in some rural areas (Rostal et al. 2014, p. 146).
Although loss of individuals may impact affected populations, we have
determined that harvest is not a significant species-level threat to
the gopher tortoise (Service 2022, p. 63).
Historically, multiple rattlesnake roundups were held throughout
the Southeast (Means 2009, p. 132). Snakes were collected by blowing
fumes of noxious liquids (``gassing'') in gopher tortoise burrows to
collect snakes for these roundups. Gassing of inhabited burrows
negatively impacts the resident tortoise, though research that
quantifies mortality associated with this practice is limited (Means
2009, p. 139). The practice of gassing tortoise burrows is now
prohibited across the species' range. Gopher tortoise mortality due to
rattlesnake collection is primarily historical and is not likely a
significant current influence on populations, as only one roundup still
takes place in Alabama and the use of gasoline or other chemical or
gaseous substances to drive snakes from burrows is now prohibited
across the Southeast (Alabama Regulation 220-2-.11, Georgia codes
sections 27-1-130 and 27-3-130, Florida Administrative Code 68A-
4.001(2), and Mississippi Code R 5-2.2 B). Therefore, harvest and take
resulting from rattlesnake roundups are considered historical threats
to the species, and the best available science indicates these are not
current threats to the species.
Nonnative Invasive Species--Flora and Fauna
The spread of nonnative invasive plant species alters and degrades
gopher tortoise habitat by reducing forage quality and quantity and the
availability of burrowing and nesting locations, and ultimately
influences gopher tortoise viability. Some species postulated to impact
tortoise habitat include kudzu (Pueraria montana), Chinese privet
(Ligustrum sinense), Callery pear (Pyrus calleryana), natal grass
(Melinis repens), and Japanese climbing fern (Lygodium japonicum),
though quantified impacts of these species on tortoises are unknown.
One species known to impact gopher tortoise use of habitat is
cogongrass (Imperata cylindrica), a prolific invasive that occurs
throughout much of the gopher tortoise's range. Unlike other invasive
plant species in upland communities, cogongrass can rapidly spread
following disturbances including prescribed fire (Yager et al. 2010,
entire; Holzmueller and Jose 2011, pp. 436-437). It can quickly form a
tall, dense ground cover with a dense rhizome layer and can outcompete
native vegetation (Dozier et al. 1998, pp. 737-740; Mushinsky et al.
2006, p. 360; Minogue et al. 2018, pp. 1-4). Widespread areas of dense
cogongrass could result in habitat loss as gopher tortoises do not use
these areas, nor do they consume cogongrass (Basiotis 2007, p. 21).
Cogongrass can also decrease gopher tortoise habitat quality by
reducing forage quality and quantity and the availability of burrowing
and nesting locations (Lippincott 1997, pp. 48-65; Basiotis 2007, p.
24).
Nonnative invasive fauna can also negatively influence the gopher
tortoise and its habitat. Throughout the gopher tortoise's range, the
red imported fire ant (Solenopsis invicta) occurs in disturbed soil in
upland habitats (Wetterer and Moore 2005, p. 352; Shearin 2011, pp. 22,
30; USDA 2017, unpaginated). Fire ants are not able to breach gopher
tortoise eggs, but the ants will depredate hatchlings (Mann 1995, p.
24; Butler and Hull 1996, p. 17; Epperson and Heise 2003, p. 320;
Diffie et al. 2010, p. 295; Dziadzio et al. 2016, pp. 531, 536). Fire
ants are aggressive, and their stings can result in direct mortality
and reduced survival by limiting growth, altering behavior, and
changing foraging patterns of hatchlings (Wilcox and Giuliano 2014, pp.
3-4; Dziadzio et al. 2016, pp. 532-533). In the western portion of the
range, gopher tortoise conservation banks and other related sites must
include fire ant monitoring and control as part of their management
plan to reduce the effects of predation on tortoise eggs and hatchlings
(74 FR 46401, September 9, 2009).
The nine-banded armadillo (Dasypus novemcinctus), Argentine black
and white tegu (Salvator merianae), Burmese python (Python bivittatus),
and black spiny-tailed iguana (Ctenosaura similis) use gopher tortoise
burrows and are known predators of tortoise eggs (Service 2022, pp. 68-
69). Frequent damage to gopher tortoise burrows by wild pigs (Sus
scrofa), domestic dogs (Canis lupus familiaris), and possibly domestic
cats (Felis catus) may impact some gopher tortoises as well.
The current impact of these nonnative invasive floral and faunal
species on gopher tortoise appears low at the species level. Although
impacts to individuals and populations have been documented to occur,
we did not find nonnative invasive species to be a key factor in gopher
tortoise viability.
Conservation Efforts and Regulatory Mechanisms
In this section, we describe key protections and conservation
efforts
[[Page 61846]]
provided by various Federal and State entities, private landowners, and
nongovernmental organizations. Additional information regarding
conservation efforts and Federal and State protections may be found is
the SSA report (Service 2022, pp. 79-102).
Federal and State Protections
In addition to the protections provided to the gopher tortoise in
the listed portion of the range under sections 7 and 10 of the Act, we
implement conservation delivery tools and programs that aid in the
conservation of listed and at-risk species, such as the gopher
tortoise, on non-Federal lands. Cooperative conservation programs such
as the Partners for Fish and Wildlife Program provide technical and
financial assistance to private landowners and others for the
conservation of wildlife and associated habitat. Between 2010 and 2019,
under the Partners for Fish and Wildlife Program, approximately 65,000
ac (26,305 ha) of restoration and enhancement activities were
implemented in gopher tortoise habitat on private lands in Alabama,
Florida, Georgia, and Mississippi (Service 2020, unpaginated).
The Gopher Tortoise Conservation and Crediting Strategy (Strategy)
is a conservation initiative designed to balance military mission
activities and gopher tortoise conservation on Department of Defense
(DoD) lands in the Southeast (Service 2017, entire); see below under
Conservation Lands for further discussion about DoD lands. The Service-
approved Strategy establishes the framework for determining credit for
DoD conservation actions and is intended to achieve a net conservation
benefit to the species. It focuses on identification, prioritization,
management, and protection of viable gopher tortoise populations and
the best remaining habitat. It provides guidelines designed to result
in an increase in the size and/or carrying capacity of populations
while promoting the establishment of new populations through increased
habitat connectivity or translocation of gopher tortoises (Service
2017, entire).
The U.S. Department of Agriculture Natural Resources Conservation
Service (NRCS) offers technical and financial assistance to help
agricultural producers voluntarily implement conservation activities
and practices that benefit the gopher tortoise. The gopher tortoise is
identified as a target species eligible for conservation funding in the
national Working Lands for Wildlife partnership, which is a
collaborative approach to conserving habitat on working lands. In
addition, the NRCS works to restore longleaf pine across its historical
range through the Longleaf Pine Initiative. Between 2012 and 2021,
private landowners across the range of the species have received
assistance to implement management practices that benefit gopher
tortoises and gopher tortoise habitat on 943,740ac (381,918ha) through
NRCS programs.
Each State within the range of the gopher tortoise provides some
measure of protection for the species. The States of Florida, Georgia,
and South Carolina provide protection for the gopher tortoise through
the requirement of land management plans for State lands. The gopher
tortoise is protected by regulation as a non-game species in Alabama,
is State-listed as threatened in Florida, Georgia, and Louisiana, and
is State-listed as endangered in Mississippi and South Carolina. Gopher
tortoise protections vary by State; however, laws within most States in
the range focus on prohibitions against the take, possession, export/
sale, and killing of gopher tortoises. States in the gopher tortoise
range also implement conservation programs in partnership with private
landowners. For example, Florida's Landowner Assistance Program assists
private landowners with plans to improve their wildlife habitat through
the development of 10-year management plans on an estimated 44,000 ac
(17,806 ha) of gopher tortoise habitat per year (FWC 2020b, p. 6).
Florida has also developed the Gopher Tortoise Management and Gopher
Tortoise Permitting Guidelines to guide gopher tortoise recovery
efforts and regulatory actions (FWC 2007, revised 2012, entire; FWC
2008, revised July 2020; entire). Florida regulations also require that
construction or other activities that disturb gopher tortoise burrows
must obtain a relocation permit and that the impacts be considered and
mitigated.
Translocation and Headstarting
Gopher tortoises have been considered one of the most translocated
species in the Southeast, and translocation is commonly used as a
conservation strategy to mitigate the loss of tortoises from land under
development (Dodd and Seigel 1991, p. 340). Displaced tortoises are
often translocated to suitable habitat to reestablish extirpated
populations or augment existing populations (Griffith et al. 1989, p.
477). Numerous studies have attempted to evaluate the success of gopher
tortoise translocation and improve its efficacy. However, gopher
tortoise life history characteristics (e.g., long-lived, slow-growing,
and slow to reach maturity) make it difficult to determine if
translocations result in sufficiently viable tortoise populations since
the typical monitoring periods are shorter than the generation time for
the species. Gopher tortoises disperse at a high rate in the year
following translocation; however, soft-releases, or the temporary
penning of gopher tortoises within a recipient area, are highly
effective at limiting dispersal post-translocation (Tuberville et al.
2005, pp. 353-354; Tuberville et al. 2008, pp. 2694-2695; Bauder et al.
2014, pp. 1449-1450). Translocation is successful at removing tortoises
from immediate danger due to development (Tuberville et al. 2005, p.
356; Tuberville et al. 2008, p. 2695).
Gopher tortoise relocation and translocation practices are being
implemented and included as guidance across the range of the species
(Service 2022, pp. 85-87). The primary goals for recipient sites are to
prevent the loss of tortoises and retain the existing tortoises; and
while habitat is lost on the development site, recipient sites can
contribute to habitat conservation if sites receive long-term
protection and subsequent habitat management. These sites can provide
high conservation value by restocking tortoises to appropriately
suitable lands where populations have previously been depleted.
However, this practice could result in an overall net loss of habitat
if not implemented in conjunction with acquisition and additional
protection of habitat when needed. Additional information regarding
specific translocation efforts in each State may be found in the SSA
report (Service 2022, pp. 83-87).
Headstarting, or the process of hatching and/or rearing juvenile
turtles in captivity through their most vulnerable period, has shown
success as a technique to boost depleted gopher tortoise populations
(Holbrook et al. 2015, pp. 542-543; Tuberville et al. 2015, pp. 467-
468; Spencer et al. 2017, p. 1341; Quinn et al. 2018, p. 1552;
Tuberville et al. 2021, p. 92). Headstarting has been explored as a
management tool for the gopher tortoise with increasing recognition of
its potential role, particularly when used in concert with other
management actions (Spencer et al. 2017, entire; Quinn et al. 2018, pp.
1552-1553). For example, the gopher tortoise headstarting program at
Camp Shelby in Forrest County, Mississippi (funded by the Mississippi
Army National Guard and in partnership with The Nature Conservancy) has
been ongoing since 2013 and has shown initial success with headstarted
juveniles surviving at a
[[Page 61847]]
much higher rate than their wild counterparts (70-80 percent versus 30
percent for wild 2- to 3-year-old tortoises). Similar survival rates
were noted in post-release monitoring of headstarted yearling gopher
tortoises in Georgia and South Carolina (Tuberville et al. 2015,
entire).
Other Conservation Mechanisms
In the eastern portion of the range, the gopher tortoise is
included in a candidate conservation agreement (CCA) (revised 2018)
with State, nongovernmental and private organizations and in a
candidate conservation agreement with assurances (CCAA) (2017) with
Camp Blanding Joint Training in Florida. These Service-approved
agreements outline management actions that landowners implement to
benefit the gopher tortoise and its habitat across the candidate range.
We developed the 2013 Rangewide Conservation Strategy for the Gopher
Tortoise to guide conservation of the gopher tortoise by our partners,
including States within gopher tortoise range, the Service, and other
public and private entities to collect and share information on gopher
tortoise threats, outline highest priority conservation actions, and
identify organizations best suited to undertake those conservation
actions (Service 2013, entire).
In Florida, where the greatest number of tortoises have been
identified, several additional conservation efforts are ongoing. The
Forestry Wildlife Best Management Practices for State Imperiled Species
and the Agriculture Wildlife Best Management Practices for State
Imperiled Species were developed in 2014 and 2015, respectively, to
enhance silviculture's contribution to the conservation of wildlife,
provide guidance to landowners who chose to implement these voluntary
practices, and reduce take of gopher tortoises (FDACS 2015, entire). By
2021, landowners provided notice of intention to FWC to implement
forestry best management practices (BMPs) on more than 3.7 million ac
(1.5 million ha) and conservation practices on approximately 425,031 ac
(172,004 ha) of agricultural lands in Florida (FWC 2020a, unpaginated;
FWC 2021, p. 1). FWC also provides technical assistance to private and
industry landowners to implement beneficial management and/or
mitigation activities across 40 counties through other programs and
agreements (FWC 2020b, p. 2; FWC 2021, p. 1).
There are numerous other gopher tortoise conservation tools and
guides, including several in the core of the species' range in Georgia.
For example, the Best Conservation Practices for Gopher Tortoise
Habitat on Working Forest Landscapes was developed to assist in best
conservation practices for the creation and maintenance of gopher
tortoise habitat in the candidate portion of the range (GDNR et al.
2018, entire). Additionally, Forest Management Practices to Enhance
Habitat for the Gopher Tortoise details the essentials of managing
habitat for gopher tortoises, including prescribed fire, timber
harvest, and selective herbicide use (GDNR 2014, unpaginated). Further,
the Georgia Gopher Tortoise Initiative is an extension of the Georgia
Department of Natural Resource's long-standing effort in conserving
longleaf pine systems. The initiative is a collaborative effort between
several public and private entities and is geared towards the
protection, restoration, and long-term management of gopher tortoise
habitat.
Implemented rangewide, America's Longleaf Restoration Initiative is
a collaborative effort involving multiple public and private partners
actively supporting efforts to restore and conserve longleaf pine
ecosystems with a goal to increase longleaf coverage on the landscape
to 8.0 million ac (3.2 million ha) (ALRI 2021, unpaginated). Several
local implementation teams work across the gopher tortoise range to
help restore longleaf pine on habitat where gopher tortoises occur.
Conservation Lands
The conservation of multiple large, contiguous tracts of habitat
provides the connectivity and landscape heterogeneity requirements to
support gopher tortoise viability. Gopher tortoise habitat occurs
across a wide range of lands in public ownership with varying levels of
management. An estimated 1.7 million ac (688,000 ha) of potential
gopher tortoise habitat occurs on protected lands including lands in
Federal, State, and local government, nongovernmental organization, and
private ownership (e.g., conservation easements) throughout the
species' range.
Managing publicly owned lands in a way that benefits the gopher
tortoise is an important mechanism for reducing the effects of habitat
loss, fragmentation, and degradation on the species. Habitat management
occurring on public conservation lands is often accomplished via
natural resource planning instruments (e.g., land management plans,
comprehensive conservation plans, resource management plans, etc.).
Each State in the gopher tortoise's range has statutory authority to
acquire land for conservation purposes. Since publication of the 12-
month finding (76 FR 45130, July 27, 2011), all States within the
species' range have made concerted efforts to protect gopher tortoise
habitat and potential gopher tortoise habitat via strategic land
acquisition. Between 2011 and 2019, Alabama, Florida, Georgia, and
South Carolina have reported fee-simple acquisition of approximately
42,000 ac (16,996 ha) of potential gopher tortoise habitat with an
additional approximately 78,000 ac (31,565 ha) acquired in conservation
easements (CCA 2019, pp. 52-73). Federal entities including the U.S.
Air Force, the U.S. Forest Service, and the Service recorded an
additional 2,740 ac (1,109 ha) of potential gopher tortoise habitat
acquired and approximately 24,000 ac (9,712 ha) of conservation
easements acquired (CCA 2019, pp. 52-73).
Several National Wildlife Refuges (NWRs) (e.g., Merritt Island NWR,
Lake Wales Ridge NWR, Lower Suwannee NWR, St. Marks NWR) occur within
the range of the gopher tortoise, providing important habitat
conservation for the species. Management activities included in NWR
Comprehensive Conservation Plans that influence gopher tortoises
include habitat restoration activities such as prescribed fire, pine
thinning, and other mechanical vegetation management for restoring
desired vegetative conditions in pine and scrub systems, and tortoise
management and monitoring actions based on priorities of the refuge and
available resources.
Rangewide, the gopher tortoise occurs on 31 DoD installations, with
potential habitat on additional installations (DoD 2022, p. 4). Many of
these installations specifically include gopher tortoise habitat and
population management prescriptions and goals within their individual
integrated natural resources management plans (INRMPs) prepared in
conjunction with the Service. Most INRMPs also include land management
for other upland species that benefit gopher tortoise habitat (and
gopher tortoises) as well. Rangewide, approximately 830,000 ac (335,889
ha) of potential gopher tortoise habitat occur on military
installations. Limited information is currently available regarding the
condition of this potential habitat and the extent to which these areas
are occupied by gopher tortoises.
National Forest (NF) plans provide an integrated framework for
analyzing and approving projects and programs, including conservation
of listed species. Several National Forests (e.g., Ocala NF, Desoto NF,
Conecuh NF, Apalachicola NF, etc.) occur within the range of the gopher
tortoise and provide important habitat conservation for the species.
Identification and implementation of
[[Page 61848]]
land management and conservation measures to benefit gopher tortoises
vary among NFs, but generally include habitat restoration and
management objectives and maintaining buffers around gopher tortoise
burrows during various forest management activities. For example, the
Desoto NF recently completed a 10-year Collaborative Forest Landscape
Restoration Program, during which actions to restore longleaf pine were
implemented on 374,000 ac (151,352 ha) of NF lands. In addition, the
Desoto NF has prioritized any management treatment that contributes to
improvement of gopher tortoise, as set forth in their Mission, Vision,
and Operational Strategy (USFS 2020, entire).
Private Lands Conservation Efforts
Most forested land within the gopher tortoise range is privately
owned. Privately owned lands account for approximately 80 percent of
potential gopher tortoise habitat, of which approximately half are
managed for forest production (NRCS 2018, p. 2; Greene et al. 2019, p.
201). Across the gopher tortoise range, large working forests account
for over 6 million ac (2.4 million ha) of forest land, representing a
significant land use with the potential to influence gopher tortoise
resiliency and viability (Weatherford et al. 2020, p. 3). While not all
working forest lands include appropriate habitat conditions for gopher
tortoises, approximately 2.78 million ac (1.12 million ha) of suitable
soil types and 2.98 million ac (1.21 million ha) of open pine
conditions are estimated to occur on private forest lands (NCASI 2021,
p. 1). We included the best available data on gopher tortoise
observations between 1977 and 2019 on private forest lands in our SSA
(Weatherford et al. 2020, pp. 9-11; Service 2022, pp. 95-99). These
observations occur on Member Company lands that are part of the
National Council for Air and Stream Improvement and landowners may
implement conservation measures including those outlined in the
Sustainable Forestry Initiative guidelines.
While working to meet a range of objectives, including timber
production, many larger private working forests also accomplish
conservation within a broad network of collaboration with Federal,
State, and local government agencies, universities, and nongovernmental
organizations. For example, forest landowners may create and maintain
areas of open pine conditions, conduct gopher tortoise burrow surveys,
conduct research, and implement BMPs that benefit the gopher tortoise.
In addition, forest certification programs, such as the Sustainable
Forestry Initiative (SFI) and Forest Stewardship Council, require
participants to adhere to a set of principles including providing
wildlife habitat to conserve biological diversity (Weatherford et al.
2020, p. 11). Adhering to these principles likely provides a benefit to
maintaining suitable gopher tortoise habitat in private working
forests. An estimated 13.7 million ac (5.5 million ha) within the
gopher tortoise's range are certified through SFI, although the
proportion of certified acres that include gopher tortoise populations
or their current habitat is unknown (SFI 2021, unpaginated). Other
forest certifications, including the American Tree Farm System, are
authorized by the Program for the Endorsement of Forest Certification,
a third-party audited certification system.
The largest forest landowner group in the United States is the
family forest landowners, controlling approximately 87 percent of
forest land in the South (Oswalt et al. 2014, p. 6). The American
Forest Foundation works with smaller, family forest landowners and has
partnered with the Service's Partners for Fish and Wildlife Program to
develop habitat improvement plans as part of a 10-year agreement. Since
2017, the partnership has implemented habitat management activities on
more than 3,500 ac (1,416 ha) and identified 762 gopher tortoises,
including 2 populations that meet the MVP criteria (AFF 2021,
unpaginated).
Additionally, The Longleaf Alliance works with private landowners
and other partners across the range of the gopher tortoise to restore
and maintain habitat as an essential part of their larger focus in
restoring the longleaf pine ecosystem. Through The Longleaf Alliance,
in 2019, landowners implemented more than 55,000 ac (22,258 ha) of
prescribed fire within gopher tortoise habitat, in addition to longleaf
pine plantings, groundcover restoration, and invasive plant management
efforts (SERPPAS 2020, p. 17).
Other private conservation efforts include several privately owned
tracts of land managed as mitigation/conservation areas for gopher
tortoises in both Mississippi and Alabama, which provide suitable
habitat, protection, and habitat management. Four conservation areas in
Alabama are managed through Service-approved habitat conservation
plans, while the Mississippi conservation bank follows national
mitigation banking guidelines for maintaining optimal habitat,
including aggressive prescribed fire and longleaf restoration programs.
Synergistic and Cumulative Effects
We note that, by using the SSA framework to guide our analysis of
the scientific information documented in the SSA report, we have not
only analyzed individual effects on the species, but we have also
analyzed their potential cumulative effects. We incorporate the
cumulative effects into our SSA analysis when we characterize the
current and future condition of the species. To assess the current and
future condition of the species, we undertake an iterative analysis
that encompasses and incorporates the threats individually and then
accumulates and evaluates the effects of all the factors that may be
influencing the species, including threats and conservation efforts.
Because the SSA framework considers not just the presence of the
factors, but to what degree they collectively influence risk to the
entire species, our assessment integrates the cumulative effects of the
factors and replaces a standalone cumulative effects analysis.
Several factors influencing gopher tortoise viability are
synergistic and related. Urbanization and development results in
habitat loss, fragmentation, and degradation through land use change
and increased road infrastructure. The anthropogenic changes associated
with urbanization and development also affect the gopher tortoise
through the introduction of nonnative invasive species and predators.
Climate change is expected to influence the gopher tortoise through
several changes as described in Climate Change, above. Sea level rise
is expected to result in an inland migration of the human population
away from inundated areas, resulting in increased urbanization and
developed inland areas that are currently undeveloped and potentially
suitable upland habitat for gopher tortoise. In addition, changes in
precipitation and temperature are expected to result in a decrease in
the number of suitable burn days in gopher tortoise habitat, leading to
reduced habitat management (another threat to gopher tortoise
viability). Urbanization and development also limit the implementation
of prescribed burns as a habitat management tool due to safety concerns
and proximity to inhabited areas.
Influences on the gopher tortoise that are not considered key
factors influencing the species' status may exacerbate the effects of
urbanization, climate change, and habitat management in affected gopher
tortoise
[[Page 61849]]
populations. Conservation of habitat through land acquisition and
conservation actions on public and private lands and the retention of
private forest lands reduces the severity of some of these threats by
providing protection of habitat across the landscape, maintaining
connectivity between habitat patches, and increasing the opportunity
for beneficial habitat management actions now and into the future.
Summary of Factors Influencing the Species
The best available information regarding the gopher tortoise and
its habitat indicates that habitat loss, degradation, and fragmentation
(due to land use changes from urbanization), climate change,
insufficient and/or incompatible habitat management, and conservation
actions are the most significant factors influencing gopher tortoise
viability. Urbanization results in a range of impacts that either
remove, degrade, or fragment remaining habitat, or impact gopher
tortoises directly through development. Urbanization brings road
construction and expansion, which may cause direct mortality of gopher
tortoises and fragment remaining habitats. In addition, this type of
development may also create conditions that prove to be beneficial to
invasive species, serve to increase predators, and establish inadequate
conditions for fire management. Temperature increases associated with
long-term climate change are likely to further constrain use of
prescribed fire through a decrease in the number of suitable burn days.
Habitat loss resulting from sea level rise associated with climate
change is a risk for coastal populations of gopher tortoise. Habitat
management through prescribed fire and other methods is important to
maintaining suitable habitat conditions, and insufficient and/or
incompatible habitat management now and in the future, especially based
on projections in reduction of prescribed fire, impacts the viability
of gopher tortoise populations. Conservation efforts to benefit the
gopher tortoise and its habitat implemented by Federal, State, and
private partners occur across the species' range and influence the
gopher tortoise condition. These factors are considered to have
population-level effects and were evaluated further in the current
condition and future condition analysis.
Current Condition
We describe the current condition of the gopher tortoise in terms
of population resiliency and species redundancy and representation. The
analysis of these conservation principles to understand the species'
current viability is described in more detail in the gopher tortoise
SSA report (Service 2022, pp. 103-143).
Data Sources
To inform the gopher tortoise SSA, we requested, received, and
reviewed a variety of data including information from State and Federal
agencies, local governments, and private lands. Data received included
two general types of information: spatially explicit data with location
information (typically from conservation lands) and private lands data
without location information. These data represent a subset of gopher
tortoises likely to occur on the landscape due to the lack of a
comprehensive private lands data set from systematic surveys. Data were
collected using burrow surveys of various methodologies and included
burrow surveys with and without burrow scoping, and line transect
distance sampling (Buckland et al. 1993, entire; Thomas et al. 2010,
entire); some burrow data were submitted with unknown methodology.
Because data were provided by a variety of sources, contained disparate
levels of data resolution, and were collected in various ways, we could
not reliably determine abundance, density, habitat availability, or
other metrics for all populations.
All population data provided were integral to evaluating the
current condition of the gopher tortoise, although different data types
come with different assumptions and limitations. Data that come from
standardized and systematic surveys result in spatially explicit burrow
locations and subsequent population estimates. The use of these
spatially explicit data allowed us to make more reliable estimates of
population size; use spatial buffering to delineate populations based
on species biology; tie site-specific habitat and management factors to
locations of gopher tortoises; and estimate future parameters, such as
estimated future abundance of gopher tortoise populations. Most
spatially explicit data (e.g., burrow locations and subsequent
population estimates) in our analyses came from assessments of
populations on lands managed for the conservation of biodiversity or
natural resources.
A large percentage of potential gopher tortoise habitat occurs on
lands in private ownership. To best assess the current and future
condition of the gopher tortoise, including populations on private
lands, we developed a landowner questionnaire and used responses to
estimate population, habitat, and management factors at a county scale
to ensure privacy for respondents (Service 2022, appendix A). The vast
majority of the private lands data obtained for the SSA lack a spatial
component because of issues associated with confidentiality of location
data; however, this concern does not preclude the use and importance of
these data in the SSA. Responses represent a small percentage of
private lands that currently support gopher tortoises, as many private
landowners express reluctance to share gopher tortoise occurrence data.
We also included information from a subsequent Florida Forestry
Association questionnaire in our analyses; however, no population
estimates were available for these lands, and we were unable to
estimate current resiliency for populations on these properties.
Because data received from these questionnaires are not spatially
explicit, there are limitations to the applicability of the data as it
relates to delineation of populations, assessment of site-specific
factors such as habitat quality and quantity and management regimes,
and use of abundance data in projections of future scenarios. We
include data from private landowners in the current condition analysis
as county-level data and also categorize habitat condition based on
landowner responses. The additional data we received on gopher tortoise
populations on private lands when developing the SSA informed our
current condition analysis of gopher tortoise viability and contributed
to the understanding of species' viability.
In this finding, we present results of the current and future
condition analyses for delineated spatially explicit populations as
described below for clarity and comparison purposes. However, the SSA
report also presents results for current conditions for county-level
data following the same analysis methodology (Service 2022, pp. 130-
142). We used spatially explicit data to inform the population model
used to forecast future scenarios for the gopher tortoise, as described
below. We did not use county-level data in our future analysis because
most information in this category lacks abundance data and we could not
apply spatially based modeling used in future analysis to the default
county center point. We note that the data included in our current and
future condition analyses represent a subset of gopher tortoises likely
to occur on the landscape, as data from private lands were lacking
(Service 2022, pp. 103-107). Thus, population estimates do not
[[Page 61850]]
represent an assessment of all populations of gopher tortoises, but
rather represent information that was provided by partners through much
of the species' range. Given we were able to use only a subset of
populations that likely occur on the landscape, our future projections
are likely an underestimate of gopher tortoises on the landscape.
Analysis Unit and Population Delineation
To assess rangewide representation for gopher tortoise, we
delineated five analysis units based on genetic differences (identified
in Gaillard et al. 2017, entire), physiographic regions, and the input
of species experts (figure 2). The Tombigbee and Mobile Rivers act as a
boundary between Unit 1 (Western) and Unit 2 (Central) analysis units,
and the Apalachicola-Chattahoochee Rivers act as a boundary between
Unit 2 (Central) and Unit 3 (West Georgia) analysis units. Because of
the high degree of admixture and lack of well-defined boundaries found
within transitional zones of physiographic regions, we used other
biogeographic barriers and expert input to delineate boundaries of the
following units: Unit 3, Unit 4 (East Georgia), and Unit 5 (Florida)
analysis units. We used U.S. Environmental Protection Agency Level IV
ecoregions to delineate the boundaries between Units 3 and 4, and Units
4 and 5 (EPA 2013, unpaginated). We used the Suwanee River to separate
Units 3 and 5, as this river represents a significant barrier to
dispersal, and gene flow between these two units is known to be low
(Gaillard et al. 2017, p. 509). Additional details regarding the
delineation of analysis units used to analyze the current and future
condition of the gopher tortoise may be found in the SSA report
(Service 2022, pp. 111-114).
BILLING CODE 4333-15-P
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In order to analyze gopher tortoise population resiliency, we
defined populations for the species as contiguous areas surrounding
known gopher tortoise burrows with habitat conducive to survival,
movement, and interbreeding among individuals within the area. Using
survey data from across the range of the gopher tortoise, we delineated
populations at two spatial scales: local populations and landscape
populations, as defined below.
Local populations are geographic aggregations of individuals that
interact significantly with one another in social contexts making
reproduction significantly greater between individuals within the
aggregation than with individuals outside of the aggregation (sensu
Smallwood 1999, pp. 103, 108). We operationally delineated local
populations by identifying aggregations of individuals or burrows where
individuals were clustered together within a 1,968-ft (600-m) buffer to
the exclusion of other adjacent
[[Page 61852]]
individuals or burrows. Gopher tortoise habitat and demography vary
across the range; therefore, the 1,968-ft (600-m) buffer represents an
average and best estimate across geography and habitat variations based
on a thorough literature search and species expert input (Diemer 1992b,
p. 161; Guyer et al. 2012, pp. 122, 125, 132, Castellon et al. 2018, p.
17; Service 2019, entire; Greene et al. 2020, pp. 52-53). We delineated
656 local gopher tortoise populations with available spatially explicit
data (table 1). We assumed that some areas were unsuitable for gopher
tortoise movement or survival and considered those barriers to movement
when delimiting local populations. These barriers included interstates,
freeways, and expressways; major rivers and lakes; wetlands; and highly
urbanized areas (USDOT 2016, unpaginated; ESRI imagery 2021,
unpaginated).
Landscape populations are a series of local populations that are
connected by some form of movement; individuals within a landscape
population are significantly more likely to interact with other
individuals within the landscape population than individuals outside of
the landscape population. Gopher tortoises have been shown to move more
than 4,921 feet (1,500 m) throughout multiple years, with distances as
large as 8,802-15,220 feet (2,683-4,639 m) (McRae et al. 1981, p. 172;
Ott-Eubanks et al. 2003, p. 317; Diemer-Berish et al. 2012, p. 52;
Guyer et al. 2012, entire; Castellon et al. 2018, entire). We
operationally delineated landscape populations by identifying local
populations connected by habitat within an 8,202-ft (2.5-km) buffer
around each local population. To be most inclusive of local
populations, we selected a landscape-population buffer consistent with
the longer gopher tortoise movements observed (McRae et al. 1981, p,
173; Diemer 1992b, p. 163; Bauder et al. 2014, pp. 1448-1449; Service
2019, entire). We delineated 253 landscape populations with available
spatial data (table 1).
Table 1--Spatially Delineated Local and Landscape Populations of Gopher
Tortoises by State in 2021
------------------------------------------------------------------------
Spatially delineated
populations
-------------------------------
Local Landscape
------------------------------------------------------------------------
Florida................................. 316 161
Georgia................................. 151 63
Mississippi............................. 99 7
Alabama................................. 77 14
Louisiana............................... 7 5
South Carolina.......................... 6 4
Total:.............................. 656 * 254
------------------------------------------------------------------------
* One delineated landscape population falls in both Georgia and Florida
and is reflected in both States' landscape population total.
Resiliency
Resiliency describes the ability of a species to withstand
stochastic events and is associated with population size, growth rate,
and habitat quality. Highly resilient populations are more likely to
withstand disturbances such as random fluctuations in fecundity
(demographic stochasticity), variation in mean annual temperature
(environmental stochasticity), or the effects of anthropogenic
activities, such as local development projects. Viability denotes a
species' ability to sustain populations over a determined timeframe and
is closely tied with population resiliency and species-level
representation and redundancy. For gopher tortoise populations to have
sufficient viability over the long term, they must have an adequate
number of individuals (population size), be above a particular density
(population density), and have sufficient genetic exchange between
local populations to maintain genetic diversity. There must also be
sufficient habitat that is beneficially managed for gopher tortoise in
order to support individual and population needs. Population size and
density are driven by a variety of underlying demographic parameters,
including fecundity, sex ratio, and survival at various life history
stages (egg, nest, hatchling, juvenile, and adult survival). Genetic
diversity is primarily driven by rates of emigration and immigration
between local populations.
We relied on the MVP criteria adopted by the Gopher Tortoise
Council for abundance, area of managed high-quality habitat, sex ratio,
evidence of recruitment, variability in size and age classes, and no
major constraints to gopher tortoise movement as described above (GTC
2013, pp. 2-3). As previously mentioned, the best available data
contain disparate levels of data resolution, thus we could not reliably
determine abundance, density, or other metrics for all populations.
Therefore, we used a burrow conversion factor for properties that
provided burrow counts and locations, but did not have a corresponding
abundance estimate. Although there is no single burrow conversion
factor that would be appropriate for all populations across the range
of the species, we selected the representative burrow conversion factor
of 0.4 individuals per burrow to calculate an estimated current
population size described in gopher tortoise literature (Guyer et al.
2012, pp. 127, 129-131). The burrow-to-tortoise conversion factor
allows the burrow count information to give an estimate of tortoises on
the landscape, although we recognize that variance in burrow abundance
is related to factors other than the number of tortoises (Burke 1989,
p. entire; Breininger et al. 1991, pp. 319-320; McCoy and Mushinsky
1992, pp. 402, 406).
We used estimated abundance of adult gopher tortoises in a local
population as a metric for categorical levels of resiliency: high
(greater than or equal to 250), moderate (51 to 249), and low (fewer
than 50). These resiliency levels align with the GTC working group's
categories for viable (high resiliency), primary support (moderate
resiliency), and secondary support (low resiliency) populations (GTC
2014, p. 4).
Current condition abundance estimates are based only on data from
spatially delineated populations (i.e., do not contain county-level
data or gopher tortoises that are present but not reported), and these
estimates substantially underestimate the true number of gopher
tortoises present across the species' range. Based on available data,
there are an estimated 149,152 gopher tortoises from 656 spatially
delineated local populations across the range of the species, with
local populations categorized as follows: 360 in low condition, 169 in
moderate condition, and 127 in high condition.
[[Page 61853]]
Resiliency of populations by analysis unit are described below and in
table 2. Most gopher tortoises are found in the eastern portion of the
range with Unit 5 (Florida) supporting 47 percent of the estimated
rangewide population total, and Units 3 (West Georgia) and 4 (East
Georgia) supporting 26 percent and 19 percent, respectively. Units 1
(Western) and 2 (Central) support much smaller numbers of gopher
tortoises, with 2 percent and 6 percent of the estimated rangewide
population total, respectively, likely driven by differences in soils,
as discussed earlier in Habitat.
Table 2--Site-Specific Data Population Factors and Current Resiliency for Spatially Delineated Local Populations of Gopher Tortoise
--------------------------------------------------------------------------------------------------------------------------------------------------------
Landscape Local
Analysis unit Burrows populations populations Abundance Current resiliency
--------------------------------------------------------------------------------------------------------------------------------------------------------
1........................... 8,815 13 106 3,100 Low (94), Moderate (10), High (2).
--------------------------------------------------------------------------------------------------------------------------------------------------------
2........................... 5,809 30 106 8,642 Low (71), Moderate (27), High (8).
--------------------------------------------------------------------------------------------------------------------------------------------------------
3........................... 17,867 55 109 38,947 Low (42), Moderate (24), High (43).
--------------------------------------------------------------------------------------------------------------------------------------------------------
4........................... 20,216 46 124 28,408 Low (35), Moderate (58), High (31).
--------------------------------------------------------------------------------------------------------------------------------------------------------
5........................... 24,783 109 211 70,055 Low (118), Moderate (50), High (43).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Rangewide................... 77,490 253 656 149,152 Low (360), Moderate (169), High (127).
--------------------------------------------------------------------------------------------------------------------------------------------------------
We relied on gopher tortoise abundance to assess resiliency of
populations as the abundance of individuals strongly reflects the
condition of the habitat and implementation of beneficial management
actions. We summarize our assessment of habitat condition and
management actions below and provide more details regarding information
used and analysis unit results in the SSA report (Service 2022, pp.
122-130). The influence of habitat size, quality, and management on the
resiliency and viability of gopher tortoise populations was also
described in the MVP criteria (GTC 2013, p. 2).
Habitat data were provided by a variety of sources and contain
disparate levels of data resolution; thus, we could not reliably
determine estimates of habitat within all populations across the range
of the gopher tortoise. Estimates of habitat with known gopher tortoise
occurrences (local populations) and potential habitat (outside local
populations, but within the species' range) are derived from the
species-specific Habitat Suitability Index (HSI) and suitable soils
(Crawford et al. 2020, entire). Rangewide, we determined using the HSI
that approximately 844,912 ac (341,923 ha) of suitable habitat occur
within spatially explicit local populations with gopher tortoise
occurrences and approximately 16,338,932 ac (6,612,131 ha) of potential
habitat (suitable habitat with unknown gopher tortoise presence) occur
outside delineated populations within the range of the species.
Additionally, information from the landowner questionnaire was used to
estimate the condition of potential habitat in each analysis unit with
24 percent of the 447,340 ac (181,032 ha) characterized as low
condition, 42 percent as moderate condition, and 34 percent as high
condition (Service 2022, p. 126). Estimates of habitat were not used to
assess resiliency of gopher tortoise populations; only abundance was
used to assess resiliency. However, estimates of potential habitat and
potential habitat quality on private lands give some information
regarding the extent of habitat where gopher tortoises could occur
compared to the extent of habitat where occurrences are known.
To assess management of gopher tortoise habitat, we used several
data sets available from multiple sources and at multiple spatial
scales, and these data may include some overlap. Again, we did not use
any management metrics in our resiliency assessment; only abundance was
used to assess population resiliency. We determined an estimate of
acres burned (prescribed fire and wildfire) using Tall Timbers
Southeast fire history dataset, derived from the U.S. Geological Survey
Burned Area (v2) Products (Hawbaker et al. 2020, entire) representing
years 1994-2019 (Hawbaker et al. 2020, entire). Acres burned across all
units have generally increased over time, with significantly more
burning occurring in Unit 5 (Florida).
We also used summary data for prescribed fire and other midstory
maintenance activities available from America's Longleaf Restoration
Initiative (ALRI) FY2019 annual report (ALRI 2019). Florida reported by
far the most acres of habitat managed for longleaf by fire and other
methods, with nearly 600,000 ac (242,811 ha) treated between October
2018 and September 2019. Much of the management implemented by partners
under the ALRI umbrella is likely to benefit gopher tortoise.
Next, we summarized management practices as detailed in the gopher
tortoise CCA 2021 annual report, which covers management actions
implemented between October 2020 and September 2021. CCA management
data have the advantages of being specific to sites known to support
gopher tortoises and include both prescribed fire and other beneficial
practices such as chemical and mechanical treatments and invasive
species control. Unfortunately, the CCA data are limited to the eastern
portion of the range, and thus do not include information for the
western portion. Finally, we summarized the responses to the landowner
questionnaire regarding acres of prescribed fire, burn frequency, and
other management practices to benefit the gopher tortoise. Most
prescribed burns occurred in Units 3 (West Georgia) and 5 (Florida);
burn frequency is often on a 1- to 3-year cycle; and many landowners
implement additional beneficial practices (Service 2022, pp. 129-130,
133-139).
We describe the results of our analysis of the abundance
(resiliency), habitat, and management metrics for each analysis unit,
below. Populations described are those delineated using spatially
explicit data and may underestimate the number of gopher tortoises and
populations on the landscape.
[[Page 61854]]
Analysis Unit 1 (Western)
Based on available data, Unit 1 is composed of many small,
disconnected populations and very few larger populations (106 local
populations; 13 landscape populations), spread across private and
public land. Abundance estimates indicate there are 94 low-, 10
moderate-, and 2 high-resiliency local populations within this unit.
Camp Shelby, a DoD property, is the stronghold of Unit 1 with a
population estimate of 1,003 individual gopher tortoises. Based on
responses to the landowner survey, 17 properties on private lands in
the unit support gopher tortoise populations, with 7 properties
reporting signs of reproduction.
More than 103,000 ac (41,682 ha) of habitat occurs within gopher
tortoise populations in Unit 1, with an additional 2 million ac
(809,371 ha) of potential gopher tortoise habitat where gopher tortoise
occurrence is unknown. The current estimates for prescribed fire
implementation show that over 35,795 ac (14,485 ha) were burned within
this unit in 2019, double the area burned since 1994. Over 90 percent
of landowners who responded to the questionnaire report implementing
prescribed fire on a 1- to 3-year rotation, with all respondents
reporting implementation of additional beneficial practices for gopher
tortoises.
Analysis Unit 2 (Central)
Based on available data, Unit 2 has 106 local populations and 30
landscape populations. Based on current abundance estimates, this unit
is composed of 71 low-, 27 moderate-, and 8 high-resiliency local
populations. The eight highly resilient populations are found on
conservation lands including Fort Rucker, Conecuh NF, Apalachee
Wildlife Management Area (WMA), Perdido WMA, Geneva State Forest, and
an unnamed private property. Based on responses to the landowner
survey, 32 properties on private lands in the unit support gopher
tortoise populations with 17 properties reporting signs of
reproduction.
More than 68,000 ac (27,518 ha) of habitat occurs within gopher
tortoise populations in Unit 2, with an additional 3.4 million ac (1.37
million ha) of potential gopher tortoise habitat where gopher tortoise
occurrence is unknown. The current estimates for prescribed fire
implementation show that approximately 106,000 ac (42,896 ha) were
burned in 2019, triple the area burned since 1994. Sixty percent of
landowners who responded to the questionnaire report implementing
prescribed fire on a 1- to 3-year rotation, with 72 percent of
respondents reporting implementation of additional beneficial practices
for gopher tortoises.
Analysis Unit 3 (West Georgia)
Based on available data, Unit 3 has 109 local populations and 55
landscape populations. Based on current abundance estimates, Unit 3 is
composed of 42 low-, 24 moderate-, and 43 high-resiliency local
populations. Of the 43 highly resilient populations, 7 populations have
estimates exceeding 1,000 individuals, including Twin Rivers State
Forest, Chattahoochee Fall Line WMA, River Bend WMA, Alapaha River WMA,
Apalachicola NF, and the Jones Center at Ichauway. Based on responses
to the landowner survey, 48 properties on private land in Unit 3
support gopher tortoise populations with 21 properties reporting signs
of reproduction.
More than 220,000 ac (89,030 ha) of habitat occurs within gopher
tortoise populations in Unit 3, with an additional 2.9 million ac (1.17
million ha) of potential gopher tortoise habitat where gopher tortoise
occurrence is unknown. The current estimates for prescribed fire
implementation show that more than 194,000 ac (78,509 ha) were burned
in 2019, almost a 10-fold increase since 1994. Sixty-seven percent of
landowners who responded to the questionnaire report implementing
prescribed fire on a 1- to 3-year rotation, with 44 percent of
respondents reporting implementing additional beneficial practices for
gopher tortoises.
Analysis Unit 4 (East Georgia)
Based on available data, Unit 4 has 124 local populations and 46
landscape populations. Based on current abundance estimates, Unit 4 is
composed of 35 low-, 58 moderate-, and 31 high-resiliency local
populations. Of the 31 highly resilient populations, 5 populations have
estimates exceeding 1,000 individuals, including Ohoopee Dunes WMA,
Ralph E. Simmons State Forest, Jennings State Forest, and Fort Stewart.
Based on responses to the landowner survey, 22 properties on private
land in the unit support gopher tortoise populations with 11 properties
reporting signs of reproduction.
More than 149,000 ac (60,298 ha) of habitat occurs within the
gopher tortoise population in Unit 4, with an additional 2.7 million ac
(1.09 million ha) of potential gopher tortoise habitat where gopher
tortoise occurrence is unknown. The current estimates for prescribed
fire implementation show that more than 161,000 ac (65,154 ha) were
burned in 2019, over a 7 times increase since 1994. Fifty-three percent
of landowners who responded to the questionnaire report implementing
prescribed fire on a 1- to 3-year rotation, with 77 percent of
respondents reporting implementing additional beneficial practices for
gopher tortoises.
Analysis Unit 5 (Florida)
Based on available data, Unit 5 has 211 spatially explicit local
populations and 109 landscape populations. Based on current abundance
estimates, Unit 5 is composed of 118 low-, 50 moderate-, and 43 high-
resiliency local populations. Of the 43 highly resilient populations,
12 populations have estimates exceeding 1,000 individuals, including
Camp Blanding and Goldhead Branch State Park, Ocala NF, Chassahowitzka
WMA, Ichetucknee Springs State Park, Bell Ridge Wildlife and
Environmental Area, Etoniah Creek State Forest, Halpata Tastanaki and
Cross Florida Greenway, Lake Louisa State Park, Kissimmee Prairie
Preserve State Park, Green Swamp West Unit WMA, Withlacoochee State
Forest's Citrus Tract, and Perry Oldenburg Wildlife and Environmental
Area and Withlachoochee State Forest's Croom Tract. Based on responses
to the landowner survey, 48 properties on private land in the unit
support gopher tortoise populations with 35 properties reporting signs
of reproduction.
More than 300,000 ac (121,405 ha) of habitat occurs within gopher
tortoise populations in Unit 5, with an additional 5.3 million ac (2.14
million ha) of potential gopher tortoise habitat where gopher tortoise
occurrence is unknown. The current estimates for prescribed fire
implementation show that more than 582,368 ac (235,675 ha) were burned
in 2019, a nearly 14 times increase over time since 1994. Twenty-three
percent of landowners who responded to the questionnaire report
implementing prescribed fire on a 1- to 3-year rotation, with 83
percent of respondents reporting implementing additional beneficial
practices for gopher tortoises.
Representation and Redundancy
We evaluated current representation by examining the genetic and
environmental diversity within and among populations across the
species' range (Gaillard et al. 2017, entire). We report redundancy for
gopher tortoise as the number and resiliency of gopher tortoise
populations and their distribution within and among analysis units.
Current representation and redundancy have likely decreased relative to
the historical condition of the species due to loss of open pine
conditions and substantial reduction in
[[Page 61855]]
longleaf pine ecosystems in the species' range.
The five delineated analysis units are based primarily on genetic
variation in gopher tortoises across the range of the species. We
expect this genetic variation to be generally indicative of the
inherent adaptive capacity of the gopher tortoise as a species (Thurman
et al. 2020, p. 522). In addition, the variety of environmental
conditions across the species' range, particularly soil characteristics
and associated life history characteristics differences between the
western and eastern portions of the range, may be used as an indication
of adaptive capacity for the gopher tortoise, allowing the species to
withstand changing conditions (Thurman et al. 2020, p. 522). Gopher
tortoise populations are distributed within and among analysis units
across the species' range, contributing to potential adaptive capacity
and current representation.
Currently, multiple local and landscape populations occur in all
five analysis units. Although the resiliency of these populations
varies across the range, all analysis units contain populations in high
and moderate resiliency. Rangewide, 45 percent of spatially explicit
local populations exhibit moderate or high resiliency. These
populations are distributed across the range of the species,
contributing to future adaptive capacity (representation) and buffering
against the potential of future catastrophic events (redundancy).
Because the species is widely distributed across its range, it is
highly unlikely any single event would put the species as a whole at
risk, although the westernmost portions of the range are likely more
vulnerable to such catastrophes given that a greater percentage of the
populations present in this unit are of low resiliency compared to
other analysis units.
Future Condition
Future Condition Modeling
To assess future viability for the gopher tortoise, we developed an
analytical framework that integrates projections from multiple models
of future anthropogenic and climatic change to project future
trajectories or trends of gopher tortoise populations and identify
stressors with the greatest influence on future populations. The
modeling framework estimates the change in population growth and number
of populations while accounting for geographic variation in life
history. The model links intrinsic factors (demographic vital rates) to
four extrinsic anthropogenic factors that are expected to impact gopher
tortoise population viability (climate warming, sea level rise,
urbanization, and shifts in habitat management). We used published
models describing extrinsic factors in the future to project gopher
tortoise demographics under six future scenarios varying in threat
magnitude and presence at three timesteps--40, 60, and 80 years in the
future. A regression analysis of model outputs was used to identify
threats that are predicted to have the greatest impact on gopher
tortoise populations. We summarize the model framework below;
additional information is available in the SSA report (Service 2022,
pp. 144-159, appendix B; Folt et al. 2022, entire).
We developed a population viability analysis (PVA) framework to
predict population growth and extinction risk for the gopher tortoise.
For the PVA, the demography of spatially explicit local gopher tortoise
populations was brought into a multi-stage, female-only model with two
discrete life stages: juveniles and adults. Recruitment into the adult
stage by immigration was also modeled. Specific demographic parameters
including recruitment, maturity age, survival, immigration, and initial
population size were modeled based on values in gopher tortoise
literature (Landers et al. 1980, p. 359; Mushinsky et al. 1994, p. 123;
Rostal and Jones 2002, p. 7; Ott-Eubanks et al. 2003, p. 319; Ashton et
al. 2007, p. 360; Guyer et al. 2012, p. 130; Perez-Heydrich et al.
2012, p. 342; Smith et al. 2013, p. 355; Tuberville et al. 2014, p.
1155; Meshaka Jr. et al. 2019, pp. 105-106; Howell et al. 2020, entire;
Folt et al. 2021, pp. 624-625, 627; Hunter and Rostal 2021, p. 661; E.
Hunter unpubl. data, 2021; J. Goessling 2021, p. 141). For the
demographic parameters (e.g., recruitment, maturity age, survival) that
vary substantially by temperature among populations, we determined the
relationships between demographic rates and mean annual temperature
(MAT) sourced from the WorldClim database (Hijmans 2020, entire).
We initialized the model with estimates of population size from
spatially delineated populations (as described in Current Condition).
In the future condition analysis in the SSA, we did not model local
populations with fewer than three adult individuals as part of the
future condition analysis as these populations do not have sufficient
viability to remain on the landscape during the timeframes modeled (40,
60, and 80 years) (i.e., these populations have reached the quasi-
extinction threshold). The process of delineating spatially explicit
local populations and landscape populations for the future condition
model resulted in a dataset of 626 local populations that formed 244
landscape populations with 70,600 individual (female) gopher tortoises
that are included in our analysis of future conditions (Service 2022,
p. 149).
A recently published peer-reviewed model uses a very similar
methodology to the future condition analysis in the SSA (Folt et al.
2022, entire). The published model varied slightly from that in the SSA
and did not model populations across the range with current abundance
of fewer than eight individuals or fewer than three adult females.
Populations with seven or fewer tortoises likely lack sufficient
genetic diversity to support sufficient long-term viability (Chesser et
al. 1980, entire; Frankham et al. 2011, p. 466; Folt et al. 2022, p.
e02143). Both the recently published and the future condition analysis
runs of the model assumed a 1:1 sex ratio and a 3:1 adult:juvenile
ratio in populations and used the ratios to isolate and separate the
female population into juvenile and adult components (Service 2022, p.
149; Folt et al. 2021, p. 626; Folt 2022, p. e02143). The published
iteration of the model resulted in the delineation of 457 local
populations that formed 202 landscape populations (metapopulations) and
approximated 70,500 female tortoises (Folt et al. 2022, p. e02143). The
slight variation in the published model did not substantively change
the considerations in our analyses of the gopher tortoise's future
condition.
Influences on Gopher Tortoise Future Viability
In coordination with scientists with expert knowledge in both
gopher tortoise population biology and habitat management, we
identified factors expected to influence gopher tortoise demographics
in the future as described in Summary of Biological Status and Threats.
We determined the key drivers of the gopher tortoise's future condition
that we could incorporate into the model are climate warming, habitat
management, urbanization, and sea level rise.
Climate change is predicted to drive warming temperatures and
seasonal shifts in precipitation across the Southeast (Carter et al.
2018, entire). Of these two effects, warming temperatures may have the
greater impact on gopher tortoises, because gopher tortoise demography
is known to be sensitive to temperature gradients across the species'
range. Specifically, maturity age and fecundity vary along a north-
south latitudinal gradient, where warmer, southern populations have
faster growth rates, younger maturity ages, and
[[Page 61856]]
increased fecundity relative to cooler, northern populations (Ashton et
al. 2007, p. 123; Meshaka Jr. et al. 2019, pp. 105-106). We modeled how
climate warming may influence gopher tortoise demography by using the
estimated linear relationships of mean annual temperature with maturity
age and fecundity to predict how warming temperatures experienced by
populations in the future will drive concurrent changes in demography.
Although the gopher tortoise exhibits temperature-dependent sex
determination, we did not include this effect in the model as gopher
tortoises can modify nest site selection and timing of nesting, as
discussed in chapter 3 of the SSA (Service 2022, p. 58). We also did
not model any potential range expansion or contraction that could occur
due to long-term climate change, because we are aware of no consensus
or projection framework related to vegetative community changes and
climate change projections; also, we expect any significant expansion
or contraction of the gopher tortoise range is likely to occur late in
or beyond our projection timeframe of 80 years.
Climate change models predict favorable burn window conditions to
shift over future decades, with favorable conditions for prescribed
fire increasing in the winter but decreasing in the spring and summer
(Kupfer et al. 2020, pp. 769-770). Overall, projections show that
seasonal shifts in favorable burn window conditions will decrease
overall opportunity for management with prescribed fire. We estimated
how habitat management influences gopher tortoise populations by
modeling use of fire as a management tool and linking the frequency of
management to adult survival (Kupfer et al. 2020, entire; Service 2022,
appendix B; Folt et al. 2022, pp. 4, 8-11). We modeled four changes in
the burn window based on climate shifts projected by Representative
Concentration Pathway (RCP) 4.5 and RCP 8.5: (1) decreased fire, (2)
very decreased fire, (3) increased fire, and (4) status quo.
Urbanization and development are expected to affect gopher tortoise
populations in the future, even those on conservation lands, through
reduced connectivity and effects to gene flow and population migration
dynamics. Urbanization may also reduce the use of prescribed fire in an
area and contribute to road mortality and the introduction of nonnative
invasive species. We modeled effects of urbanization pressure on gopher
tortoise populations by linking urbanization projections from the
SLEUTH urbanization model to habitat management of local populations
with prescribed fire and with baseline immigration rates of gopher
tortoises across landscape populations (Terando et al. 2014, entire).
We modeled three potential thresholds in urbanization: (1) Low
urbanization where cells have a 95 percent or greater probability of
being developed; (2) moderate urbanization where cells have a 50
percent or greater probability of being developed; and (3) high
urbanization where cells have a 20 percent or greater probability of
being developed. Modeled cells with a high probability of urbanization
are likely to be urbanized under any scenario (higher certainty), while
areas with a lower probability of urbanization are likely to be
urbanized in scenarios with increased impacts or greater effects.
Inclusion of areas with a lower chance of development leads to an
overall greater area expected to be developed.
Sea level rise is expected to negatively affect gopher tortoise
populations in low-lying coastal areas, such as coastal sand dune
environments (Blonder et al. 2021, pp. 6-8). We modeled effects of sea
level rise on gopher tortoises using three projections of sea level
rise: The ``intermediate-high,'' ``high,'' and ``extreme'' projections
correspond to projections from global emission scenarios RCP 6 and RCP
8.5 (IPCC 2022, entire; NOAA 2020, entire). We projected the effects of
sea level rise on the gopher tortoise in the future by modeling the
height above sea level of local populations and through reduced
connectivity between local populations.
Future Scenarios
We developed six plausible scenarios of future climate warming,
urbanization, habitat management, and sea level rise to simulate
population growth and extinction risk for gopher tortoises for 40, 60,
and 80 years into the future (table 3). Specifically, we created three
scenarios with different levels of stressors (low stressors, medium
stressors, and high stressors) that experienced habitat management
consistent with contemporary target management goals. We then held the
medium stressor values constant and developed three scenarios that
varied in habitat management treatments, ranging from scenarios for the
most habitat management to the least habitat management (table 3).
Little information is available describing gopher tortoise
immigration rates in wild populations. Given the uncertainty around
this parameter, we included four additional scenarios with the medium
stressor values and status quo habitat management to understand the
effects of varying rates of immigration on the gopher tortoise future
condition.
Table 3--Threats, Habitat Management, and Immigration Values in the Nine Plausible Scenarios Used To Project
Future Population Growth and Abundance of Gopher Tortoises
----------------------------------------------------------------------------------------------------------------
Stressors
-------------------------------------------------- Immigration
Scenarios Climate Habitat into the
warming Sea level rise Probability of management population
([deg]C) (m) urbanization (percent)
----------------------------------------------------------------------------------------------------------------
Low stressors................ 1.0 0.54 95 percent or Status quo..... 1
greater.
Medium stressors............. 1.5 1.83 50 percent or Status quo..... 1
greater.
High stressors............... 2.0 3.16 20 percent or Status quo..... 1
greater.
Decreased management......... 1.5 1.83 50 percent or Less fire...... 1
greater.
Very decreased management.... 1.5 1.83 50 percent or Much less fire. 1
greater.
Improved management.......... 1.5 1.83 50 percent or More fire...... 1
greater.
No immigration............... 1.5 1.83 50 percent or Status quo..... 0
greater.
Intermediate immigration..... 1.5 1.83 50 percent or Status quo..... 1
greater.
High immigration............. 1.5 1.83 50 percent or Status quo..... 2
greater.
Very high immigration........ 1.5 1.83 50 percent or Status quo..... 4
greater.
----------------------------------------------------------------------------------------------------------------
[[Page 61857]]
[The first three scenarios vary the levels of stressors (climate
warming, sea level rise, and urbanization), while holding habitat
management and immigration constant.
The second three scenarios vary the levels of habitat management
(through prescribed fire), while holding stressors and immigration
constant.
The last four scenarios vary only in the level of immigration into
the population and hold stressors and habitat management constant.]
To assess future resiliency, redundancy, and representation of the
gopher tortoise, we used population projections to estimate changes in
gopher tortoise populations in the future under each of the nine
scenarios. We assessed the resiliency of future populations to changing
environments by estimating persistence probability. Persistence
probability is defined in this assessment as a measure of the risk of
extinction and is expressed as the percent of current populations
projected to occur on the landscape in a given future scenario.
Although the SSA report uses the categories of ``extremely likely to
persist,'' ``very likely to persist,'' ``more likely than not to
persist,'' and ``unlikely to persist'' to characterize the future
condition of gopher tortoise populations, these terms represent a
portion of our analysis and are not fully representative of the status
on the species. We will use the phrase ``remain on the landscape'' or
``not extirpated'' in this finding to indicate the modeled future
condition categories of gopher tortoise populations of ``extremely
likely to persist,'' ``very likely to persist,'' and ``more likely than
not to persist,'' and will indicate the timeframe to which that
projection applies.
We assessed redundancy by evaluating projected changes in the total
number of individuals (abundance or resiliency), number of local
populations, number of landscape populations, and their distribution
across the landscape in the future. We summarized population trends by
estimating population growth rate as increasing (greater than 1),
stable (1), or decreasing (less than 1). We evaluated how
representation is predicted to change in the future by examining how
population growth of total population size (number of individual female
gopher tortoises), number of local populations, and number of landscape
populations will vary by the five population genetic groups of
tortoises across the species' range.
We report the rangewide model projections for each scenario at the
three future time steps, summarize the results across all populations
across the species' range, and describe differences among analysis
units in Summary of Future Analysis, below. Details regarding future
projections may also be found in the SSA report and the peer-reviewed
model resulting from the SSA analyses (Service 2022, pp. 159-175; Folt
et al. 2022, entire).
Summary of Future Analysis
While declines in abundance and number of populations are
predicted, overall projections suggest that extinction risk for the
gopher tortoise is relatively low in the future. Population projections
under six future scenarios (threats and management scenarios) predicted
declines in the number of gopher tortoise individuals, local
populations, and landscape populations at the 40-, 60-, and 80-year
timesteps. Relative to current levels of total population size,
projections for total population size suggested declines by 2060 (33-35
percent declines), 2080 (30-34 percent declines), and 2100 (28-33
percent declines). The declines reflect the projected loss of small
gopher tortoise populations in the earlier timestep (40 years), while
remaining larger populations remain on the landscape longer. The six
scenarios varied little in the impact on the total number of
individuals, local populations, and landscape populations within each
timestep, but impacts increased in each successive timestep. In
addition, the 95 percent confidence interval overlapped with 1.0 in all
cases, indicating no difference in the scenarios.
Among the future scenario projections, the number of local
populations and landscape populations were predicted to decline in each
projection interval (40-, 60-, and 80-year timesteps). Declines in
local populations and landscape populations were 47-48 percent and 25-
27 percent declines among scenarios, respectively, at the 40-year
timestep; 60-61 percent and 41-43 percent declines, respectively, at
the 60-year timestep; and 68-70 percent and 53-57 percent declines,
respectively, at the 80-year timestep. With these declines, mean
projections among scenarios at the 80-year timestep indicate 47,202-
50,846 adult female gopher tortoises remain on the landscape in 188-198
spatially explicit local populations across the range of the species.
The number of individuals, local populations, and landscape
populations varied by analysis unit. Abundance in Units 1, 3, and 5 was
projected to decline overall (27-40 percent, 51-53 percent, and 42-48
percent declines, respectively). Unit 4 was projected to experience a
more modest decline (2-14 percent decrease in abundance), and Unit 2
was projected to increase in abundance. However, declines in the number
of local populations are projected for all units. The predicted
declines in number of local populations are greatest in Units 1, 2, and
5. More populations in Units 1 and 2 currently exhibit low resiliency,
while Unit 5 contains the highest abundance and number of local
populations across the range.
Threats and habitat management scenarios did not strongly affect
projections of gopher tortoise total population size (number of females
in the total population), or the number of local and landscape
populations. No single threat scenario (low, medium, or high stressors)
or management scenario (more, less, or much less management) was
sufficient to prevent population declines. However, model projections
did change substantially based on the immigration rate in the scenario
(very high, high, intermediate, or no immigration). For example, the
total population size and the number of local and landscape populations
projected to remain on the landscape in 2080 under the ``medium
stressors'' scenario were reduced substantially when simulated with an
immigration rate of 0. Conversely, higher values for immigration (2 and
4 percent) produced projections with substantially increased total
population size above initial starting population size and decreased
declines in local and landscape populations. In addition to
immigration, the initial total population size, areal extent of the
population (ha (ac)), and predicted implementation of habitat
management through prescribed fire positively affected the chance the
population would remain on the landscape in the future. The declines in
number of local populations occurred, in part, because many local
populations (27.8 percent) had very few individuals to start with in
the current conditions. Assuming a 3:1 adult to juvenile ratio and an
even sex ratio, local populations with fewer than 8 individuals were
functionally extirpated at the start of projections, given our quasi-
extinction probability (3 or fewer adult females).
Our analysis simulated the fate of known populations largely on
protected conservation lands that we expect will be managed for
conservation in the future. Future condition projections based only on
data from spatially delineated populations (i.e., do not contain
county-level data or gopher tortoises that are present, but not
reported) likely substantially
[[Page 61858]]
underestimate the true number of gopher tortoises present across the
species' range. We expect populations on managed conservation lands to
be characterized by greater demographic rates and lower extinction risk
relative to populations that we were unable to model in our framework
(populations with no spatially explicit data). To this end, we did not
project the abundance of existing populations not included in our
dataset or estimate the formation of new populations outside of
conservation lands. While other tortoise populations exist outside of
the ones we simulated with our projection model and new tortoise
populations may form due to natural dispersal and colonization
dynamics, they may occur on lands lacking long-term protection from
development, and we did not project those populations into the future
under assumptions of land management and protection for wildlife
conservation. Similarly, we could not estimate the formation of new
populations outside of the sites we projected, or the migration of
entire populations to new areas, because we have no guarantee of land
available for the formation or migration of populations.
While the numbers of individuals, populations, and landscape
populations were all expected to decline across each projection
interval, overall projections suggest that extinction risk for the
gopher tortoise is relatively low in the future. Of the individuals,
local populations, and landscape populations modeled (a small subset of
populations likely to occur across the landscape), mean projections
among scenarios for 80 years in the future suggested the presence of
47,202-50,846 individuals (females only) among 188-198 local
populations within 106-114 landscape populations across most of the
range of the species. The presence of relatively large numbers of
individuals and populations suggests resiliency of the species in the
face of change, and redundancy to buffer from future catastrophic
events. The spatial distribution of populations predicted to occur on
the landscape in the future are distributed evenly among genetic
analysis units, which suggests adaptive capacity or representation in
the future as well.
Although we do not project any of the analysis units to be
extirpated in any scenario, we do anticipate declines in species'
representation and redundancy through the projected loss of total
number of individuals and number of local and landscape populations.
Gopher tortoise populations are projected to remain on the landscape in
all scenarios and included timesteps in each analysis unit, providing
genetic variability across the range and adaptive capacity for the
species. We expect that future gopher tortoise redundancy will be
somewhat reduced from current redundancy due to the loss of some local
and landscape populations. For example, in Unit 1, approximately 16
percent of current populations are expected to remain on the landscape
at the 80-year timestep, under the medium stressor and less management
scenario. Populations in this unit are more isolated, small, and
fragmented compared to the remainder of the range.
Determination of Gopher Tortoise's Status
Section 4 of the Act (16 U.S.C. 1533) and its implementing
regulations (50 CFR part 424) set forth the procedures for determining
whether a species meets the definition of ``endangered species'' or
``threatened species.'' The Act defines an ``endangered species'' as a
species that is in danger of extinction throughout all or a significant
portion of its range, and a ``threatened species'' as a species that is
likely to become an endangered species within the foreseeable future
throughout all or a significant portion of its range. The Act requires
that we determine whether a species meets the definition of
``endangered species'' or ``threatened species'' because of any of the
following factors: (A) The present or threatened destruction,
modification, or curtailment of its habitat or range; (B)
overutilization for commercial, recreational, scientific, or
educational purposes; (C) disease or predation; (D) the inadequacy of
existing regulatory mechanisms; or (E) other natural or manmade factors
affecting its continued existence.
Status Throughout All of Its Range
After evaluating threats to the species and assessing the
cumulative effect of the threats under the section 4(a)(1) factors, we
determined that the species currently has sufficient resiliency,
redundancy, and representation contributing to its overall viability
across its range. The primary stressors affecting the gopher tortoise's
biological status include habitat loss, degradation, and fragmentation
due to land use changes from urbanization (Factor A), climate change
(Factor E), and insufficient and/or incompatible habitat management
(Factor E). Upper respiratory tract disease and other viral, bacterial,
fungal, and parasitic infections (Factor C) affect individual gopher
tortoises and can have localized effects, but these threats do not
appear to have species-level impacts. Predation of eggs, hatchlings,
and juvenile tortoises (Factor C) impacts some gopher tortoise
populations. Overutilization for commercial or recreational purposes
(harvest and rattlesnake roundups) (Factor B) of gopher tortoises was a
historical threat and may affect individuals, but is not currently an
impact to the species rangewide. The effects of nonnative invasive
species (Factor E) on gopher tortoise habitat also negatively influence
gopher tortoise viability. Conservation efforts and regulatory
mechanisms are in place across the range of the species and are
addressing some of the identified threats by restoring, enhancing, or
providing gopher tortoise habitat, relocating tortoises, and augmenting
populations through captive propagation.
Urbanization results in a range of impacts that either remove or
degrade/fragment remaining habitat, or can impact gopher tortoises
directly through development. Urbanization brings road construction and
expansion, which may cause direct mortality of gopher tortoises. In
addition, this stressor creates conditions beneficial to nonnative
invasive species and predators as well as conditions that limit fire
management of gopher tortoise habitat. Temperature increases associated
with long-term climate change are likely to further constrain use of
prescribed fire through a decrease in the number of suitable burn days.
Additionally, habitat loss resulting from sea level rise associated
with climate change is a risk for coastal populations of gopher
tortoise.
A variety of conservation efforts to benefit the gopher tortoise
and its habitat have been implemented by Federal and State agencies,
nongovernmental organizations, private landowners, and partnerships
across the range of the species. These conservation measures and
existing regulatory mechanisms also influence gopher tortoise viability
through the conservation and restoration of gopher tortoise habitat and
prevention of habitat loss, particularly efforts implemented since our
July 27, 2011, 12-month finding on the petition to list the eastern
portion of the gopher tortoise range as threatened.
While threats have acted on the species to reduce available habitat
and species abundance, the gopher tortoise occurs in the six States
comprising the historical and current range of the species. In
addition, based on best available information, we estimate that more
than 149,000 gopher tortoises occur in 656 spatially delineated local
populations across the range of the species. Approximately 38 percent
of
[[Page 61859]]
local populations exhibit high or moderate current resiliency, and the
species is widely distributed across much of its range. In addition,
the 360 gopher tortoise populations in low resiliency are widely
distributed across the species' range. These low-resiliency populations
often occur near other local populations (within a landscape
population) and contribute to the resiliency of the landscape
populations and the species' redundancy and representation. Despite the
historical and current loss of habitat with the open pine conditions
required by the gopher tortoise, sufficient quality and quantity of
habitat remains to provide adequate resiliency to contribute to the
viability of the species. Although the species-level redundancy has
likely decreased from historical levels due to loss of habitat and the
effects to the 3Rs, the gopher tortoise retains a sufficient number of
populations with high or moderate resiliency that are distributed
across the range to respond to catastrophic events. The five genetic
groups delineated across the species' range provide adaptive capacity
and sufficient species-level representation for the gopher tortoise.
Thus, after assessing the best available information, we conclude that
the gopher tortoise currently exhibits levels of resiliency,
redundancy, and representation such that the species is not in danger
of extinction throughout all of its range.
Therefore, we proceed with determining whether the gopher tortoise
is likely to become an endangered species within the foreseeable future
throughout all of its range. We evaluated the future condition of the
species based on projections under nine plausible scenarios. We
evaluated the viability of the species under these scenarios over the
foreseeable future and considered the condition of the species in
relation to its resiliency, redundancy, and representation. We analyzed
future conditions based on input from species experts, generation time
for the species, and the confidence in predicting patterns of climate
warming, sea level rise, urbanization, and habitat management, enabling
us to reliably predict threats and the species' response over time.
Using the best available information, we evaluated future conditions at
40, 60, and 80 years in the future. These timesteps allowed us to
project relevant threats to the species in view of its life-history
characteristics, including lifespan and reproduction and recruitment.
Within this timeframe, these projections are sufficiently reliable to
provide a reasonable degree of confidence in the predictions. Details
regarding the future condition analyses are available in the SSA report
and associated future condition model (Folt et al. 2022; Service 2022,
appendix B).
In modeling the future condition of the species, we projected the
number of individuals, local populations, and landscape populations,
population growth, and the probability that populations will remain on
the landscape (percent of current local populations extant on the
landscape) under each scenario at timesteps 40, 60, and 80 years into
the future as described in Future Condition, above. The projection
outcomes did not differ significantly by different threat scenarios;
however, immigration and management actions did affect model results.
The threats included in future condition modeling are projected to
result in a decline in the number of individuals, populations, and
landscape populations across each projection interval. Of the
individuals, local populations, and landscape populations modeled (a
subset of populations likely to occur across the landscape), mean
projections among scenarios for 80 years in the future suggested the
presence of 47,202-50,846 individuals (adult females) among 188-198
local populations within 106-114 landscape populations. We recognize
this is likely an underestimation of the gopher tortoise's future
condition since only existing populations on protected lands were
modeled. In addition, any new populations in the future (formed or
translocated) were not included in this future projection modeling.
Many of the populations predicted not to remain on the landscape were
currently small populations. Although the model projects declines in
the future that include the loss of these smaller populations, the
overall projections suggest that extinction risk for the gopher
tortoise is low in the future.
Although the threats to the species of habitat loss and
fragmentation due to urbanization, climate change, sea level rise, and
habitat management are expected to persist in the foreseeable future
and the effects of these threats on this long-lived species will
continue at some level, some threats have been reduced and will
continue to be reduced through implemented and ongoing conservation
actions and regulatory mechanisms, as discussed above under
Conservation Efforts and Regulatory Mechanisms. Rangewide, the future
condition of the species with relatively large numbers of individuals
and populations suggests resiliency to withstand stochastic
environmental and demographic change, and redundancy to buffer from
future catastrophic events. The spatial distribution of populations
predicted to remain extant in the future is distributed among genetic
analysis units, which suggests sufficient genetic representation in the
future as well.
After evaluating threats to the species and assessing the
cumulative effect of the threats under the section 4(a)(1) factors, we
conclude that the risk factors acting on the gopher tortoise and its
habitat, either singly or in combination, are not of sufficient
imminence, scope, or magnitude to rise to the level to indicate that
the species is in danger of extinction now (an endangered species), or
likely to become endangered within the foreseeable future (a threatened
species), throughout all of its range.
Status Throughout a Significant Portion of Its Range
Under the Act and our implementing regulations, a species may
warrant listing if it is in danger of extinction or likely to become so
within the foreseeable future throughout all or a significant portion
of its range. Having determined that the gopher tortoise is not in
danger of extinction or likely to become so in the foreseeable future
throughout all of its range, we now consider whether it may be in
danger of extinction or likely to become so in the foreseeable future
in a significant portion of its range--that is, whether there is any
portion of the species' range for which it is true that both (1) the
portion is significant; and (2) the species is in danger of extinction
now or likely to become so in the foreseeable future in that portion.
Depending on the case, it might be more efficient for us to address the
``significance'' question or the ``status'' question first. We can
choose to address either question first. Regardless of which question
we address first, if we reach a negative answer with respect to the
first question that we address, we do not need to evaluate the other
question for that portion of the species' range.
In undertaking this analysis for the gopher tortoise, we chose to
address the status question first. We began by identifying any portions
of the range where the biological status of the species may be
different from its biological status elsewhere in its range. The range
of a species can theoretically be divided into portions in an infinite
number of ways, so we focus our analysis on portions of the species'
range that contribute to the conservation of the species in a
biologically meaningful way. For this purpose, we considered
information pertaining to the geographic distribution of (a)
individuals of the species, (b) the threats that the species faces, and
(c) the
[[Page 61860]]
resiliency condition of populations. For the gopher tortoise, we
considered whether the threats or their effects are occurring in any
portion of the species' range such that the species is in danger of
extinction now or likely to become so in the foreseeable future in that
portion of the range.
We examined the following past, ongoing, and future anticipated
threats: habitat loss and fragmentation due to urbanization, climate
warming, sea level rise, habitat management, disease, predation, and
nonnative invasive species, including cumulative effects. The location
and magnitude of some threats varies across the species' range and
accordingly may impact the species differently in different portions.
For example, sea level rise influences gopher tortoise viability
primarily in coastal areas.
Less habitat management to benefit gopher tortoise has been
implemented in the western portion of the range (Units 1 and 2)
compared to the remainder of the range; therefore, the effects of lack
of habitat management influences gopher tortoise populations in the
westernmost unit to a greater extent. Although threats to the gopher
tortoise's viability differ spatially and in magnitude, we find that
the overall level of threats is similar in populations or analysis
units across the range of the species. These threats are certain to
occur, and in those analysis units with fewer populations that exhibit
predominantly low resiliency, these populations are facing the same
level of threats. In those analysis units with populations that are
overall less resilient compared to those in other units, we expect that
a similar level of threats will have a disproportionate impact in these
areas with lower resiliency populations. These low resiliency
populations (or analysis units) will be impacted or have a stronger
negative response to threats than moderate or high resiliency
populations (or analysis units). We looked across the range of the
gopher tortoise and identified three portions of the range where the
biological status may be different than the rangewide status. The three
areas we found to warrant further evaluation were the two westernmost
analysis units corresponding to Unit 1 (Western; west of the Mobile and
Tombigbee Rivers) and Unit 2 (Central; west of the Apalachicola and
Chattahoochee Rivers and east of Unit 1) and Unit 5 (Florida).
The impacts of habitat loss and fragmentation, climate change, and
habitat management combined with other stressors are expected to reduce
the viability of the populations to withstand stochastic and
catastrophic events. Although most threats occur at a similar level
throughout the range of the species, the threats of habitat management
and sea level rise differ across the range.
Sea level rise primarily affect populations along the coast in Unit
5 (Florida). Although sea level rise is projected to affect coastal
populations of gopher tortoise, the number of populations affected
varies by location and elevation of the population, site-specific
characteristics, and climate change scenario. Unit 5 currently has 43
populations that exhibit high resiliency and 50 populations that
exhibit moderate resiliency. Even though declines are predicted to be
more significant in this unit than others, future condition modeling
projects between 58 and 62 local populations and 37 to 43 landscape
populations will remain on the landscape in Unit 5, including the very
large populations (exceeding 1,000 individuals). The current and future
condition analyses of gopher tortoise indicate sufficient resiliency,
representation and redundancy in Unit 5. Given the species' current and
future condition within this unit, we determined that the gopher
tortoise in Unit 5 does not have a different status than the remainder
of the range.
The best available information indicates that less habitat
management occurs in the western portion of the range (Units 1 and 2)
compared to the remainder of the range. The populations in the western
two units (particularly Unit 1) are characterized by ecological and
physiological characteristics that lead to lower resiliency.
Populations in Units 1 (Western) and 2 (Central) experience lower
abundance, smaller clutch size, lower hatch rate, slower growth, and
less extensive suitable habitat leading to lower resiliency for a
higher proportion of populations in the two units. In Units 1 (Western)
and 2 (Central), approximately 11 and 33 percent of populations exhibit
moderate or high resiliency, respectively, compared to 45 percent
rangewide. A higher proportion of populations in Units 1 (Western) and
2 (Central) exhibit low resiliency, with 88 percent of populations in
Unit 1 (Western) and 67 percent of populations in Unit 2 (Central) in
low resiliency. Less habitat management beneficial to gopher tortoise
occurs in Units 1 and 2, and the overall lower resiliency of
populations in these units is lower. As a result of lower resiliency,
the species' response is more pronounced, and the rangewide threats and
lower levels of habitat management are having a greater impact than
elsewhere in the range. Despite the lower current resiliency of
populations in Units 1 (Western) and 2 (Central), the gopher tortoise
is still widespread throughout this extensive geographic area and high
and moderate resiliency populations also occur throughout the units. In
addition, given the current population distribution across these units,
it is not likely that a single catastrophic event would currently place
the species from this portion of its range at risk of extinction.
Modeling of future conditions projects declines in abundance and
fewer extant local and landscape populations in Units 1 (Western) and 2
(Central) compared to the rest of the range in the foreseeable future.
For example, Unit 1 (Western) and Unit 2 (Central) are projected to
have 15 and 14 local populations, respectively, on the landscape in
2100 under the medium stressors and less habitat management scenario.
These projected declines would significantly increase the risk of
extirpation of Units 1 (Western) and 2 (Central) from a catastrophic or
stochastic event. Although the species currently has sufficient
resiliency and distribution to withstand a stochastic or catastrophic
event, projected declines in resiliency or extirpation of populations
will further reduce the species redundancy and representation in this
portion of the range. Given the species' future condition within these
units, we have identified Units 1 (Western) and 2 (Central) of the
gopher tortoise as an area that has a different status than the
remainder of the range.
We then proceeded to the significance question, asking whether this
portion of the range (i.e., Units 1 (Western) and 2 (Central)) is
significant. The Service's most recent definition of ``significant''
within agency policy guidance has been invalidated by court order (see
Desert Survivors v. U.S. Department of the Interior, 321 F. Supp. 3d
1011, 1070-74 (N.D. Cal. 2018)). In undertaking this analysis for the
gopher tortoise, we considered whether this portion of the species'
range is significant based on its biological importance to the overall
viability of the gopher tortoise. Therefore, for the purposes of this
analysis, when considering whether this portion is significant, we
considered whether the portion may (1) occur in a unique habitat or
ecoregion for the species, (2) contain high-quality or high-value
habitat relative to the remaining portions of the range, for the
species' continued viability in light of the existing threats, (3)
contain habitat that is essential to a specific life-history function
for the species and that is not found in the other portions, or (4)
[[Page 61861]]
contain a large geographic portion of the suitable habitat relative to
the remaining portions of the range for the species.
We evaluated the available information about this portion of the
species to assess its significance. The portion of the range that
comprises Units 1 (Western) and 2 (Central) contains approximately 20
percent of the suitable habitat currently occupied by the species, with
approximately 103,582 ac (41,918 ha) in Unit 1 (Western) and 68,430 ac
(27,692 ha) in Unit 2 (Central). Although these units contribute to the
rangewide representation and redundancy of the gopher tortoise, Units 1
(Western) and 2 (Central) do not constitute a large geographic area
relative to the remaining portions of the range of the species. This
portion does not contribute high-quality habitat or constitute high
value habitat for gopher tortoise. The best available science indicates
this portion generally contains lower quality or less extensive habitat
for gopher tortoises than in the remainder of the range. In addition,
this portion does not constitute an area of habitat that is essential
to a specific life-history function for the species that is not found
in the remainder of the range.
Overall, we found no substantial information that would indicate
this portion of the gopher tortoise's range is significant in terms of
the above habitat considerations. As a result, we determined that the
portion comprising Units 1 (Western) and 2 (Central) does not represent
a significant portion of the gopher tortoise's range. Therefore, we
conclude that the species is not in danger of extinction now or likely
to become so in the foreseeable future in any significant portion of
its range. This finding does not conflict with the courts' holdings in
Desert Survivors v. Department of the Interior, 321 F. Supp. 3d 1011,
1070-74 (N.D. Cal. 2018), and Center for Biological Diversity v.
Jewell, 248 F. Supp. 3d 946, 959 (D. Ariz. 2017) because, in reaching
this conclusion, we did not apply the aspects of the Final Policy's
definition of ``significant'' that those court decisions held to be
invalid.
We have carefully assessed the best scientific and commercial
information available regarding the current and future threats to the
gopher tortoise. Because the species is neither in danger of extinction
now nor likely to become so in the foreseeable future throughout all or
any significant portion of its range, the gopher tortoise does not meet
the definition of an endangered species or threatened species.
Therefore, we find that listing the gopher tortoise as an endangered or
threatened species rangewide under the Act is not warranted at this
time.
Distinct Population Segment (DPS) Analysis
Under the Act, we have the authority to consider for listing any
species, subspecies, or, for vertebrates, any distinct population
segment (DPS) of these taxa if there is sufficient information to
indicate that such action may be warranted. The term ``species''
includes any subspecies of fish or wildlife or plants and any DPS of
any species of vertebrate fish or wildlife that interbreeds when mature
(16 U.S.C. 1532(16)). To guide the implementation of the DPS provisions
of the Act, we and the National Marine Fisheries Service (National
Oceanic and Atmospheric Administration--Fisheries), published the
Policy Regarding the Recognition of Distinct Vertebrate Population
Segments Under the Endangered Species Act (DPS Policy) in the Federal
Register on February 7, 1996 (61 FR 4722). Under our DPS Policy, we use
two elements to assess whether a population segment under consideration
for listing may be recognized as a DPS: (1) The population segment's
discreteness from the remainder of the species to which it belongs, and
(2) the significance of the population segment to the species to which
it belongs. If we determine that a population segment being considered
for listing is a DPS, then the population segment's conservation status
is evaluated based on the five listing factors established by the Act
to determine if listing it as either endangered or threatened is
warranted.
Based on the information available regarding potential discreteness
and significance for the species, we determined it was appropriate to
review the status of the gopher tortoise by conducting a DPS analysis
for the species. The western portion of the gopher tortoise range
(Western) where the species is currently listed as threatened (52 FR
25376, July 7, 1987)) consists of those populations of gopher tortoise
found west of the Mobile and Tombigbee Rivers in Alabama, Louisiana,
and Mississippi. The eastern portion of the range (Eastern), where the
species was identified as a candidate in 2011, consists of those gopher
tortoise populations east of the Mobile and Tombigbee Rivers in
Alabama, Georgia, Florida, and South Carolina. Below, we evaluate the
western and eastern portions of the gopher tortoise range as population
segments to determine whether they meet the definition of a DPS under
our DPS Policy.
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Discreteness
Under our DPS Policy, a population segment of a vertebrate taxon
may be considered discrete if it satisfies either of the following
conditions: (1) It is markedly separated from other populations of the
same taxon as a consequence of physical, physiological, ecological, or
behavioral factors (Quantitative measures of genetic or morphological
discontinuity may provide evidence of this separation.); or (2) it is
delimited by international governmental boundaries within which
differences in control of exploitation, management of habitat,
conservation status, or regulatory mechanisms exist
[[Page 61863]]
that are significant in light of section 4(a)(1)(D) of the Act. In
determining whether the test for discreteness has been met under the
DPS policy, we allow, but do not require genetic evidence to be used.
Significance
Under our DPS Policy, once we have determined that a population
segment is discrete, we consider its biological and ecological
significance to the larger taxon to which it belongs. This
consideration may include, but is not limited to: (1) Evidence of the
persistence of the discrete population segment in an ecological setting
that is unusual or unique for the taxon, (2) evidence that loss of the
population segment would result in a significant gap in the range of
the taxon, (3) evidence that the population segment represents the only
surviving natural occurrence of a taxon that may be more abundant
elsewhere as an introduced population outside its historical range, or
(4) evidence that the discrete population segment differs markedly from
other populations of the species in its genetic characteristics. Of
particular note, as we explained in our draft (76 FR 76987, December 9,
2011, p. 76998) and final (79 FR 37577, July 1, 2014, pp. 79 FR 37579,
37585) Policy on Interpretation of the Phrase ``Significant Portion of
Its Range'' in the Endangered Species Act's Definitions of ``Endangered
Species'' and ``Threatened Species'' (SPR Policy), the definition of
``significant'' for the purpose of significant portion of the range
analysis differs from the definition of ``significant'' found in our
DPS Policy and used for DPS analysis. Considering the potential results
of using the same standard for significance under the DPS policy to
define ``significant'' in the SPR Policy led us to conclude that the
two provisions cannot use the same definitions for ``significant.''
Accordingly, the analysis for ``significant'' under the DPS Policy
differs from the analysis of ``significant'' under the SPR provision.
While the definition contained in the SPR Policy has been vacated, our
consideration of ``significant'' in the ``significant portion of its
range'' provision for this analysis is also different than the standard
for significance under the DPS Policy for the same reasons.
The DPS Policy requires that for a vertebrate population to meet
the Act's definition of ``species,'' it must be discrete from other
populations and must be significant to the taxon as a whole. The
significance criterion under the DPS Policy is necessarily broad and
could be met under a wider variety of circumstances even if it could
not be met under the SPR Policy. For example, in this case, we
determined (see section below) that the western and eastern population
segments are ``significant'' for the purposes of DPS, and we did not,
as discussed above, conclude that the western portion constituted a
``significant'' portion of the gopher tortoise's range.
Discreteness of the Western and Eastern Population Segments of the
Gopher Tortoise Range
The western and eastern population segments of the gopher tortoise
range are markedly separated from each other (other populations)
geographically (physical) and genetically. The western and eastern
population segments of the range are separated by the Mobile and
Tombigbee Rivers. Thus, the western population segment includes all
gopher tortoises occurring in southwestern Alabama, southern
Mississippi, and southeastern Louisiana, and the eastern population
segment includes all gopher tortoises occurring in the remainder of
Alabama and all of Georgia, South Carolina, and Florida (figure 3).
These rivers act as a physical impediment to crossing by gopher
tortoises in either direction and represent a barrier to dispersal and
gene flow. The rivers are wide and deep year-round, and human
development (e.g., roads and towns) is adjacent to some areas of the
rivers. Due to the physical separation of these two population segments
by the Mobile and Tombigbee Rivers, gopher tortoises in these portions
do not, and will likely never, naturally interact with individuals or
populations in the other population segment.
In terms of genetic separation, there is a phylogenetic break
(difference in genetics) between the western and eastern population
segments of the gopher tortoise's range (Ennen et al. 2012, pp. 113-
116). Several studies show genetic assemblages across the geographic
range, but these studies are not entirely congruent in their
delineations of western and eastern genetic assemblages (Osentoski and
Lamb 1995, p. 713; Clostio et al. 2012, pp. 617-620; Ennen et al. 2012,
pp. 113-120; Gaillard et al., 2017, pp. 501-503). No shared haplotypes
on a mitochondrial gene were noted in populations found on opposite
sides of the Mobile and Tombigbee Rivers (Clostio et al. 2012, pp. 619-
620). However, the phylogenetic break does not entirely correspond to a
particular geographic barrier with some shared haplotypes found in both
the western portions of the tortoise's range and the panhandle of
Florida and Georgia populations in a similar study (Ennen et al. 2012,
pp. 113-116). Recent microsatellite analysis suggests there are five
main genetic groups in the taxon, delineated by the Tombigbee and
Mobile Rivers, Apalachicola and Chattahoochee Rivers, and the
transitional areas between several physiographic province sections of
the Coastal Plains (i.e., Eastern Gulf, Sea Island, and Floridian)
(Gaillard et al. 2017, pp. 505-507).
Based on our review of the best available information, we conclude
the western and eastern population segments of the gopher tortoise
range are markedly separated from each other due to geographic
(physical) and genetic separation. Therefore, we have determined that
the western and eastern population segments of the gopher tortoise
range each meet the condition of discreteness under our DPS policy.
Significance of the Western and Eastern Population Segments of the
Gopher Tortoise Range
We determine that the western and eastern discrete population
segments are significant based, in part, upon evidence that loss of
portions would result in a significant gap in the range of the taxon.
The loss of either the western or eastern population segment would
result in a substantial change in the overall range and distribution of
the gopher tortoise. The loss of the western portion would shift the
taxon's western range boundary eastward and result in the loss of
species' presence west of the Mobile and Tombigbee Rivers, which are
natural barriers to the eastern portion. A loss of the eastern portion
of the range would result in a significant gap in the range by losing
98 percent of the current estimated rangewide abundance (in spatially
explicit populations), 88 percent of the geographic area of the range,
and the core of the current species' distribution (Service 2022, pp.
119-120).
In addition, the western and eastern population segments differ
markedly from each other in their genetic characteristics (unique
haplotypes and pronounced nuclear differentiation), as described in
Discreteness, above. The loss of the western population segment would
result in a substantial reduction in the presence of these genetic
characteristics in the species. The eastern population segment is
genetically valuable to the taxon, because it contains the greatest
genetic diversity and may contribute more to the overall adaptive
capacity of the species. Therefore, we have determined that the western
and eastern population segments differ markedly in the genetic
[[Page 61864]]
characteristics, and loss of this genetic diversity would likely impact
the species' adaptive capacity.
Given the evidence that the western and eastern population segments
would result in a significant gap in the gopher tortoise's range if
lost, and that these population segments differ markedly from each
other based on their genetic characteristics, we consider the western
and eastern population segments to be significant to the species as a
whole. Thus, the western and eastern population segments of the gopher
tortoise's range meet the criteria for significance under our DPS
Policy.
DPS Conclusion for the Western and Eastern Portions
Our DPS Policy directs us to evaluate the significance of a
discrete population in the context of its biological and ecological
significance to the remainder of the species to which it belongs. Under
our DPS policy, the standard for discreteness does not require absolute
separation because such separation can rarely be demonstrated for any
population of organism. Based on an analysis of the best available
scientific and commercial data, we conclude that the western and
eastern portions of the gopher tortoise's range are discrete due to
marked separation geographically, ecologically, and genetically from
one another. Furthermore, we conclude that the western and eastern
portions of the range are significant for the reasons described above,
including that loss of either portion would result in a significant gap
in the range of the taxon. Therefore, we conclude that the western and
eastern portions of the gopher tortoise's range are both discrete and
significant under our DPS policy, and, therefore, these populations are
listable entities under the Act. We will subsequently refer to them as
the Western DPS and the Eastern DPS.
As mentioned above, we have determined the gopher tortoise in the
western portion of its range, the current listed entity of gopher
tortoise, meets the criteria of a DPS, but the best available
information does not support any taxonomic change for the species. This
document does not propose a revision of the defined entity. We will
take regulatory action in the future to assign the correct nomenclature
to the listed entity if we deem this action to be necessary for
clarity.
Based on our DPS Policy, if a population segment of a vertebrate
species is both discrete and significant relative to the taxon as a
whole (i.e., it is a distinct population segment), its evaluation for
endangered or threatened status will be based on the Act's definition
of those terms and a review of the factors enumerated in section 4(a)
of the Act. Having found that the western and eastern portions of the
gopher tortoise's range each meet the definition of a distinct
population segment, we now evaluate the status of each DPS to determine
whether it meets the definition of an endangered or threatened species
under the Act.
Status Throughout All of the Western DPS's Range
In the analysis above for the gopher tortoise as a whole, we have
carefully assessed the best scientific and commercial information
available regarding the past, present, and future threats to the
Western DPS (i.e., Unit 1) of the species. We considered whether the
Western DPS of the gopher tortoise is presently in danger of extinction
throughout all of its range. As described above under Status Throughout
a Significant Portion of its Range, the ongoing and future impacts of
habitat loss and fragmentation, climate change, and habitat management
in combination with secondary threats act to reduce the viability of
the Western DPS. Other secondary, rangewide threats, including disease,
predation, and nonnative invasive species, also have some effect on the
Western DPS. However, the magnitude and impacts of these threats are
exacerbated by population characteristics in this DPS.
The local gopher tortoise populations in the Western DPS are
generally smaller than in the Eastern DPS; in particular, the local
populations have lower abundance, decreased reproduction, and decreased
recruitment compared to the remainder of the range. However, 106
spatially explicit local populations at varying levels of resiliency
occur in the Western DPS and are distributed across the geographic area
of the DPS. Approximately 87 percent of local populations in the
Western DPS currently exhibit low resiliency, with 10 percent (12
populations) in moderate or high resiliency. Populations in the Western
DPS occur in habitat that is more fragmented than in the Eastern DPS
with the De Soto National Forest in southern Mississippi as one of the
few extensive reaches of suitable habitat.
More than 103,000 ac (41,682 hectares) of habitat with gopher
tortoise occurrences are currently known in the Western DPS with almost
2 million ac (809,371 ha) of potential habitat where gopher tortoise
occupancy is unknown. The best available information indicates that
less habitat management occurs in the Western DPS compared to the
Eastern DPS, although fire implementation has more than doubled since
1994 (Service 2022, p. 130). Gopher tortoises are a long-lived species
and populations in high (2) or moderate (10) resiliency currently occur
in the Western DPS with reproduction and recruitment reported from
populations on public and private lands. We expect individuals will
remain on the landscape for several decades despite current and ongoing
threats. Despite the lower current resiliency of populations in the
Western DPS, the gopher tortoise is still widespread throughout this
extensive geographic area. In addition, it is not likely that a single
catastrophic event would result in the extirpation of the species from
this portion, but loss of populations would reduce gopher tortoise
representation and redundancy. We have determined that the Western DPS
is not currently in danger of extinction throughout its range.
We next analyzed whether the Western DPS is likely to become an
endangered species within the foreseeable future throughout its range.
In our consideration of foreseeable future, we evaluated how far into
the future we could reliably predict the threats to this unit, as well
as the gopher tortoise's response to those threats. Based on the
modeling and scenarios evaluated, we considered our ability to make
reliable predictions in the future and the uncertainty in how and to
what degree the unit could respond to those risk factors in this
timeframe. We determined a foreseeable future of 80 years for the
Western DPS. We analyzed future conditions based on input from species
experts, generation time for the species, and the confidence in
predicting patterns of climate warming, sea level rise, urbanization,
and habitat management, enabling us to reliably predict threats and the
species' response over time. Details regarding the future condition
analyses are available in the SSA report and associated future
condition model (Folt et al. 2022, SSA 2022, appendix B).
In future condition models, the populations in the Western DPS show
low or no recruitment and population growth, leading to projected loss
of populations, particularly small populations, in the foreseeable
future. As described above, we developed nine plausible future
scenarios to include varying levels of stressors and habitat management
to project the future number of individuals, population growth rate,
and number of local and landscape populations. The Western DPS is
predicted to decline overall with reduced abundance and reductions in
local and landscape populations. We included spatially explicit
populations
[[Page 61865]]
with current population estimates of more than three tortoises in our
analysis of future conditions. In the Western DPS, 102 spatially
explicit local populations met this criteria and were modeled in our
future condition analysis. In the moderate stressors and status quo
habitat management scenario, 84 percent of modeled populations in the
Western DPS are unlikely to remain on the landscape in 2100.
For example, with the exception of one population, the model
projects the remaining six spatially explicit populations in Louisiana
were unlikely to remain on the landscape in 80 years in the future.
Mississippi was projected to lose 77 percent of current local
populations, but maintain 71 percent of its landscape populations
(landscape populations will be composed of fewer local populations).
Further, approximately 80 percent of spatially explicit local
populations in the Western DPS are projected as unlikely to remain on
the landscape in 80 years under the status quo threats, less management
(prescribed fire), and immigration scenario. As mentioned above, less
habitat management currently occurs in the Western DPS compared to the
Eastern DPS. Therefore, we expect that status quo threats (medium
stressors) and less habitat management are reasonable and a plausible
mechanism to project future species' condition in the Western DPS. The
low resiliency of these populations significantly increases the impact
of current and ongoing threats to the populations in the Western DPS.
In addition to reduced resiliency, the impact of a catastrophic or
stochastic event would reduce representation and redundancy in the
Western DPS within the foreseeable future.
After assessing the best available information, we conclude that
the Western DPS of gopher tortoise is likely to become endangered
within the foreseeable future throughout the Western DPS.
Status Throughout a Significant Portion of the Western DPS's Range
Under the Act and our implementing regulations, a species may
warrant listing if it is in danger of extinction or likely to become so
in the foreseeable future throughout all or a significant portion of
its range. The court in Center for Biological Diversity v. Everson, 435
F. Supp. 3d 69 (D.D.C. 2020) (Everson), vacated the aspect of the Final
Policy on Interpretation of the Phrase ``Significant Portion of Its
Range'' in the Endangered Species Act's Definitions of ``Endangered
Species'' and ``Threatened Species'' (Final Policy) (79 FR 37578; July
1, 2014) that provided that the Service does not undertake an analysis
of significant portions of a species' range if the species warrants
listing as threatened throughout all of its range. Therefore, we
proceed to evaluating whether the species is endangered in a
significant portion of its range--that is, whether there is any portion
of the species' range for which both (1) the portion is significant;
and (2) the species is in danger of extinction in that portion.
Depending on the case, it might be more efficient for us to address the
``significance'' question or the ``status'' question first. We can
choose to address either question first. Regardless of which question
we address first, if we reach a negative answer with respect to the
first question that we address, we do not need to evaluate the other
question for that portion of the species' range.
Following the court's holding in Everson, we now consider whether
there are any significant portions of the species' range where the
species is in danger of extinction now (that is, endangered). In
undertaking this analysis for the Western DPS, we choose to address the
status question first--we consider information pertaining to the
geographic distribution of both the species and the threats that the
species faces to identify any portions of the range where the species
is endangered.
Habitat loss, degradation and fragmentation affect gopher tortoise
populations in the Western DPS at a similar level rangewide. In the
Western DPS, urbanization, climate change, and incompatible and/or
insufficient habitat management influence the current and future
condition of the species at a level comparable to the remainder of the
range across the DPS. Therefore, we found that the threats are acting
on the species relatively uniformly across the Western DPS's range.
However, we identified one portion of the Western DPS range where the
effects may have a more pronounced effect and, accordingly, that may
have a different status than the remainder of the DPS. The portion we
considered was the geographic area of the Western DPS in the State of
Louisiana, which has seven spatially explicit local populations and
five landscape populations. The seven local populations in the
Louisiana portion of the Western DPS exhibit low current resiliency.
This low resiliency and limited distribution within this geographic
area may increase the impact of a catastrophic or stochastic event on
the representation and redundancy of the gopher tortoise in Louisiana.
We have identified the Louisiana portion as one that has a different
status than the remainder of the Western DPS.
We then proceeded to the significance question, asking whether this
portion of the Western DPS (i.e., Louisiana) is significant. The
Service's most recent definition of ``significant'' within agency
policy guidance has been invalidated by court order (see Desert
Survivors v. U.S. Department of the Interior, 321 F. Supp. 3d 1011,
1070-74 (N.D. Cal. 2018)). In undertaking this analysis for the Western
DPS, we considered whether the Louisiana portion of the species' range
may be significant based on its biological importance to the overall
viability of the Western DPS. Therefore, for the purposes of this
analysis, when considering whether this portion is significant, we
considered whether the portion may (1) occur in a unique habitat or
ecoregion for the Western DPS of gopher tortoise, (2) contain high-
quality or high-value habitat relative to the remaining portions of the
Western DPS' range, for the gopher tortoise's continued viability in
light of the existing threats, (3) contain habitat that is essential to
a specific life-history function for the species and that is not found
in the other portions of the DPS, or (4) contain a large geographic
portion of the suitable habitat relative to the remaining portions of
the Western DPS.
This area does not act as a refugia or an important breeding area
for this portion. It does not contain proportionally higher quality
habitat or higher value habitat than the remainder of the DPS. It does
not act as an especially important resource to a particular life-
history stage for the gopher tortoise than elsewhere in the Western
DPS.
Overall, there is little evidence to suggest that the Louisiana
portion of the Western DPS' range has higher quality or higher value
habitat or any other special importance to the species' life history in
the Western DPS. In addition, this portion constitutes a small
proportion of the Western DPS range (approximately 17 percent of
Western DPS. Thus, based on the best available information, we find
that this portion of the Western DPS's range is not significant in
terms of the habitat considerations discussed above. Therefore, no
portion of the Western DPS's range provides a basis for determining
that it is in danger of extinction in a significant portion of its
range. This finding does not conflict with the courts' holdings in
Desert Survivors v. Department of the Interior, 321 F. Supp. 3d 1011,
1070-74 (N.D. Cal. 2018), and Center for Biological Diversity v.
Jewell, 248 F. Supp. 3d 946, 959 (D. Ariz. 2017) because, in reaching
this conclusion, we did not apply the
[[Page 61866]]
aspects of the Final Policy's definition of ``significant'' that those
court decisions held to be invalid.
Determination of the Western DPS's Status
We have determined that the western portion of the gopher tortoise
range is a valid DPS, and the Western DPS of the gopher tortoise is
likely to become endangered within the foreseeable future throughout
all of its range. On the basis of this status review, we continue to
find the western portion (Western DPS) of the gopher tortoise is a
threatened species.
Status Throughout the Eastern DPS's Range
We identified the eastern portion of the gopher tortoise range as a
candidate species in the July 27, 2011, 12-month finding (76 FR 45130)
and have included it in the Candidate Notices of Review in subsequent
years. At the time of the 12-month finding, our assessment indicated
the species was being impacted by the primary threat of habitat
destruction and modification (Factor A) due to land conversion,
urbanization, and habitat management. Other important threats to the
species at that time included overutilization through rattlesnake
roundups (Factor B), predation (Factor C), incompatible use of
silvicultural herbicides (Factor E), and inadequacy of existing
regulatory mechanisms (Factor D). We had determined disease (Factor C),
road mortality (Factor E), and the effects of climate change (Factor E)
to be additional stressors to the species.
In subsequent CNORs, we reviewed the status of the eastern portion
of the range (now Eastern DPS) and described additional information and
conservation actions needed. In addition, we noted that the extent to
which the many potentially viable gopher tortoise populations are
sufficient in number, arrangement, and security to ensure the long-term
viability of the species was unknown. In development of the SSA, we
compiled and analyzed the best available information including
population information and conservation measures. We also developed a
new population viability model based on the best available information;
this model was not considered in previous CNORs or the original
petition finding.
Currently, the Eastern DPS comprises the majority of gopher
tortoise populations (approximately 84 percent) and habitat with known
gopher tortoise occurrences (approximately 88 percent) of the gopher
tortoise range, and, as such, the discussion of threats and the
species' response to those threats in Status Throughout All of Its
Range may be applied to the Eastern DPS as well. The Eastern DPS also
includes the majority of spatially explicit local gopher tortoise
populations across the range (84 percent or 550 populations), with 127
populations (19 percent) exhibiting high current resiliency and 169
populations (21 percent) exhibiting moderate resiliency (table 2). With
many highly and moderately resilient populations widely distributed
across the Eastern DPS's geographic area, the species' current level of
redundancy provides the ability to withstand catastrophic events. The
Eastern DPS includes four of the identified genetic groups for the
species, conveying much of the species' representation and adaptive
capacity. More than 741,330 ac (300,006 hectares) are currently known
to be occupied by gopher tortoise in the Western DPS with more than
14.4 million ac (5.8 million ha) of potential habitat where gopher
tortoise occupancy is unknown. The best available information indicates
that a greater degree of habitat management occurs in the Eastern DPS
compared to the Western DPS. Implementation of prescribed fire has
increased from 3 to 14 times the number of acres burned in 1994, and 44
to 83 percent of landowners are carrying out additional beneficial
practices for gopher tortoise (Service 2022, pp. 126-140). Therefore,
the Eastern DPS is not currently in danger of extinction throughout its
range.
Accordingly, we next analyze whether the Eastern DPS is likely to
become an endangered species within the foreseeable future throughout
its range. In our consideration of foreseeable future, we evaluated how
far into the future we could reliably predict the threats to these
units, as well as the gopher tortoise's response to those threats.
Based on the modeling and scenarios evaluated, we considered our
ability to make reliable predictions in the future and the uncertainty
in how and to what degree the units could respond to those risk factors
in this timeframe. We determined a foreseeable future of 80 years for
the Eastern DPS. The methodology and timeframe used to determine the
foreseeable future for the Eastern DPS followed the process described
in Status Throughout All of the Western DPS's Range, above. We analyzed
future conditions based on input from species experts, generation time
for the species, and the confidence in predicting patterns of climate
warming, sea level rise, urbanization, and habitat management, enabling
us to reliably predict threats and the species' response over time.
Details regarding the future condition analyses are available in the
SSA report and associated future condition model (Folt et al. 2022, SSA
2022, appendix B).
Rangewide threats continue to impact the Eastern DPS in the future,
including the key drivers of habitat loss and fragmentation due to
urbanization, climate warming, sea level rise, and habitat management.
Conservation efforts by Federal, State, and private partners benefit
the gopher tortoise and its habitat in the Eastern DPS and these
actions are expected to continue into the future. Although the Eastern
DPS (Units 2, 3, 4, and 5) is projected to decrease in the number of
local and landscape populations in the future, 46,176 to 49,697
individuals, 167 to 175 local populations, and 101 to 107 landscape
populations are projected to remain across the Eastern DPS into the
foreseeable future. These populations are distributed across the
Eastern DPS in the foreseeable future similar to the current
distribution.
Based on our analysis of the five factors identified in section
4(a)(1) of the Act, we conclude that the previously recognized threats
to the eastern portion of the gopher tortoise range (Eastern DPS) from
present or threatened destruction, modification, or curtailment of its
habitat or range (Factor A) (urbanization and development, major road
construction, incompatible and/or insufficient habitat management, and
certain types of agriculture) are not impacting the species such that
the species is in danger of extinction now or in the foreseeable
future. We evaluated additional potential threats under the five
listing factors stated above. In that evaluation, we found potential
impacts such as URTD and other diseases (Factor C), predation (Factor
C), overutilization (harvest and rattlesnake roundups) (Factor B), and
nonnative invasive species (Factor E) impact individuals or
populations, but do not have an impact at the species level at this
time. Additionally, conservation measures and protection provided by a
variety of conservation efforts to benefit the gopher tortoise and its
habitat have been implemented by Federal and State agencies,
nongovernmental organizations, private landowners, and partnerships
across the range of the species, and we anticipate these conservation
measures and protections will continue to benefit the gopher tortoise
into the foreseeable future (in part due to other sensitive and
federally listed species occurring in these areas). These conservation
efforts and
[[Page 61867]]
regulatory mechanisms are in place across the range of the species and
are addressing some of the identified threats by restoring, enhancing,
or providing gopher tortoise habitat, relocating tortoises, and
augmenting populations through captive propagation. See the SSA for a
thorough discussion of all potential and current threats (Service 2022,
pp. 46-102).
Conservation efforts by the Service, State agencies,
nongovernmental organizations, and private groups as described in
Conservation Efforts and Regulatory Mechanisms, above, have informed
our analysis of the species' condition by providing additional
information regarding species abundance, density, and habitat
conditions within the range of the species. In addition, habitat
restoration actions and species-specific conservation measures
including translocation of individuals and improved awareness of the
species' needs and threats have contributed to the improved condition
of the species. In particular, Service-approved plans or other plans
including the gopher tortoise CCA, CCAA, rangewide conservation
strategy with the DoD, and the Gopher Tortoise Initiative have resulted
in the protection of gopher tortoise habitat and populations across the
range of the species. Many of the management actions and conservation
easements under these plans are expected to remain in place in the
future, benefiting the species. The BMPs implemented on working forests
benefit the gopher tortoise and its habitat; these BMPs are expected to
continue to be implemented in the future and will continue to benefit
the species and its habitat.
Based on our analysis of the five factors identified in section
4(a)(1) of the Act, we conclude that the Eastern DPS is not in danger
of extinction or likely to become so in the foreseeable future
throughout all of its range.
Status Throughout a Significant Portion of the Eastern DPS's Range
Under the Act and our implementing regulations, a species may
warrant listing if it is in danger of extinction or likely to become so
within the foreseeable future throughout all or a significant portion
of its range. Having determined that the Eastern DPS is not in danger
of extinction or likely to become so in the foreseeable future
throughout all of its range, we now consider whether it may be in
danger of extinction or likely to become so in the foreseeable future
in a significant portion of its range--that is, whether there is any
portion of the species' range for which it is true that both (1) the
portion is significant; and (2) the species is in danger of extinction
now or likely to become so in the foreseeable future in that portion.
Depending on the case, it might be more efficient for us to address the
``significance'' question or the ``status'' question first. We can
choose to address either question first. Regardless of which question
we address first, if we reach a negative answer with respect to the
first question that we address, we do not need to evaluate the other
question for that portion of the species' range.
In undertaking this analysis for the Eastern DPS, we chose to
address the status question first. We began by identifying any portions
of the range where the biological status of the species may be
different from its biological status elsewhere in its range. The range
of a species can theoretically be divided into portions in an infinite
number of ways, so we focus our analysis on portions of the species'
range that contribute to the conservation of the species in a
biologically meaningful way. For this purpose, we considered
information pertaining to the geographic distribution of (a)
individuals of the species, (b) the threats that the species faces, and
(c) the resiliency condition of populations. For the Eastern DPS, we
considered whether the threats or their effects are occurring in any
portion of the DPS' range such that the Eastern DPS is in danger of
extinction now or likely to become so in the foreseeable future in that
portion of the range.
The Eastern DPS comprises the majority of gopher tortoise
populations and habitat across the range of the species, and,
therefore, threats that affect the species rangewide also affect the
gopher tortoise in the Eastern DPS. We evaluated the past, ongoing, and
anticipated threats affecting the species including habitat loss,
degradation, and fragmentation due to land use changes from
urbanization, climate warming, sea level rise, and insufficient and/or
incompatible habitat management. We also considered effects from URTD
and other diseases, predation, overutilization, and nonnative invasive
species, and cumulative effects. Conservation efforts and regulatory
mechanisms also influence the gopher tortoise and its habitat in the
Eastern DPS. These factors and threats influence the gopher tortoise
similarly rangewide; however, we identified two portions of the Eastern
DPS range where the impact of these factors may have a more pronounced
effect such that it may have a different status than the remainder of
the DPS. The portions we considered were the geographic area described
as Unit 5 (Florida) and Unit 2 (Central; west of the Apalachicola and
Chattahoochee Rivers and east of Unit 1) in the SSA report.
Sea level rise primarily affect populations along the coast in Unit
5 (Florida). Although sea level rise is projected to affect coastal
populations of gopher tortoise, the number of populations affected
varies by location and elevation of the population, site-specific
characteristics, and climate change scenario. Of the 21 local
populations occurring in coastal areas rangewide, 18 of these
populations occur in Unit 5. Of these 18 coastal populations, 5
currently exhibit high resiliency and 13 exhibit moderate resiliency.
Overall, Unit 5 currently has 43 populations that exhibit high
resiliency and 50 populations that exhibit moderate resiliency. In our
future projections, small populations in coastal areas decline in the
same proportion as small populations throughout Unit 5 and rangewide.
Future condition modeling projects between 58 and 62 local populations
and 37 to 43 landscape populations will remain on the landscape in Unit
5, including the very large populations (exceeding 1,000 individuals).
The current and future condition analyses of gopher tortoise indicate
sufficient resiliency, representation and redundancy in Unit 5. Given
the species' current and future condition within this unit, we
determined that the gopher tortoise in Unit 5 does not have a different
status than the remainder of the Eastern DPS.
As described in Status Throughout a Significant Portion of Its
Range, populations in Unit 2 are generally less resilient and are
characterized by low abundance, smaller clutch size, lower hatch rate,
slower growth, and less extensive suitable habitat. Within the Eastern
DPS, 26.7 percent of the populations in current low resiliency are
found in Unit 2, which holds 5.9 percent of the abundance in the DPS.
Although threats are similar throughout the Eastern DPS, the species'
response is more pronounced in Unit 2 (Central) due to lower
resiliency, and threats are having a greater impact than elsewhere in
the DPS. For example, 14 local populations are projected to remain on
the landscape in Unit 2 (Central) in 2100 under the medium stressors
and less habitat management scenario. This projected decline in the
number of populations would increase the impact of a catastrophic or
stochastic event on the representation and redundancy in Unit 2
(Central) Given the species' future condition within this units, we
have identified Unit 2 (Central) within
[[Page 61868]]
the Eastern DPS as an area that has a different status than the
remainder of the Eastern DPS.
We then proceeded to the significance question, asking whether this
portion of the DPS (i.e., Unit 2) is significant. The Service's most
recent definition of ``significant'' within agency policy guidance has
been invalidated by court order (see Desert Survivors v. U.S.
Department of the Interior, 321 F. Supp. 3d 1011, 1070-74 (N.D. Cal.
2018)). In undertaking this analysis for the Eastern DPS, we considered
whether the Unit 2 (Central) portion of the Eastern DPS is significant
based on its biological importance to the overall viability of the
Eastern DPS. Therefore, for the purposes of this analysis, when
considering whether this portion is significant, we considered whether
the portion may (1) occur in a unique habitat or ecoregion for the DPS,
(2) contain high-quality or high-value habitat relative to the
remaining portions of the DPS, for the species' continued viability in
light of the existing threats, (3) contain habitat that is essential to
a specific life-history function for the species and that is not found
in the other portions of the DPS, or (4) contain a large geographic
portion of the suitable habitat relative to the remaining portions of
the DPS.
Although Unit 2 (Central) contributes to the condition of the
species within the Eastern DPS, it does not represent a large area of
suitable habitat relative to the remainder of the Eastern DPS. Unit 2
(Central) holds approximately 9.2 percent of suitable habitat with
known gopher tortoise occurrences in the Eastern DPS, and this habitat
is of generally lower quality and is less extensive than in the
remainder of the Eastern DPS. It does not contain proportionally higher
quality habitat or higher value habitat than the remainder of the
range. This area does not act as a refugia or an important breeding
area for this portion. The area does not act as an especially important
resource to a particular life-history stage for the gopher tortoise
than elsewhere in the Eastern DPS.
Overall, there is little evidence to suggest that the geographical
area of Unit 2 (Central) of the Eastern DPS's range has higher quality
or higher value habitat to the species' life history in the Eastern
DPS. In addition, this unit constitutes a small portion of the gopher
tortoise habitat in the Eastern DPS (approximately 14 percent of this
portion of the range). Thus, based on the best available information,
we find that this portion of the Eastern DPS's range is not
biologically significant in terms of the habitat considerations
discussed above. Therefore, no portion of the Eastern DPS's range
provides a basis for determining that the species is in danger of
extinction now or within the foreseeable future in a significant
portion of its range. This finding does not conflict with the courts'
holdings in Desert Survivors v. U.S. Department of the Interior, 321 F.
Supp. 3d 1011, 1070-74 (N.D. Cal. 2018) and Center for Biological
Diversity v. Jewell, 248 F. Supp. 3d 946, 959 (D. Ariz. 2017) because,
in reaching this conclusion, we did not need to consider whether any
portions are significant and, therefore, did not apply the aspects of
the Final Policy's definition of ``significant'' that those court
decisions held were invalid.
Determination of the Eastern DPS's Status
Our review of the best available scientific and commercial
information indicates that the Eastern DPS of the gopher tortoise does
not meet the definition of an endangered species or a threatened
species in accordance with sections 3(6) and 3(20) of the Act.
Therefore, we find that listing the Eastern DPS of the gopher tortoise
is no longer warranted for listing under the Act. With the publication
of this document, the eastern portion of the gopher tortoise range (now
the Eastern DPS) will be removed from the list of candidate species.
References Cited
A complete list of references cited is available on the internet at
https://www.regulations.gov and upon request from the Florida
Ecological Services Field Office (see ADDRESSES).
Author(s)
The primary authors of this notice are the staff members of the
Florida Ecological Services Field Office and the Species Assessment
Team.
Signing Authority
Martha Williams, Director of the U.S. Fish and Wildlife Service,
approved this action on September 20, 2022, for publication. On
September 30, 2022, Martha Williams authorized the undersigned to sign
the document electronically and submit it to the Office of the Federal
Register for publication as an official document of the U.S. Fish and
Wildlife Service.
Madonna Baucum,
Chief, Policy and Regulations Branch, U.S. Fish and Wildlife Service.
[FR Doc. 2022-21659 Filed 10-11-22; 8:45 am]
BILLING CODE 4333-15-P