Endangered and Threatened Wildlife and Plants; 12-Month Finding on a Petition To List the Gopher Tortoise as Threatened in the Eastern Portion of Its Range, 45130-45162 [2011-18856]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 76, Number 144 (Wednesday, July 27, 2011)]
[Rules and Regulations]
[Pages 45130-45162]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-18856]



[[Page 45129]]

Vol. 76

Wednesday,

No. 144

July 27, 2011

Part V





Department of the Interior





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Fish and Wildlife Service





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50 CFR Part 17





Endangered and Threatened Wildlife and Plants; 12-Month Finding on a 
Petition To List the Gopher Tortoise as Threatened in the Eastern 
Portion of Its Range; Final Rule

Federal Register / Vol. 76 , No. 144 / Wednesday, July 27, 2011 / 
Rules and Regulations

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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R4-ES-2009-0029; MO 92210-0-0008-B2]


Endangered and Threatened Wildlife and Plants; 12-Month Finding 
on a Petition To List the Gopher Tortoise as Threatened in the Eastern 
Portion of Its Range

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of 12-month petition finding.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a 
12-month finding on a petition to list the gopher tortoise (Gopherus 
polyphemus) in the eastern portion of its range (east of the Mobile and 
Tombigbee Rivers) as threatened and to designate critical habitat under 
the Endangered Species Act of 1973, as amended. In this finding, we 
also evaluate whether the status of the gopher tortoise in the western 
portion of its range (west of the Mobile and Tombigbee Rivers) is 
accurate. After review of all available scientific and commercial 
information, we find that the current listing of the gopher tortoise as 
a threatened species in the western portion of its range is accurate 
and that listing the gopher tortoise in the eastern portion of its 
range is warranted. Currently, however, listing the gopher tortoise in 
the eastern portion of its range is precluded by higher priority 
actions to amend the Lists of Endangered and Threatened Wildlife and 
Plants. We will add the gopher tortoise in the eastern portion of its 
range to our candidate species list, and we will develop a proposed 
rule to list the gopher tortoise in the eastern portion of its range as 
our priorities allow. We will make any determination on critical 
habitat during development of the proposed listing rule. In any interim 
period we will address the status of the candidate taxon through our 
annual Candidate Notice of Review and will work through partnerships to 
conserve the species by improving the habitat and removing the threats 
with the objective to make listing unnecessary. The Service's candidate 
conservation efforts place great emphasis on coordination with the 
states and other partners, voluntary conservation efforts, and may 
include tools such as Candidate Conservation Agreements with 
Assurances. Even though we are currently unable to take action to list 
the gopher tortoise in the eastern portion of its range, this does not 
affect the status of the gopher tortoise in the western portion of its 
range, where it remains listed as threatened.

DATES: The finding announced in this document was made on July 27, 
2011.

ADDRESSES: This finding is available on the Internet at https://www.regulations.gov at Docket Number [FWS-R4-ES-2009-0029]. Supporting 
documentation we used in preparing this finding is available for public 
inspection, by appointment, during normal business hours at the U.S. 
Fish and Wildlife Service, North Florida Field Office, 7915 Baymeadows 
Way, Suite 200, Jacksonville, FL 32256. Please submit any new 
information, materials, comments, or questions concerning this finding 
to the above address.

FOR FURTHER INFORMATION CONTACT: David L. Hankla, Field Supervisor, 
North Florida Field Office (see ADDRESSES); by telephone at 904-731-
3308; or by facsimile at 904-731-3048 mailto:. If you use a 
telecommunications device for the deaf (TDD), please call the Federal 
Information Relay Service (FIRS) at 800-877-8339.

SUPPLEMENTARY INFORMATION:

Background

    Section 4(b)(3)(B) of the Endangered Species Act of 1973, as 
amended (Act) (16 U.S.C. 1531 et seq.) requires that, for any petition 
to revise the Federal Lists of Threatened and Endangered Wildlife and 
Plants that contains substantial scientific or commercial information 
that listing a species may be warranted, we make a finding within 12 
months of the date of receipt of the petition. In this finding, we 
determine that the petitioned action is: (a) Not warranted, (b) 
warranted, or (c) warranted, but the immediate proposal of a regulation 
implementing the petitioned action is precluded by other pending 
proposals to determine whether species are threatened or endangered and 
expeditious progress is being made to add or remove qualified species 
from the Federal Lists of Endangered and Threatened Wildlife and 
Plants. Section 4(b)(3)(C) of the Act requires that we treat a petition 
for which the requested action is found to be warranted but precluded 
as though resubmitted on the date of such finding, that is, requiring a 
subsequent finding to be made within 12 months. We must publish these 
12-month findings in the Federal Register.

Previous Federal Action

    On July 7, 1987, we listed the population of the gopher tortoise as 
a threatened species in the western portion of its range (west of the 
Mobile and Tombigbee Rivers in Alabama, Louisiana, and Mississippi) (52 
FR 25376). 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 (east of the Mobile and Tombigbee Rivers in Alabama, Florida, 
Georgia, and South Carolina) be listed as a threatened species under 
the Act and critical habitat be designated. The petition included 
supporting information regarding the species' taxonomy, biology, 
historical and current distribution, present status, and a summary of 
actual and potential threats. We acknowledged receipt of the petition 
in a letter to Wild-Law, legal counsel for Save Our Big Scrub, Inc. and 
Wild South, dated February 24, 2006. In that letter we also stated 
that, due to a substantial number of listing-related actions in fiscal 
year 2006, there were insufficient funds to begin processing the 
petition at that time. We indicated that we would reevaluate our 
ability to respond to outstanding petitions as additional funding 
became available.
    Funding became available to begin processing the petition in early 
February, 2007. On September 9, 2009, we published a 90-day finding (74 
FR 46401) that the petition presented substantial scientific and 
commercial information indicating that listing may be warranted and 
that we would initiate a status review. We indicated we would accept 
information to assist us in the review until November 9, 2009. Several 
commenters requested additional time to provide their comments, and on 
January 12, 2010, we published clarification that we would accept 
information through https://www.regulations.gov until March 15, 2010 (75 
FR 1567). Thereafter, we indicated that information could be submitted 
to the Service's North Florida Field Office (see ADDRESSES) throughout 
the time period of our review. This notice constitutes the 12-month 
finding on the January 13, 2006, petition to list the population of the 
gopher tortoise in the eastern portion of its range as a threatened 
species.

Species Information

    Our 90-day finding summarized much of the current literature 
regarding the gopher tortoise's distribution, habitat requirements, and 
life history and

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should be reviewed for detailed information (74 FR 46401; September 9, 
2009). Below, we summarize previously presented information and provide 
new information that we believe is relevant to understanding our 
analysis of the factors that may threaten the gopher tortoise.

Taxonomy and Genetics

    The gopher tortoise is one of four living North American tortoise 
species and the only one indigenous to the southeastern United States 
(Ernst and Lovich 2009, p. 581). The other three species are found in 
the western United States. First described by F.M. Daudin in 1802, G. 
polyphemus is classified as belonging to class Reptilia, Order 
Testudines, and Family Testudinidae. Bramble (1982, p. 864) proposed 
that G. polyphemus along with its cladistic relative G. flavomarginatus 
should be the only members of genus Gopherus, placing the other members 
of this genus G. berlandieri and G. agassizii into a new genus 
Scaptochelys. However, more recent morphological and genetic studies 
have reinforced the traditional assignment of all four species into 
genus Gopherus (Crumly 1994, pp. 12-16). Allozyme differentiation has 
indicated that G. polyphemus is most closely related to G. 
flavomarginatus and is thus placed in a clade (genetically related 
group) distinct from the clade containing G. berlandieri and G. 
agassizii (Morafka et al. 1994, p. 1669). Mitochondrial DNA (mtDNA) 
sequences for the cytochrome b gene show a seven percent sequence 
divergence between the two clades (Lamb and Lydeard 1994, p. 283).
    The taxonomic status of the gopher tortoise throughout its range is 
considered valid (Interagency Taxonomic Information System 2010, p. 1). 
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. We are aware of no efforts to describe subspecies. There 
have been several phylogeographic studies of the gopher tortoise 
including mtDNA (Osentoski and Lamb, 1995 entire; Clostio 2010) and 
microsatellites (Schwartz and Karl 2005, entire; Ennen 2009, pp. 66-85; 
Clostio 2010). Several showed genetically distinct population 
assemblages across the geographic range (Osentoski and Lamb 1995, p. 
713; Ennen 2009, p. 78; Clostio 2010) although the three studies were 
not entirely congruent in their delineations of western and eastern 
genetic assemblages. Osentoski and Lamb (1995, pp. 713-714) described 
three major genetic groups; an eastern group, containing 21 haplotypes 
(combination of DNA sequences) and ranging from South Carolina to 
southern Florida; a mid-Florida group, made up of seven haplotypes and 
located in a small region in central peninsular Florida; and a western 
group, containing seven haplotypes in a range from the Florida 
panhandle north to west-central Georgia and west to Louisiana.
    Ennen (2009, p. 73) reported a phylogenetic (difference in 
genetics) break between the western and eastern portions of the 
tortoise's range based on a 712 base pair portion of a mitochondrial 
gene. However, the phylogenetic break did not entirely correspond to 
one particular geographic barrier because shared haplotypes from the 
eastern and western portions of the tortoise's range were found in the 
panhandle of Florida and in Georgia populations (Ennen 2009, p. 73). 
Recent research using another mitochondrial gene similarly found no 
shared haplotypes across the Mobile and Tombigbee Rivers (Clostio 
2010). However, analysis of microsatellite markers indicates 
phylogenetic division of G. polyphemus into eastern and western 
lineages apparently corresponding to the ranges east and west of the 
Apalachicola River (Clostio 2010).
    There are a number of other smaller-scale genetic analyses that 
have been conducted to better understand local and regional genetic 
variation. From comparisons of nine microsatellite loci sampled 
throughout Florida and southern Georgia (Schwartz et al. 2003, p. 285), 
it was subsequently determined that the populations could be further 
subdivided into at least eight genetic assemblages, five of which were 
showing effects of population bottlenecks and four of which showed 
signs of genetic admixture from separate populations (Schwartz and Karl 
2005, pp. 921-925). In the Florida panhandle, mitochondrial DNA 
analysis found minimal genetic diversity among six populations and 
suggested that gene flow has occurred among these populations (Berish 
2010), which would be in conflict with the findings of Clostio (2010) 
and consistent with Ennen (2009, p. 78). Subsequent analysis compared 
the above-referenced Florida panhandle genetics with those collected by 
Schwartz and Karl (2005, entire) and found a genetic break between 
peninsular Florida and the Florida panhandle as did Osentoski and Lamb 
1995 (as cited in Winters 2010, pp. 3-4), but these data indicated 
genetic exchange across the panhandle of Florida from Wakulla County to 
Escambia County, with no significant break at the Apalachicola River as 
suggested by Clostio (2010).
    Microsatellite DNA markers and mitochondrial DNA were used to 
determine whether gopher tortoise populations on Camp Shelby, 
Mississippi, were spatially structured, if spatial structure was 
affected by military activity and habitat quality, and whether there 
was a correlation between geographic distance and genetic relatedness 
(Theodorakis 2008, p. 6). Results indicated that there was genetic 
structure within these populations, and that genetic diversity and gene 
flow were affected by habitat and land use. Genetic distance did not 
seem to correlate with geographic distance (Theodorakis 2008, p. 21).
    Based on the diversity of six microsatellite loci from 96 
individual tortoises from Kennedy Space Center in east-central Florida, 
it was determined that the population was one nearly continuous 
population; there were no genetically distinct assemblages (Sinclair et 
al. 2010, p. 192). These findings resulted in a recommendation to 
manage the Space Center's tortoises as one single population.
    Drawing conclusions about genetic subdivisions and unique genetic 
assemblages based on available genetic data are difficult because 
methodologies varied between studies, sample sizes were small in some 
areas, distances between samples were large in some cases, and areas 
covered by each study varied. Conclusions from rangewide 
phylogeographic studies of the gopher tortoise are somewhat 
contradictory. However, other important information about gopher 
tortoises can be synthesized from these studies. For example, analyses 
of mitochondrial DNA and nuclear DNA microsatellite markers indicate a 
long-term population decline since the Pleistocene era of G. polyphemus 
in the western portion of its range (i.e., the listed portion of its 
range) and past population bottlenecks (Clostio 2010). These findings 
are supported by a recent evaluation of genetic diversity indices which 
indicated that four gopher tortoise populations in Mississippi have 
lower genetic diversity than some populations in the eastern portion of 
the tortoise's range (Ennen et al. 2010, p. 31, 36). This lower genetic 
variation and heterozygocity (different genes) suggests either a prior 
population bottleneck, or that historically the western populations 
persisted naturally with low genetic diversity (Ennen et al. 2010, p. 
35).

Distribution

    The gopher tortoise occurs in the southeastern Coastal Plain from

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southeastern South Carolina to extreme southeastern Louisiana 
(Auffenberg and Franz 1982, p. 95). Throughout much of the western 
range of the gopher tortoise, only small populations remain in isolated 
habitat patches (Landry and Gregory 2008, pp. 2-3). The largest 
populations and greatest density of populations in the western portion 
of its range occur in the De Soto National Forest, Mississippi (Hammond 
2009, p. 12). The eastern portion of the gopher tortoise's range 
includes Alabama (east of the Tombigbee and Mobile Rivers), Florida, 
Georgia, and South Carolina. The core of the current distribution of 
the gopher tortoise in the eastern portion of its range includes 
central and north Florida and southern Georgia.
    There has been no rangewide survey of gopher tortoises, and there 
are only a limited number of comprehensive surveys over relatively 
small geographic areas. As a result, the distribution of gopher 
tortoises would be incomplete if we used only existing survey data, so 
we relied on the location of potential habitat to identify where 
tortoises may be present. It is important to note, however, this 
Geographic Information System (GIS) effort does not reflect the current 
distribution of gopher tortoise populations nor the size or 
connectivity of gopher tortoise populations. In all likelihood, the 
actual distribution of gopher tortoises is less, perhaps much less, 
than modeled because much of the modeled potential habitat may be 
unsuitable. However, the information generated from the Hoctor and 
Beyeler (2010, entire) GIS model and subsequent model revisions for 
Florida (FWC 2011a) is the best information currently available and 
roughly estimates the amount and distribution of potential gopher 
tortoise habitat throughout the eastern portion of the tortoise's 
range.
    In their assessment, Hoctor and Beyeler (2010, pp. 6-7) defined 
potential primary habitat as having appropriate vegetative communities 
(e.g., longleaf pine forests, scrub, coastal dunes), soils, and canopy 
cover of less than 65 percent within the known historic range of the 
tortoise. Potential secondary habitat was defined as having appropriate 
forest cover types and soils, but not suitable canopy cover. Potential 
foraging habitat was defined as areas with appropriate habitat types 
within 300 meters (m) (984 feet) of either potential primary or 
potential secondary habitat. Hoctor and Beyeler (2010, p. 16) conducted 
a goodness-of-fit analysis comparing known gopher tortoise data points 
from Florida with habitat categories established in the GIS analysis. 
The analysis indicated that the location of gopher tortoise point data 
in Florida was not randomly distributed in relation to any grouping. 
This suggests the GIS analysis distinguished between potential habitat 
and non-habitat fairly well: primary habitat ([chi]\2\ = 3091.58, df = 
1, P < 0.001); primary and secondary habitat combined ([chi]\2\ = 
2157.66, df = 1, P < 0.001); primary, secondary, and foraging habitat 
combined ([chi]\2\ = 1319.44, df = 1, P < 0.001); appropriate soils 
([chi]\2\ = 826.07, df = 1, P < 0.001). These statistics indicate that 
the model accurately identified gopher tortoise potential habitat in 
Florida.
    The FWC slightly modified the Hoctor and Beyeler model to account 
for variations in potential gopher tortoise habitat that were thought 
to be unique to Florida (FWC 2011a). The inclusion of beach and dune 
habitat, inclusion of depth to water table of 0.5 to 2.3 meters (1.5 to 
6.5 feet), and the exclusion of the 300 meter buffer surrounding 
primary habitat. These model modifications resulted in a decrease in 
the acreage of potential gopher tortoise habitat identified in Florida 
(3.0 million to 2.2 million) but likely more closely estimates the 
distribution of habitat in Florida. For consistency and comparative 
purposes, we use acreages reported by Hoctor and Beyeler (2010). 
Refined analyses such as those conducted by FWC are not available for 
the remainder of the range and reductions in acreages such as those 
indicated in Florida's model revisions bolsters our prior assumption 
that the Hoctor and Beyeler model overestimates the actual distribution 
of potential habitat. Future conservation actions for the species would 
no doubt benefit from more site-specific data included in modeling 
efforts such as that carried out by FWC.
    A total of about 9.5 million hectares (ha) [23.5 million acres 
(ac)] of potential primary, secondary, and foraging habitat is 
estimated to currently occur within the eastern portion of the 
tortoise's range (Hoctor and Beyeler 2010, p. 12). Nearly 88 percent of 
the habitat is estimated to be in private ownership, and the remainder 
is controlled by local, State, Federal, or private conservation 
entities (Table 1). The largest patches of contiguous potential habitat 
(those greater than 100 ha or 250 ac) accounted for about 5.6 million 
ha (13.9 million ac), and 85 percent of this area was privately owned 
(Hoctor and Beyeler 2010, pp. 13-14). Using a similar GIS analysis 
based on the Hoctor and Beyeler (2010, entire) model for the eastern 
range, the distribution of potential gopher tortoise habitat was 
estimated throughout the western range (Ginger 2010). A total of 1.8 
million ha (4.5 million ac.) of potential primary, secondary, and 
foraging habitat was estimated using the model, with the largest 
habitat patches (those greater than 100 ha or 250 ac) accounting for 
about 0.5 million ha (1.4 million ac). For two counties, Greene 
(Mississippi) and Washington (Alabama), base soils information was not 
available, so those counties were not included in the analysis. The 
base layers represent coarse and sometimes outdated data, and the model 
was not field tested and no goodness-of-fit analysis was conducted for 
data originating from the western portion of the tortoise's range. 
However, the results are likely inflated values that may represent the 
amount of habitat closer to the historic range rather than the current 
potential distribution.
    Table 1. Distribution of all (primary, secondary and foraging) 
potential gopher tortoise habitat on private and public lands currently 
in the eastern portion of its range (summarized from Hoctor and Beyeler 
2010, p. 14).

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Alabama...............................  Private..................  1,798,369 ha (4,444,371 ac)
Alabama...............................  Public...................  57,493 ha (142,065 ac)
Florida...............................  Private..................  2,378,338 ha (5,876,794 ac)
Florida...............................  Public...................  753,272 ha (1,861,312 ac)
Georgia...............................  Private..................  3,569,093 ha (8,819,109 ac)
Georgia...............................  Public...................  135,599 ha (335,599 ac)
South Carolina........................  Private..................  640,987 ha (1,583,858 ac)
South Carolina........................  Public...................  73,941 ha (182,707 ac)
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 Habitat

    Gopher tortoises require well-drained, sandy soils for burrowing 
and nest construction, an abundance of herbaceous ground cover for 
food, and a generally open canopy that allows sunlight to reach the 
forest floor (Landers 1980, p. 6; Auffenberg and Franz 1982, p. 98). 
Longleaf pine and oak uplands, xeric hammock, sand pine and oak ridges 
(beach scrub), and ruderal (disturbed) habitat most often provide the 
conditions necessary to support gopher tortoises (Auffenberg and Franz 
1982, p. 99). In the western range, soils contain more silt, and xeric 
(dry) conditions are less common west of the Florida panhandle (Crual 
et al. 2005, p. 73). Ground cover in this Coastal Plains area can be 
separated into two general regions with the division in the central 
part of southern Alabama and northwest Florida. To the west, bluestem 
(Andropogon spp.) and panicum (Panicum spp.) grasses predominate; to 
the east, wiregrass (Aristida stricta) is most common (Boyer 1990, p. 
3). However, gopher tortoises do not necessarily respond to specific 
plants but rather the physical characteristics of habitat (Diemer 1986, 
p. 126). Longleaf pine and oak uplands (e.g., sandhills) are the 
preferred habitat for gopher tortoises (Landers and Speake 1980, p. 
515; McRae et al. 1981, p. 177; Auffenberg and Franz 1982, p. 100; 
Diemer 1986, p. 126). Ruderal (i.e., disturbed or atypical) habitats 
include roadsides and utility rights-of-way, grove/forest edges, 
fencerows, and clearing edges. Historic gopher tortoise habitats were 
open pine forests, savannahs, and xeric grasslands that covered the 
coastal plain from Mexico and Texas to Florida. Historic habitats might 
have had wetter soils at times and been somewhat cooler but were 
generally xeric, open, and diverse (Ashton and Ashton 2008, p. 73).
    Sandy soils are most appropriate for burrow construction (Jones and 
Dorr 2004, p. 461), and most burrows are found on loam and sandy loam 
type soils (Tuma 1996, p. 43). Much of the remaining undisturbed gopher 
tortoise habitat in the eastern portion of the range consists primarily 
of coastal dunes or xeric uplands dominated by wiregrass and longleaf 
pine-turkey oak or scrub communities (Landers et al. 1980, pp. 353-354; 
Diemer 1986, p. 126). Conversely, most tortoise habitat in the western 
portion of the range (western Alabama, Louisiana, and Mississippi) 
consists of soils with a low sand content and a more substantial clay 
component. Jones and Dorr (2004, p. 461) suggest that higher clay 
content in soils may contribute to lower abundance and density of 
tortoises in Mississippi versus the remainder of the range.
    Sand texture is most important in the formation of the burrow 
apron, which impedes rain from entering the burrow (Landers 1980, p. 
6). Sand depth is also important because soil layers underlying it, 
such as clay, can impede digging and influence burrow depth (Baskaran 
et al. 2006, p. 347). Burrows are shorter in clay soils, and clay soils 
may adversely affect nest success because these soils reduce exchange 
of oxygen and carbon dioxide (Wright 1982, p. 21; Ultsch and Anderson 
1986, p. 790; Smith et al. 1997, p. 599). Larger diameter burrow 
openings tend to result in longer burrows (Hansen 1963, p. 355). 
Burrows are usually distributed on higher ridge tops rather than 
wetlands, and their depths are sometimes limited by the water table 
(Baskaran et al. 2006, p. 346).
    Gopher tortoises use their burrows as a respite from extreme 
surface temperatures, desiccation, and predators (Hansen 1963, p. 359; 
Landers 1980, p. 7; Wright 1982, p. 50; Diemer 1986, p. 127; Boglioli 
2000, p. 699). Digging burrows benefits the surrounding habitat by 
returning leached nutrients to the surface (Auffenberg and Weaver 1969, 
p. 191; Landers 1980, p. 7), as well as increasing the heterogeneity 
(diversity) of the habitat in the vicinity of the burrow (Kaczor and 
Hartnett 1990, p. 107). Burrows can also serve to shelter seeds from 
fires (Kaczor and Harnett 1990, p. 108). Many organisms adapted to hot 
summers and cool winters use gopher tortoise burrows for refuge 
(Landers and Speake 1980, p. 515). Jackson and Milstrey (1989, p. 87) 
compiled a list of 60 vertebrates and 302 invertebrates that share 
tortoise burrows. Gopher tortoise burrows not only provide other 
species shelter from extreme environmental conditions and predation, 
but may also be used as feeding or reproduction sites, as well as 
permanent microhabitats for one or all life stages (Jackson and 
Milstrey 1989, p. 86).
    Gopher tortoises have a well-defined activity range where all 
feeding and reproduction take place and that is limited by the amount 
of herbaceous ground cover (Auffenberg and Iverson 1979, p. 549). 
Tortoises are obligate herbivores eating mainly grasses, plants, fallen 
flowers, fruits, and leaves. Gopher tortoises prefer grassy, open-
canopy microhabitats (Boglioli et al. 2000, p. 703), and their 
population density directly relates to the density of herbaceous 
biomass (Auffenberg and Iverson 1979, p. 558; Landers and Speake 1980, 
p. 522; Wright 1982, p. 22; Stewart et al. 1993, p. 79) and a lack of 
canopy (Breininger 1994, p. 63; Boglioli et al. 2000, p. 703). Grasses 
and grass-like plants are important in gopher tortoise diets 
(Auffenberg and Iverson 1979, p. 558; Landers 1980, p. 9; Garner and 
Landers 1981, p. 123; Wright 1982, p. 25; McDonald and Mushinsky 1988, 
p. 351; Mushinsky et al. 2003, p. 480; Birkhead et al. 2005, p. 146). A 
lack of vegetative diversity may negatively impact the long-term 
sustainability of gopher tortoise populations (Ashton and Ashton 2008, 
p. 78).
    Gopher tortoises may enhance nitrogen cycling by augmenting legume 
germination and abundance around burrows. Boglioli et al. (2000, p. 
704) found that legumes were three times more abundant around burrows 
than at control points. Since legumes have thick seed coats, they may 
benefit from scarification after passing through the digestive tract 
(Boglioli et al. 2000, p. 704). Low food availability negatively 
affects tortoise population densities and can be caused by plant growth 
suppression due to accumulated leaves, litter, and low light associated 
with canopy closure (Landers and Speake 1980, p. 522).
    Gopher tortoises require a sparse canopy and litter-free ground not 
only for feeding, but also for nesting (Landers and Speake 1980, p. 
522). In Florida, McCoy and Mushinsky (1988, p. 35) found that the 
number of active burrows per tortoise was lower where canopy cover was 
high. Females require almost full sunlight for nesting (Landers and 
Buckner 1981, p. 5) because eggs are often laid in the burrow apron or 
other sunny spot and require the warmth of the sun for appropriate 
incubation (Landers and Speake 1980, p. 522).
    At one site in southwest Georgia, Boglioli (et al. 2000, p. 703) 
found most tortoises in areas with 30 percent or less canopy cover. 
Diemer (1992, p. 162) found that ecotones created by clearing were also 
favored by tortoises in north Florida. When canopies become too dense, 
usually due to fire suppression, tortoises tend to move into ruderal 
habitats such as roadsides with more herbaceous ground cover, lower 
tree cover, and significant sun exposure (Garner and Landers 1981, p. 
122; McCoy et al. 1993, p. 38; Baskaran et al. 2006, p. 346). In 
Georgia, Hermann et al. (2002, p. 294) found that open pine areas 
(e.g., pine forests with canopies that allow light to penetrate to the 
forest floor) were more likely to have burrows, support higher burrow 
densities, and have more burrows used by large, adult tortoises than 
closed-canopy forests. Historically, open-canopied pine forests

[[Page 45134]]

were maintained by frequent, lightning-generated fires. Subsequently, 
grazing and mowing have contributed to the maintenance of some gopher 
tortoise habitat (Ashton and Ashton 2008, p. 78).

Status

    Effectively assessing the status (i.e., whether it is increasing, 
decreasing, or stable) of the gopher tortoise throughout its range 
requires evaluation of the distribution of tortoises, number of 
tortoises and populations, number of individuals in populations, and 
trends in population growth. As we indicated above, we do not have 
specific distribution data for most of the tortoise's range, but we 
estimated where potential habitat existed and where tortoises may still 
be present. Below, we provide summaries of survey data about the sizes 
and, in some cases, trends of gopher tortoise populations. There is a 
noticeable disparity between the apparently large area (expressed in 
hectares or acres, or ha/ac) of potential gopher tortoise habitat 
reported above and actual numbers of individual tortoises known from 
populations that have been surveyed, as summarized below. Upon cursory 
examination, there seem to be few tortoises where there are millions of 
hectares of potential habitat. Many Federal and State agencies, non-
governmental organizations (NGO), and timber owners have only recently 
begun to assess where and how many gopher tortoises are present on 
lands they own or manage. Nonetheless, we have evaluated the status of 
the gopher tortoise based on the best available scientific information, 
which is summarized in the next section.
    Our review of the literature indicates that the status of an 
individual gopher tortoise population is dependent on the size of the 
population and its demographic performance. For comparative purposes, 
and as described in greater detail below, we considered tortoise 
populations to be large enough to persist in the future (i.e., viable) 
if they contained 250 or more reproductively active individuals. 
Ideally, recruitment should exceed mortality, but few long-term studies 
provide this demographic information. In the absence of these data, 
burrow surveys that report hatchling- and juvenile-sized burrows 
indicate that recent recruitment occurred, but we still often lack 
information about whether the observed level of recruitment is 
sufficient to offset mortality. The amount of habitat necessary to 
support a population of at least 250 breeding individuals likely varies 
depending on habitat quality. Populations in poor-quality habitat, such 
as those in atypical vegetative communities and in areas not 
aggressively managed, will likely require more area than populations in 
high-quality soils where there would be sparse canopy cover, multi-aged 
pine forests with abundant ground cover, and where prescribed fire is 
used periodically to maintain habitat conditions. Because of these 
variations, the density of gopher tortoises in a population that is 
large and demographically viable will vary.
    Using available information we can estimate that 250 individual 
tortoises are needed to represent a viable population. We also 
estimated how much habitat an ancestral (conditions prior to human 
disturbance) gopher tortoise population of 250 individuals may have 
required. The recovery criteria for the populations in western portion 
of the range on priority soils calls for gopher tortoise densities of 
five active burrows per ha (two active burrows per ac). With a reported 
0.61 burrow occupancy correction factor (i.e., proportion of burrows 
occupied by tortoises) this equates to about 3.0 tortoises per ha (1.2 
per ac) (Service 1990, p. 14). Based on historic survey data, tortoise 
densities as high as 4.9 per ha (2.0 per ac) are targeted for some 
high-quality recipient sites under Florida's gopher tortoise management 
plan (Plan) (Fish and Wildlife Conservation Commission (FWC) 2007, p. 
76). Burrow densities on two conservation parcels containing mature 
longleaf pine forests in Georgia that have been managed with short-
return (i.e., 1-3 years) fire intervals for 20 to 70 years had burrow 
densities 2.7-5.1 per ha (1.1-2.1 per ac) (Guyer 2010, Hermann et al. 
2002, p. 296). Based on the above data, we estimate that a viable 
ancestral (prior to human disturbance) tortoise population contained a 
minimum of 250 breeding individuals, with active burrow densities 
ranging between 1.5-5.1 per ha (0.6-2.1 per ac). Using an occupancy 
correction factor 0.37 from the best representative ancestral extant 
population (Hermann et al. 2002, p. 296), these burrow densities would 
equate to 0.6-1.9 tortoises per ha (0.2-0.8 per ac). At these 
densities, ancestral tortoise populations of 250 tortoises in southern 
Georgia would likely have occurred in habitat patches ranging from 132-
416 ha (326-1,028 ac). Using the 0.61 correction factor specified in 
the gopher tortoise recovery plan results in 0.9-3.1 tortoises per ha 
(0.4-1.3 per ac) and would have occupied 81-278 ha (192-687 ac). Few 
extant gopher tortoise populations currently meet these criteria.

Status in Western Portion of the Range

    Alabama: On commercial forests in Alabama and Mississippi, tortoise 
surveys were conducted from July 1999 through May 2001 on about 11,838 
ha (29,252 ac). Survey sites were selected opportunistically and not 
based on known tortoise populations or habitat suitability for 
tortoises. About 0.05 active burrows per ha (0.02 per ac) were found in 
these mostly closed-canopy slash and loblolly pine forests (National 
Council for Air and Stream Improvement, Inc. 2010, pp. 15-16). Burrow 
surveys conducted on corporate pine forests in southern Mississippi and 
southwestern Alabama on soils that were variably suitable for gopher 
tortoises did not detect active burrows on about 88 percent of surveyed 
sites (Jones and Dorr 2004, p. 461). Where burrows were detected, 
densities of active burrows ranged from 0.10-0.60 burrows per ha (0.04-
0.24 burrows per ac) (Jones and Dorr 2004, p. 460).
    Louisiana: Tortoises are not widespread or abundant in Louisiana, 
and all known populations are small and occur in fragmented habitat. 
Determining the status of tortoises in Louisiana is difficult because 
of limited survey data (Diaz-Figueroa 2005, p. 5). The most recent 
surveys during 2007 and 2008 in Washington, Tangipahoa, and St. Tammany 
parishes, where the largest known gopher tortoise populations remain, 
found 54 active and 45 inactive burrows on Ben's Creek Wildlife 
Management Area. Sandy Hollow Wildlife Management Area contained 25 
active, 12 inactive, and 4 abandoned burrows. A natural gas pipeline 
corridor supported 26 active, 31 inactive, and 4 abandoned gopher 
tortoise burrows (Landry and Gregory 2008, pp. 2-3). Burrow density 
estimates were not included in the survey results for locations in 
Louisiana.
    Mississippi: Data gathered in the De Soto National Forest evaluated 
gopher tortoise population trends over a 12-year period based on three 
burrow surveys conducted in 1995, 2002, and 2007. The surveys were 
limited to only the deep, sandy soil types, which comprise only 2.5 
percent of the De Soto National Forest. Nonetheless, gopher tortoise 
burrow densities declined by 35.7 percent from 1995 to 2007, and 18 
locations that contained tortoises in 1995 had no tortoises in 2007 
(Conservation Southeast, Inc. 2009, pp. 1, 12, 27). Eighty percent of 
locations containing adults contained no juvenile burrows. The mean 
adult active burrow density on priority soils ranged from 0.12-0.67 per 
ha (0.05-0.27 per ac) on three sections of the National Forest

[[Page 45135]]

(Conservation Southeast, Inc. 2009, p. 21). Qualls (2010) observed that 
the majority of tortoise populations on the De Soto National Forest 
appeared to be small and adult-dominated and recruitment was low or 
absent. Analysis of gopher tortoise population sizes from Wester (2005, 
pp. 18-19) on the Camp Shelby Training Site (within the De Soto 
National Forest) found that 159 of 162 colonies (98 percent) contained 
fewer than 50 individual tortoises and up to 25 percent of all 
tortoises found were not associated with a population (Ginger 2010). 
These findings support earlier observations of small, fragmented 
populations on many of the study sites in Mississippi evaluated by Mann 
(1995, pp. 1, 2, 24). Implementation of recent management efforts 
within the De Soto National Forest may be slowing the observed 
population decline (Conservation Southeast, Inc. 2009, p. 13).
    A subsample of gopher tortoise survey locations from 1995 on Camp 
Shelby were resurveyed in 1999 and 2000. The distribution of tortoise 
colonies did not change between surveys and most were still located in 
ruderal habitats, and the largest number of burrows was located in 
fire-suppressed pine forests (Epperson and Heise 2001, p. 26). 
Populations appear to be declining, and age classes are shifting 
towards more adults (Epperson and Heise 2001, p. 38). Burrow densities 
were not estimated from data gathered during this study, but evaluation 
of three prior surveys on the De Soto National Forest showed that 
burrow densities (including all active, inactive, and abandoned 
burrows) ranged from 0.11-1.38 burrows per ha (0.04-0.56 burrows per 
ac) (Epperson and Heise 2001, p. 25). A subsequent comparison of gopher 
tortoise survey data from 1995 with information obtained during 2003 
and 2004 surveys found the number of active burrows declined from 1,133 
to 856 (33 percent reduction) while the number of inactive or abandoned 
burrows increased by 923 (Wester 2005, p. 17). The 33 percent decline 
in active burrows was consistent with documented tortoise declines 
throughout the remainder of the De Soto National Forest (Conservation 
Southeast, Inc. 2009, pp. 1, 12).
    Surveys in known gopher tortoise habitat were conducted from 1993-
1995 (during the months between May and August) on 1,554 ha (3,840 ac) 
of planted pines in southern Mississippi. The planted pines had been 
recently thinned and frequently burned. About 0.20 active burrows per 
ha (0.08 per ac) and 0.7 active burrow per kilometer (1.1 per mile) in 
linear (e.g., roads, gas line right of ways, electrical transmission 
lines) habitats were found (National Council for Air and Stream 
Improvement, Inc. 2010, p. 15).
    Estes and Mann (1996, p. 1) conducted surveys on sites with 
suitable soils on Section 16 lands (i.e., in each township, Section 16 
is set aside for maintenance of public schools) in southern 
Mississippi. Surveys covered about 1,090 ha (2,693 ac) and found an 
average of 1.0 burrow (active and inactive) per ha (0.4 per ac). 
Burrows were most dense on suitable soils in longleaf pine habitats 
that were regularly burned. Based on burrow sizes encountered, the 
authors concluded that recruitment was low. Gopher tortoise populations 
were small and isolated, and few had evidence of recruitment. The 
researchers questioned the long-term viability of most Section 16 
tortoise populations (Estes and Mann 1996, pp. 23-24).
    We also reviewed data collected during a mail survey seeking 
information on the status of gopher tortoises on private lands within 
the historic range of the tortoise in Mississippi. Although data were 
not useful in evaluating numbers, densities, or status of tortoises in 
southern Mississippi, we found that few reporting landowners had 
tortoises (19 percent); of the remaining tortoises, most were 
persisting in longleaf pine habitats, and most tortoise populations had 
recently disappeared from other habitat types (Underwood et al. 2010, 
pp. 8, 11, 15).

Status in the Eastern Portion of the Range

    Alabama: The official Web site of the Alabama Department of 
Conservation and Natural Resources, https://www.outdooralabama.com 
(accessed September 9, 2010)), reports that gopher tortoises are found 
in Baldwin, Barbour, Bullock, Butler, Clarke, Coffee, Conecuh, 
Covington, Crenshaw, Dale, Escambia, Geneva, Henry, Houston, Monroe, 
Montgomery, Pike, and Wilcox Counties. Small introduced populations 
also occur in Autauga and Macon counties. Alabama is in the initial 
stages of planning surveys or censuses for the gopher tortoise in the 
eastern portion of the range. Therefore, no data currently exist to 
evaluate the status of tortoises on public lands in the eastern portion 
of the range in Alabama, beyond general counties of occurrence.
    In 2003, surveyors found 636 active gopher tortoise burrows at Fort 
Rucker, Alabama, which was reported to have about 19,830 ha (49,000 ac) 
of potential tortoise habitat (Southeast Regional Partnership for 
Planning and Sustainability 2010, pp. 11, 27).
    Florida: In north central Florida, a gopher tortoise population was 
intensively monitored for 6 years on a 66-ha (163-ac) 33-year-old slash 
pine plantation beginning in 1981. After the study site was clear cut 
in 1988, a follow-up assessment found that tortoises had moved to 
ecotones (ecological transition zone) between cut and mature forests, 
but roughly the same number of tortoises were captured pre- (n = 60) 
and post-clearcut (n = 58). In 2009, an additional follow-up in the now 
11-year-old plantation that had been burned and planted in longleaf 
pine in preparation for gopher tortoise introductions indicated about 
the same number of tortoises (n = 52), but a substantial decline in the 
number of juveniles was detected (Berish 2010). The investigator 
concluded that viable and robust populations can persist long term in 
habitat with ongoing intensive silviculture. However, in this case, we 
noted that efforts were under way to enhance gopher tortoise habitat on 
the study site in preparation for introduction of additional tortoises. 
The researcher's conclusion of a viable tortoise population persisting 
in an intensive silvicultural forest did not take into account the 
possible positive demographic response tortoises may have had to 
habitat enhancement activities in the later stages of this monitoring 
effort or the substantial decline in the number of juvenile tortoises.
    Tortoise populations on 10 public lands were evaluated twice over a 
12-year period and the number of active and inactive burrows decreased 
at 9 of the 10 sites. On eight of the sites, there was at least a 10 
percent decline over the 12-year period (McCoy et al. 2006, p. 123). No 
strong correlation was observed between burrow declines and habitat 
quality between surveys, but the response of a population to decline in 
habitat quality may depend on the initial habitat structure, the degree 
of change in habitat structure, the period of time over which change is 
measured, the amount of habitat involved, and the level of habitat 
management (McCoy et al. 2006, p. 1).
    At Cape Sable, in south Florida, burrow counts using line- or 
strip-transects were conducted in 1979, 1990, and 2001. The density of 
active burrows decreased 76 percent between 1979 and 2001. Between 1979 
and 1990 the population was probably stable or slightly increasing, but 
declined substantially between 1990 and 2001, despite evidence of 
recruitment. Reduced habitat quality and tropical storms may have been 
responsible for

[[Page 45136]]

the observed declines between 1990 and 2001 (Waddle et al. 2006, pp. 
280-283).
    Burrow counts were completed at six locations on Naval Air Station 
Pensacola and at eight sites at Naval Air Station Whiting Field in 1996 
and again in 2006 (Davis and Russo 2007a, entire; 2007b, entire; Naval 
Air Station Pensacola Natural Resources Division 2008, entire). On 
Naval Air Station Pensacola active burrows were not detected from two 
locations where they were observed in 1996, but increased at three 
others (Davis and Russo 2007a, pp. 2-3). Small burrow sizes indicated 
that juvenile tortoises were present in the remaining three areas 
demonstrating successful reproduction. On Naval Air Station Whiting 
Field the number of active burrows declined on three sites, was 
unchanged at one site, and increased at four others. Burrow numbers 
were small in all areas, and reproduction was evident at two locations. 
Most burrows were located in ruderal habitat, and native pine forests 
were in need of management (Davis and Russo 2007b, p. 2).
    Surveys for gopher tortoise burrows on Camp Blanding Joint Training 
Center, Clay County, Florida, in 2008 estimated a total of 6,433 active 
burrows by extrapolating from a survey of 10 percent of the 7,350 ha 
(18,170 ac) of potential habitat on the Center (Southeast Regional 
Partnership for Planning and Sustainability 2010, pp. 11, 27).
    A recent survey conducted on a 230-ha (570-ac) property in Alachua 
County, FL, in a high-density slash pine plantation with no burning 
history and substantial mid-story hardwood found 58 active burrows in 
the area (Plum Creek 2010, p. 3). The location of the burrows was not 
described.
    A 2009 survey on Egmont Key National Wildlife Refuge (NWR), 
Hillsborough County, Florida, found 148 active burrows on about 132 ha 
(328 ac) (Southeast Regional Partnership for Planning and 
Sustainability 2010, p. 31). On Ding Darling NWR, 12 active and one 
inactive burrow were detected, and from five populations on Sanibel-
Captiva Islands near Ding Darling NWR, a total of 170 active burrows 
and 39 inactive burrows were found during surveys in late 2009. Archie 
Carr NWR recorded 11 active burrows on two acres, and Pelican Island 
NWR found one active burrow during 2010 surveys.
    Surveys conducted on a 74 ha (183 ac) parcel of the Jennings Forest 
Wildlife Management Area in 1999, 2005, and 2010 indicated that the 
gopher tortoise population apparently responded positively to habitat 
restoration and management activities (FWC 2010a). The number of 
tortoise burrows increased from 378 active and inactive in 1999, to 442 
active and inactive burrows in 2005, and then to 657 active and 
inactive burrows in 2010. Using a burrow occupancy correction factor of 
0.614, FWC concluded that the tortoise population increased from 271 to 
403 individuals over the 11-year monitoring period. The reason(s) for 
the observed increase in population size was not described (e.g., 
increased immigration or increased recruitment).
    A survey was completed in 2010 on a 100 ha (246 ac) parcel 
representing about 27 percent of available potential gopher tortoise 
habitat on Fort White Wildlife and Environmental Area, Florida. Burrow 
estimates for all potential habitat equaled 1994  95 
burrows, or 1810 to 2185 burrows with a 95 percent confidence interval 
(Sullivan 2010).
    Georgia: In seven southwest Georgia counties, tortoise burrow 
surveys conducted at randomly selected forest units with suitable soils 
for gopher tortoises found that 64 percent of the parcels contained no 
gopher tortoise burrows (Hermann et al. 2002, p. 292). On parcels that 
were occupied, burrow densities ranged from 0.04 per ha (0.02 per ac) 
to 2.2 per ha (0.9 per ac) with a mean of 1.1 per ha (0.4 per ac) 
(Hermann et al. 2002, p. 293). Suitable soils that had non-timber 
agriculture, hardwoods, and planted pine plantations were about 6 times 
less likely to have burrows and contained 20 times fewer tortoise 
burrows than open pine sites (Hermann et al. 2002, p. 294-295).
    Recently, burrow surveys using line-transect distance sampling and 
burrow scoping were attempted on 20 wildlife management areas, State 
parks, and other public lands in southern Georgia. No tortoises were 
observed at one parcel, and seven others had burrow densities that were 
insufficient to accurately estimate population levels (Smith et al. 
2009, p. 361). Thirteen sites contained populations ranging in 48-321 
individuals with densities of 0.21-1.65 tortoises per ha (0.08-0.68 
tortoises per ac). In general, burrow size class distribution were 
skewed toward adult tortoises suggesting low recruitment of juveniles.
    One-time burrow surveys from Kings Bay Naval Submarine Base in 
southeastern Georgia indicated a total of 200 active burrows including 
juvenile and hatchling-sized burrows. The majority of burrows occurred 
in ruderal, edge, or transition habitat, sandhill, and young pine 
(Tuberville et al. 2009, p. 7). Area of gopher tortoise habitat for 
Kings Bay Naval Submarine Base was not provided. Native pine forests 
were degraded and in need of management (Tuberville et al. 2009, p. 8).
    Surveys on 12 study sites at Fort Benning, Georgia, during 1995 
found active and recently used burrow densities ranging from 0.05-1.2 
per ha (0.02-0.49 per ac) (Styrsky 2010, p. 405). About 2,700 active 
burrows were estimated on Fort Benning during 1998 surveys, and with 
nearly 25,375 ha (62,700 ac) of potential habitat, this equates to 
about 0.11 active burrows per ha (0.04 burrows per ac) (Southeast 
Regional Partnership for Planning and Sustainability 2009, p. 11, 27). 
Surveys on Fort Gordon, Georgia, located 147 active burrows, which 
contained about 4,570 ha (11,300 acres) of tortoise habitat or about 
0.03 active burrow per ha (0.01 per ac). During 2009 surveys on Fort 
Stewart, Georgia, 4,045 active burrows were located with a reported 
5,790 ha (14,300 ac) of tortoise habitat or about 0.70 burrows per ha 
(0.28 per ac) (Southeast Regional Partnership for Planning and 
Sustainability 2009, p. 11, 27).
    Okeefenokee NWR surveyed two tracts of 11 and 18 ha (26 and 45 ac) 
in 2010 and found. The 11 ha tract had 73 active, and 35 inactive, 
burrows and the 18 ha tract had 31 active and 16 inactive, 
respectively. Surveys on a 102 ha (250 ac) tract on the Eufaula NWR in 
both Georgia and Alabama found 30 active tortoise burrows.
    South Carolina: Little is known about the population status of the 
tortoise in Aiken County or in the Coosawhatchie region (Bennett and 
Buhlmann 2005, p. 2). The Aiken Gopher Tortoise Heritage Preserve 
contains a small population that is believed to be in decline (Bennett 
and Buhlmann 2005, p. 2). Augmentation into this population is ongoing, 
and the effects of these translocations are not known (Bennett 2010). 
Tortoises on the Tillman Sand Ridge Heritage Preserve have been 
surveyed in the past (Auffenberg and Franz 1982, entire; Wright 1982, 
entire; Tuberville and Dorcas 2001, entire), and population estimates 
from these studies indicate a historical decline in the adult 
population of gopher tortoises. Recent assessments suggest this 
population may be stabilizing or growing, but several more years of 
monitoring will be necessary to confirm this trend (Bennett 2010). No 
other natural tortoise populations are known in South Carolina.
    Multi-State Surveys: A one-time survey on 22 tracts of commercial 
forest containing 88 stands known to support gopher tortoises was 
conducted in late 2009 and early 2010 (National Council for Air and 
Stream Improvement, Inc.

[[Page 45137]]

2010, p. 15). Surveys covered 1,938 ha (4,789 ac) of longleaf pine (n = 
47 stands), loblolly pine (n = 16 stands), and slash pine (n = 14 
stands)), sandpine (n = 4 stands), and recently harvested stands (n = 
7) in Alabama, Florida, Georgia, and Mississippi. Potentially active 
and abandoned gopher tortoise burrow density averaged 2.8 per ha (1.1 
per ac) and 1.8 per ha (0.7 per ac), respectively, for each stand.
    Population Modeling: In the absence of field surveys and long-term 
monitoring, models may be used to project the status of populations in 
the future based on a specific set of assumptions and assignment of 
demographic parameters. There have been four substantive modeling 
efforts evaluating the long-term persistence of gopher tortoises 
(Tuberville et al. 2009, pp. 5-10). Two early modeling efforts focused 
on estimating the minimum number of tortoises needed for a population 
to persist for 200 years (Cox et al. 1987, p. 28). Although relatively 
small population sizes (40-50 adults) were modeled to persist over the 
model duration, all populations declined and were projected to go 
extinct at some point in the future depending on model parameters.
    Miller et al. (2001, p. 1) assessed the likelihood of tortoises 
being extirpated from Florida over a 100-year period when evaluating 
all known tortoise populations or only those on public lands 
considering a variety of assumptions regarding survivorship, carrying 
capacity constraints, disease, etc. (Miller et al. 2001, pp. 12-26). 
The model results suggest that gopher tortoises have greater than 80 
percent chance of persisting in Florida over the next 100 years whether 
looking at all known populations or only those on public lands (Miller 
et al. 2001, pp. 27-28). Furthermore, they concluded that populations 
as small as 50 individuals can have conservation value under favorable 
conditions, but under less favorable habitat conditions populations 
larger than 250 individuals would be necessary to protect against 
extinction due to stochastic factors that increase hatchling and adult 
mortality (Miller et al. 2001, p. 28).
    The most recent modeling effort recognized the need to evaluate the 
viability of individual populations, rank populations most appropriate 
for in-situ protection, and determine if nonviable populations are more 
likely to contribute to conservation through augmentation or 
translocation (Tuberville et al. 2009, p. 9). All model scenarios 
resulted in a population decline of one to three percent per year, 
which varied as a function of habitat quality and location within the 
range (Tuberville et al. 2009, p. 17). Only modeled populations with at 
least 250 tortoises were able to persist for 200 years, which is 
substantially different than earlier model results.
    We can draw two very general conclusions from the models described 
above. First, gopher tortoise populations are likely to decline in the 
future under a wide array of demographic and environmental conditions 
that exist today. Second, gopher tortoise populations, although 
declining, and in some cases functionally extinct, will persist for 100 
to 200 years. The effect of these may be that tortoises will be seen 
for long periods of time throughout their range, not because their 
populations are stable or increasing, but because they are long-lived.
    Other efforts have focused on identifying the minimum area needed 
to support viable gopher tortoise populations. As described above, Cox 
(1987, pp. 30-31) used viability modeling to estimate that 50 
individual tortoises would persist and calculated that 10-20 ha (25-50 
ac) would be required to support a population of this size. Breininger 
et al. 1994 (p. 64) concluded that based on burrow densities on Kennedy 
Space Center, Florida, it would require 30-35 ha (74-86 ac) to support 
a population of 50 tortoises. Eubanks et al. 2002 (pp. 469-470) 
estimated that 50 tortoises would require 19-41 ha (47-101 ac) based on 
burrow densities and 25-81 ha (62-200 ac) based on home range size 
estimates. More recently McCoy and Mushinsky (2007, p. 1404-1405) used 
a variant of the density-area method to evaluate minimum patch size for 
the gopher tortoise. Where tortoise populations were spatially 
constrained (e.g., not able to disperse) tortoise populations were 
estimated to require about 100 ha (247 ac), and unconstrained 
populations required 143-250 ha (353-618 ac). Furthermore, if 
metapopulation dynamics are important to the long-term persistence of 
gopher tortoises, then the minimum patch size for unconstrained 
populations must be multiplied by the number of populations necessary 
to constitute a viable metapopulaton (e.g., 429-750 ha or 1,060-1,853 
ac for three populations in a metapopulation, etc.) (McCoy and 
Mushinsky 2007, p. 1405).
    The density of tortoises affects their social interactions and 
recent research has shown that when tortoise densities fall below 0.4 
individuals per ha (0.2 per ac), social interactions decrease 
dramatically because it takes too much energy to search for mates 
(Guyer 2010). This decrease in socialization is predicted to limit mate 
selection opportunities because male tortoises will not travel great 
distances to find females and, therefore, females will not be able to 
select among several potential mates. Viability of low-density 
populations is expected to decline due to adverse genetic impacts. 
Comparison of density data from other studies to the threshold data 
from this study indicates that many extant gopher tortoise populations 
are below the density threshold identified above. Successful 
conservation of the gopher tortoise will require active habitat 
management to provide opportunities for tortoise populations to exceed 
the threshold density necessary to ensure long-term persistence in 
longleaf pine forests (Guyer 2010).
    Recently, segmented regression models were developed to evaluate 
the relationship between area of habitat occupied by gopher tortoises 
and abundance of gopher tortoises to define how many individuals 
constitute a population and how much area is required for such a 
population. Data synthesized from 21 study sites in Alabama, Georgia, 
and Mississippi with varying tortoise population numbers indicated that 
an average gopher tortoise population consists of 444 burrows, covers 
755 ha (1,865 ac), and contains 240 tortoises (Styrsky et al. 2010, p. 
407). This average population contained a density of 0.3 tortoises per 
ha (0.1 per ac), which is below the threshold identified by Guyer 
(2010) for maintaining a persistent population. The authors noted that 
this average tortoise population was calculated based on a variety of 
existing landscapes that differed in their current management and past 
land use history and, therefore, did not represent what a population of 
tortoises might be in areas that were all managed with frequent fire 
and contained the uneven-aged trees of old-growth longleaf pine 
forests. Thus, it is likely that tortoises could persist on smaller 
parcels, but only if habitat were aggressively managed (Styrsky et al. 
2010, p. 408). Lack of prescribed fire or ineffective use of prescribed 
fire is known to be a substantial impediment to the restoration and 
maintenance of gopher tortoise habitat throughout much of its range. 
The model results depict a typical tortoise population as one occupying 
a large area. This seems congruent with existing habitat conditions 
that are reported throughout much of the tortoise's range. Therefore, 
the model results show that most existing conservation lands contain 
too few tortoises and too little suitable habitat to support persistent 
tortoise populations.

[[Page 45138]]

    Expert Opinion: Expert opinion is often used in combination with 
available data or in the absence of data to gather information and draw 
conclusions on wildlife resource issues (Lawrence et al. 1997, p. 1; 
Johnson and Gillingham 2004, pp. 1037-1038). In 2003, a group of 21 
individuals from academia, State, and Federal agencies and 
nongovernmental organizations with knowledge of gopher tortoise biology 
and conservation gathered to discuss the ecology, status, and 
management of the gopher tortoise (Smith et al. 2006, p. 1). In 
addition, the group completed a questionnaire that indicated about 86 
percent of the participants felt that the gopher tortoise was declining 
and 76 percent indicated the decline would require additional legal 
protection in the next 50 years. About 43 percent felt that local or 
regional extinction was likely within a 50-year period. Slightly less 
than five percent thought populations were increasing. Major threats 
identified by the participants included: Fire suppression or lack of 
growing-season fire, management of high-density pine forests, 
predation, road mortality, disease, translocation, and habitat 
degradation due to invasive plants. Participants felt that many 
populations on protected areas were too small (<100 individuals) to be 
viable long term (Smith et al. 2006, p. 327).

Summary of the Status of the Gopher Tortoise

    A wide variety of information is available on the number and 
density of gopher tortoises and their burrows from many areas 
throughout their range. These data resulted from numerous surveys/
censuses using a variety of methodologies ranging from one-time 
censuses to repeated surveys over several decades. The diversity of 
data poses a challenge when trying to evaluate the status of a species 
from a landscape perspective. For example, in some areas we have more 
data (e.g., Florida and in portions of the listed range), and we have 
higher confidence in drawing conclusions about status of tortoises in 
these areas. In other areas, where there is little or no data, our 
confidence in assessing the status of tortoises is lower. Because of 
disparities in the type of data collected, methodologies in collecting 
data, and differences in the scope of studies, it is not possible to 
simply combine datasets to evaluate the status of the gopher tortoise 
throughout its range. Instead, we considered each individual dataset in 
the context of all other best available science to form general 
conclusions about the status of the gopher tortoise.
    In the western portion of their range, gopher tortoise populations 
are small and occur in fragmented habitat. The largest and most 
substantial gopher tortoise populations in the western portion of its 
range occur on the De Soto National Forest in southern Mississippi. 
Long-term monitoring here indicates a decline in population sizes, a 
tendency towards adult-dominated populations, and a lack of, or very 
low, recruitment. Results of smaller-scale surveys of forest lands in 
Mississippi and public and private lands in Louisiana are largely 
consistent with findings on the De Soto National Forest. There are no 
known populations large enough (e.g., > 250 individuals) to persist 
long-term based on projections resulting from recent modeling efforts.
    The gopher tortoise is more widespread and abundant in parts of the 
eastern portion of its range, particularly southern Georgia and central 
and northern Florida. Long-term monitoring data indicate that many 
populations have declined and most are relatively small and fragmented. 
Smaller-scale, short-term or one-time surveys throughout the unlisted 
portion of the range indicate that tortoise populations typically occur 
in fragmented and degraded habitat, are small, and