Endangered and Threatened Wildlife and Plants; 90-Day Finding on a Petition to List the Northern Leopard Frog (Lithobates [=Rana] pipiens) in the Western United States as Threatened, 31389-31401 [E9-15539]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 74, Number 125 (Wednesday, July 1, 2009)]
[Proposed Rules]
[Pages 31389-31401]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E9-15539]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[FWS-R2-ES-2009-0030; 92210-1111-FY08-B2]


Endangered and Threatened Wildlife and Plants; 90-Day Finding on 
a Petition to List the Northern Leopard Frog (Lithobates [=Rana] 
pipiens) in the Western United States as Threatened

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of a 90-day petition finding and initiation of status 
review.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a 
90-day finding on a petition to list the western U.S. population of the 
northern leopard frog (Lithobates [=Rana] pipiens) as threatened under 
the Endangered Species Act of 1973, as amended (Act). Following a 
review of the petition, we find that the petition presents substantial 
scientific or commercial information indicating that listing the 
western U.S. population of northern leopard frog may be warranted. 
Therefore, with the publication of this notice, we are initiating a 
status review of the species, and we will issue a 12-month finding to 
determine if listing the species throughout all or a significant 
portion of its range is warranted. To ensure that the status review of 
the northern leopard frog is comprehensive, we are soliciting 
scientific and commercial information and other information regarding 
this species.

DATES: We made the finding announced in this document on July 1, 2009. 
To allow us adequate time to conduct a status review, we request that 
information be submitted on or before August 31, 2009.

ADDRESSES: You may submit comments by one of the following methods:
     Federal eRulemaking Portal: https://www.regulations.gov. 
Follow the instructions for submitting comments.
     U.S. mail or hand-delivery: Public Comments Processing, 
Attn: FWS-R2-ES-2009-0030; Division of Policy and Directives 
Management; U.S. Fish and Wildlife Service; 4401 N. Fairfax Drive, 
Suite 222; Arlington, VA 22203.
    We will post all information received on https://www.regulations.gov. This generally means that we will post any 
personal information you provide us (see the Information Solicited 
section below for more details).

FOR FURTHER INFORMATION CONTACT: Steven L. Spangle, Field Supervisor,

[[Page 31390]]

Arizona Ecological Services Office, U.S. Fish and Wildlife Service, 
2321 West Royal Palm Drive, Suite 103, Phoenix, AZ 85021; telephone 
602-242-0210; facsimile 602-242-2513. If you use a telecommunications 
device for the deaf (TDD), please call the Federal Information Relay 
Service (FIRS) at 800-877-8339.

SUPPLEMENTARY INFORMATION:

Information Solicited

    When we make a finding that a petition presents substantial 
information indicating that listing a species may be warranted, we are 
required to promptly commence a review of the status of that species. 
To ensure that the status review is complete and based on the best 
available scientific and commercial information, we are soliciting 
information concerning the status of the northern leopard frog. We 
request information from the public, other concerned governmental 
agencies, Native American Tribes, the scientific community, industry, 
or any other interested parties concerning the status of the northern 
leopard frog. We are seeking information regarding:
    (1) The historical and current status and distribution of the 
northern leopard frog, its biology and ecology, and ongoing 
conservation measures for the species and its habitat, and threats to 
the species and its habitat;
    (2) information relevant to the factors that are the basis for 
making a listing determination for a species under section 4(a) of the 
Endangered Species Act of 1973, as amended (Act) (16 U.S.C. 1531 et 
seq.), which are:
    (a) The present or threatened destruction, modification, or 
curtailment of the species' 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 and threats to the species or its habitat; and
    (3) its taxonomy (particularly genetics of the western U.S. 
population and of the convergence zone of the eastern and western 
haplotypes in Wisconsin and Ontario, Canada).
    If we determine that listing the northern leopard frog is 
warranted, it is our intent to propose critical habitat to the maximum 
extent prudent and determinable at the time we would propose to list 
the species. Therefore, with regard to areas within the geographical 
range currently occupied by the northern leopard frog, we also request 
data and information on what may constitute physical or biological 
features essential to the conservation of the species, where these 
features are currently found, and whether any of these features may 
require special management considerations or protection. In addition, 
we request data and information regarding whether there are areas 
outside the geographical area occupied by the species which are 
essential to the conservation of the species. Provide specific 
information as to what, if any, critical habitat should be proposed for 
designation if the species is proposed for listing, and why the 
suggested critical habitat meets the requirements of the Endangered 
Species Act of 1973, as amended (Act; 16 U.S.C. 1531 et seq.).
    Please note that submissions merely stating support or opposition 
to the action under consideration without providing supporting 
information, although noted, will not be considered in making a 
determination, as section 4(b)(1)(A) of the Act directs that 
determinations as to whether any species is a threatened or endangered 
species shall be made ``solely on the basis of the best scientific and 
commercial data available.'' At the conclusion of the status review, we 
will issue the 12-month finding on the petition, as provided in section 
4(b)(3)(B) of the Act.
    You may submit your information concerning this status review by 
one of the methods listed in the ADDRESSES section.
    If you submit information via https://www.regulations.gov, your 
entire submission--including any personal identifying information--will 
be posted on the website. If your submission is made via a hardcopy 
that includes personal identifying information, you may request at the 
top of your document that we withhold this information from public 
review. However, we cannot guarantee that we will be able to do so. We 
will post all hardcopy submissions on https://www.regulations.gov. 
Please include sufficient information with your comments to allow us to 
verify any scientific or commercial information you include.
    Information and materials we receive, as well as supporting 
documentation we used in preparing this finding, will be available for 
public inspection on https://www.regulations.gov, or by appointment, 
during normal business hours, at the U.S. Fish and Wildlife Service, 
Arizona Ecological Services Office (see FOR FURTHER INFORMATION 
CONTACT).

Background

    Section 4(b)(3)(A) of the Act requires that we make a finding on 
whether a petition to list, delist, or reclassify a species presents 
substantial scientific or commercial information indicating that the 
petitioned action may be warranted. We are to base this finding on 
information contained in the petition, supporting information submitted 
with the petition, and information otherwise available in our files. To 
the maximum extent practicable, we are to make this finding within 90 
days of receipt of the petition, and publish our notice of this finding 
promptly in the Federal Register.
    Our standard for substantial scientific or commercial information 
within the Code of Federal Regulations (CFR) with regard to a 90-day 
petition finding is ``that amount of information that would lead a 
reasonable person to believe that the measure proposed in the petition 
may be warranted'' (50 CFR 424.14(b)). If we find that substantial 
scientific or commercial information was presented, we are required to 
promptly commence a status review of the species.
    We received a petition dated June 5, 2006, from the Center for 
Native Ecosystems, Biodiversity Conservation Alliance, Defenders of 
Black Hills, Forest Guardians, Center for Biological Diversity, The Ark 
Initiative, Native Ecosystems Council, Rocky Mountain Clean Air Action, 
and Jeremy Nichols requesting that the northern leopard frog 
(Lithobates (=Rana) pipiens) occurring in the western United States 
(Arizona, California, Colorado, Idaho, Iowa, Minnesota, Missouri, 
Montana, Nebraska, Nevada, New Mexico, North Dakota, Oregon, South 
Dakota, Texas, Utah, Washington, and Wyoming) be listed as a threatened 
distinct population segment (DPS) under the Act. The petition clearly 
identified itself as such and included the requisite identification 
information for the petitioners, as required in 50 CFR 424.14(a). In 
response to the petitioners' request, we sent a letter to the 
petitioners dated August 7, 2006, explaining that we would not be able 
to address their petition at that time. The reason for this delay was 
that responding to court orders and settlement agreements for other 
listing actions required nearly all of our listing funding. Delays in 
responding to the petition have continued due to higher priority 
actions, until funding recently became available to respond to this 
petition.
    In reviewing the petition, there were two issues for which the 
Service requested clarification from the

[[Page 31391]]

petitioners. We were petitioned to list the population west of the 
Mississippi River and the Great Lakes region in the United States and 
south of the international boundary between the United States and 
Canada. However, the petition map does not show Wisconsin as a part of 
the petition, and the status of the species is not mentioned in that 
State. However, Wisconsin is located west of the Great Lakes region. 
Therefore, we requested that the petitioners clarify whether they 
intended to include or exclude Wisconsin from the petitioned DPS. The 
Service also sought clarification as to whether the petitioners were 
requesting we review only the western U.S. population of the northern 
leopard frog as a DPS or if they were also requesting us to consider 
listing the entire species or a significant portion of the range of the 
species. The petitioners responded to our clarification request in a 
letter dated February 8, 2008, requesting we review whether Wisconsin 
should be included in the western U.S. population of the northern 
leopard frog. In addition, the petitioners clarified that, if we find 
that listing the western U.S. population of northern leopard frogs as a 
DPS is not warranted, we review whether listing the entire species is 
warranted because of threats in a significant portion of its range.

Previous Federal Action

    No previous Federal action has been taken on the northern leopard 
frog. The northern leopard frog has no Federal regulatory status under 
the Act.

Species Information

    The northern leopard frog is in the family Ranidae (Frost et al. 
2008, pp. 7-8), the true frogs, and is 1 of about 29 species within the 
genus Lithobates that occur in North America (Lannoo 2005, p. 371). The 
northern leopard frog is a smooth-skinned green, brown, or sometimes 
yellow-green frog covered with large, oval dark spots, each of which is 
surrounded by a lighter halo or border (Stebbins 2003, pp. 234-235). 
Adult snout-vent lengths range from 2 to 4.5 inches (5 to 11 
centimeters) (Stebbins 2003, p. 234). Citations within the petition 
provide a more detailed description of the northern leopard frog 
(Baxter and Stone 1985, pp. 41-42; Hammerson 1999, pp. 145-146; Patla 
and Keinath 2005, p. 13).
    The northern leopard frog requires a mosaic of habitats, which 
includes overwintering, breeding, and upland post-breeding habitats, as 
well as habitat linkages, to meet the requirements of all of its life 
stages (Pope et al. 2000, p. 2505; Smith 2003, pp. 6-15). Northern 
leopard frogs breed in a variety of aquatic habitats that include slow-
moving or still water along streams and rivers, wetlands, permanent or 
temporary pools, beaver ponds, and human-constructed habitats such as 
earthen stock tanks and borrow pits (Rorabaugh 2005, p. 572). Breeding 
areas typically do not contain predaceous fish or other predators 
(Merrell 1968, p. 275; Smith 2003, pp. 19-21), and emergent vegetation 
such as sedges and rushes are thought to be important features of 
breeding and tadpole habitats (Smith 2003, pp. 8-9).
    Sub adult northern leopard frogs typically migrate to feeding sites 
along the borders of larger, more permanent bodies of water (Merrell 
1970, p. 49). Recently metamorphosed frogs will move up and down 
drainages and across land in an effort to disperse from breeding areas 
(Seburn et al. 1997, p. 69); however, in some areas of the western 
United States, subadults may remain in the breeding habitat within 
which they metamorphosed (Smith 2003, p. 10). In addition to the 
breeding habitats, adult northern leopard frogs require stream, pond, 
lake, and river habitats for overwintering and upland habitats adjacent 
to these areas for summer feeding. In summer, adults and juveniles 
commonly feed in open or semi-open wet meadows and fields with shorter 
vegetation, usually near the margins of water bodies, and seek escape 
cover underwater. During winter, northern leopard frogs are found 
inactive underwater on the bottom of deeper streams or waters that do 
not freeze to the bottom and are well-oxygenated (Stewart et al. 2004, 
p. 72).
    As soon as males leave overwintering sites, they travel to breeding 
ponds and call in shallow water (Smith 2003, p. 13). Male frogs attract 
females by calling from specific locations within a breeding pond, with 
several males typically calling together to form a chorus (Merrell 
1977, p. 7). Eggs are typically laid within breeding habitats, two to 
three days following the onset of chorusing (Corn and Livo 1989, p. 5). 
Eggs are laid and larvae typically develop in shallow, still water that 
is exposed to sunlight. Eggs are usually attached to vegetation, just 
below the water surface. Egg masses may include several hundred to 
several thousand eggs (Lannoo 2005, p. 371) and are deposited in a 
tight, oval mass (Rorabaugh 2005, p. 572). Time to hatching is 
correlated with temperature and ranges from 2 days at 81 degrees 
Fahrenheit (27 degrees Centigrade) to 17 days at approximately 53 
degrees Fahrenheit (12 degrees Centigrade) (Nussbaum et al. 1983, p. 
182).
    Northern leopard frog tadpoles are predominantly generalist 
herbivores, typically eating attached and free-floating algae (Hoff et 
al. 1999, p. 215), however they may feed on animal material (Hendricks 
1973, p. 100). Adult and subadult frogs are generalist insectivores 
(Merrell 1977, p. 15; Smith 2003, p. 12). Prey includes insects, 
spiders, mollusks, and crustaceans.
    A genetic study published in 2004 using mitochondrial DNA (mtDNA) 
reports that the northern leopard frog is split into two populations 
containing discrete eastern and western mtDNA markers (haplotypes), 
with the Mississippi River and Great Lakes region dividing the 
geographic ranges (Hoffman and Blouin 2004, p. 152). Results of the 
study indicate that the two populations have been isolated for 
approximately 2 million years, except for a small zone of likely 
secondary contact in Ontario, Canada.
    The northern leopard frog historically ranged from Newfoundland and 
southern Quebec, south through New England to West Virginia, west 
across the Canadian provinces and northern and central portions of the 
United States to British Columbia, Oregon, Washington, and northern 
California, and south to Arizona, New Mexico, and extreme western Texas 
(Rorabaugh 2005, p. 570). However, since the 1970s the northern leopard 
frog has experienced significant declines throughout its range, 
particularly in the western United States and Canada (Corn and Fogelman 
1984, p. 147; Hayes and Jennings 1986, p. 491; Clarkson and Rorabaugh 
1989, p. 534; Weller and Green 1997, p. 323; Casper 1998, p. 199; 
Leonard et al. 1999, p. 51; Smith 2003, pp. 4-6). The species tends to 
become less abundant the further west one proceeds. The northern 
leopard frog is now considered uncommon in a large portion of its range 
in the western United States, and declines of the species have been 
documented in most western States (Rorabaugh 2005, pp. 570-571; Smith 
2003, pp. 4-6; Stebbins 2003, p. 235).

Distinct Population Segment

    We consider a species for listing under the Act if available 
information indicates such an action might be warranted. ``Species'' is 
defined in section 3 of the Act to include any subspecies of fish or 
wildlife or plants, and any distinct vertebrate population segment of 
fish or wildlife that interbreeds when mature (16 U.S.C. 1532 (16)). 
We, along with the National Marine Fisheries Service (now the National 
Oceanic and Atmospheric Administration--Fisheries), developed

[[Page 31392]]

the Policy Regarding the Recognition of Distinct Vertebrate Population 
Segments (DPS Policy) (February 7, 1996; 61 FR 4722) to help us in 
determining what constitutes a DPS. The policy identifies three 
elements that we are to consider in making a DPS determination. These 
elements include: (1) The discreteness of the population segment in 
relation to the remainder of the species to which it belongs; (2) the 
significance of the population segment to the species to which it 
belongs; and (3) the population segment's conservation status in 
relation to the Act's standards for listing. If we determine that a 
population segment meets the discreteness and significance standards, 
then the level of threat to that population segment is evaluated, based 
on the five listing factors established by the Act, to determine 
whether listing the DPS as either threatened or endangered is 
warranted.

Discreteness

    Citing the Services' DPS policy (61 FR 4722), the petition asserts 
that the western U.S. population of the northern leopard frog may 
qualify as a DPS based on discreteness. The DPS policy states that a 
population may be considered discrete if it satisfies either one 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 that are 
significant in light of section 4(a)(1)(D) of the Act.
    The petitioners assert that the western U.S. population of the 
northern leopard frog is markedly separated and geographically isolated 
from the eastern population, based on genetic differences and analyses 
of haplotypes (Hoffman and Blouin 2004, pp. 145-159). A haplotype is a 
set of closely linked genetic markers that are present on one 
chromosome and tend to be inherited together. The petitioners cited 
Hoffman and Blouin (2004) to support their assertion that the western 
U.S. population of the northern leopard frog is discrete. The petition 
states that there is a marked separation of western populations from 
eastern populations based on the following measures from Hoffman and 
Blouin (2004, pp. 145-159): (1) Eastern and western haplotypes have 
been differentiated for approximately 2 million years; (2) eastern and 
western haplotypes are divided by the Mississippi River and Great 
Lakes; and (3) there is an average sequence divergence of 3 percent 
between eastern and western haplotypes.
    The only area of potential overlap between the eastern and western 
population of northern leopard frog occurs north of the Great Lakes 
region in Ontario (Hoffman and Blouin 2004). Only one population 
(located near Attawapiskat, Ontario) appears to be in an area of 
geographic convergence of eastern and western haplotypes. This 
population is located north of the Great Lakes region, and contains 
both eastern and western haplotypes, likely due to secondary contact 
during the current interglacial period. Thus, it represents the maximum 
extent of postglacial eastward expansion of the western haplotypes and 
westward expansion of the eastern haplotypes (Hoffman and Blouin 2004, 
p. 152). Several studies on both plants and animals have documented a 
genetic discontinuity associated with the Mississippi River region 
(Fontanella et al. 2007, p. 1063).
    Thus, based on the Hoffman and Blouin (2004) genetic analyses, the 
petitioners believe that the western population is not only markedly 
separated from the eastern population in relation to its genetics, but 
clearly geographically isolated and discrete in relation to the eastern 
northern leopard frog population. The petition asserts that the genetic 
differentiation between the haplotypes of eastern and western northern 
leopard frogs, which was found to average 3 percent, is considered to 
be relatively high for an intraspecific comparison (Hoffman and Blouin 
2004, p. 152). Hoffman and Blouin (2004, p. 152) explain that this 
amount of genetic variation is comparable to that found between some 
recognized species of frogs in the family Ranidae (ranid frogs) such as 
R. pretiosa-R. luteiventris, about 3 percent (K. Monsen and M.S. 
Blouin, unpubl. data). In addition, Jaeger et al. (2001, pp. 339-354) 
found that there was about 4.7 percent genetic variation between R. 
yavapaiensis and R. onca, and approximately 4.9 percent genetic 
variation between R. blairi and R. berlanderi. However, the purpose of 
the Hoffman and Blouin (2004) study was not to undertake taxonomic 
revisions, but to better understand the evolutionary history of the 
northern leopard frog; as such, the authors do not recommend splitting 
the northern leopard frog into two distinct species based upon their 
analyses. The authors do recommend that further work be conducted on 
the taxonomic status of the two northern leopard frog populations to 
further understand their initial findings.
    As stated above, a population may be considered discrete if it 
satisfies either one of the discreteness conditions listed in the 
policy. The second condition is that the petitioned population be 
delimited by international governmental boundaries within which 
differences in control of exploitation, management of habitat, 
conservation status, or regulatory mechanisms exist that are 
significant in light of section 4(a)(1)(D) of the Act. Section 
4(a)(1)(D) of the Act discusses the adequacy of existing regulatory 
mechanisms in the Act's ``5-factor'' analysis for determining whether a 
species is threatened or endangered. In assessing a population for 
discreteness based on delimitation by international governmental 
boundaries, we focus specifically on whether the factors named above 
are significantly different between the two countries because of the 
inadequacy of existing regulatory mechanisms.
    The petitioners state that the western U.S. population of the 
northern leopard frog is delimited by international government 
boundaries, namely between Canada and the United States (Smith 2003, p. 
5). The petitioners reference Seburn and Seburn (1998, pp. 4-11) in 
providing information documenting significant declines in northern 
leopard frog populations in British Columbia, Alberta, Manitoba, 
southern Northwest Territories, Saskatchewan, and western Ontario. In 
British Columbia, only one northern leopard frog population is known to 
remain (Seburn and Seburn 1998, p. 10). The species has also 
disappeared from much of its range in Alberta since 1979 (Seburn and 
Seburn 1998, p. 10). In Manitoba and Saskatchewan, the northern leopard 
frog experienced significant declines in the 1970s and many dead and 
dying frogs were found (Seburn and Seburn 1998, p. 9). Less is known 
about the status of the frog in the Northwest Territories, but the 
species is reported from only nine sites, all of which are fragmented 
and isolated from populations further south in Alberta and Manitoba 
(Seburn and Seburn 1998, pp. 6, 8). Declines have also occurred in 
northern and southwestern Ontario (Seburn and Seburn 1998, p. 10; 
Hecnar 1997, p. 9).
    The petition claims that habitat declines throughout the Canadian 
range of the northern leopard frog have also been significant (Seburn 
and Seburn 1998, p. 13). The decline is thought to be related to the 
loss of wetland habitat throughout Canada. Approximately 65 to 80 
percent of historical wetlands in

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Canada have been drained, mostly for agriculture and urban development 
(Natural Resources Canada 2004, p. 1), and are considered to be an 
endangered habitat (Findlay and Houlahan 1997, p. 1001). Seburn and 
Seburn (1998, p. 13) describe this loss of habitat as occurring 
throughout all of the provinces, with southern Saskatchewan having 59 
percent of its wetland basins and 78 percent of its wetland margins 
affected by agriculture.
    The Committee on the Status of Endangered Wildlife in Canada 
determines the national status of wild species, subspecies, varieties, 
and nationally significant populations that are considered to be at 
risk in Canada (Seburn and Seburn 1998, p. vi). The British Columbia 
population (Southern Mountain Region) is listed as Endangered under the 
Species at Risk Act, which provides protection similar to that of the 
Endangered Species Act in the United States. The northern leopard frog 
is also on the provincial Red List and is listed as ``Endangered'' 
under British Columbia's Wildlife Act, and as ``Threatened'' under 
Alberta's Wildlife Act (Alberta Northern Leopard Frog Recovery Team 
2005, p. 1). However, the provincial Wildlife Acts do not prohibit take 
of listed species or provide a means by which agencies must ensure 
their actions are not jeopardizing the species. Neither Saskatchewan 
nor Ontario affords the northern leopard frog any specific protection 
(Seburn and Seburn 1998, p. 7). In the United States, northern leopard 
frog protection and collection policies are implemented by a wide 
variety of Federal and State agencies. States predominately control the 
management, collection, and importation of the species throughout its 
range, while Federal land management agencies manage habitat for the 
species, particularly throughout the western portion of its range. 
Therefore, because of differences in regulatory mechanisms between the 
United States and Canada, we find there is evidence to suggest that the 
international boundary with Canada may be significant in terms of 
section 4(a)(1)(D) of the Act.
    The Service's DPS policy requires that only one of the discreteness 
criteria be satisfied in order for a population of a vertebrate species 
to be considered discrete. After reviewing the information provided in 
the petition, we believe that the petition presents substantial 
information that the northern leopard frog western U.S. population may 
be physically isolated from northern leopard frogs in the eastern 
United States and may be genetically distinct. In addition, it presents 
substantial information that differences in regulatory mechanisms 
between the United States and Canada may be significant in terms of 
section 4(a)(1)(D) of the Act. Therefore, we find that the petition 
presents substantial information indicating that the northern leopard 
frog in the western United States may satisfy the discreteness element 
of the DPS policy.

Significance

    If we determine that a population meets the DPS discreteness 
element, we then consider if it also meets the DPS significance 
element. The DPS policy (61 FR 4722) states that if a population 
segment is considered discrete under one or more of the discreteness 
criteria, its biological and ecological significance will be considered 
in light of Congressional guidance that the authority to list DPSs be 
used ``sparingly'' while encouraging the conservation of genetic 
diversity. In making this determination, we consider available 
scientific evidence of the discrete population's importance to the 
taxon to which it belongs. Since precise circumstances are likely to 
vary considerably from case to case, the DPS policy does not describe 
all of the classes of information that might be used in determining the 
biological and ecological importance of a discrete population. However, 
the DPS policy does provide four possible reasons why a discrete 
population may be significant. As specified in the DPS policy (61 FR 
4722), this consideration of significance may include, but is not 
limited to, the following:
    (1) Persistence of the discrete population segment in an ecological 
setting unusual or unique to the taxon;
    (2) Evidence that loss of the discrete population segment would 
result in a significant gap in the range of a taxon;
    (3) Evidence that the discrete population segment represents the 
only surviving natural occurrence of a taxon that may be more abundant 
elsewhere as an introduced population outside its historic range; or
    (4) Evidence that the discrete population segment differs markedly 
from other populations of the species in its genetic characteristics.
    The petition asserts that the western U.S. population of the 
northern leopard frog, being discrete from other populations, also 
meets the significance element of the DPS policy for two of the four 
reasons above: (1) Loss of the population would create a significant 
gap in the range of the taxon and (2) the population differs markedly 
from the eastern population based on genetic characteristics.
    The petitioners present three reasons why the loss of the western 
U.S. population would represent a significant gap in the range of the 
species. First, it would represent an approximately 50 percent loss in 
the historical range of the species. Second, the loss of the western 
U.S. population would leave only frogs in western Canada to represent 
the western population of northern leopard frog, thereby creating a 
significant gap in the range. Third, loss of the western U.S. 
population would create an irreversible gap in the range of the species 
because the Mississippi River and Great Lakes are barriers to dispersal 
by the eastern population into the western United States.
    According to the petition, the western U.S. portion of the range in 
19 western and Midwestern States west of the Mississippi River and the 
Great Lakes region constitutes approximately 50 percent of the 
historical overall range and nearly 70 percent of the western 
population in the United States and Canada (Rorabaugh 2005, p. 571). 
The petition states that the species' range has declined in almost 
every State that it inhabits in the western United States.
    The most recent summary of distributional and abundance patterns of 
the northern leopard frog is from Rorabaugh (2005, pp. 570-577), which 
documents a substantial contraction of the species' range, especially 
in the western two-thirds of the United States, where widespread 
extinctions have occurred. Information provided in the petition 
indicates that the species is declining, considered rare, or locally 
extinct from historical locations in Arizona, California, Colorado, 
Idaho, Iowa, Minnesota, Missouri, Montana, Nebraska, Nevada, New 
Mexico, North Dakota, Oregon, Texas, Utah, Washington, Wisconsin, and 
Wyoming (Hayes and Jennings 1986, p. 491; Stebbins and Cohen 1995, p. 
220; Johnson and Batie 1996; Bowers et al. 1998, p. 372; Casper 1998, 
p. 199; Lannoo 1998, p. xvi; Mossman et al. 1998, p. 198; Smith 2003, 
pp. 4-6; McCleod 2005, pp. 292-294; Rorabaugh 2005, p. 571; Smith and 
Keinath 2004, pp. 57-60). The species is possibly extirpated from 
almost 100 percent of its historical range in Texas, California, 
Oregon, and Washington (Stebbins and Cohen 1995, p. 220; McAllister et 
al. 1999, p. 15; Stebbins 2003, p. 235). The status of the frog is not 
clear in South Dakota. Smith (2003, p. 39) states that, although 
northern leopard frogs may still be common in the Black Hills, surveys 
are incomplete, monitoring does not occur, and no habitat delineation 
has been completed for the species. The

[[Page 31394]]

petitioners estimate a decline of at least 35 percent based on 
estimates of wetland loss in the State. In summary, the petition 
presents substantial information that the northern leopard frog is 
declining in the western United States, that such a large geographic 
area may represent a significant part of the range, and that loss of 
the western U.S. population may create a significant gap in the range 
of the species.
    The petition also argues that the western U.S. population is 
isolated, peripheral and genetically different, and that it is 
important to the survival, evolution, and conservation of the species. 
The petitioners argue that the western U.S. population of the northern 
leopard frog is significant because it is markedly different from the 
eastern population based on genetic characteristics and because its 
loss would represent a significant gap in the range of the species. 
Citing Hoffman and Blouin (2004, p. 152), the petition presents 
information that the level of mtDNA genetic variation between the 
eastern and western populations of 3 percent is relatively high for an 
intraspecific comparison of ranid frogs, akin to the genetic difference 
between the Columbia spotted frog (Rana luteiventris) and the Oregon 
spotted frog (R. pretiosa). The western population also differs from 
the eastern population in having significantly lower diversity of 
genetic materials (nucleotides) (Hoffman and Blouin 2004, p. 151).
    Based on the significant gap in the species' range that potentially 
would be created by the loss of the western U.S. population and the 
potential genetic differences, we find that the petition presents 
substantial information that the western U.S. population of the 
northern leopard frog may satisfy the significance element of the DPS 
policy.

DPS Conclusion

    We have reviewed the information presented in the petition, and 
have evaluated the information in accordance with 50 CFR 424.14(b). In 
a 90-day finding, the question is whether a petition presents 
substantial information that the petitioned action may be warranted. 
Based on our review, we find that the petition, supported by 
information in our files, presents substantial scientific or commercial 
information to indicate that the western U.S. population of the 
northern leopard frog may be a DPS based on genetic evidence. The 
information presented in the petition presents substantial scientific 
or commercial information to demonstrate that the western U.S. 
population of the northern leopard frog may be discrete from the 
eastern U.S. population. Further, the petition also presents 
substantial information that the western U.S. population of the 
northern leopard frog may be significant to the taxon as a whole. Thus, 
the western U.S. population of the northern leopard frog may be a 
listable entity under the Act as a DPS. To meet the third element of 
the DPS policy, we evaluate the level of threat to the DPS based on the 
five listing factors established by the Act. We thus proceeded with an 
evaluation of information presented in the petition, as well as 
information in our files, to determine whether there is substantial 
scientific or commercial information indicating that listing this 
population may be warranted. Our threats analysis and conclusion 
follow.

Threats Evaluation

    Section 4 of the Act (16 U.S.C. 1533) and its implementing 
regulations (50 CFR 424) set forth the procedures for adding species to 
the Federal Lists of Endangered and Threatened Wildlife and Plants. A 
species, subspecies, or distinct population segment of vertebrate taxa 
may be determined to be endangered or threatened due to one or more of 
the five factors described in section 4(a)(1) of the Act: (A) The 
present or threatened destruction, modification, or curtailment of 
habitat or range; (B) overutilization for commercial, recreational, 
scientific, or educational purposes; (C) disease or predation; (D) the 
inadequacy of existing regulatory mechanisms; or (E) other natural or 
manmade factors affecting its continued existence.
    In making this 90-day finding, we evaluated whether information 
regarding the northern leopard frog as presented in the petition and 
other information available in our files is substantial, thereby 
indicating that the petitioned action may be warranted. Our evaluation 
of this information is presented below.

A. Present or Threatened Destruction, Modification, or Curtailment of 
the Species' Habitat or Range

    The petitioners assert that loss and degradation of habitat has 
been widespread and has affected the species in every State in the 
western United States in which the northern leopard frog is 
historically known to have occurred (Maxell 2000, p. 15; Hitchcock 
2001, pp. 64-66; Rorabaugh 2005, p. 576; Clarkson and Rorabaugh 1989, 
p. 535; Smith 2003, p. 26-31). Habitat loss and degradation is reported 
to be the primary threat to all ranid frogs in the western United 
States (Bradford 2005, p. 923) and a principal threat to northern 
leopard frogs in the western United States (Smith 2003, p. 4; Rorabaugh 
2005, p. 571). The petition asserts that the northern leopard frog is 
threatened with loss and degradation of habitat due to livestock 
grazing, agricultural development, urban development, oil and gas 
development, road development, poor forestry practices, groundwater 
pumping, mining, and invasive species.
    The petitioners claim that western U.S. northern leopard frog 
populations are vulnerable to local extirpation from the effects of 
livestock grazing (Maxell 2000, pp. 15-16; Smith 2003, p. 30). 
Specifically, the petition states that livestock grazing may result in 
the trampling of individual frogs (Maxell 2000, p. 15; Smith 2003, p. 
30) and may trample soils around aquatic habitats, thereby decreasing 
infiltration of water into the soil, increasing soil erosion, and 
contributing to stream channel down cutting (Kauffman and Kreuger 1984, 
pp. 432-434; Belskey et al. 1999, pp. 419-431). These impacts could 
hinder or prevent movements of northern leopard frogs by reducing and 
eliminating riparian vegetation that provides cover. Impacts to water 
quality through increased sedimentation (Belskey et al. 1999, pp. 420-
424) may reduce the depth of breeding ponds or overwintering habitats, 
increase water temperatures, and create favorable environments for 
diseases and parasites known to contribute to mortality in northern 
leopard frogs (Maxell 2000, pp. 15-16; Johnson and Lunde 2005, pp. 133-
136; Ouellet et al. 2005, p. 1435).
    The petitioners note that livestock grazing and associated actions 
are specifically identified as being responsible for habitat loss and 
degradation and negatively affecting northern leopard frog populations 
at some sites in Arizona (Clarkson and Rorabaugh 1989, p. 535; Sredl 
1998, pp. 573-574), California (California Department of Fish and Game 
2008), Idaho (Idaho Department of Fish and Game 2005, Appendix F), 
Montana (Maxell 2000, p. 15), Nevada (Hitchcock 2001, p. 66), North 
Dakota (Euliss, Jr. and Mushet 2004, p. 82), and South Dakota (Smith 
2003, p. 27). In addition, the petition lists approximately 281 grazing 
allotments on Forest Service National System Lands in Colorado, 
Nebraska, New Mexico, South Dakota, and Wyoming that the U.S. Forest 
Service (Forest Service) determined would adversely impact northern 
leopard frogs. We did not verify each of these allotment 
determinations, but the Forest Service Region 2 website (accessed April 
24, 2008) does contain documents noting adverse effect determinations 
for the northern leopard

[[Page 31395]]

frog resulting from livestock grazing (for instance, see Forest Service 
2005a and Forest Service 2003 as cited in the petition). Information in 
our files also indicates that leopard frogs may be able to persist with 
well-managed livestock grazing (Hitchcock 2001, p. 62; Service 2007, 
pp. 32-34).
    The petitioners state that agricultural development may directly 
destroy northern leopard frog habitat due to de-watering or indirectly 
through the introduction of contaminants and invasive species into 
habitats (Leonard et al. 1999, p. 58; Leja 1998, pp. 345-353; Rorabaugh 
2005, p. 576). The petitioners provide information indicating that 
agricultural development has occurred throughout the range of the 
northern leopard frog, but particularly in the Midwestern States (Leja 
1998, p. 349). The petition presents 1990 data that indicate that 
greater than 90 percent of the total land area in Iowa, Nebraska, North 
Dakota, and South Dakota is used for agricultural purposes (Demographia 
2000). Agricultural development can result in modification of river 
valley habitat, including draining of wetlands, channelization and 
damming of rivers, and the development of irrigation systems (Wang et 
al. 1997, p. 11; Findlay and Houlahan 1997, p. 1001), all of which may 
modify breeding, overwintering, and dispersal habitat for northern 
leopard frogs.
    The petition presents information on urbanization of the western 
United States and the resulting loss of northern leopard frog habitat 
throughout the western States (Hitchcock 2001, pp. 64-66). The 
petitioners provide information from the U.S. Census Bureau (2006) that 
the only State within the range of the northern leopard frog in the 
western United States that is not gaining human population is North 
Dakota. Projected population growth is expected to result in increased 
needs for water (surface diversions and groundwater pumping) to support 
growth (Deacon et al. 2007, p. 688). This could decrease water 
availability for northern leopard frogs and thereby impact the amount 
and extent of habitat for northern leopard frogs.
    The petitioners also discuss how oil and gas development threatens 
the northern leopard frog and its habitat in the western United States. 
The petition states that the Bureau of Land Management (BLM) and Forest 
Service have determined that the drilling and maintenance of wells, 
related construction of roads, and disposal of wastes resulting from 
oil and gas development will negatively affect the northern leopard 
frog. The petitioners argue that oil and gas development in the Black 
Hills of South Dakota, northern Idaho, Wyoming, and the Arkansas River 
drainage in Colorado are reported to have disturbed habitat, altered 
hydrology, introduced contaminants into water, and reduced the 
availability of water for the frog. Coal-bed methane development is 
currently occurring primarily in Wyoming, but the petitioners note that 
other western States may be impacted in the future. Impacts associated 
with coal-bed methane development include road-related mortality, 
discharge of contaminated water into breeding ponds, loss of spring 
flows related to groundwater withdrawals, discharge of extremely cold 
water into breeding habitats, and discharge of water containing 
nonnative predatory fish in these same areas (Allan 2002, pp. 5-8; Gore 
2002, pp. 1-14; Noss and Wuethner 2002, pp. 1-20). Mining and oil and 
gas development may also lead to contamination of habitats (Smith 2003, 
pp. 26, 31; Spengler 2002, pp. 7-26).
    The petition presents information and cites references indicating 
that roads may pose barriers to dispersal and contribute nonpoint 
source pollution (Smith 2003, pp. 27, 38; Maxell 2000, p. 25; Fahrig et 
al. 1995, pp. 177-182). Road building is often tied to other activities 
such as oil and gas, urban, and agricultural development, so the 
indirect effects of road construction, maintenance, and use could 
negatively affect northern leopard frog populations.
    The petition also claims that timber harvest activities may be a 
threat to northern leopard frog populations (Maxell 2000, pp. 12-14; 
Smith 2003, p. 29). The petitioners state that the Forest Service has 
determined that logging activities planned on the Arapaho-Roosevelt, 
Routt, Medicine Bow, Bighorn, and Black Hills National Forests 
(Colorado, South Dakota, and Wyoming) would adversely affect the 
northern leopard frog, and cite several project planning and land use 
plan documents prepared by the Forest Service (Center for Native 
Ecosystems et al. 2006, pp. 186-191). Smith (2003, p. 29) found that 
the northern leopard frog may be especially affected by logging on the 
Black Hills National Forest of western South Dakota and northeastern 
Wyoming more than 80 percent of the 1.2 million-acre (485,623 hectare) 
National Forest is forested, most areas were harvested three or four 
times in the last century, and logging projects may include cutting 
within approximately 500 feet (152.4 meters) of breeding ponds. 
However, it may be difficult to predict the extent of the potential 
negative impact to northern leopard frogs due to our poor understanding 
of their use of upland habitat.
    The petition lists 11 harvesting projects where the Forest Service 
authorized cutting within 100 feet of breeding habitats. Information 
cited in the petition indicates that this practice may result in 
increased sedimentation, increased temperature, and reduced dispersal 
corridors for leopard frogs (Smith 2003, pp. 29-38). The petition 
focuses on the effects to northern leopard frogs on the Black Hills 
National Forest and does not show how this threat may be affecting 
northern leopard frogs across the western United States. However, 
information in our files indicated that fuels reduction and logging 
occur throughout the western range of the northern leopard frog and 
that logging operations in riparian areas should maintain buffers near 
riparian habitats or only conduct partial harvests of trees to mitigate 
the effects of timber harvest to amphibians (Perkins and Hunter 2006, 
pp. 664-668; McComb et al. 1993, pp. 7-15).
    The petitioners provide limited information regarding the effects 
of groundwater depletion, but information in our files indicates that 
pumping groundwater can decrease spring output and recharge in many 
areas (Wirt et al. 2005, pp. G1-11; Alley et al. 1999, pp. 33-44). The 
petition does note that groundwater depletion may have reduced the 
availability of surface water in areas across the range of the western 
portion of the northern leopard frog. In addition, the petition gives 
two examples from Nevada and New Mexico to describe how groundwater 
pumping may impact leopard frog habitat. Brussard et al. (1998, pp. 
505-542) found that pumping of groundwater from gold mines threatened 
spring communities in the north-central region of Nevada. Groundwater 
pumping by the city of Albuquerque, New Mexico, has contributed to the 
loss of wetland habitat in the Rio Grande valley as well (Bogan 1998, 
pp. 562-563).
    The petition also identifies the introduction of nonnative aquatic 
animal and plant species as a threat to the northern leopard frog. 
Nonnative animals (e.g., crayfish, bullfrogs, and fish) may displace 
northern leopard frogs by degrading habitat (e.g., destroying emergent 
vegetation, increasing turbidity, and reducing algal or invertebrate 
populations) or through direct predation on eggs, tadpoles, and even 
adult leopard frogs. The petitioners state that nonnative, invasive 
plants may also threaten northern leopard frog habitat in the western 
United States (Maxell 2000, pp. 21-22; Hitchcock 2001, pp. 5-6). 
Tamarisk and other

[[Page 31396]]

nonindigenous aquatic and terrestrial plants may alter riparian 
habitats by forming dense stands that exclude native amphibians (Maxell 
2000, p. 21) and enhance the survival of other introduced species, such 
as bullfrogs (Lithobates catesbeiana), which compete with and predate 
northern leopard frogs (Adams et al. 2003, pp. 343-351; Maxell 2000, p. 
21; Hitchcock 2001, pp. 5-6, 62-66).
    Citing Jezouit 2004 (pp. 423-445), the petitioners state that the 
emissions of certain gases into the air may lead to acid precipitation 
and the acidification of aquatic habitats, which then leads to the 
direct destruction of vegetation needed for habitat (EPA 2000, pp. 
48699-48701). Additionally, as discussed under Factor D, the 
petitioners state that the National Ambient Air Quality Standards 
(NAAQS) for sulfur dioxide, which contributes to the formation of acid 
precipitation, are not adequate and do not protect aquatic ecosystems 
from the adverse impacts of acid precipitation and acidification 
impacts. They cite literature indicating that continued acid 
precipitation may cause vegetation damage under the current sulfur 
dioxide NAAQS. The petitioners state this information indicates that 
the current NAAQS allow for the emission of sulfur dioxide that may 
harm northern leopard frog habitat. We were unable to locate the 
documents cited by the petitioners for this claim.
    The petitioners make the same claim for nitrogen dioxide, which 
also contributes to the formation of acid rain (Baron et al. 2000, p. 
352; Fenn et al. 2003, p. 404; Jezouit 2004, pp. 423-445; EPA 2005, p. 
59594); nitrogen dioxide can increase the acidity of soils and aquatic 
ecosystems, may contribute to eutrophication (a process whereby 
increased nutrients leads to decreased dissolved oxygen), and may 
possibly change plant community composition (e.g., enhanced growth of 
invasive species and shifts in phytoplankton productivity) (Baron et 
al. 2000, p. 358; Fenn et al. 2003, pp. 404-418). The petitioners 
contend that scientific studies document continued acid precipitation 
and adverse habitat effects from nitrogen deposition under the current 
NAAQS (Baron et al. 2000, p. 365; Fenn et al. 2003, pp. 417-418).
    The petition also considers water pollution to be a significant 
threat to the northern leopard frog (Leja 1998, pp. 345-348; Smith and 
Keinath 2004 pp. 46-53; Bradford 2005, p. 917). The petition claims 
that agriculture is the primary source of water pollution throughout 
the western range of the northern leopard frog and that this water 
pollution occurs primarily through sedimentation, nutrient pollution, 
pesticide pollution, and mineral pollution (Ribaudo 2000, pp. 5-11). 
Bradford (2005, p. 919) indicates that chemical contamination of water 
(defined as pollution; acid precipitation; acid mine drainage; mine 
water pollution; sewage; and, heavy metals) was the third most 
implicated adverse factor for frog population decline in the United 
States.
    Based on our evaluation of the information presented in the 
petition and available in our files regarding the livestock grazing, 
agricultural development, urban development, oil and gas development, 
road development, forestry practices, groundwater pumping, mining, 
invasive species, air emissions, and water pollution within the range 
of the northern leopard frog, we find that the petition presents 
substantial information. Therefore, listing the western U.S. population 
of the northern leopard frog may be warranted due to the present or 
threatened destruction, modification, or curtailment of habitat or 
range.

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

    The petitioners state that overutilization of the northern leopard 
frog is not reported to be a threat to the species in the western 
United States except in Minnesota and Nebraska, where large numbers of 
leopard frogs are used for commercial purposes, and collection has 
likely contributed to population declines (Moriarty 1998, p. 168; Smith 
2003, p. 21). From 1995-1999, approximately 174,772 northern leopard 
frogs were collected in Nebraska to supply only two biological supply 
houses (Smith 2003, p. 21). In addition, northern leopard frogs in 
Minnesota have been heavily collected for fish bait and for the 
biological supply trade (Moriarty 1998, p. 168).
    In 1971, Gibbs et al. (p. 1027) published a paper describing the 
frog trade and the decline of northern leopard frogs throughout most of 
their range. However, due to the declines noted by Gibbs et al. (1971), 
many States began establishing laws to prevent uncontrolled collecting. 
Today, State wildlife agencies, including those in the western United 
States, use commercialization and collection regulations to control 
human actions that may harm wildlife populations, such as collection of 
amphibians (Adams et al. 1995, p. 394). Although these regulations may 
be somewhat inconsistent among States, information in our files 
indicates that, except for the isolated instances cited by the 
petition, overutilization does not appear to threaten the western U.S. 
population of the species. Therefore, we find that the petition and 
information in our files do not provide substantial information to 
support the claim that the western U.S. population of the northern 
leopard frog may be threatened by overutilization for commercial, 
recreational, scientific, or educational purposes.

C. Disease or Predation

    The petition states that the western U.S. northern leopard frog is 
threatened by fungal, viral, and bacterial diseases, all of which may 
cause mass mortality and/or contribute to population decline (Rorabaugh 
2005, pp. 575-577). The petition provides information from the U.S. 
Geological Survey in 2006 (Table 16 in petition, pp. 96-97) indicating 
that disease has caused mass mortality in ranid frogs in almost every 
western State in the United States. There are several fungal diseases 
that affect the northern leopard frog (Faeh et al. 1998, p. 263); of 
those, amphibian chytridiomycosis caused by the fungus Batrachochytrium 
dendrobatidis (Bd) has likely had a large impact on northern leopard 
frogs in the western United States. Mortality from Bd is reported for 
several leopard frog species, including the northern leopard frog, in 
Arizona, California, and Colorado (Bradley et al. 2002, pp. 206-212; 
Muths et al. 2003, p. 361; Briggs et al. 2005, p. 3149). Information in 
Muths et al. (2003, p. 364) notes a northern leopard frog museum 
specimen from Colorado preserved in 1974 was examined histologically 
and tested positive for Bd, which means the presence of Bd in Colorado 
can be traced back to the 1970s.
    The petition also cites information from recent studies that 
indicates that factors such as habitat degradation, habitat 
fragmentation, and climate change may exacerbate the lethal effects of 
Bd on amphibian populations (Carey et al. 1999, pp. 459-472; Ouellet et 
al. 2005, p. 1437). Habitat fragmentation may prevent populations from 
recovering after lethal outbreaks of Bd (Ouellet et al. 2005, p. 1437), 
and other stressors such as water pollution may make northern leopard 
frogs more susceptible to Bd (Carey et al. 1999, pp. 459-472; Kiesecker 
et al. 2004, p. 138). The petition provides information indicating that 
saprolegniasis, a water-borne fungal disease, may also threaten 
populations of northern leopard frogs (Faeh et al. 1998, p. 263). 
However, this fungal disease is usually secondary to other stressors 
such as bacterial

[[Page 31397]]

infections or trauma (Faeh et al. 1998, p. 263). The petition asserts 
that saprolegnia has been associated with embryonic die-offs of ranid 
frogs in Oregon, and is found in Columbia spotted frog eggs in Idaho 
and Montana (Patla and Keinath 2005, p. 43), but there is no other 
information provided to indicate that this disease is a threat to 
northern leopard frogs.
    Faeh et al. (1998, pp. 260-261) are also cited as a source of 
information regarding five viral diseases that have and could 
potentially affect the northern leopard frog. These include the 
iridoviruses, which include ranavirus, polyhedral cytoplasmic amphibian 
virus, tadpole edema virus, and frog erythrocytic virus. Ranavirus may 
be extremely lethal, and all life stages of frogs may acquire the 
disease, although tadpoles are the most susceptible to the disease 
(Daszak et al. 1999, p. 744). The loss of 80 to 90 percent of tadpoles 
in a population from ranavirus may result in an 80 percent loss of 
adult recruitment (survival of individuals to sexual maturity and 
joining the reproductive population), which may negatively affect 
population viability (Daszak et al. 1999, pp. 742-745). The petition 
provides information indicating that the introduction of bullfrogs and 
spread of tiger salamanders throughout the western U.S. range of the 
northern leopard frog may increase the threat of ranavirus infection 
(Daszak et al. 1999, p. 745; Lannoo and Phillips 2005, pp. 636-639).
    The petition also states that bacterial diseases are resulting in 
loss of populations of northern leopard frogs. Septicemia or ``red 
leg'' may have contributed to northern leopard frog declines in the 
Midwestern United States in the early 1970s (Koonz 1992, p. 20) and 
caused declines in Colorado between 1974 and 1982 (Carey 1993, pp. 356-
358). However, ``red leg'' may be triggered by a variety of 
environmental factors, and it is unclear how it may be influencing 
northern leopard frog declines in the western United States (McAllister 
et al. 1999, p. 19).
    One of the widespread and pervasive threats to the northern leopard 
frog in the western United States is predation by nonnative fishes and 
other introduced aquatic invasive species. The petition asserts that 
predation, particularly by nonnative fish and bullfrogs, has likely 
contributed to population declines and extirpation of northern leopard 
frogs across their western range (Hayes and Jennings 1986, pp. 490-509; 
Hecnar and M'Closkey 1997, pp. 125-127; Hammerson 1999, pp. 140-141; 
Maxell 2000, pp. 19-20; Hitchcock 2001, pp. 6, 63; Smith 2003, pp. 20-
21; Smith and Keinath 2004, pp. 57-59). Information from Bradford 
(2005, pp. 922-923) indicates that ranid frogs in the western United 
States may be adversely affected more so than ranid frogs in the 
eastern United States due to their greater exposure to exotic, 
introduced species. Because northern leopard frogs in the West evolved 
in permanent or semi-permanent waters without large aquatic predators 
(Merrell 1968, p. 275), they may be more vulnerable to predation by 
introduced sport fish, bullfrogs, and crayfish (Bradford 2005, p. 923).
    Information in our files (Rorabaugh 2005, p. 575) supports the 
conclusion that predation by nonnative species may be severely 
impacting northern leopard frogs in the western United States. 
Nonnative fishes and other invasive species such as crayfish and 
bullfrogs that prey upon, compete with, or otherwise impact native 
aquatic species are now implicated as the single most important 
deterrent to conservation and recovery of the native fish in the West 
(Minckley 1991, pp. 124-177; Marsh and Pacey 2005, pp. 59-63; Mueller 
2005, pp. 10-19) as well as many amphibians and aquatic reptiles (Rosen 
and Schwalbe 2002, pp. 220-240). Nonnative, predacious fish, crayfish, 
and bullfrogs are currently impacting watersheds and riparian habitat 
across the west and likely are responsible for some declines of 
northern leopard frogs (Rorabaugh 2005, p. 575).
    The data presented in the petition, as well as information in our 
files, relating to threats to the western U.S. population of the 
northern leopard frog indicate both disease, in particular, Bd fungal 
infections, and predation by introduced predators are credible and 
substantial. We find that the petition presents substantial information 
that the western U.S. population of the northern leopard frog may be 
threatened by the predation and disease.

D. Inadequacy of Existing Regulatory Mechanisms

    The petitioners contend that existing regulatory mechanisms, at 
both State and Federal levels, have failed to cease or reverse the 
decline of the northern leopard frog. The petitioners identified the 
Service, U.S. Environmental Protection Agency (EPA), BLM, Forest 
Service, and State wildlife agencies as governmental entities who share 
a responsibility to protect the northern leopard frog either via 
jurisdictional directive or through land-management decisions.
    The petition states that air pollution is reported to be a threat 
to the northern leopard frog (Rorabaugh 2005, pp. 575-576) and that the 
emissions of certain gases into the air may lead to acid precipitation 
and the acidification of aquatic habitats (Jezouit 2004, pp. 423-445). 
The petitioners assert that this situation then leads to the direct 
destruction of vegetation needed for habitat (EPA 2000, pp. 48699-
48701). Additionally, as stated earlier, the petitioners state that the 
NAAQS for sulfur dioxide, which contributes to the formation of acid 
precipitation (Baron et al. 2000, p. 352; Fenn et al. 2003, p. 404; 
Jezouit 2004, pp. 423-445; EPA 2005, pp. 59582-59600), are not adequate 
and do not protect aquatic ecosystems from the adverse impacts of acid 
precipitation and acidification impacts. The primary NAAQS for sulfur 
dioxide are limited to concentrations of no more than an arithmetic 
mean of 0.03 parts per million (ppm) on an annual basis or 0.14 ppm on 
a 24-hour basis (see 40 CFR Sec.  50.4), and the secondary NAAQS for 
sulfur dioxide are limited to 0.5 ppm over a 3-hour averaging period 
(see 40 CFR 50.5). The petitioners, citing literature we were unable to 
locate, state that continued acid precipitation causes vegetation 
damage under the current sulfur dioxide NAAQS and thus, the emission of 
sulfur dioxide that may harm the northern leopard frog and its habitat. 
The petitioners make the same claim for nitrogen dioxide, which also 
contributes to the formation of acid rain (Baron et al. 2000, p. 352; 
Fenn et al. 2003, p. 404; Jezouit 2004, pp. 423-445; EPA 2005, pp. 
59582-59600). As discussed under Factor A, increased acidity may 
destroy, modify, or curtail northern leopard frog habitat (Baron et al. 
2000, p. 358; Fenn et al. 2003, pp. 404-418).
    The primary and secondary NAAQS for nitrogen dioxide are limited to 
concentrations of no more than an annual arithmetic mean of 0.053 ppm 
(see 61 FR 52853, October 8, 1996). The petitioners contend that 
although scientific studies document continued acid precipitation and 
adverse habitat effects from nitrogen deposition under the current 
NAAQS (Baron et al. 2000, p. 365; Fenn et al. 2003, pp. 417-418), the 
standards have also remained unchanged since 1971. Therefore, the 
petitioners contend that the Clean Air Act is currently allowing for 
harmful emissions of nitrogen dioxide. Finally, the petition concludes 
that, because the Clean Air Act does not regulate the potential impacts 
of hydrofluorocarbons and perfluorocarbons to climate, the current laws 
may not protect the northern leopard frog from alleged adverse impacts 
of climate change. The potential effects of climate change on

[[Page 31398]]

the northern leopard frog in the western United States as described in 
the petition are discussed under Factor E.
    The petitioners contend that implementation of the Clean Water Act 
(CWA) is allowing waters to be polluted and, as such, is not protecting 
northern leopard frog habitats. The petitioners state that although the 
CWA regulates point source pollution through the National Pollutant 
Discharge Elimination System (NPDES), and is required to protect 
aquatic life through the protection of designated uses (petition cites 
40 CFR Sec.  131.2), in most cases the northern leopard frog is not 
considered in the determination of whether NPDES permits meet this 
criterion. The petitioners cite examples from Wyoming where dozens of 
NPDES permits have recently been issued by the Wyoming Department of 
Environmental Quality authorizing the discharge of wastewater from 
coalbed methane development. The petition asserts that none of these 
permits considered or mitigated impacts to the northern leopard frog 
(Wyoming Department of Environmental Quality 2005a, 2005b, 2005c, 
2006a). We reviewed the permit for Wyoming Department of Environmental 
Quality 2005a and although there are no specif