[Federal Register Volume 76, Number 193 (Wednesday, October 5, 2011)]
[Proposed Rules]
[Pages 61896-61931]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-25498]
[[Page 61895]]
Vol. 76
Wednesday,
No. 193
October 5, 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 Northern Leopard Frog in the Western United States
as Threatened; Proposed Rule
Federal Register / Vol. 76 , No. 193 / Wednesday, October 5, 2011 /
Proposed Rules
[[Page 61896]]
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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS-R2-ES-2009-0030; 92210-1111-FY08-B2]
Endangered and Threatened Wildlife and Plants; 12-Month Finding
on a Petition To List the Northern Leopard Frog in the Western United
States as Threatened
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, announce a 12-month
finding on a petition to list the northern leopard frog (Lithobates
(=Rana) pipiens) under the Endangered Species Act of 1973, as amended
(Act). After review of the best scientific and commercial information,
we find that listing the northern leopard frog is not warranted at this
time. However, we ask the public to submit to us any new information
that becomes available concerning threats to the northern leopard frog
or its habitat at any time.
DATES: The finding announced in this document was made on October 5,
2011.
ADDRESSES: This finding is available on the Internet at http://www.regulations.gov at Docket Number FWS-R2-ES-2009-0030. 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, Arizona Ecological Services Office, 2321
West Royal Palm Road, Suite 103, Phoenix, AZ 85021. Please submit any
new information, materials, comments, or questions concerning this
finding to the above street address.
FOR FURTHER INFORMATION CONTACT: Steven L. Spangle, Field Supervisor,
Arizona Ecological Services Office (see ADDRESSES); by telephone at
(602) 242-0210; or by facsimile at (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:
Background
Section 4(b)(3)(B) of the Act (16 U.S.C. 1531 et seq.), requires
that, for any petition to revise the Federal Lists of Endangered and
Threatened Wildlife and Plants that contains substantial scientific or
commercial information that listing the species may be warranted, we
make a finding within 12 months of the date of receipt of the petition.
In our finding, we are required to determine if 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 endangered or threatened, and expeditious progress is being made to
add or remove qualified species from the Federal Lists of Endangered
and Threatened Wildlife and Plants. Section 4(b)(3)(C) of the Act
requires that we treat a petition for which the requested action is
found to be warranted but precluded as though resubmitted on the date
of such finding, that is, requiring a subsequent finding to be made
within 12 months. We must publish these 12-month findings in the
Federal Register.
Previous Federal Actions
On June 5, 2006, we received a petition 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 Mr. 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 contained
detailed information on the natural history, biology, current status,
and distribution of the western population of the northern leopard
frog. It also contained information on what the petitioners reported as
potential threats to the western population of the northern leopard
frog such as habitat loss and degradation, predation and competition by
nonnative species, disease, water pollution, climate change, and other
factors. We acknowledged the receipt of the petition in a letter to the
petitioners dated August 7, 2006. That letter explained 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.
In reviewing the petition, there were two issues for which the
Service requested clarification from the 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, although
Wisconsin is located west of the Great Lakes region, the petition map
did not show Wisconsin as a part of the petition, and the status of the
species is not mentioned in that State. Therefore, we requested that
the petitioners clarify whether they intended to include or exclude
Wisconsin from the petitioned DPS. We also sought clarification as to
whether the petitioners were requesting that 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.
On July 1, 2009, we published our 90-day finding (74 FR 31389) that
the petition presented substantial scientific information indicating
that listing the western population of the northern leopard frog may be
warranted, and we initiated a status review to determine if listing the
species as a DPS or throughout all or a significant portion of its
range is warranted. Our July 1, 2009, 90-day finding opened a 60-day
period to send us information for our status review. On October 28,
2009, we reopened this information solicitation period for our status
review for an additional 30 days, ending November 27, 2009 (74 FR
55525). This notice constitutes our 12-month finding on the February 8,
2008, petition to list the northern leopard frog.
Species Information
Below we provide information relevant to understanding the analysis
of information pertaining to the five factors. See Rorabaugh (2005) for
a more complete description of the distribution and life history of the
northern leopard frog.
Taxonomy
The northern leopard frog is in the family Ranidae (Lannoo 2005, p.
371), the true frogs, and is one of about 28 species within the genus
Lithobates (formerly Rana (Frost et al. 2006, p. 10;
[[Page 61897]]
Frost et al. 2008, pp. 7-8)) that occur in North America (Lannoo 2005,
p. 371). For more than a century, nomenclatural and taxonomic confusion
has surrounded members of the Lithobates (=Rana) complex (Moore 1944,
p. 349; Pace 1974, pp. 11-16; Merrell 1977, pp. 1-2; Hillis et al.
1983, p. 132 among others), and there is a wealth of literature from
the late 1800s to present day that has attempted to accurately describe
the different species and geographic variation within the complex.
Until recently, all North American ranid frogs (frogs in the family
Ranidae) were included within the single genus Rana. However, Frost et
al. (2006, p. 10) placed most of these species into the genus
Lithobates. This change is recognized by the Committee on Standard
English and Scientific Names, which is the official names list of the
American Society of Ichthyologists and Herpetologists, the
Herpetologists' League, and the Society for the Study of Amphibians and
Reptiles (Frost et al. 2008, pp. 7-8). Accordingly, the Service also
recognizes and accepts Frost et al.'s (2008) Lithobates classification.
Physical Description
The northern leopard frog is a slim, smooth-skinned green, brown,
or sometimes yellow-green frog with webbed hind feet. The frog is
covered with large, oval dark spots, each of which is surrounded by a
lighter halo or border (Stebbins 2003, pp. 234-235). The snout (nose)
is pointed and the tympanum (eardrum) is round and approximately equal
in diameter to the eye (Baxter and Stone 1980, p. 41). Northern leopard
frogs have a white stripe on the upper jaw and the dorsolateral folds
(paired, glandular ridges that run along each side of the back from
behind the eyes to the rear) are light cream to yellow and are
continuous (not broken posteriorly). The belly is white to cream-
colored, and the posterior thigh has a light background color with dark
spots. There are two different color morphs (variants) of the northern
leopard frog that most often occur in western Minnesota, eastern North
Dakota, and South Dakota (Rorabaugh 2005, p. 570; McKinnel1 et al.
2005, p. 7). These color morphs do occur in other locations (for
example, see Ammon 2002, p. 11), but they are most prevalent in
Minnesota, North Dakota, and South Dakota, as described above. The
burnsi morph lacks dorsal spots and the kandiyohi morph has mottled
pigment patches (speckles) between the dorsal spots. Adult body lengths
(snout-vent) range from 2 to 4.5 inches (in) (5 to 11 centimeters (cm))
(Stebbins 2003, p. 234). Females average slightly larger than males
(Leonard et al. 1993, p. 138; Werner et al. 2004, p. 97). Subadult, or
recently metamorphosed frogs (see Biology section below), range in
length from 1 to 2 in (2 to 5 cm) (Merrell 1977, pp. 10-11). During the
breeding season, males have enlarged or swollen thumbs (innermost
digit) on forefeet, and vocal sacs are not apparent except when the
frog is calling (Baxter and Stone 1980, p. 41; Hammerson 1999, p. 145).
The typical breeding call is a prolonged ``snore'' followed by a series
of stuttering croaks or chuckles that tend to accelerate towards the
end (Hammerson 1999, p. 145). These vocalizations may be interspersed
with chuckling sounds (Stebbins 2003, p. 235).
Northern leopard frogs deposit their egg masses underwater in
clusters, which they attach to vegetation. Eggs are laid in a single
orange- to grapefruit-sized globular clump, and may be laid
individually or communally in groups (Nussbaum et al. 1983, p. 182).
Each egg mass may contain 645 to 7,648 individual eggs (Rorabaugh 2005,
p. 572). The eggs hatch into tadpoles. Tadpoles (the larval stage in
the lifecycle of the frog) are dark green to brown above with metallic
flecking, and a cream to white translucent underside (Werner et al.
2004, p. 97). Tadpoles metamorphose into young frogs. For a detailed
description of northern leopard frog tadpoles, see Scott and Jennings
(1985, pp. 4-16).
Distribution
The northern leopard frog historically ranged from Newfoundland and
southern Quebec, south through the northeast portions of the United
States 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).
Current range maps tend to show an extensive and connected
distribution for the northern leopard frog; however, its actual
distribution is sparse and fragmented in Washington, Oregon, Idaho,
California, Nevada, Arizona, New Mexico, Utah, Colorado, western
Montana, and western Wyoming in the western United States (Rorabaugh
2005, pp. 570-571), throughout New England (New Hampshire Fish and Game
Department 2005, pp. A208-A209), and in British Columbia, Northern
Territories, Alberta, Saskatchewan, and parts of Manitoba in Canada
(Committee on the Status of Endangered Wildlife in Canada 2009, p.
iii).
Habitat
The northern leopard frog is an amphibian (a cold-blooded
vertebrate that spends some time on land, but must breed and develop
into an adult in water) and as such is ectothermic (incapable of
generating their own body heat) (Wells 2007, p. 2). They have highly
permeable skin, which allows for rapid passage of water and gases so
that they can use their external environment to regulate body
temperature and moisture loss (Wells 2007, pp. 2-3). As part of its
complex life history, the northern leopard frog requires a mosaic of
habitats, which includes aquatic overwintering and breeding habitats,
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; Rorabaugh 2005, pp. 571-575). Although aquatic
breeding habitat is required for long-term population survival, upland
foraging, dispersal, and overwintering habitats are critical if
individual leopard frogs are to survive to reproductive maturity. For
example, researchers noted an area near Chicago that had low northern
leopard frog abundance, but extensive potential aquatic breeding
habitat. It was not until habitat surrounding the ponds was restored
from scrub forest to grasslands that leopard frog numbers increased
dramatically (K.S. Mierzwa, pers. comm. in Pope et al. 2000, p. 2506).
These complex habitat requirements make northern leopard frogs
particularly vulnerable to the impacts of habitat loss and
fragmentation. Reduction or removal of these habitats or loss of
connectivity between habitat components could reduce the capacity of
the landscape to support the species (Pope et al. 2000, p. 2505; Green
2005, p. 31).
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). Successful breeding areas typically do not contain predaceous
fish or other predators (Merrell 1968, p. 275; Hine et al. 1981, p. 12;
Orr et al. 1998, p. 92; Smith 2003, pp. 19-21). Emergent vegetation,
such as sedges and rushes, are important features of breeding and
tadpole habitats (Gilbert et al. 1994, p. 468; Smith 2003, pp. 8-9),
and tadpoles are most often found in backwaters and still pools
(Rorabaugh 2005, p. 572).
Sub-adult northern leopard frogs typically move from breeding areas
to
[[Page 61898]]
feeding sites along the borders of larger, more permanent bodies of
water, as smaller frogs are closely tied to 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) and may disperse more than 0.5 mile (mi) (800 meters (m))
from their place of metamorphosis (Dole 1971, p. 223). Dole (1971, p.
226) found that dispersal in Michigan occurred on warm, rainy nights
and that frogs dispersed overland; however, warm rains are not common
in all parts of the species' range and other dispersal routes may be
important as well. Streams are an important corridor for dispersing
juvenile frogs (Seburn et al. 1997, pp. 68-69), and vegetated drainage
ditches may also facilitate connectivity between seasonal habitats
(Pope et al. 2000, p. 2505). 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, or 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. Post-breeding summer habitats
do not include barren ground, open sandy areas, heavily wooded areas,
cultivated fields, heavily grazed pastures, or mowed lawns (Rorabaugh
2005, p. 573). Buffer zones around wetland breeding sites should be
maintained for movement to surrounding upland foraging habitat.
Rittenhouse and Semlitsch (2007, p. 154) collected data from 13
published radio telemetry and tagging studies looking at frog and
salamander use of terrestrial habitat surrounding wetlands. They found
that, on average, a buffer width of 1,877 ft (572 m) around the
breeding site is needed to encompass the non-breeding habitat used by
90 percent of the frogs in a given population (Rittenhouse and
Semlitsch 2007, pp. 155-157).
During winter, northern leopard frogs are thought to hibernate
underwater in ponds, in lakes, or on the bottom of deeper streams or
waters that do not freeze to the bottom and that are well-oxygenated
(Nussbaum 1983, p. 181; Stewart et al. 2004, p. 72). Northern leopard
frogs are intolerant of freezing and of waters that have severely
reduced or complete loss of dissolved oxygen. If these conditions occur
during hibernation, death of northern leopard frogs is likely
(Rorabaugh 2005, p. 574).
Based upon their research in Wisconsin, Hine et al. (1981)
described the ideal ``breeding pond'' as having the following features:
(1) The pond or wetland site should be located within approximately
1.0 mile (mi) (1.6 kilometers (km)) of suitable overwintering habitat
(larger bodies of water) so that adults can find the breeding habitat
when they emerge in the spring and juvenile frogs are able to find
overwintering sites in the fall.
(2) In the spring, the water depth should be approximately 5 ft
(1.5 m) or more so that there is balance of open water and vegetation
cover.
(3) Emergent vegetation (such as sedge, bulrush, and cattail)
should occur along at least two-thirds of the pond or wetland to
provide escape cover and places to attach egg masses.
(4) The slope should be gradual to promote habitat for emergent
vegetation.
(5) Natural terrestrial habitats should be maintained peripheral to
wetlands summer habitat for adults post-breeding, for juvenile growth,
and for dispersal or movement corridors.
(6) Water should be relatively permanent throughout the year, but
should dry every decade or so in order to eliminate any predaceous fish
that become established.
Water quality and temperature are important determinants of
northern leopard frog habitat. Because northern leopard frogs have
permeable skin, which may transfer external contaminants to its
internal organs, good (i.e., non-polluted) water quality is important
at breeding locations. Chemical contamination of habitats can result in
malformations, population declines, decreased growth rates, reduced
activity, and other impacts to northern leopard frogs (Diana and
Beasley 1998, pp. 267-276). Temperature plays an important role in both
the springtime migratory and breeding behaviors of northern leopard
frogs (Merrell 1970, pp. 50-51; Merrell 1977, pp. 5-6, 9). When ambient
air temperature is greater than or equal to 50 degrees Fahrenheit
([deg]F) (10 degrees Celsius ([deg]C)), northern leopard frogs move
from their overwintering sites to their breeding sites (Merrell 1970,
p. 50). The calling sites and areas where egg masses are deposited are
not random and appear to be chosen based upon temperature as these
activities tend to be located in the warmest portions of breeding ponds
(Merrell 1977, p. 6).
Biology
As soon as males leave overwintering sites, they travel to breeding
ponds and call in shallow water (Smith 2003, p. 13). Breeding typically
occurs during a short period in the spring beginning in early April
(Pace 1974, p. 92; Corn and Livo 1989, p. 4); at higher elevations and
more northern latitudes, the onset of breeding is late April to early
May (Corn and Livo 1989, p. 5; Gilbert et al. 1994, p. 467). Most
northern leopard frogs are sexually mature at age 2, although the age
of sexual maturity may vary from age 1 to age 3 in any given population
depending upon environmental conditions (Leclair and Castanet 1987, p.
368; Gilbert et al. 1994, pp. 468-469). Male frogs attract females by
calling from specific locations within a breeding pond when
temperatures are close to 68 [deg]F (20 [deg]C) or more, with several
males typically calling together to form a chorus (Merrell 1977, p. 7).
Eggs are typically laid within breeding habitats, 2 to 3 days following
the onset of chorusing (Corn and Livo 1989, p. 5). Eggs are laid in
non-acidic, shallow (4 to 26 in (10 to 65 cm)), still water that is
exposed to sunlight, and are usually attached to emergent vegetation
just below the water surface (Merrell 1977, p. 6; Gilbert et al. 1994,
pp. 467-468; Pope et al. 2000, p. 2505). Egg masses may include several
hundred to several thousand eggs (Corn and Livo 1989, pp. 6-7) 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
[deg]F (27 [deg]C) to 17 days at approximately 53 [deg]F (12 [deg]C)
(Nussbaum et al. 1983, p. 182).
Tadpoles are the ephemeral, feeding, non-reproductive, completely
aquatic larvae in the life cycle of the frog (McDiarmid and Altig 1999,
p. 2). The length of time required for metamorphosis (the development
of the aquatic tadpole to a frog) is variable, and depending upon
temperature, may take 3 to 6 months from time of egg-laying (Merrell
1977, p. 10; Hinshaw 1999, p. 105). Northern leopard frog tadpoles are
predominantly generalist herbivores (plant eaters), typically eating
attached and free-floating algae (Hoff et al.1999, p. 215); however
they may feed on dead animals (Hendricks 1973, p. 100). Adult and
subadult frogs are generalist insectivores (insect eaters) that feed on
a variety of terrestrial invertebrates such as insect adults, larvae,
spiders, and leeches (Merrell 1977, p. 15; Collier et al. 1998, p. 41;
Smith 2003, p. 12; Rorabaugh 2005, p. 575). In addition, adult northern
leopard frogs have also been known to prey upon small
[[Page 61899]]
northern leopard frogs, birds, and snakes (Merrell 1977, p. 15).
Status
Northern leopard frogs, like many amphibian populations, are
dynamic, and their individual numbers may naturally fluctuate in size
within populations. However, across the range of the northern leopard
frog, information suggests that there is an ongoing loss of populations
throughout the species' range. The loss of populations across the
landscape is what results in species' declines (Green 2005, p. 29).
Population declines of northern leopard frogs are well-documented in
the western United States and western Canada, but are also documented
rangewide (through the Midwestern and Eastern United States), as
described below.
The most recent complete summary of distributional and abundance
patterns of the northern leopard frog is from Rorabaugh (2005, pp. 570-
571), which documents a substantial contraction of the species' range,
especially in the western two-thirds of the United States, where
widespread extirpations have occurred. Other authors have also compiled
summary data indicating population declines (e.g., Smith and Keinath
2007, p. 14). Since the 1960s, the northern leopard frog has
experienced significant declines and losses throughout its range (Gibbs
et al. 1971, p. 1028), particularly in the western United States and
western Canada, and tends to become less abundant the farther west one
proceeds (Corn and Fogelman 1984, p. 150; Hayes and Jennings 1986, p.
491; Clarkson and Rorabaugh 1989, p. 534; Corn et al. 1989, pp. 26-29;
Koch and Peterson 1995, pp. 84-87; Corn et al. 1997, pp. 37-38; Weller
and Green 1997, p. 323; Casper 1998, p. 199; Hammerson 1999, pp. 146-
147; Leonard et al. 1999, p. 51; Dixon 2000, p. 77; Smith 2003, pp. 4-
6; Jennings and Fuller 2004, pp. 125-127; Werner et al. 2004, pp. 97-
98; Committee on the Status of Endangered Wildlife in Canada 2009, p.
v; Germaine and Hays 2009, p. 537; Johnson et al. 2011, p. 557).
Based upon this and other information, the northern leopard frog
appears to be declining, is considered rare, or is locally extirpated
from many historical locations in Arizona, California, Colorado, Idaho,
Iowa, Minnesota, Missouri, Montana, Nebraska, Nevada, New Mexico,
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; Smith
and Keinath 2004, pp. 57-60; McCleod 2005, pp. 292-294; Rorabaugh 2005,
p. 571; Johnson et al. 2011, p. 561). The species is nearly 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; Germaine and Hays 2009, p.
537).
Table 1 lists current NatureServe ranks for States and provinces in
which the northern leopard frog is known to occur. NatureServe
conservation status assessment procedures have different criteria,
evidence requirements, purposes, and taxonomic coverage than the
Federal Lists of Endangered and Threatened Wildlife and Plants, and
therefore, these rankings may not coincide with legal listing processes
(NatureServe 2008, p. 1). However, for a species as widespread as the
northern leopard frog, the NatureServe rankings aid in summarizing the
relative risks facing the northern leopard frog throughout its range
and are provided here for this reason.
NatureServe lists Maryland and New Jersey as States where the
northern leopard frog occurs. However, the Maryland Department of
Natural Resources lists the northern leopard frog as an introduced
species that occurs in one county (Maryland Department of Natural
Resources 2011, p. 2), and the frog does not occur in New Jersey
(Gessner and Stiles 2001, pp. 1-9; New Jersey Division of Fish and
Wildlife 2006, pp. 1-2).
Table 1--NatureServe and State, Province, and Territory Ranks for
Northern Leopard Frogs in States and Provinces It Is Known To Occur
[NatureServe 2011, p. 1]
------------------------------------------------------------------------
State, province, territory Natural heritage State, province,
or sovereign nation program rank * territory rank
------------------------------------------------------------------------
Arizona..................... S2 (Imperiled)...... Species of Greatest
Conservation Need.
California.................. S2 (Imperiled)...... Species of Greatest
Conservation Need.
Colorado.................... S3 (Vulnerable)..... Species of Greatest
Conservation Need,
Species of Special
Concern.
Connecticut................. S2 (Imperiled)...... Special Concern
Species.
Idaho....................... S3 (Vulnerable)..... Species of Greatest
Conservation Need.
Illinois.................... S5 (Secure)......... Non-game Indicator
Species.
Indiana..................... S2 (Imperiled)...... Species of Greatest
Conservation Need.
Iowa........................ S5 (Secure)......... No ranking or
status.
Kentucky.................... S3 (Vulnerable)..... Species of Greatest
Conservation Need.
Maine....................... S3 (Vulnerable)..... Species of Greatest
Conservation Need
(Priority 3).
Maryland.................... S4 (Apparently No ranking or status
Secure), introduced (considered an
spp. introduced
species).
Massachusetts............... S3/S4 (Vulnerable/ Species of Special
Apparently Secure). Concern, Species of
Greatest
Conservation Need.
Michigan.................... S5 (Secure)......... Species of Greatest
Conservation Need.
Minnesota................... S4 (Apparently No ranking or
Secure). status.
Missouri.................... S2 (Imperiled)...... Species of
Conservation
Concern.
Montana..................... S1/S3 (Critically Species of Concern,
Imperiled/ Species of Greatest
Vulnerable). Conservation Need.
Navajo Nation (NE Arizona, S2 (Imperiled)...... Endangered.
NW New Mexico, SE Utah).
Nebraska.................... S5 (Secure)......... At-Risk Species
(Tier II).
Nevada...................... S2/S3 (Imperiled/ Species of
Vulnerable). Conservation
Priority.
New Hampshire............... S3 (Vulnerable)..... Species of Concern.
New Jersey.................. SNR (Unranked), Species not present.
species not present.
[[Page 61900]]
New Mexico.................. S1 (Critically Species of Greatest
Imperiled). Conservation Need.
New York.................... S5 (Secure)......... No ranking or
status.
North Dakota................ SNR (Unranked)...... No ranking or
status.
Ohio........................ SNR (Unranked)...... No ranking or
status.
Oregon...................... S1/S2 (Critically Sensitive Critical,
Imperiled/ List 2 Species
Imperiled). (threatened with
extinction or
presumed extinct).
Pennsylvania................ S2/S3 (Imperiled/ Priority
Vulnerable). Conservation
Species (Tier 5).
Rhode Island................ S2 (Imperiled)...... Species of Greatest
Conservation Need.
South Dakota................ S5 (Secure)......... No ranking or
status.
Texas....................... S1 (Critically No ranking or status
Imperiled). (likely
extirpated).
Utah........................ S3/S4 (Vulnerable/ Species of Concern
Apparently Secure). (Tier III).
Vermont..................... S4 (Vulnerable)..... No ranking or
status.
Washington.................. S1 (Critically Endangered.
Imperiled).
West Virginia............... S2 (Imperiled)...... Species in Greatest
Need of
Conservation.
Wisconsin................... S4 (Vulnerable)..... No ranking or
status.
Wyoming..................... S3 (Vulnerable)..... Species of Greatest
Conservation Need.
Alberta..................... S2/S3 (Imperiled/ Threatened.
Vulnerable).
British Columbia............ S1 (Critically Endangered.
Imperiled).
Labrador and Newfoundland... S3/S4 (Vulnerable/ No ranking or
Apparently Secure). status.
Manitoba.................... S4 (Vulnerable)..... No ranking or
status.
New Brunswick............... S5 (Secure)......... No ranking or
status.
Northwest Territories....... SNR (Unranked)...... No ranking or
status.
Nova Scotia................. S5 (Secure)......... No ranking or
status.
Ontario..................... S5 (Secure)......... Not at risk.
Prince Edward Island........ S4/S5 (Apparently No ranking or
Secure/Secure). status.
Quebec...................... S5 (Secure)......... No ranking or
status.
Saskatchewan................ S3 (Vulnerable)..... Interim Species at
Risk.
------------------------------------------------------------------------
* S1 = Critically Imperiled: At very high risk of extinction due to
extreme rarity (often 5 or fewer populations), very steep declines, or
other factors.
S2 = Imperiled: At high risk of extinction due to restricted range, few
populations (often 20 or fewer), steep declines, or other factors.
S3 = Vulnerable: At moderate risk of extinction due to a restricted
range, relatively few populations (often 80 or fewer), recent and
widespread declines, or other factors. Such species are often rare or
found locally in a restricted range.
S4 = Apparently Secure: Uncommon but not rare; some cause for long-term
concern due to declines or other factors. Such species are likely to
be quite rare in parts of their range, especially at the periphery.
S5 = Secure: Common; widespread and abundant. Such species are
potentially rare in parts of their range, especially at the periphery.
SNR = Unranked. State or Province conservation status not yet assessed.
The International Union for the Conservation of Nature's ``Red List
Categories and Criteria'' were developed for classifying species at
high risk of global extinction (IUCN 2003, p. 1), and as such have
different criteria, evidence requirements, purposes, and taxonomic
coverage than the Federal Lists of Endangered and Threatened Wildlife
and Plants. However, just as with the NatureServe data, because we are
reviewing the entire range of the northern leopard frog, the
International Union for the Conservation of Nature assessment is useful
in summarizing the current status of the northern leopard frog
throughout its range.
The International Union for the Conservation of Nature currently
lists the northern leopard frog as a species of `least concern' in view
of its wide distribution, tolerance to degree of habitat modification,
and presumed large population (Hammerson et al. 2004, p. 2). The
International Union for the Conservation of Nature states that the
population trend is decreasing (Hammerson et al. 2004, p. 3), but the
authors believe that the northern leopard frog is not declining fast
enough to qualify for listing in a more threatened category (Hammerson
et al. 2004, p. 2). The International Union for the Conservation of
Nature reviewed Hammerson et al. (2004, pp. 1-6) in 2011, and no
updates were made to the 2004 review. Since 2004, Rorabaugh (2005, pp.
570-577) completed a status review for the northern leopard frog in the
United States (Rorabaugh 2005, pp. 570-577), and the Committee on the
Status of Endangered Wildlife in Canada published the Assessment and
Update Status Report for the Northern Leopard Frog in Canada (Committee
on the Status of Endangered Wildlife in Canada 2009, pp. 1-76). The
Rorabaugh (2005, pp. 570-577) status review found that for a variety of
reasons the northern leopard frog is declining throughout its range,
but particularly in the western United States. The Committee on the
Status of Endangered Wildlife in Canada (2009, pp. iii) assessment
notes that there are continued declines for the northern leopard frog
throughout the western provinces and evidence of declines in eastern
Canada. The current International Union for the Conservation of Nature
review does not cite either of these documents or provide any current
threats assessment. The International Union for the Conservation of
Nature analysis for the northern leopard frog also includes leopard
frogs in Panama, which likely belong to the Lithobates complex, but do
not belong to the same species as the northern leopard frog. Therefore,
we do not consider the International Union for the Conservation of
Nature review for the northern leopard frog a current assessment of the
species' status in North America.
Western States
Until the late 1970s, northern leopard frogs were widespread and
abundant in much of northern Arizona (Apache, Coconino, Greenlee,
Mohave, Navajo, and Yavapai Counties) in springs, streams, rivers,
stock tanks, and lakes throughout northern Arizona (Arizona Game and
Fish Department 2009, p. 1).
[[Page 61901]]
Currently, there is one northern leopard frog population located near
Seligman, Arizona; a metapopulation (several breeding locations in
close proximity to one another) located south of Flagstaff, Arizona;
and three refugial sites developed by the State and Service (and other
partners) to assist in stocking northern leopard frogs to other
locations in Arizona, north of the Colorado River. All of these
locations are located in Coconino County. Outside of these locations,
fairly rigorous visual encounter surveys conducted within the species'
historical range, including Grand Canyon National Park and the Kaibab
National Forest, have not located northern leopard frogs (Kaibab
National Forest 2007, p. 1; Kaibab National Forest 2008, p. 1; Drost et
al. 2008, p. 7). The species is listed as a Species of Greatest
Conservation Need in the Arizona State Wildlife Action Plan (Arizona
Game and Fish Department 2006, Appendix M, p. 153) and has a
NatureServe rank of S2 (Imperiled) (NatureServe 2011, p. 1). In
Arizona, there is no open season for northern leopard frog, and
collecting is illegal except as authorized by State permit, effective
January 1, 1993 (Commission Order 41). The northern leopard frog has
also significantly declined on the Navajo Nation (which is situated in
southeastern Utah, northeastern Arizona, and northwestern New Mexico)
in the last century. Most remote desert populations of northern leopard
frogs were lost between the 1920s and 1970s, and mountain populations
were lost in the late 1980s. The Navajo Nation has listed the northern
leopard frog as a ``Group 2--Endangered Species'' on the Navajo
Endangered Species List, which means its prospects of survival or
recruitment on the Navajo Nation are in jeopardy (Navajo Nation
Department of Fish and Wildlife 2009, p. 3).
The northern leopard frog is a State of California species of
special concern and is listed as a Species of Special Concern (native
populations only) (California Department of Fish and Game, Natural
Diversity Database, 2009) and as a Species of Greatest Conservation
Need in California Department of Fish and Game's State Wildlife Action
Plan (California Department of Fish and Game 2007); however, the
northern leopard frog is not listed under the California Endangered
Species Act. The northern leopard frog may be taken under the authority
of a sport fishing license, subject to restrictions (California Code of
Regulations, Title 14, Section 5.05). The frog is ranked S2 (Imperiled)
by NatureServe (NatureServe 2011, p. 1). Northern leopard frogs are
likely native to the region east of the Sierra Nevada-Cascade crest in
the following areas of California: upper Pit River basin (Shasta,
Lassen, and Modoc counties), Surprise Valley (Modoc County), lower
Klamath Lake basin (Siskiyou County), Lake Tahoe region (El Dorado
County), Carson River drainage (Alpine County) and Owens River Valley
(Mono and Inyo counties) (Jennings and Fuller 2004, p. 122). The
northern leopard frog was introduced to at least 15 other sites in
California, but most of these introductions have not resulted in
naturalized populations that continue to exist today (Jennings and
Hayes 1994, p. 80; Jennings and Fuller 2004, p. 119). There is a small,
introduced population in Merced County, near the Merced National
Wildlife Refuge (NWR) that persisted as recently as 2007 (Jennings and
Fuller 2004, pp. 119, 127; Woolington 2009, pers. comm.). Since the
1970s, northern leopard frogs have disappeared from most (approximately
95 percent) of their historic range in California, (Jennings and Fuller
2004, p. 119; Rorabaugh 2005, p. 571) and may be completely extirpated
from these areas of the State as we are not aware of any recent
confirmed sightings. Jennings and Hayes (1994, p. 82) knew of only two
extant, native northern leopard frog populations as of the 1990s: one
adult was observed at Tule Lake National NWR (Siskiyou County) in 1990,
and 8 to 10 juveniles were found near Pine Creek in Round Valley near
Bishop (Inyo County) in 1994. Northern leopard frogs are no longer
found on Tule Lake NWR (Adams 2011, pers. comm.), and no northern
leopard frogs have been observed during amphibian surveys conducted on
the Klamath Falls NWR Complex, including Tule Lake NWR (Austin 2009,
pers. comm.). Recent surveys conducted by the California Department of
Fish and Game did not locate any northern leopard frogs in the Owens
River Area (Becker 2011, pers. comm.). In addition, surveys found that
sites previously considered to be northern leopard frog habitat now
contain nonnative aquatic species, and the habitat has been extensively
modified such that there are likely few areas of suitable habitat left
in the Owens Valley (Becker 2011, pers. comm.). Northern leopard frogs
have not been found in the Lake Tahoe basin for over 20 years, and the
species is presumed to be extirpated from the area (Jennings and Fuller
2004, p. 125). Jennings and Fuller (2004, p. 126) also report that a
formerly isolated native northern leopard frog population on Hat Creek,
Shasta County, is now apparently extirpated as well. Modoc NWR in
northeastern California reported no known occurrences of northern
leopard frogs on the refuge in recent times, and no northern leopard
frogs were reported during numerous hours of amphibian survey time in
2004, 2005, and 2010 (Bachman 2011, pers. comm.).
The northern leopard frog was historically quite common throughout
Colorado, but over the last 30 to 40 years, populations have declined
and even been locally extirpated from portions of eastern and north-
central Colorado, including Rocky Mountain and Mesa Verde National
Parks (Corn and Fogleman 1984, p. 148; Corn et al. 1989, p. 15;
Stebbins and Cohen 1995, p. 220; Corn et al. 1997, pp. 37-38; Hammerson
1999, pp. 146-147; Mesa Verde National Park 2009, p. 1; Johnson et al.
2011, p. 561). The Colorado Division of Wildlife has designated the
northern leopard frog a Species of Greatest Conservation Need as well
as a Species of Special Concern due to low population status and a
declining population trend (Colorado Division of Wildlife 2006, pp. 2,
28, 305). These are not statutory categories; however, the northern
leopard frog is classified as ``nongame'' wildlife and their
harassment, taking, or possession is prohibited without a permit
(Colorado Division of Wildlife 2009, p. 3). NatureServe ranks the
northern leopard frog as S3 (Vulnerable) in Colorado (NatureServe 2011,
p. 1). Intensive surveys conducted from 2007 through 2009 in the Front
Range of Colorado indicate that northern leopard frogs there have
become rare and documented losses are widespread (Johnson and McKenzie
2009, p. 9; Keeley 2009, pp. 5-6; Johnson et al. 2011, p. 562).
Historically, northern leopard frogs were found at high densities in
this region (Johnson et al. 2011, p. 562). Along the Western Slope (the
area west of the continental divide in Colorado), data suggest that
northern leopard frog populations remain viable, especially in the
northern region (Johnson and McKenzie 2009, p. 10). This supports
information from Arapaho and Browns Park NWRs, both located in
northwestern Colorado, that continue to support northern leopard frogs
(Johnson 2009, pers. comm.; Smart 2009, pers. comm.). Northern leopard
frogs were the most common amphibian in southwest Colorado until the
late 1960s, but now they are rare (San Miguel 2009, pers. comm.).
Despite conducting amphibian surveys for 15 years with an emphasis on
locating northern leopard frogs, none have been detected within Mesa
Verde National Park, Colorado. Historically,
[[Page 61902]]
this species was found abundantly along the Mancos River in the park
and adjacent lands (San Miguel 2009, pers. comm.). However, the overall
status of the northern leopard frog in western Colorado is not
currently known (Johnson et al. 2011, p. 563).
The Idaho Department of Fish and Game designated the northern
leopard frog a Type 2 Species of Greatest Conservation Need (Idaho
Department of Fish and Game 2005, Appendix B p. 6). A Type 2 species of
greatest conservation need is defined as a rangewide or globally
imperiled species that is experiencing significant declines throughout
its range with a high likelihood of being listed in the foreseeable
future due to its rarity (Idaho Department of Fish and Game 2005,
Appendix B, p. 4). Reduced distribution and a declining population
trend are noted in the Idaho Comprehensive Wildlife Conservation
Strategy as reasons for the designation (Idaho Department of Fish and
Game 2005, Species Account, p. 1). The northern leopard frog is also a
protected nongame species, which means take or possession of the
species is prohibited without a permit (Idaho Administrative Code
13.01.06-300.02). NatureServe ranks the northern leopard frog in Idaho
as S3 (Vulnerable) (NatureServe 2011, p. 1). Both the Targhee National
Forest and Kootenai NWR have records of northern leopard frogs from the
1970s (Service 1972, p. 11; Stebbins and Cohen 1995, p. 220). However,
surveys in 1992 at 98 sites on the Targhee National Forest did not
locate northern leopard frogs (Stebbins and Cohen 1995, p. 220), and
Kootenai NWR has no records of frogs for the last 30 years (Rose 2009,
pers. comm.). Deer Flat NWR amphibian surveys have only detected
American bullfrogs (Lithobates catesbeiana). Northern leopard frogs are
known to be present on Bear Lake, Grays Lake, and Minidoka NWRs, and
presumed to be present on Camas NWR and Oxford Slough Wetland
Protection Area (WPA) (Fisher and Mitchell 2009, p. 1).
Localized declines of northern leopard frogs are documented in Iowa
(Lannoo et al. 1994, pp. 317-318; Hemesath 1998, p. 216). Lannoo et al.
1994 (p. 311) states, ``From descriptions of the turn-of-the-century
commercial ``frogging'' industry in Dickinson County (Iowa), we
estimate that the number of leopard frogs has declined by at least two,
and probably three orders of magnitude.'' However, the northern leopard
frog is ranked as Secure (S5) in Iowa by NatureServe (2011, p. 1) and
is not considered a Species of Greatest Conservation Need (Iowa
Department of Natural Resources 2006, p. 42). Currently, there is a
continuous open season for northern leopard frogs in inland and
boundary waters in Iowa, and up to 48 frogs can be collected per day
(Iowa Department of Natural Resources 2011, p. 1). In 1991, the Iowa
Department of Natural Resources initiated an annual anuran (frog and
toad) survey. The survey is conducted by volunteers, and until 2007,
volunteers were not required to distinguish between species of leopard
frogs on the report forms (Iowa Department of Natural Resources 2009,
p. 1). Survey data from 2007 and 2008 (when the species were separated)
and older data from counties where it was thought only the northern
leopard frog occurred were reviewed by the State. The analyses of this
information suggest a possible downward trend in northern leopard frog
presence, but the trend was not statistically significant (Iowa
Department of Natural Resources 2009, p. 1).
Northern leopard frog populations began declining in Minnesota in
the late 1960s or early 1970s (Rittschof 1975, p. 103; Minnesota
Department of Natural Resources 2011a, pp. 1-2). The declines of
northern leopard frog populations from the past are thought to have
been substantial, but information is not detailed enough to know if the
population is now stable or if it is still declining in Minnesota
(Moriarty 1998, p. 168). However, because the species is still
considered to be fairly common, it is not considered a Species of
Greatest Conservation Need in Minnesota's Comprehensive Wildlife
Strategy (Minnesota Department of Natural Resources 2006, Appendix B p.
9). The Minnesota Department of Natural Resources' northern leopard
frog fact page does indicate that the northern leopard frog is still
declining (Minnesota Department of Natural Resources 2011a, p. 2). The
species is ranked S4 (Apparently Secure) by NatureServe (NatureServe
2011, p. 1). In Minnesota, from May 16 to March 31, licensed anglers
and children under age 16 may take, use, buy, and sell an unlimited
number of northern leopard frogs up to 6 inches long for bait
(Minnesota Department of Natural Resources 2011b, p. 70). A Minnesota
Department of Natural Resources commercial license is required to take
northern leopard frogs for purposes other than bait.
Missouri is located on the periphery of the range for northern
leopard frogs and the frog is currently only known to occur in two
counties (Atchison and Mercer) that border Iowa (Missouri Department of
Conservation 2009, p. 1). The northern leopard frog is listed as a
Species of Conservation Concern by the Missouri Department of
Conservation and NatureServe ranks it as Imperiled (S2) (Missouri
Department of Conservation 2009, p. 1; NatureServe 2011, p. 1). This
ranking is based upon the low number of known occurrences in Missouri
and not based upon declining population trends (Missouri Department of
Conservation 2009, p. 1). The Missouri Department of Conservation noted
that it is likely that more populations are present in northern
Missouri, but further surveys need to be completed to affirm this
assumption (Missouri Department of Conservation 2009, p. 1). In
Missouri, northern leopard frogs have regulatory protection from
commercial take and non-resident collection. Missouri residents are
allowed to possess up to five northern leopard frogs for education use
(Wildlife Code Missouri 3CSR10-9.110); however, these five individuals
cannot be sold, traded, shipped over State lines, or taken from public
lands (Missouri Department of Conservation 2009, p. 2). Northern
leopard frogs also cannot be used as live bait in Missouri (Wildlife
Code Missouri 3CSR10-6.605).
Montana Fish, Wildlife, and Parks classified the northern leopard
frog as a Species of Concern in Montana and it is considered a Species
of Greatest Conservation Need in their Wildlife Conservation Strategy
(Montana Fish, Wildlife, and Parks 2009, p. 1). Northern leopard frogs
are protected from commercial collection in Montana (Montana Code
Annotated 2009 87-5-116). Historically, northern leopard frogs occurred
across the eastern plains of Montana and in the mountain valleys on
both sides of the Continental Divide (Montana Fish, Wildlife, and Parks
2009, p. 1). However, since the 1990s, most previously known northern
leopard frog populations on the west side of the Continental Divide in
Montana are considered extirpated, and there has been a clear range
contraction of northern leopard frogs (Werner 2003, p. 26; Montana
Fish, Wildlife, and Parks 2009, p. 1). Currently, only two populations
exist in western Montana. Surveys in the mid-1990s of historically
occupied sites in central Montana, east of the Continental Divide,
found only 19 percent of the sites to be occupied by northern leopard
frogs (Montana Fish, Wildlife, and Parks 2009, p. 1). NatureServe
provides a split rank for the State that reflects the difference in
status between western (S1 Critically Imperiled) and eastern (S3
Vulnerable) Montana (NatureServe 2011, p. 1). Habitat restoration and
survey efforts are being planned Statewide to provide
[[Page 61903]]
a current assessment of northern leopard frog distribution (Montana
Fish, Wildlife, and Parks, 2009, p. 2).
The northern leopard frog occurs commonly in the State of Nebraska
(McLeod 2005, p. 292) and has a NatureServe rank of S5 (Secure)
(NatureServe 2011, p. 1). However, surveys conducted in 1997 and 1998
indicated a significant decline in northern leopard frog occurrences at
the State level (McLeod 2005, p. 292). It is difficult to ascertain if
this information represents a real decline or is representative of
normal stochastic events, but data indicated significant differences
from location data collected in the 1970s (McLeod 2005, p. 292). The
Nebraska Game and Parks Commission identified the northern leopard frog
as a Tier II At-Risk Species during development of the Nebraska Natural
Legacy Project (2005, p. 319). Tier II species are typically those that
are not at-risk from a global or national perspective, but are rare or
imperiled within Nebraska. As of 2011, northern leopard frogs can no
longer be commercially harvested or sold for bait in Nebraska; however,
anglers can still collect them as bait for personal use (Nebraska Game
and Parks Commission 2011, p. 5).
In Nevada, northern leopard frogs are currently ranked S2/S3
(Imperiled/Vulnerable) by NatureServe (NatureServe 2011, p. 1) and are
on the Nevada Natural Heritage Program's Animal and Plant Watch List,
which means they could be declining in Nevada or across much of their
range, or may be less common than currently thought and could become
at-risk in the future. The northern leopard frog is identified as a
Species of Conservation Priority in the Nevada Wildlife Action Plan
(Wildlife Action Plan Team 2006, p. 61). In addition, the northern
leopard frog is a protected amphibian by Nevada statute (NAC 503.075)
and cannot be collected for commercial, recreational, or educational
purposes without a permit (Nevada Department of Wildlife 2009, p. 5).
The Nevada Department of Wildlife notes that there is little historical
or current information available to accurately assess the distribution
and status of the northern leopard frog in Nevada (Nevada Department of
Wildlife 2009, p. 1). However, recent surveys suggest that northern
leopard frogs may no longer be abundant in Nevada and that there have
been numerous local extirpations, for example, along the Truckee and
Carson rivers in western Nevada and in springs of southern and eastern
Nevada (Panik and Barrett 1993, p. 203; Hitchcock 2001, pp. 9, 109-
110). While historical records and anecdotal evidence indicated that
northern leopard frogs were once widely distributed in the State, the
current species distribution is much smaller than the historical
distribution (Hitchcock 2001, pp. 9, 38, 48). In addition, suitable
northern leopard frog habitat is patchily distributed in the State due
to the aridity and isolated nature of many wetland systems, which
results in a discontinuous and limited distribution (Nevada Department
of Wildlife 2009, p. 1). Recent Nevada Department of Wildlife records
document northern leopard frog populations in Ruby Valley (including
Ruby Lakes NWR) and Lower Mary's River in Elko and White Pine Counties;
Spring Valley and Lake Valley in White Pine County; Lake Valley and
Pahranagat Valley (including Pahranagat NWR) in Lincoln County; Carson
River near Carson City; the lower Truckee River and Truckee meadows in
Washoe County; and a small number of additional sites in western and
northeastern Nevada (Hitchcock 2001, pp. 96-102; Service 2009, pp. 1-2;
Nevada Department of Wildlife 2009, p. 2). Efforts to restore northern
leopard frog habitat and re-establish the species have occurred along
the lower Truckee River in western Nevada and on Pahranagat NWR (Horton
2010, pers. comm.; Rogers 2010, p. 7).
Historically, the northern leopard frog was documented from a large
area in the northern and western part of New Mexico and along the
entire length of the Rio Grande River valley, except southern Elephant
Butte and northern Caballo Reservoirs (New Mexico Department of Game
and Fish 2009, p. 1). Declines in northern leopard frogs have been
reported from the Lower Rio Grande (below Caballo Reservoir), in the
Jemez Mountains, and in the Chuska Mountains (Christman 2009, p. 5; New
Mexico Department of Game and Fish 2009, p. 2). The species is believed
to be extirpated from the Rio Grande Valley, south of Albuquerque (New
Mexico Department of Game and Fish 2009, p. 3). Recent survey efforts
indicate that northern leopard frogs are persisting in northern New
Mexico, but most occupied sites contained small numbers of frogs with
very few robust populations (Christman 2009, p. 13). The northern
leopard frog is not listed as endangered or threatened in New Mexico
under the Wildlife Conservation Act, but was designated a Species of
Greatest Conservation Need by the New Mexico Department of Game and
Fish, and NatureServe ranks it as S1 (Critically Imperiled) in New
Mexico (New Mexico Department of Game and Fish 2006, p. 540;
NatureServe 2011, p. 1). The northern leopard frog is protected from
commercial take (Section 17-1-14 NMSA); however, take by New Mexico
State residents for pets or other uses are uncontrolled (New Mexico
Department of Game and Fish 2009, p. 2).
Historically, the northern leopard frog ranged Statewide in North
Dakota and is still quite common today (North Dakota Game and Fish
Department 2009, p. 1). Northern leopard frogs are widely distributed
throughout the State and locally abundant in some locations (Newman
2009, p. 1; Scherr 2009, pers. comm.) but surveys conducted by Bowers
et al. (1998, p. 372) found that the range of the northern leopard frog
was less extensive in the prairie potholes region of North Dakota than
previously described. Because of its distribution and local abundance,
the northern leopard frog has no special status in the State, and there
are no conservation programs that specifically target the northern
leopard frog (North Dakota Game and Fish Department 2009, p. 1).
Commercial frog licenses are available for unlimited collection of
northern leopard frogs (North Dakota Administrative Code 30-03-04).
NatureServe does not have a current ranking for North Dakota as it is
currently under review (NatureServe 2011, p. 1).
The Oregon Department of Fish and Wildlife ranks the northern
leopard frog as a ``Sensitive Critical'' species, meaning that it is
imperiled with extirpation from a specific geographic area of the State
due to small population sizes, habitat loss or degradation, or
immediate threats (Oregon Biodiversity Information Center 2010, p. 7,
13). The sensitive species list is primarily a non-regulatory tool
designed to provide a voluntary, proactive approach to conservation
(Oregon Department of Fish and Wildlife 2008, p. 1). The Oregon
Biodiversity Information Center lists the northern leopard frog as a
``List 2 Species'' meaning that it is threatened with extirpation or
presumed to be extirpated from the State of Oregon (Oregon Biodiversity
Information Center 2010, pp. 4, 13) and it is ranked S1/S2 (Critically
Imperiled/Imperiled) by NatureServe (NatureServe 2011, p. 1). The
Oregon Biodiversity Information Center (2010, p. 13), lists the
following counties as containing historical locations for the northern
leopard frog: Hood River, Wasco, Sherman, Gilliam, Morrow, Umatilla,
Jefferson, Crook, Grant, Baker, Malheur, Klamath, and Jackson Counties.
Rorabaugh (2005, p. 571) reported that northern leopard frogs are
extirpated from most historical
[[Page 61904]]
localities in Oregon. The six records we have from the Oregon Natural
Heritage Information Center are observations from 1975, 1980, 1990,
1995, 1996, and 2003. We have found no records, current or historical,
to indicate the presence of northern leopard frogs on either the Hart
Mountain National Antelope Refuge (southern Oregon) or Sheldon NWR
(northern Nevada) (Harper Collins 2009, pers. comm.). Frog surveys were
conducted at Sheldon NWR in summer 2009, but they detected only
nonnative American bullfrogs.
The status of the northern leopard frog in South Dakota is thought
to be stable and NatureServe lists the frog as secure (S5) (South
Dakota Department of Game, Fish, and Parks 2009, p. 1; NatureServe
2011, p. 1). The northern leopard has no specific protection in South
Dakota and can be collected for commercial and non-commercial bait
(South Dakota Laws and Regulations for Commercial Bait Dealers 2009, p.
1; South Dakota Department of Game, Fish, and Parks 2011, p. 23). The
species' range includes almost the entire State based upon historical
and current distribution maps (Fischer et al. 1999, p. 12; Naugle et
al. 2005, p. 285). Smith et al. (2005, p. 9) found northern leopard
frogs to be common in the Black Hills, and a Statewide herpetology
(amphibian and reptile) survey report indicates that the distribution
of the northern leopard frog in the State is stable (Backlund 2004, p.
8). However, there is no historical or recent abundance data to compare
current survey data that would indicate population trend (Backlund
2004, p. 9). Information received from Lacreek and Waubay NWRs and the
Huron Wetland Management District indicate northern leopard frogs are
prevalent (Flannders-Wanner 2009, pers. comm.; Hubers 2009, pers.
comm.; Koerner 2009, pers. comm.). Anuran auditory surveys (1997-1998)
found northern leopard frogs to be one of the most widespread and
wetland-abundant species in eastern South Dakota (Naugle et al. 2005,
p. 290).
The northern leopard frog's historic range in Texas was in the Rio
Grande Valley, El Paso County (a relatively small portion of the
State). However, extensive efforts to locate the frog have been
unsuccessful (Dixon 2000, pp. 42, 77). The northern leopard frog is
ranked S1 (Critically Imperiled) by NatureServe (NatureServe 2011, p.
1), but is not listed as a species of conservation concern in the Texas
Comprehensive Wildlife Conservation Strategy (Texas Parks and Wildlife
Department 2005, pp. 748-751). The Texas Parks and Wildlife Department
webpage (Texas Parks and Wildlife Department 2011a, p. 11) lists the
species as occurring in Texas, but the most current field guide for
amphibians and reptiles of Texas indicates the species is likely
extirpated (Dixon 2000, p. 77). The Texas Parks and Wildlife Department
requires that anyone who captures a wild animal, including frogs, be
licensed or permitted (Texas Parks and Wildlife Department 2011b, p.
1).
The Utah Division of Wildlife Resources considers northern leopard
frog populations in Utah to be secure (Utah Division of Wildlife
Resources 2009, p. 1). NatureServe ranks the northern leopard frog as
S3/S4 (Vulnerable/Apparently Secure) (NatureServe 2011, p. 1). In Utah,
the northern leopard frog is classified as ``controlled'' for
collection, importation, and possession, and may only be collected with
a certificate of registration (Administrative Rule R657-53: Amphibian
and Reptile Collection, Importation, Transportation, and Possession).
Historically the northern leopard frog is considered to be a wide-
ranging species in Utah and is verified to have occurred in all but
Davis and Wayne Counties (Utah Division of Wildlife Resources 2009, p.
2). Utah's Wildlife Action Plan lists the northern leopard frog as a
Tier III Species of Concern (Sutter et al. 2005, p. 5-6). Tier III
species are of conservation concern because they are linked to at-risk
habitats, they have suffered significant population declines, or there
is little information regarding the species. The northern leopard frog
was listed as a species of concern due to lack of information, water
development, and disease. In 2006, the Utah Division of Wildlife
Resources began compiling survey information and conducting surveys to
determine the current distribution of northern leopard frogs in Utah.
Recent surveys have documented northern leopard frogs at 97 new sites
(not historical sites), for a total of 683 known sites in Utah (Utah
Division of Wildlife Resources 2009, p. 2). Of these sites, 75 percent
(512) are extant, and 25 percent (171) are considered historical, as
the observations occurred prior to 1989 (Utah Division of Wildlife
Resources 2009, p. 2). We do not have information regarding how many of
these sites are breeding sites versus other observations (such as
dispersing frogs).
The northern leopard frog was listed in 2000 as an endangered
species under the Endangered, Threatened, and Sensitive Species
Classification (Washington Administrative Code, Title 232, Chapter 12,
Section 014) in Washington State after surveys of 17 known historic
locations confirmed occupancy at only two sites (Leonard et al. 1999,
p. 52; Germaine and Hays 2009, p. 537). ``Endangered'' in this context
means any wildlife species native to the State of Washington that is
threatened with extinction throughout all or a significant portion of
its range within the State. The northern leopard frog is ranked S1
(Critically Imperiled) in Washington State by NatureServe (NatureServe
2011, p. 1). Historically, the northern leopard frog occurred in six
major watersheds in eastern Washington (Germaine and Hays 2009, p.
537). However, extensive surveys conducted at Gloyd Seeps and Potholes
Reservoir in 2002-2005 indicate that the Gloyd Seeps population is
likely no longer a functional breeding population and the Potholes
Reservoir population is in sharp decline (Germaine and Hays 2009, p.
542). Although inclement weather prevented Washington Department of
Fish and Wildlife from completing surveys in 2009, no observations of
northern leopard frogs were made during what limited field time was
available (Washington Department of Fish and Wildlife 2009, p. 32).
The northern leopard frog is not currently listed in Wisconsin, but
over the past several decades, declines have been documented (Hine et
al. 1981, pp. 2-3; Mossman et al. 1998, pp. 191-192, 198; Wisconsin
Department of Natural Resources 2009, p. 1). In 1981, the Wisconsin
Frog and Toad Survey began to monitor several species, including the
northern leopard frog. The occurrence of a species is determined by
whether or not the species is heard calling, and the abundance is
ranked by the relative number of individuals heard calling at a site
(Kitchell and Hay 2007, p. 1). Survey results from 1984 to 2007
indicate an overall decrease in the estimated population trend for
northern leopard frogs (Kitchell and Hay 2007, p. 7). NatureServe ranks
the northern leopard frog as S4 (Secure) (NatureServe 2011, p. 1). In
Wisconsin, northern leopard frogs may be collected and possessed in
unlimited numbers if the collector or possessor has a valid Class A
Captive Wild Animal Farm License or a Commercial Bait License
(Wisconsin Department of Natural Resources 2011, p. 13).
The northern leopard frog is considered to be widely distributed in
Wyoming (Wyoming Game and Fish Department 2009, p. 1). The Wyoming Game
and Fish Department identified the species as a Species of Greatest
Conservation Need due to potential habitat degradation and loss,
disease, absence of data, and contaminants (Wyoming Game and Fish
Department
[[Page 61905]]
2005, p. 13). NatureServe ranks it as S3 (Vulnerable) (NatureServe
2011, p. 1). Population declines have been documented from the Laramie
Plains, Targhee National Forest, and Grand Teton National Park (Baxter
and Stone 1980, p. 44; Lewis et al. 1985, p. 167; Koch and Peterson
1995, p. 85). No population trend data are available for northern
leopard frogs in Wyoming. Anecdotal reports and local survey
information indicate that the frog may be common throughout eastern and
southwestern Wyoming (Wyoming Game and Fish Department 2009, p. 1);
however, others reports indicate that the present abundance of northern
leopard frogs in Wyoming is unknown and the population trend is
declining (Smith and Keinath 2007, p. 14). The Wyoming Game and Fish
Department manages commercial, scientific, and education activities
through their collection permitting system (Wyoming Game and Fish
Department 2009, p. 3).
Eastern States
The northern leopard frog still occurs throughout the eastern
States it is historically known from (Connecticut, Illinois, Indiana,
Kentucky, Maine, Massachusetts, Michigan, New Hampshire, New York,
Ohio, Pennsylvania, Rhode Island, Vermont, and West Virginia)
(Rorabaugh 2005, pp. 571-572). However, the frog currently has a very
disjunct distribution throughout the northeast (New Hampshire Fish and
Game Department 2005, pp. A208-A209); some populations are thought to
be both locally and regionally declining (Smith and Keinath 2007, p.
14; Spriggs 2009, p. 29), and, in some cases, local extirpations have
occurred (Rorabaugh 2005, p. 571; Spriggs 2009, p. 26). For example,
habitat loss from urban development has resulted in local extirpations
in Connecticut, Massachusetts, and Rhode Island (Klemens 2000, p. 41;
Rorabaugh 2005, p. 571). Northern leopard frog declines also occurred
in the Midwest in Michigan, Minnesota, and northeastern Illinois in the
late 1960s or early 1970s (Rittschof, 1975, p. 103; Moriarty 1998, p.
168; Mierzwa 1998, p. 117), and although some populations have
recovered, others have not (Mierzwa 1998, p. 117; Moriarty 1998, p.
168).
In 1999, the Northeast Endangered Species and Wildlife Diversity
Technical Committee published a list of regional species of
conservation concern, which included the northern leopard frog. The
northern leopard frog was added to the list based upon declining
populations or high risk of disappearing from the Northeast, lack of
data with suspicion of risk of disappearing from the region, and
special circumstances (such as vulnerability to collecting pressures)
(Therres 1999, p. 97).
Northeast Partners in Amphibian and Reptile Conservation, using
information from State wildlife action plans and other sources,
developed the Northeast Amphibian and Reptile Species of Regional
Responsibility and Conservation Concern (Northeast Partners in
Amphibian and Reptile Conservation 2010, pp. 2-3). Based upon their
analysis, the Northeast Partners in Amphibian and Reptile Conservation
ranked the northern leopard frog as a species of High Concern and
Regional Responsibility that should be considered a target for habitat
and landscape-based conservation initiatives (such as land protection),
may be an appropriate indicator for long-term monitoring to detect
changes in distribution due to climate change, and should be among the
highest priority species for Northeast Partners in Amphibian and
Reptile Conservation to target conservation efforts (e.g., create a
regional species working group) (Northeast Partners in Amphibian and
Reptile Conservation 2010, pp. 3-5). The ranking is based upon the
number of northeastern States that comprise a species' U.S.
distribution and the number of States that listed the species in their
Wildlife Action Plans. Based upon their analysis, the northeastern
States make up less than 50 percent of the northern leopard frog's U.S.
distribution (occurs in 9 of 14 northeastern States), and it is listed
as a Species of Greatest Conservation Concern in 6 of the 9 States it
inhabits (Northeast Partners in Amphibian and Reptile Conservation
2010, p. 5).
In Connecticut, the northern leopard frog is locally common along
sections of the Connecticut River and its tributaries (the Farmington,
Scantic, and Coginchaug Rivers) (Klemens 2000, p. 40). Historical
records of northern leopard frog distribution indicate that the frog
was once widespread; current information indicates that the northern
leopard frog no longer is found in some of these areas (Klemens 2000,
p. 41). The northern leopard frog is considered a ``Special Concern''
species under Connecticut's State Endangered Species Act (Connecticut
Department of Environmental Protection 2005, Appendix 1-b p. 18), and
the NatureServe rank is S2 (Imperiled) (NatureServe 2011, p. 1). There
is no open season for taking northern leopard frogs in Connecticut
(Title 26 Fisheries and Game, Department of Environmental Protection
Sec. 26-66-13).
Northern leopard frogs experienced a die-off in the 1960s or early
1970s in northeastern Illinois, but have since recovered in localized
areas where extensive wetland habitat still occurs (Mierzwa 1998, p.
117). The northern leopard frog is less common in areas where
significant wetland loss has occurred (Mierzwa 1998, p. 117).
Statewide, the northern leopard frog is considered to be abundant with
a stable and secure population trend in Illinois (S5 (Secure) ranking
from NatureServe) (Smith and Keinath 2007, p. 14; NatureServe 2011, p.
1). However, most amphibian sampling efforts in Illinois have been
largely opportunistic, and data are likely insufficient to accurately
determine changes in distribution and abundance of species such as the
northern leopard frog (Illinois Department of Natural Resources 2005,
p. 102). The Illinois Comprehensive Wildlife Conservation Plan and
Strategy identified the northern leopard frog as a non-game indicator
species for improving wetland habitat (Illinois Department of Natural
Resources 2005, p. 172). It is unlawful to take, possess, buy, sell,
offer to buy or sell or barter any reptile, amphibian, or their eggs or
parts taken from the wild in Illinois for commercial purposes unless
otherwise authorized by statute (17 Illinois Adm. Code Section 880-10).
If a person possesses a valid fishing license, they may take up to
eight northern leopard frogs per day (17 Illinois Adm. Code Section
880-20, 880-30).
The northern leopard frog's range in Indiana includes northern and
eastern Indiana. Minton (1998, pp. 217-220) noted significant declines
in the northern leopard frogs populations based on observations he made
from 1948 to 1993 throughout Indiana. The species is listed as a
Species of Greatest Conservation Need in the Indiana Comprehensive
Wildlife Strategy, listed as a Species of Special Concern by the
Indiana Department of Natural Resources, and is ranked as Imperiled
(S2) by NatureServe (Indiana Department of Natural Resources 2006, p.
30; NatureServe 2011, p. 1). In Indiana, an individual with a valid
hunting or fishing license may collect up to four northern leopard
frogs for non-commercial purposes (Indiana Department of Natural
Resources 2011, p. 11).
The northern leopard frog is known historically from 22 counties in
northern Kentucky (Kentucky Department of Fish and Wildlife Resources
2010, Amphibian Species Accounts, Northern leopard frog).
[[Page 61906]]
However, the species is considered to be decreasing in Kentucky, and
populations have declined throughout the frog's historical State range.
Kentucky Department of Fish and Wildlife Resources' recent survey
records (1984-2004) show northern leopard frogs persisting in 10
counties, and no longer present in 12 counties (Kentucky Department of
Fish and Wildlife Resources 2010, Amphibian Species Accounts, Northern
leopard frog). The species is considered to be a Species of Greatest
Conservation Need and ranked by NatureServe as Vulnerable (S3)
(Kentucky Department of Fish and Wildlife Resources 2010, Appendix 1-1
p. 6; NatureServe 2011, p. 1). The northern leopard frog may be
collected for personal bait use in Kentucky (301 Kentucky
Administrative Regulations 1:130).
The northern leopard frog is a Species of Special Concern in Maine
(Maine Department of Inland Fisheries and Wildlife 2005, p. 28) and is
listed as a Priority 3 Species of Greatest Conservation Need in the
Comprehensive Wildlife Conservation Strategy (Maine Department of
Inland Fisheries and Wildlife 2005, p. 90). The Maine Department of
Inland Fisheries and Wildlife chose this ranking due to the low to
moderate potential for the northern leopard frog to become extirpated
in the State, but concerns remain regarding restricted distribution,
status, or extreme habitat specialization. Currently, the present
abundance and population trend for the northern leopard frog in Maine
are unknown (Smith and Keinath 2007, p. 14), and NatureServe ranks the
species as S3 (Vulnerable) (NatureServe 2011, p. 1). A wildlife or fish
possession permit is required from the Commissioner to take, possess,
or hold in captivity northern leopard frogs (Maine Department of Inland
Fisheries and Wildlife 2009, p. 1).
The northern leopard frog occurs Statewide in Massachusetts, except
in Barnstable, Dukes, and Nantucket Counties (Massachusetts Division of
Fisheries and Wildlife 2006, p. 406). Due to the widespread release of
captive northern leopard frogs, their historical distribution and
native status in Massachusetts is uncertain (Cardoza and Mirick (2002)
in Massachusetts Division of Fisheries and Wildlife 2006, p. 406). As
part of the Massachusetts Audubon Herp Atlas Project (1992 through
1998), the northern leopard frog was reported to be well-distributed
and confirmed from approximately 13 percent of the quadrants
(Massachusetts Division of Fisheries and Wildlife 2006, p. 406). Though
the northern leopard frog is not listed in Massachusetts (Massachusetts
Division of Fisheries and Wildlife 2006, p. 107), because its status in
the State is unclear, it is a species of regional conservation concern,
a Species of Special Concern, and a Species of Greatest Conservation
Need in the Massachusetts Comprehensive Wildlife Conservation Strategy
(Massachusetts Division of Fisheries and Wildlife 2006, pp. 137, 274,
292, 343, 348). There is a closed season on the hunting, fishing,
taking and possession of northern leopard frogs in Massachusetts
(Massachusetts Division of Fisheries and Wildlife 2002, p. 1).
NatureServe ranks the northern leopard frog in Massachusetts as S3/S4
(Vulnerable/Apparently Secure) (NatureServe 2011, p. 1).
The Michigan Department of Natural Resources describes the northern
leopard frog's distribution in Michigan as unknown, but considered
patchy, and notes that it appears to be declining based upon the lack
of reports compared to historical records from the current Frog and
Toad Surveys (Eagle et al. 2005, Species of Greatest Conservation Need,
p. 152; Smith and Keinath 2007, p. 14). The northern leopard frog is a
Species of Greatest Conservation Need in Michigan's Wildlife Action
Plan (Eagle et al. 2005, p. 20 in Aquatic Threats by Species of
Greatest Conservation Need), but is ranked by NatureServe as S5
(Secure) (NatureServe 2011, p. 1). In Michigan, an all-species fishing
license is required to take northern leopard frogs for personal bait
use (Michigan Department of Natural Resources 2011, p. 9).
The northern leopard frog is a Species of Concern in New Hampshire
and ranked as S3 (Vulnerable) by NatureServe (2011, p. 1). Possession
of northern leopard frogs in New Hampshire is prohibited without a
permit (New Hampshire Fish and Game Department 2011, p. 1).
Distribution records from 1992 to 2004 were verified for Coos,
Merrimack, Rockingham, and Sullivan Counties; reports from a number of
other towns have not been verified with a voucher photograph or
specimen (New Hampshire Fish and Game Department 2005, p. A-209).
Throughout the area that the ranges of northern leopard frogs and
pickerel frogs (Lithobates palustrus) overlap, it is important to
verify distribution records via a photograph or a specimen as northern
leopard frogs are commonly confused with pickerel frogs. New Hampshire
is the only State we found that appears to require this information for
distribution records. Based upon this information, it is likely that
the current distribution of northern leopard frogs in New Hampshire is
unknown.
The northern leopard frog is not identified as species of greatest
conservation need or a species of concern in the Comprehensive Wildlife
Conservation Strategy for New York (New York Department of
Environmental Conservation 2005, p. 73), and NatureServe (2011, p. 1)
ranks the northern leopard frog as S5 (Secure). Persons holding a
freshwater fishing license or combined hunting and fishing license
(including those entitled to fish without a license) may take northern
leopard frogs for personal bait use (except in New York City, Suffolk
County, and Nassau County), and frogs may be imported, bought, and sold
at any time (New York Department of Environmental Conservation 2010,
pp. 10-11, 16). The northern leopard frog distribution map for New York
shows it having a very wide distribution throughout the State (New York
Department of Environmental Conservation 2011, p. 1), but local
herpetologists have reported declines throughout New York (O'Donnell
2011, pers. comm.). It is likely that the current abundance and
population trends for northern leopard frogs in New York are unknown
(Smith and Keinath 2007, p. 14).
The northern leopard frog is broadly distributed throughout Ohio
and is considered to be secure by the Ohio Department of Natural
Resources, Division of Wildlife (2005, pp. 125, 138, 143) and other
sources (Smith and Keinath 2007, p. 14). Currently, NatureServe does
not have a ranking for Ohio (NatureServe 2011, p. 1). In Ohio, a permit
is required to possess northern leopard frogs (Ohio Revised Code
1531.02). Walker (1946, p. 88) described the northern leopard frog as
being one of the most abundant frogs in Ohio. It is still considered to
be locally abundant, but it does appear to be declining where wetlands
have been drained. The range appears to be contracting in the
southeastern counties where extensive field efforts have yielded few
recent records (Ohio Frog and Toad Calling Survey 2011, p. 1).
The current distribution, abundance, and population trend for
northern leopard frogs in Pennsylvania is unknown (Smith and Keinath
2007, p. 14; Gipe 2011, pers. comm.). The Comprehensive Wildlife
Conservation Strategy states that there has been a reduction in the
northern leopard frog's range, and although it was previously common in
Pennsylvania and the northeast, it is suspected that it has
significantly declined in recent years (Pennsylvania Game Commission
and
[[Page 61907]]
Pennsylvania Fish and Boat Commission 2005, p. 10-41). The northern
leopard frog is considered a Priority Conservation Tier 5 Species, and
the need for a long-term monitoring program is identified (Pennsylvania
Game Commission and Pennsylvania Fish and Boat Commission 2005, p. 10-
41). This conservation priority tier represents species that are fairly
secure in Pennsylvania, but for which the Pennsylvania Biological
Survey recommends some level of management attention. NatureServe
(2011, p. 1) ranks the northern leopard frog in Pennsylvania as S2/S3
(Imperiled/Vulnerable). The collection of one northern leopard frog per
day from Pennsylvania waters requires a fishing license, but a license
is not required to take a frog from land (Pennsylvania Fish and Boat
Commission 2011, pp. 1-2).
The northern leopard frog is a Species of Greatest Conservation
Need and ranked by NatureServe as S2 (Imperiled) in Rhode Island (Rhode
Island Department of Environmental Management, Division of Fish and
Wildlife 2005, p. 24; NatureServe 2011, p. 1). Rhode Island currently
has one small population of northern leopard frogs on an island;
several other populations have been extirpated in recent years
(O'Donnell 2011, pers. comm.). The removal from the wild, for any
purposes, of northern leopard frogs is prohibited in Rhode Island,
except by special permit (Rhode Island Department of Environmental
Management, Division of Fish and Wildlife 2011, p. 38).
The Vermont Fish and Wildlife Department considers the northern
leopard frog to be secure in Vermont (Kart et al. 2005, p. 1 Secure
Species Summary; NatureServe 2011, p. 1). The species is distributed
along the western edge of Vermont and then scattered populations are
documented throughout the rest of the State (Kart et al. 2005,
Distribution Map). Collection of northern leopard frogs for scientific
research, education purposes, or for the purpose of using them as the
subjects of art or photography is authorized through issuance of a
scientific collection permit; other collections or take are authorized
by Commissioner Letter with a valid hunting license (Vermont Fish and
Wildlife Regulations Title 10, Chapter 1, Section 25).
The West Virginia Natural Heritage Program and NatureServe list a
State rank of S2 (Imperiled) for the northern leopard frog (West
Virginia Natural Heritage Program 2007, p. 11; NatureServe 2011, p. 1).
The species is also listed as a Species in Greatest Need of
Conservation (West Virginia Division of Natural Resources 2005, pp. 4F-
Habitats-20, 5F-49, 5F-56). Statewide surveys were conducted between
March 2008 and April 2009 to determine the status and distribution of
northern leopard frogs in West Virginia (Spriggs 2009, p. 17). Surveys
of 70 sites found only four occupied sites and only one of the sites
constituted a breeding population (only single adult or juvenile frogs
were located at the three other locations) (Spriggs 2009, pp. 38-39).
In 2010, surveyors searched for northern leopard frogs at the known
breeding population at Greenbottom Wildlife Management Area, West
Virginia (including one day with four experienced surveyors), and found
only one dead northern leopard frog (O'Donnell 2011, pers. comm.).
Based upon Statewide survey data collected, Spriggs (2009, p. 29)
recommended that the northern leopard frog NatureServe rank be changed
to S1 (Critically Imperiled).
Canada
Historically, the northern leopard frog ranged across Canada from
British Columbia to Nova Scotia. Canada represents approximately half
of the current range of the northern leopard frog based on an
estimation of land area in the United States and Canada. Within Canada,
the northern leopard frog's range includes small to large portions of
the area within the Northwest Territories, British Columbia, Alberta,
Saskatchewan, Manitoba, Ontario, Quebec, New Brunswick, Nova Scotia,
Prince Edward Island, and Newfoundland. The distribution of northern
leopard frogs in western Canada is more closely tied to major river
drainages than is the species' distribution in eastern Canada (Seburn
and Seburn 1998, p. 9).
The northern leopard frog is uncommon in the Northwest Territories
and is historically known from nine sites (Fournier 1997, p. 104).
These historical locations encompass a small area between the northern
borders of Alberta and Saskatchewan and the southern border of Great
Slave Lake (Weller and Green 1997, p. 323). Since 1980, a few frogs
have been reported from three sites (Seburn and Seburn 1998, p. 6). The
northern leopard frog is considered rare within this restricted range,
and a lack of data precludes any determination of a population trend
(Fournier 1997, p. 104). The northern leopard frog is not ranked in the
Northwest Territories by NatureServe (NatureServe 2011, p. 1).
In British Columbia, the northern leopard frog historically
occurred in the Kootenay and Columbia River valleys and in the Rocky
Mountains east of Fernie (Seburn and Seburn 1998, p. 6). Currently,
there is one native northern leopard frog population remaining at the
Creston Valley Wildlife Management Area (estimated population less than
60 adults), plus one introduced population that has likely been
extirpated (Committee on the Status of Endangered Wildlife in Canada
2009, pp. 42-43). The British Columbia (or Rocky Mountain) population
is listed as Endangered under the Species at Risk Act (Statues of
Canada 2002, c.29), 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 (Revised Statutes of British Columbia
1996, c. 488). The northern leopard frog is ranked as critically
imperiled (S1) (NatureServe 2011, p. 1) in British Columbia.
Historically, northern leopard frogs were widely distributed and
locally abundant in central and southern Alberta, and in the extreme
northeastern region of the province (Alberta Northern Leopard Frog
Recovery Team 2005, p. 3). Beginning in 1979, the northern leopard frog
disappeared suddenly from much of its range in Alberta (Roberts 1992,
p. 14; Seburn and Seburn 1998, p. 10). All previously known populations
in central Alberta are no longer present, and to the south, populations
have disappeared or are restricted to small, fragmented habitats with
limited opportunity for dispersal (Roberts 1992, p. 14). In 1990-1991
and 2000-2001, province-wide surveys were conducted to determine the
distribution of northern leopard frogs in Alberta. In the first survey,
24 sites were found to be occupied; the more recent survey found that
of 269 historical sites surveyed, only 54 supported northern leopard
frogs (Alberta Northern Leopard Frog Recovery Team 2005, p. 4).
Currently, the northern leopard frog is thought to occur in about 20
percent of historically occupied areas in Alberta (Wilson et al. 2008,
p. 864), and the NatureServe ranking is S2/S3 (imperiled/vulnerable)
(NatureServe 2011, p. 1). The species is listed as Threatened under
Alberta's Wildlife Act (Revised Statutes of Alberta 2000, Chapter W-
10), and a recovery plan was prepared in 2005 (Alberta Northern Leopard
Frog Recovery Team 2005).
Historically, northern leopard frogs were considered to be
widespread and abundant in Saskatchewan (Seburn 1992, p. 18). However,
the northern leopard frog experienced significant declines in the 1970s
and is now absent
[[Page 61908]]
throughout most of its historical range (Didiuk 1997, p. 112; Weller
and Green 1997, p. 323). Currently, the number of northern leopard frog
populations in Saskatchewan is unknown, and there is no data to
evaluate the population trends (Didiuk 1997, p. 112). Anecdotal
information indicates that populations may be recovering (Seburn 1992,
pp. 17-18), but declines and die-offs have also been reported and the
overall population status is unknown (Committee on the Status of
Endangered Wildlife in Canada 2009, p. 29). The current range of the
northern leopard frog within Saskatchewan is thought to be
discontinuous, and the majority of occurrences are in the very southern
portion of the province (Saskatchewan Conservation Data Center 2006, p.
1). The northern leopard frog is currently on Saskatchewan's Interim
Species at Risk List (Wildlife Act 1998, Chapter W-13.12), and is
protected in provincial and national parks (Committee on the Status of
Endangered Wildlife in Canada 2009, p. vi). The NatureServe rank for
the northern leopard frog in Saskatchewan is S3 (Vulnerable)
(NatureServe 2011, p. 1).
In Manitoba, northern leopard frogs suffered a significant die-off
from 1975-1976, and within a year were absent from previously known
population cores (Koonz 1992, p. 19; Committee on the Status of
Endangered Wildlife in Canada 2009, p. 29). Since this time,
populations have increased in some areas and remained extremely low in
others (Koonz 1992, p. 20). Northern leopard frogs are not monitored in
Manitoba and the current number and distribution of extant populations
is not known (Committee on the Status of Endangered Wildlife in Canada
2009, p. 29). The current NatureServe rank for the northern leopard
frog in Manitoba is S4 (secure) (NatureServe 2011, p. 1).
The northern leopard frog is thought to be common, widespread, and
secure throughout southern and central Ontario, with sparse
distribution in the north (Weller and Green 1997, p. 323; NatureServe
2011, p. 1). The species is currently listed as ``Not at Risk'' under
the Ontario Endangered Species Act of 2007 (Statutes of Ontario 2007,
Chapter 6) and under the Canadian Species at Risk Act (Ontario Nature
2011, p. 2). However, as with many parts of Canada, northern leopard
frog populations have declined precipitously, particularly in northern
and southwestern Ontario (Hecnar 1997, p. 9; Seburn and Seburn 1998, p.
10; Committee on the Status of Endangered Wildlife in Canada 2009, p.
29; Desroches et al. 2010, pp. 308-309). Although the widespread
declines of the 1970s did not occur in Ontario as they did in the
provinces to the west, relatively recent mass mortality events
resulting from ranavirus have been documented in Ontario (Greer et al.
2005, p. 11; Committee on the Status of Endangered Wildlife in Canada
2009, p. 29). A 4-year study in the eastern and central regions of the
province found declines of 23 percent (1992-1993) and 5 percent (1993-
1994) in abundance of northern leopard frogs (Hecnar 1997, pp. 9, 11;
Committee on the Status of Endangered Wildlife in Canada 2009, p. 29).
Regional declines of northern leopard frogs have also been documented
in southern Ontario, including the southern Great Lakes Region
(Committee on the Status of Endangered Wildlife in Canada 2009, pp. 29-
30). Hecnar (1997, p. 11) notes, ``Anecdotal reports suggest that R.
pipiens is the most abundant frog in the Essex Plain. During this study
(1992-1993), R. pipiens declined in occurrence across all regions of
southwestern Ontario.''
The northern leopard frog is widely distributed throughout the
southern region of Quebec, with sparse populations in the central
region of the province (Weller and Green 1997, p. 323). Weller and
Green (1997, p. 323) note that there is no evidence of historic or
recent declines in Quebec, but Gilbert et al. (1994, p. 468) found
lower densities of northern leopard frog egg masses than reported in
Wisconsin and anecdotal declines of northern leopard frogs in the
Richelieu River system of Quebec. Bonin (1992, p. 24) states that
trends in northern leopard frog populations in Quebec are not known
based upon data collected for the Amphibian and Reptile Atlas. In
addition, Desroches et al. (2010, pp. 308-309) found that the northern
leopard frog was uncommon on the Quebec side of James Bay.
In New Brunswick, the northern leopard frog is distributed
throughout the province and populations are thought to be secure (S5
NatureServe rank) (McAlpine 1997, p. 123; Weller and Green 1997, p.
323; NatureServe 2011, p. 1). The northern leopard frog occurs
throughout mainland Nova Scotia and Cape Breton Island and is
considered to be secure (S5 NatureServe rank) with no evidence of
declines (Weller and Green 1997, p. 323; NatureServe 2011, p. 1). On
Prince Edward Island, the northern leopard frog status is apparently
secure (S4) or secure (S5) (NatureServe 2011, p. 1).
In Newfoundland, the northern leopard frog was introduced to the
western side of the island on several occasions, but is no longer
present (Buckle 1971, p. 74; Maunder 1997, p. 94). The species is at
the edge of its range in Labrador, but occurs in a few, discrete
locations that are apparently secure (Committee on the Status of
Endangered Wildlife in Canada 2009, p. 30; NatureServe 2011, p. 1).
Summary
In summary, the northern leopard frog appears to be absent or
declining throughout a large portion of its historical and current
range in the western United States and western Canada (Rorabaugh 2005,
pp. 570-571). The species generally tends to be more abundant and more
secure in the eastern portion of its range, but there are indications
that local, and possibly regional, declines may also be occurring in
the eastern United States (such as in Connecticut, Indiana, Kentucky,
Maine, Massachusetts, Michigan, New Hampshire, Rhode Island, and West
Virginia) as well. Historically, regional declines in the western
United States and Canada occurred in the 1960s through 1970s, and since
this time the northern leopard frog has either not recovered in many of
these areas (such as in Alberta, Arizona, British Columbia, Colorado,
Idaho, western Montana, Nevada, New Mexico, Oregon, Texas, Washington,
and western Wyoming) or the status of that recovery is unknown due to a
lack of information regarding changes in the number of sites occupied
across the species' range over time (such as in Manitoba, Minnesota,
Saskatchewan, and Utah). Occupancy trend data are also lacking
throughout much of the western and eastern portions of the northern
leopard frog's range where the northern leopard frog's status appears
to be stable or where it is unknown (such as in Iowa, Illinois,
Nebraska, New York, North Dakota, Ontario, Pennsylvania, South Dakota,
and Wisconsin), and as such, the overall range status is likely
unknown. However, despite the lack of occupancy trend data, information
indicates that in the eastern United States and eastern Canada, the
northern leopard frog is still widespread and relatively common.
Distinct Vertebrate Population Segment
We consider a species for listing under the Act if available
information indicates such an action might be warranted. ``Species'' is
defined by the Act as including any subspecies of fish or wildlife or
plants, and any distinct population segment (DPS) of any species of
vertebrate 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 61909]]
the Policy Regarding the Recognition of Distinct Vertebrate Population
Segments (61 FR 4722; February 7, 1996), to help us in determining what
constitutes a DPS. The policy identifies three elements that are to be
considered regarding the status of a possible DPS. 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 (i.e., is the population segment, when treated as
if it were a species, is endangered or threatened?) (61 FR 4722;
February 7, 1996). The first two elements are used to determine if a
population segment constitutes a valid DPS. If it does, then the third
element is used to consider whether such DPS warrants listing. In this
section, we will consider the first two criteria (discreteness and
significance) to determine if the western northern leopard frog is a
valid DPS (i.e., a valid listable entity). Our policy further
recognizes it may be appropriate to assign different classifications
(i.e., threatened or endangered) to different DPSes of the same
vertebrate taxon (61 FR 4722; February 7, 1996).
Discreteness
Under the DPS policy, a population segment of a vertebrate species
may be considered discrete if it satisfies either one of the following
two 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 (separation based on genetic or morphological characters)
may provide evidence of this separation.
(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.
Marked Separation
In our evaluation of discreteness under the DPS policy, we
primarily used the results of two recent genetic studies (Hoffman and
Blouin 2004a, pp. 145-159; O'Donnell et al. 2011, pp. 1-11) to evaluate
whether any populations of the northern leopard frog should be
considered markedly separate. We based our determination on these two
studies because they provided comprehensive data on the genetic
variation across the range of the species. The petition to list a
``western DPS'' of the northern leopard frog was mainly based on the
genetic information and conclusions from the study by Hoffman and
Blouin (2004a). There has since been an additional genetic study
conducted on the species by O'Donnell et al. (2011) that we also used
in this 12-month finding. We found no other relevant information
regarding the other factors to consider in evaluating population
discreteness, such as physical, physiological, ecological, or
behavioral factors, or morphological characters. We therefore focused
our analysis on these two genetic studies in determining whether the
best available information supports that there are discrete populations
of the northern leopard frog that would be considered markedly separate
under our DPS policy.
Hoffman and Blouin (2004a) reported two different lineages (lines
of descent from a common ancestor) of mitochondrial DNA (mtDNA)
haplotypes in northern leopard frogs. Analyzing mtDNA data is one way
to measure the genetic variation within a species. When mtDNA lineages
are geographically localized and separated by geographic barriers, this
information can be used to identify evolutionarily separate units when
it is used in combination with patterns displayed by other genetic
markers (Avise 2004, p. 301). A haplotype refers to a set of closely
linked genetic markers present on one chromosome that tend to be
inherited together. The more similar these genetic markers, or
haplotypes, are in a given sample of frogs, the more closely related
those frogs are likely to be (with the opposite also being the case).
This study (Hoffman and Blouin 2004a, p. 152) showed haplotypes of
mtDNA genetic markers grouping into a ``western'' lineage, occurring
mostly west of the Mississippi River and Great Lakes region in the
United States and Canada, and an ``eastern'' lineage, occurring to the
east of this area.
The initial study by Hoffman and Blouin (2004a, pp. 146, 150) found
that on a broad scale the eastern and western haploypes have diverged
for approximately 2 million years, indicating that the western and
eastern lineages have likely been separate to some degree for a long
time period, with secondary contact following Pleistocene glaciation
events that occurred in North America (Hoffman and Blouin 2004a, p.
152). The overall differences were measured at approximately 4 percent
sequence divergence, and this amount of mtDNA divergence is considered
to be relatively high and is comparable to the differences found
between some other recognized ranid frog species (Jaeger et al. 2001,
p. 344; Hoffman and Blouin 2004a, p. 152). Hoffman and Blouin (2004a,
p. 152) note that mtDNA divergence alone is not enough evidence to
split eastern and western lineages into separate species and that more
taxonomic work (such as research regarding nuclear genetic markers,
morphology, and behavior) is needed before such a taxonomic revision
would be justified. The results of this study indicated important
genetic differences broadly between northern leopard frogs in the
eastern and western portions of North America. However, additional data
were needed to determine if the ``western'' lineage represented a
separate population of the species.
Although a preliminary administrative report, the recent O'Donnell
et al. (2011) study report by the U.S. Geological Survey was peer-
reviewed and presents the findings of a robust analysis of the genetic
variation of the northern leopard frog across its range in North
America. The study replicated the earlier mtDNA analysis but had larger
sample sizes (20-24 individuals per sample compared with 12 individuals
per sample at most sample localities) and had more sample locations in
the area of contact between the eastern and western lineages. In
addition, it also included nuclear gene sequencing as well. Nuclear
genetic sequences provided an additional way to measure genetic
variation in populations of the northern leopard frog. Because of its
maternal (mother to daughter) pattern of inheritance, mtDNA is
inherited only as a single genetic unit and has some limits in value
for evaluating recent and localized relationships within a species.
However, DNA sequences from multiple nuclear genes provided more
information from additional genetic makers. This is an important
distinction because identification of geographic subdivisions, like
judging population distinction in the case of this analysis of the
northern leopard frog, depends on the related geographic patterns of
different genetic markers (Avise 2004, p. 303).
The study by O'Donnell et al. (2011) was specifically designed to
look at the genetic relationships of the species and to supplement the
results of Hoffman and Blouin (2004) by increasing the number of
samples in the area of probable overlap of the two lineages in the
upper Midwest of the United States. The analysis for one mtDNA gene
produced similar results to that of the earlier study--with strong
divergence between east and west lineages and a narrow area of overlap
(O'Donnell et al.
[[Page 61910]]
2011, pp. 2-3). However, the study also analyzed DNA from four nuclear
genes. These nuclear genetic data still indicated deeply divergent
eastern and western lineages of the northern leopard frog. However, and
most importantly for our DPS analysis, the results of the nuclear data
showed a broad zone of introgression between the two areas (in other
words, a mixing of haplotypes) (O'Donnell et al. 2011, p. 10). We
considered this large zone of introgression as the primary reason that
a potential western population of the northern leopard frog is not
considered markedly separate from other populations of the species.
So to determine whether these two lineages should be considered
markedly separate populations and be considered discreet under our DPS
policy, we looked at the relative amount of overlap in the distribution
of northern leopard frogs that contain haplotypes from the eastern and
western lineages. Hoffman and Blouin (2004a, pp. 147, 152, 155) found
that the distributions of eastern and western haplotypes meet roughly
at the Mississippi River and Great Lakes region, initially indicating
that these geographic features may serve as physical barriers
separating the eastern and western lineages. However, the additional
nuclear genetic data from O'Donnell et al. (2011, p. 10) discussed
above indicate the eastern and western lineages are not separated along
these geographic features. Hoffman and Blouin (2004a, pp. 147, 152)
also found some areas of co-occurrence of haplotypes of both lineages
in Ontario, Canada, and indicated that this is likely the result of
more recent (during the current interglacial period in North America)
secondary contact between eastern and western lineages that were
formerly separated. In addition, O'Donnell et al. (2011) reveal that
the haplotype mixing evident in the nuclear analyses is more likely
associated with introgression and that more research is needed to
clearly explain the pattern of haplotype mixing. The full extent of
current contact (and presumably gene flow from interbreeding) between
northern leopard frogs with eastern and western haplotypes could not be
evaluated in detail as a part of earlier study because there were only
a few sample sites from the likely areas of contact in Wisconsin,
Michigan, and western Ontario and limitations due to small sample
sizes. Further, there are multiple factors that may be responsible for
the co-occurrence of frogs with eastern and western haplotypes, for
example, it is possible that the mixing of haplotypes between the east
and west in the overlap zone may be attributable in part to the
anthropogenic movement of individuals associated with the trade in
northern leopard frogs that has taken place in this area since at least
the 1950s (Gibbs et al. 1971, p. 1027; Collins and Wilbur 1979, p. 17).
Hoffman and Blouin (2004a, pp. 150-151) also found one individual
frog (from a sample of 10) from Arizona with an eastern haplotype. They
suggested this haplotype is likely not from a native frog, but from a
released pet or laboratory animal. It is reasonable to believe it was a
released eastern frog, or a descendant of one, because there is
commercial trade in leopard frogs and tadpoles transported to pet
stores, laboratories, and schools throughout the United States and
Canada for recreational and scientific uses (Fisher and Garner 2007, p.
3). Their supposition is also supported by specific genetic research
regarding this Arizona population of northern leopard frogs, which
found haplotypes of mtDNA consistent with frogs from extreme eastern
North America (from New York, New England, and adjacent areas of Quebec
and Ontario) widespread in the Stoneman Lake area of northern Arizona
(Theimer et al. 2011, p. 32).
The relatively small sample sizes (about 12 individuals were used
for most sample localities) were a disadvantage of the Hoffman and
Blouin (2004a, Appendix pp. 1-8) study in evaluating genetic variation
across a narrow part of the range. While these sample sizes were useful
for looking at broad patterns of geographic variation (which was the
object of the study), they were less useful in answering our question
of separation, because of their limited power for detecting haplotypes
that may occur at low frequencies and there were few sample sites in
the area of suspected overlap. The small differences in the amount of
genetic variation at specific locations are important because even
haplotypes at low frequencies can help us understand the relationships
between the eastern and western lineages of northern leopard frogs and
inform our determination of whether the western lineage is a markedly
separate population. The O'Donnell et al. (2011, pp. 2-9) study
utilized larger sample sizes and provides a level of detail more
appropriate and helpful to evaluate similarities and differences in
western and eastern lineages.
The results of O'Donnell et al. (2011, pp. 2-9) indicated that
neither the Mississippi River nor the Great Lakes are acting as a
physical barrier between western and eastern lineages of northern
leopard frogs. The existence of western haplotypes in northern leopard
frog populations located east of the Mississippi River and of eastern
haplotypes in northern leopard frog populations located both north and
south of the Great Lakes does not support a marked separation between
eastern and western northern leopard frogs. Although the nuclear
genetic sequences continue to show east-west trends in different
haplotypes (supporting the mtDNA data of east-west differences), these
nuclear data also indicate that western haplotypes (from frogs in the
west) occur in frogs much farther to the east than the mtDNA data
indicated. Western haplotypes of some of the nuclear genes were found
extending east of the Mississippi River to the eastern end of the Great
Lakes in New York (O'Donnell et al. 2011, pp. 6-8), and eastern
haplotypes of some of the nuclear genes were found as far west as
Nebraska (O'Donnell et al. 2011, p. 9). This area of overlap of
haplotypes spans roughly 1,900 km (1,200 mi) from east to west across
North America.
This broad co-occurrence of haplotypes of nuclear genes, as well as
the more gradual geographic trends in haplotype distributions
(O'Donnell et al. 2011, pp. 4-9), indicates there is not a marked
separation between eastern and western lineages of the northern leopard
frogs. The overlap in genetic markers across the midwestern United
States leads us to conclude that there is no physical barrier or other
processes keeping northern leopard frogs in the western part of the
range discrete from the frogs in the eastern part of the range. Ongoing
genetic analyses (such as microsatellite allele frequency analyses)
will likely provide additional information regarding geographic
patterns of genetic variation in northern leopard frogs (O'Donnell et
al. 2011, p. 10), but these data are not currently available.
Therefore, based upon the genetic information presented above (Hoffman
and Blouin 2004a, pp. 145-159; O'Donnell et al. 2011, pp. 1-10), there
does not appear to be marked separation between possible eastern and
western populations of northern leopard frogs. We do recognize that
this lack of a marked separation between the eastern and western
populations may be a result of a variety of factors, including the
anthropogenic movement of individuals for the trade in northern leopard
frogs, but at this time, we do not have data supporting this claim.
Because the potential eastern and western populations are not markedly
separate, they are not considered discrete under
[[Page 61911]]
the DPS policy. Based upon the best available information, we conclude
that the potential western U.S. population of northern leopard frog is
not genetically discrete, in other words not markedly separate, from
other northern leopard frogs.
International Border
In order to determine that the populations of northern leopard frog
in the western United States are a DPS, we must have found that the
western United States populations were discrete from populations in the
eastern United States and that the western United States populations
were discrete from population in Canada. The DPS policy allows us to
use international borders to delineate the boundaries of a DPS if there
are differences in control of exploitation, conservation status, or
regulatory mechanisms between the countries. However, because we do not
have a discrete east-west boundary of the potential DPS, we did not
conduct further analysis regarding the northern boundary of the
potential DPS between Canada and the United States.
Evaluation of Discreteness
The information discussed in the preceding section provides
information on the geographic patterns that we evaluated to determine
that the genetic information does not indicate that northern leopard
frogs from the western United States are markedly separate from other
populations of the northern leopard frog.
We note that our application of the DPS policy does not require
absolute reproductive isolation as a prerequisite to recognizing the
discreteness of a population segment. The presence of a small degree of
sharing of genetic markers would not necessarily preclude us from
concluding that there is discontinuity between populations and that
they were markedly separated. However, in this case of the northern
leopard frog, we do not have the information to make such an evaluation
of whether or not the two populations are actually reproductively
isolated. Although the genetic patterns indicate discontinuity in
eastern and western mtDNA and nuclear haplotypes, the available genetic
data do indicate there is more than a small degree of sharing of
genetic markers. Rather than a small degree of shared markers, we found
a broad extent of introgression that has western haplotypes of some
nuclear genes occurring in samples of northern leopard frogs as far as
New York. Therefore, because of the large area of overlap in haplotypes
indicating no apparent barrier between the two lineages, we conclude at
this time based on the best available scientific data that there is not
marked separation between the western and eastern U.S. populations.
This does not mean that the western and eastern populations of northern
leopard frogs, as has been suspected for many years, are not unique and
do not have significant conservation value. It simply means that, per
our policy, the best available data at this time do not support a
marked separation between the two populations, based on genetics and
other information available to us.
In conclusion, based on our review of the best available
information and pursuant to our DPS policy, we find that the western
U.S. populations of northern leopard frog are not discrete from other
populations of northern leopard frogs.
Significance
Under our DPS Policy, once we have determined that a population
segment is not discrete, we do not need to consider whether that
population segment is significant.
Conclusion
On the basis of the best available information, we determined that
the western U.S. population of the northern leopard frog is not
discrete in relation to the other populations of northern leopard frog.
Therefore, we find that the western U.S. populations of northern
leopard frog do not represent a valid DPS.
Having determined that the western U.S. populations of northern
leopard frog are not a valid DPS, we proceed below with an analysis of
threats for the northern leopard frog throughout its range.
Summary of Information Pertaining to Five Factors
Section 4 of the Act (16 U.S.C. 1533) and implementing regulations
(50 CFR part 424) set forth procedures for adding species to, removing
species from, or reclassifying species on the Federal Lists of
Endangered and Threatened Wildlife and Plants. Under section 4(a)(1) of
the Act, a species may be determined to be endangered or threatened
based on any of the following five factors:
(A) The present or threatened destruction, modification, or
curtailment of its habitat or range;
(B) Overutilization for commercial, recreational, scientific, or
educational purposes;
(C) Disease or predation;
(D) The inadequacy of existing regulatory mechanisms; or
(E) Other natural or manmade factors affecting its continued
existence.
In making this finding, information pertaining to the northern
leopard frog in relation to the five factors provided in section
4(a)(1) of the Act is discussed below.
In considering what factors might constitute threats to a species
we must look beyond the exposure of the species to a particular factor
to evaluate whether the species may respond to that factor in a way
that causes actual impacts to the species. If there is exposure to a
factor and the species responds negatively, the factor may be a threat
and, during the status review, we attempt to determine how significant
a threat it is. The threat is significant if it drives, or contributes
to, the risk of extinction of the species such that the species
warrants listing as endangered or threatened as those terms are defined
in the Act. However, the identification of factors that could impact a
species negatively may not be sufficient to compel a finding that the
species warrants listing. The information must include evidence
sufficient to suggest that these factors are operative threats that act
on the species to the point that the species may meet the definition of
endangered or threatened under the Act.
Due to the wide geographic range of the northern leopard frog, and
the diversity of habitat types which it occupies throughout its range,
there are a wide variety and relatively large number of factors that
have the potential to impact the species. However, these factors may
result in impacts at the individual, population, or species scale, and
may have a variety of effects from minor habitat degradation to
complete habitat loss and mortality. As such, it is important to
consider the magnitude and extent of impacts when assessing the factors
affecting a species, and we attempt to provide this context throughout
our discussions below.
Factor A. The Present or Threatened Destruction, Modification, or
Curtailment of Its Habitat or Range
A number of hypotheses, including habitat loss, have been proposed
for global amphibian declines (Blaustein et al. 1994, p. 61; Collins
and Storfer 2003, pp. 90-94; Stuart et al. 2004, p. 1783; Green 2005,
p. 28). In our review of the best scientific and commercial data
available, impacts that are potentially affecting northern leopard
frogs and their habitats throughout their range include habitat
destruction, habitat fragmentation, and habitat degradation resulting
from development, modification, and loss of wetland habitat. Because
the northern leopard
[[Page 61912]]
frog, an amphibian, depends upon breeding ponds, upland foraging areas,
overwintering aquatic habitats, and connectivity between these habitats
across the landscape, it is very susceptible to the destruction
(defined as complete loss of all or part of the frog's necessary
habitat), fragmentation (isolation of all or part of the frog's
necessary habitat without its alteration or destruction), and
degradation (the deleterious alteration of all or part of the frog's
necessary habitat) of its habitat (Green 2005, p. 28).
The destruction and degradation of northern leopard frog habitat
has been widespread and has affected, and continues to affect, the
species to some extent throughout its range (Maxell 2000, p. 15;
Hitchcock 2001, pp. 64-66; Rorabaugh 2005, p. 576; Clarkson and
Rorabaugh 1989, p. 535; Smith 2003, pp. 26-31). Habitat destruction and
degradation is reported to be the primary threat to all ranid and
lithobatid frogs in the United States (Bradford 2005, p. 923) and a
principal cause of decline of northern leopard frogs in the western
United States and Canada (Smith 2003, p. 4; Alberta Northern Leopard
Frog Recovery Team 2005, p. 6; Rorabaugh 2005, p. 571; Committee on the
Status of Endangered Wildlife in Canada 2009, p. 32). Factors with the
potential to impact northern leopard frog habitat include wetland loss,
agricultural development, livestock grazing, urban development, oil and
gas development, forest management, roads, groundwater withdrawal, and
air pollution. Below we present information about these factors and
discuss the magnitude and extent of the impacts from these factors on
the northern leopard frog.
Wetland Loss
As a species with aquatic and semi-aquatic life-history phases,
freshwater wetland habitat is an extremely important component of
northern leopard frog habitat. In order to discuss the different
actions that result in destruction or modification of northern leopard
frog habitat, it is important to understand what is known about the
current overall status of wetlands throughout the range of the northern
leopard frog.
It has been estimated that 53 percent of the Nation's former
wetland area was lost from the 1780s to the 1980s (Dahl 1990, p. 5). In
terms of States where the northern leopard frog occurs, Minnesota (42
percent loss), Maine (20 percent loss), Michigan (50 percent loss), and
Wisconsin (46 percent loss) have the most remaining wetland area
compared to historical times (Dahl 1990, p. 5). New Hampshire (9
percent loss) was the only State in the range of the northern leopard
frog that lost less than 20 percent of its original wetland acreage
(Dahl 1990, p. 5). California (91 percent loss), Connecticut (74
percent loss), Illinois (85 percent loss), Indiana (87 percent loss),
Iowa (89 percent loss), Kentucky (81 percent loss), Missouri (87
percent loss), and Ohio (90 percent loss) lost over 70 percent of their
original wetland acreage (Dahl 1990, pp. 5-6). The remaining States
within the range of the northern leopard frog had estimated wetland
losses ranging from 20 percent to 60 percent (Dahl 1990, p. 6).
Dahl (1990, p. 10) noted that wetland area in the lower 48 States
had declined to the point that ``environmental, and even socio-economic
benefits (ground water supply, water quality, shoreline erosion,
floodwater storage, trapping of sediments, and climatic change) are now
seriously threatened.'' The destruction and degradation of wetland and
riparian habitat is thought to represent the most widespread impact to
northern leopard frog populations in Arizona (Arizona Game and Fish
Department 2009, p. 1), Colorado (Colorado Division of Wildlife 2009,
p. 2), Idaho (Idaho Department of Fish and Game 2005), Montana (Montana
Fish Wildlife and Parks 2009, p. 2), Nevada (Nevada Department of
Wildlife 2009, p. 4), New Mexico (New Mexico Department of Game and
Fish 2009, p. 3), North Dakota (North Dakota Game and Fish Department
2009, p. 2), Utah (Utah Department of Wildlife Resources 2009, pp. 2-
3), Wisconsin (Wisconsin Department of Natural Resources 2009, p. 1),
Connecticut (Klemens 2000, p. 1), Indiana (Indiana Department of
Natural Resources 2006, p. 113), Kentucky (Kentucky Department of Fish
and Wildlife Resources 2010, p. 27), Maine (Maine Department of Natural
Resources 2005, p. 90), Massachusetts (Massachusetts Department of Fish
and Wildlife 2006, pp. 276, 292, 328), Michigan (Eagle et al. 2005,
Threats p. 20), New Hampshire (New Hampshire Fish and Game Department,
p. A-210), New York (New York Department of Environmental Conservation
2005, pp. 57-58), and Rhode Island (Rhode Island Department of
Environmental Management, Division of Fish and Wildlife 2005, p. 22).
While the total wetland losses in the United States are
significant, the information regarding status and trend of wetlands
only looks at total losses and gains of wetland area; there is no
comprehensive data assessing trends in the quality or function of lost
wetlands (Dahl 2006, p. 74). Therefore, we do not know how much of the
lost wetland habitat would have naturally functioned as northern
leopard frog habitat. In short, while the extent of wetland losses is
broad and widespread throughout the range of the species, we are unable
to assess the magnitude or severity of impact of these losses at the
species scale. There have most likely been losses of northern leopard
frog habitat concurrent with these wetland losses, but large areas of
wetland remain intact in many States, particularly in the eastern
portion of its range in the United States. Further, the data above
address total change in wetland area without reference to the causes of
the losses; thus it is difficult to relate past losses to future losses
in this context. Ongoing impacts to northern leopard frog habitats will
be discussed more specifically in the following sections.
Since the late 1980s, creation of new wetland area has occurred,
although the rate of replacement area is much slower than the
historical loss rate (Dahl 1990, p. 5). Data collected from 1998 to
2004 indicate that for the first time since uniform monitoring began,
wetland creation actions resulted in a larger net gain of wetlands than
net loss of wetlands during this time period (Dahl 2006, p. 15).
However, the location and types of wetlands that represent this gain in
wetland acres has not necessarily resulted in the creation of northern
leopard frog habitat. In terms of location, a majority of the wetland
areas gained were created in the southeast, particularly in Florida,
which is outside the range of the northern leopard frog (Dahl 2006, p.
62). Further, review of created ponds from 1986 to 1997 indicates that
only 2 percent of these ponds were reclassified as vegetated wetlands;
most created ponds are designed and maintained to function as open
water basins--deep waters with little vegetated shoreline and steep
slopes--that are not conducive to northern leopard frog breeding,
foraging, or dispersal (Hine et al. 1981, p. 12; Leja 1998, p. 351;
Semlitsch 2000, p. 624). All of the created ponds that Dahl (2006, pp.
76-78) noted were manmade farm ponds, freshwater fishing ponds,
detention ponds, and aquaculture ponds. Deepwater lakes and reservoirs
also increased in area over this time period (typically associated with
urban development) (Dahl 2006, p. 78). Many of these ponds or open
water bodies are not an equivalent replacement for vegetated wetlands
(Dahl 2006, p. 76), and although they count towards the total of
wetland area in the conterminous United States, they do not necessarily
indicate a gain in northern
[[Page 61913]]
leopard frog habitat, particularly if water quality, vegetation, and
native species are not objectives for the created wetland.
In Canada, wetland loss has also occurred throughout the range of
the northern leopard frog. Wetland habitat quality is considered to be
a limiting factor for the one remaining northern leopard frog
population in British Columbia (Committee on the Status of Endangered
Species in Canada 2009, p. 16). It is estimated that approximately 60
percent of basins and 80 percent of wetland margins in the 1980s in
southern Alberta were degraded and that local extirpations of northern
leopard frogs likely occurred as a result (Alberta Northern Leopard
Frog Recovery Team 2005, p. 6). By 1990, approximately 20 percent of
prairie wetlands that likely functioned as northern leopard frog
habitat in Manitoba were lost (Committee on the Status of Endangered
Species in Canada 2009, p. 17). Similar patterns of significant wetland
loss have occurred in southern Ontario and southern Quebec.
Historically, 69 percent of southwestern Ontario consisted of wetlands;
however, it is estimated that as much as 90 percent of southwestern
Ontario wetlands no longer exist (Committee on the Status of Endangered
Species in Canada 2009, p. 17). Again, similar to the situation in the
United States, we do not have information assessing how much of this
lost habitat may have functioned as northern leopard frog habitat or if
any mitigation (such as created wetlands) has resulted in replacement
habitat. While it is likely there have been losses of northern leopard
frog habitat concurrent with these wetland losses, large areas of
wetland remain intact, particularly in the eastern portion of Canada.
Across the range of the species, it is clear that significant total
wetland area has been lost since colonial times. It is logically
certain that some of these areas represented historic habitat for
northern leopard frogs; however, it is not possible to assess the
extent of loss of actual northern leopard frog habitats based on a
generalized review of loss of wetlands. Further, while wetland losses
have occurred, large areas of wetland remain, particularly in the
eastern portion of the United States and Canada.
Agricultural Development
Agricultural development has occurred across the range of the
northern leopard frog, but particularly in the Midwestern States of the
United States (Leja 1998, p. 349). The U.S. Department of Agriculture,
Natural Resource Conservation Service (USDA NRCS) has a broad land
cover and use map that shows by State the amount of land in cropland,
pastureland, rangeland, forest land, developed land, Federal lands, and
other lands. Data from this map shows that greater than 80 percent of
the total land area (outside Federal lands) in Iowa, Nebraska, North
Dakota, and South Dakota is used for agricultural purposes, such as
cropland, pastureland, and rangeland (USDA NRCS 2001). In addition,
many other western and Midwestern States also have significant amounts
of land identified as agricultural within the range of the northern
leopard frog (USDA NRCS 2001). While agricultural development continues
to be a large land-use practice in South Dakota (57 percent cropland),
North Dakota (35 percent cropland), and Ohio (45 percent cropland)
(USDA NRCS 2001), the northern leopard frog appears to be relatively
stable in these States (Hossack et al. 2005, p. 428; Rorabaugh 2005, p.
571), despite this level of usage.
Agricultural development may fragment, destroy, or degrade northern
leopard frog habitat directly due to conversion of native habitats to
cropland and de-watering of adjacent habitats, or indirectly through
the introduction of contaminants and invasive species into habitats
(Wang et al. 1997, p. 10; Leonard et al. 1999, p. 58; Leja 1998, pp.
345-353; Knutson et al. 2004, p. 675; Rorabaugh 2005, p. 576). Most of
the historic wetland loss discussed above is thought to be due to
conversion to agriculture (Leja 1998, p. 349). Agricultural development
can result in modification of river valley habitat, including draining
of wetlands, channelization and damming of rivers, and 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 (Scott and Jennings 1985,
p. 19; Lannoo et al. 1994, pp. 317-318; Leja 1998, pp. 345-353; Knutson
et al. 2000, p. 139; Ammon 2002, p. 2; Idaho Department of Fish and
Game 2005, Northern leopard frog species account; Colorado Division of
Wildlife 2009, p. 1; Rogers 2010, p. 8). For example, in Idaho, Camas
NWR is losing wetlands to groundwater depletion by nearby agriculture,
and Grays Lake NWR and Minidoka NWR cannot control water levels because
of senior water rights assigned to other agencies, and their use for
agriculture (Fisher and Mitchell 2009, pers. comm.). In Canada, the
past conversion of large areas of grassland to agriculture has also
likely resulted in the loss of northern leopard frog habitat,
particularly foraging and overwintering habitats near breeding sites
(Didiuk 1997, p. 113; Hecnar 1997, p. 13). In southern Alberta,
drainage of wetlands for agricultural use in the 1980s was extensive
and is thought to have contributed to local extirpations of northern
leopard frogs (Alberta Northern Leopard Frog Recovery Team 2005, p. 6).
The land being used for agriculture in the prairies has lately
increased by 62 million acres (25 million hectares), and there is
pressure to alter remaining wetland areas (Committee on the Status of
Endangered Wildlife in Canada 2009, p. 32).
Geographically isolated (or depressional) wetlands surrounded by
upland watersheds (such as the prairie potholes region) make up a large
proportion of the wetland resource in arid and semi-arid regions of the
northern leopard frog's range (Skagen et al. 2008, p. 594). However,
although the ``wet'' (surface water) portion of the wetland is vitally
important for northern leopard frog breeding, the upland terrestrial
habitat adjacent to the wetland is also a critical component of their
habitat needs (Semlitsch 2000, p. 620; Pope et al. 2000, p. 2506;
Gibbons 2003, p. 630; Semlitsch and Bodie 2003, p. 1223). Although
agricultural development may result in the maintenance or creation of
actual ``wet'' wetland habitat (Leja 1998, p. 350), crops and
pastures--areas that provide poor or no habitat for northern leopard
frog--typically occur on the immediate edge of the water (Guerry and
Hunter 2002, p. 752; Committee on the Status of Endangered Species in
Canada 2009, p. 32). Research indicates that land use practices around
the wetland may be as important as the size of the wetland itself
(Findlay and Houlahan 1997, p. 1007). Amphibian species richness
increases with wetland area, and herpetofauna abundance, including the
northern leopard frog, show a strong positive correlation with the
proportion of forest cover on lands within 1.2 mi (2 km) of wetlands
(Findlay and Houlahan 1997, pp. 1006-1007). Northern leopard frogs
breeding in active agricultural lands may end up crossing roads and
tilled agricultural fields which would increase the likelihood of
mortality, and northern leopard frogs that breed in active agricultural
lands require larger home ranges than do frogs that breed in intact
wetlands and grasslands (Pember et al. 2002, p. 4.9)
Habitat fragmentation caused by agriculture has also likely limited
northern leopard frog dispersal, as frogs may have difficulty moving
through active croplands (Didiuk 1997, p. 113;
[[Page 61914]]
Saskatchewan Conservation Data Centre 2006, p. 2). Agricultural
development also tends to result in disturbed ground, which can impact
the distance and the quality of habitat between habitat patches (Didiuk
1997, p. 113; Pember et al. 2002, p. 4.9; Alberta Northern Leopard Frog
Recovery Team 2005, p. 6; Mazerolle and Desrochers 2005, p. 455;
Committee on the Status of Endangered Wildlife in Canada 2009, p. 32).
Barren land, agricultural lands, and recently cut forests increase the
resistance of the landscape to northern leopard frog movement
(Mazerolle and Desrochers 2005, p. 462). Vegetation on undisturbed
sites likely reduces evaporative water loss in dispersing or moving
frogs through protection from the wind and sun (reduced dehydration),
while surfaces with no vegetative cover likely endanger individual
frogs and constitute barriers to frog movement (Mazerolle and
Desrochers 2005, p. 462). In addition, agriculturally induced habitat
fragmentation can increase the role of genetic drift, which may hamper
adaptive responses to local environments (Johansson et al. 2007, p.
2699). Research regarding the European common frog (Rana temporia)
found that populations in fragmented agricultural habitats were smaller
and had lower genetic diversity compared to populations in a more
continuous landscape. More genetic diversity leads to healthier
populations. Breeding pond isolation, resulting from fragmented
landscapes, has also been shown to negatively affect population
persistence and recolonization of ranid and lithobatid frogs to
suitable habitats (Witte et al. 2008, p. 381).
Agriculture is also the primary source of water pollution
throughout the western range of the northern leopard frog and occurs
primarily through sedimentation, nutrient pollution, pesticide
pollution, and mineral pollution (Ribaudo 2000, pp. 5-11). On many
NWRs, pesticide and herbicide use are regulated by Service Pesticide
Use Plans, but these plans may not adequately account for toxicity to
northern leopard frogs, and thus pesticide and herbicide use may result
in impacts to individuals or populations of the species (Dickerson and
Ramirez 1993, pp. 1-2; Fisher and Mitchell 2009, pers. comm.).
Overwintering northern leopard frogs in permanent waters are likely to
be in close contact with sediments on the pond bottom that may contain
agricultural chemicals resulting from run-off (Didiuk 2007, p. 113).
This close contact with chemicals may make the northern leopard frog
more susceptible to potential adverse chemical effects in these areas.
Leopard frogs that inhabit agricultural wetlands and landscapes are
also vulnerable to pesticide exposure (King et al. 2008, p. 13) (see
Pesticides under Factor E for further discussion). In addition,
``hotspots'' of amphibian malformations, including northern leopard
frog malformations, tend to occur in altered wetlands (Lannoo 2008, p.
200) (see Malformations under Factor E for further discussion).
As described above, agricultural development has been shown to
result in adverse effects to northern leopard frogs in some portions of
its range. The above review of the best available information indicates
that large areas of historical habitat have likely been lost due to
agricultural development and that current habitats may continue to be
subject to ongoing impacts of agricultural development. The most
significant impacts associated with agricultural development are likely
the loss of historical habitats due to conversion to agricultural
lands. Ongoing impacts to areas currently associated with agriculture
likely negatively impact local populations through reduced breeding
success and individual survival. However, even States with a
significant land base in agriculture (such as South Dakota, North
Dakota, and Ohio) appear to be maintaining stable populations of
northern leopard frogs. Therefore, though research indicates that
agricultural development can have a negative impact on local
populations of northern leopard frogs, the best available information
does not indicate the ongoing impacts are significant at the species
level. Based upon the best available information, agricultural
development does not constitute a significant threat to the northern
leopard frog at the species level now, nor do we have indication that
it will in the future.
Livestock Grazing
Approximately 70 percent of the land surface in the western United
States (including Montana, Wyoming, Colorado, New Mexico, Arizona,
Utah, Nevada, California, Idaho, Oregon, and Washington) is or has been
grazed by livestock (Fleischner 1994, p. 630; Krausman et al. 2009, p.
15). Historical and ongoing livestock grazing are specifically
identified as being responsible for the loss and degradation of
northern leopard frog habitats, and for negatively affecting northern
leopard frog populations at sites in Arizona (Clarkson and Rorabaugh
1989, p. 535; Sredl 1998, pp. 573-574), California (California
Department of Fish and Game 2007), 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), South
Dakota (Smith 2003, p. 27), and Wyoming (BLM 2009, p. 3). For example,
most of the habitat in the Pit River-Modoc Plateau area and the Owens
Valley of California, where the northern leopard frog occurred
historically, has been severely altered and fragmented largely because
of livestock grazing practices. The essential habitats bordering
riparian zones are either no longer present or so fragmented that the
habitat can no longer support northern leopard frog populations
(Jennings and Hayes 1994, p. 82). Although management may be changing
in some areas, many wetland habitats are likely still recovering from
historical grazing impacts (Krausman et al. 2009, p. 16). This is
particularly true because the western United States has a relatively
arid climate, which can result in longer habitat recovery intervals,
and perennial waters tend to be rarer and more disjunct from other
waters than in the eastern United States.
Livestock select riparian habitats for water, shade, and cooler
temperatures. They tend to spend a disproportionate amount of their
time in riparian zones, and they can adversely affect these systems in
a number of important ways (Fleischner 1994, pp. 633-635; Belsky et al.
1999, pp. 420-424; Jones 2000, pp. 159-161). Because of this
disproportionate use of mesic and riparian habitats by livestock,
northern leopard frog populations are vulnerable to the effects of
poorly managed livestock grazing (Maxell 2000, pp. 15-16; Smith 2003,
p. 30). Specifically, trampling by livestock may result in the death of
individual frogs (Bartlet 1998, p. 96; Maxell 2000, p. 15; Smith 2003,
p. 30), and the compaction of 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; Belsky 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 (Belsky et
al. 1999, pp. 420-424; Alberta Northern Leopard Frog Recovery Team
2005, p. 7) may reduce the depth of breeding ponds or overwintering
habitats, increase water temperatures, and create favorable
environments for diseases and parasites
[[Page 61915]]
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). Increased watershed erosion caused by livestock grazing
can accelerate sedimentation of deep pools used by frogs (Gunderson
1968, p. 510). The indirect effects of grazing on northern leopard frog
habitat may also include increases in sedimentation generated by
grazing. Sediment can alter primary productivity and fill interstitial
spaces in drainage materials with fine particulates that impede water
flow, reduce oxygen levels, and restrict waste removal (Chapman 1988,
pp. 5-10).
Disturbance from livestock wading and defecating in northern
leopard frog habitat has been found to have negative effects on the
reproductive success of northern leopard frogs and to result in
negative impacts to habitat (Knutson et al. 2004, p. 677). The
significant input of urine and manure and the turbidity caused by
livestock disturbance was found to lead to poor water quality (such as
increased nitrates) and low oxygen concentrations, which can result in
reduced development and survival of egg masses and tadpoles (Marco et
al. 1999, p. 2837; Rouse et al. 1999, pp. 800-802; Ortiz et al. 2004,
pp. 235-236; Alberta Northern Leopard Frog Recovery Team 2005, p. 7;
Earl and Whiteman 2009, p. 1336). In addition, Knutson et al. (2004 p.
675) found that the grazed ponds had little or no aquatic or emergent
vegetation, and that this was a result of livestock wading in the pond.
In contrast, there is information from some portions of the range
of the species that indicates leopard frog species can persist, and
even benefit from, well-managed livestock grazing (Hitchcock 2001, p.
62; Service 2007, pp. 32-34; Alberta Northern Leopard Frog Recovery
Plan 2005, p. 7; Arizona Game and Fish Department 2009, pp. 2-3; New
Mexico Department of Fish and Game 2009, p. 3). Limited grazing around
riparian areas can create open foraging areas for leopard frogs, and
livestock management can result in the creation of stock tanks (ponds
or impoundments that function as waterholes) that can provide breeding
and dispersal habitat for northern leopard frogs, particularly in arid
western landscapes (Sredl et al. 1997, pp. 46, 49; Theimer et al. 2011,
p. 11).
Historically, livestock grazing has likely resulted in degraded
habitats and local declines and extirpations of northern leopard frogs
in some portions of their range. However, the information reviewed
above suggests that livestock grazing has only resulted in substantive
impacts in the western portions of the United States and Canada, with
very little to no information suggesting how livestock grazing has or
is adversely impacting northern leopard frog populations in the eastern
United States or eastern Canada. Further, declines and extirpations
associated with livestock grazing are likely historical impacts in most
areas, with ongoing impacts manifesting primarily through effects
associated with degraded habitats. Finally, there is no evidence that
livestock grazing use is spreading to areas that are not already
subject to those uses. Therefore, the best available scientific
information indicates that livestock grazing does not constitute a
significant threat to the northern leopard frog at the species level
now, nor do we have indication that it will in the future.
Urban Development
Urbanization refers to the development of areas for human uses.
Areas subject to urbanization tend to be correlated to areas with
increased human population growth. This development is resulting in
impacts to northern leopard frog habitat across its range (Hitchcock
2001, pp. 64-66; Smith and Keinath 2007, p. 29; Connecticut Department
of Environmental Protection 2005, pp. 2-16-2-18; Maine Department of
Inland Fisheries and Wildlife 2005, Chapter 5 p. 109; New Hampshire
Fish and Game Department 2005, p. A210-212; Wisconsin Department of
Natural Resources 2009, p. 1). The 2010 Census reported that the human
population in the United States has increased almost 10 percent since
2000. The only State within the range of the northern leopard frog that
did not have an increase in population is Michigan (Mackun and Wilson
2011, pp. 1-2). Nevada, Arizona, Utah, Texas, and Idaho were the
fastest growing States, and New Hampshire and South Dakota were the
fastest growing States in the northeast and Midwest, respectively.
Pennsylvania ranks fifth in the nation in the amount of open space it
loses to development every day and it has lost over half of its
wetlands to development (Pennsylvania Game Commission and Pennsylvania
Fish and Boat Commission 2005, pp. 10-34). In Canada, Ontario and
Quebec are the largest provinces in terms of numbers of people; larger
numbers of people typically contribute more to increases in urban
development and modification of northern leopard frog habitats.
Projected human population growth is also expected to result in
increased needs for water (surface diversions and groundwater pumping)
to support this 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.
Reexamination of historic northern leopard frogs sites in northeastern
Ohio (Orr et al. 1998, p. 92) found that two sites had been destroyed
by development and three had been eliminated by high-intensity
agriculture. A study in Iowa and Wisconsin found a negative association
with urban land use and relative abundance of northern leopard frogs
(Knutson et al. 1999, p. 1441; Knutson et al. 2000, p. 140). From 1998
to 2004, 140,400 ac (56,800 ha) or 61 percent of wetland losses in the
United States occurred due to urban and rural development (Dahl 2006,
p. 47). These wetland losses are considered to be irreversible as they
are the result of permanent construction (such as houses and roads)
that alters wetland hydrology (Dahl 2006, pp. 47, 63). Urban
development often results in conversion of natural habitats to homes,
roads, and industrial uses, which can result in direct mortality from
traffic (Mazerolle 2004, p. 47; Bouchard et al. 2009, p. 23), chemical
contamination of wetlands (Fahrig et al. 1995, p. 177), and
modification of existing wetland habitats to benefit sport fish rather
than native amphibians (Knutson et al. 1999, p. 1444).
Based upon the above information, urban development has likely
resulted in the historical and continued loss of northern leopard frogs
and their habitat throughout their range. While the magnitude of these
impacts is conceivably high in localized areas, urbanization is not
ubiquitous throughout the range of the northern leopard frog. General
information about human population growth and associated urbanization
cannot be extrapolated to support high magnitude threats throughout all
portions of the range of the northern leopard frog. Further, despite
urbanization trends, the northern leopard frog is apparently still
considered to be widespread and common in the eastern United States and
eastern Canada. Therefore, the best available scientific information
indicates that urbanization does not constitute a significant threat to
the northern leopard frog at the species level now, nor do we have
indication that it will in the future.
Oil and Gas Development
Natural gas drilling is currently occurring in at least 25 States
that have populations of northern leopard frogs. In 2007, there were
449,000 natural gas
[[Page 61916]]
wells in 32 States, which was a 30 percent increase from 2000; it is
estimated that 32,000 new natural gas wells per year could be drilled
by 2012 (Lustgarten 2008, p. 2). Examples of the increase in magnitude
of drilling in the United States can be observed by the increase in
approved permits in Wyoming and Pennsylvania. The first natural gas
well in Sublette County, Wyoming, was drilled in 1939, and by 2008, 700
gas wells were producing natural gas on the Pinedale Anticline (a major
gas field in Sublette County). In 2008, the Bureau of Land Management
approved 4,400 more natural gas wells in Sublette County (Lustgarten
2008, p. 3). In Susquehanna County, Pennsylvania, there was a 27-fold
increase in natural gas well permits from 2007 to 2009. Natural gas
mining is also occurring in Canada, the world's third-largest producer
and exporter of natural gas (Natural Resources Canada 2011, p. 1).
However, we have minimal specific information assessing the overlap of
occupied northern leopard frog habitats with planned oil and gas
development operations for most of the range of the species.
The Powder River Basin in Wyoming and Montana and the San Juan
Basin in Colorado and New Mexico, areas within the range of the
northern leopard frog, currently have the highest coalbed methane (a
natural gas) productions in the United States (Environmental Protection
Agency 2004, p. 1-1). Possible impacts to northern leopard frogs
associated with coalbed methane development may include discharge of
contaminated water into breeding ponds, loss of spring flows related to
groundwater withdrawals, discharge of extremely cold water into
breeding habitats, discharge of water containing nonnative predatory
fish in these same areas, and road-related mortality associated with
increased use of roads or new roads to support the coalbed methane
development (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 (Spengler 2002, pp. 7-26; Smith 2003,
pp. 26, 31). Domestic and stock tank waters have dried or become
contaminated with gas in Wyoming's Powder Basin (Powder River Basin
Resource Council 2009, p. 1). Although some States that have
populations of the northern leopard frog are implementing wetland and
riparian protections in connection with oil and gas drilling (Colorado
Division of Wildlife 2009, p. 5), it is unclear if all States are
implementing such measures and whether or not these measures have
resulted in decreased impacts to northern leopard frogs.
Another area where there is information about oil and gas
development activities in northern leopard frog habitats is the
Marcellus Shale. The Marcellus Shale is a black shale formation
extending underground from Ohio and West Virginia northeast into
Pennsylvania and southern New York that contains natural gas reserves.
Although there are areas where the Marcellus Shale is exposed at the
surface, it is as deep as 7,000 ft (2,134 m) or more below the ground
surface along the Pennsylvania border. Natural gas drilling operations
have proliferated in Pennsylvania over the past years, and at least
1,415 new wells were drilled in 2010 (Goldberg 2011, p. 2). The
drilling is expected to expand into Ohio and West Virginia. New York is
currently conducting a comprehensive review of the potential
environmental impacts associated with natural gas development and
Ohio's State government approved drilling in Ohio's State parks on June
15, 2011.
Hydraulic fracturing is a method used to extract natural gas from
the earth. Environmental concerns with hydraulic fracturing include
water use and management, and the composition of the fluids used
(Environmental Protection Agency 2011, p. 1). Hydraulic fracturing
consists of pumping chemicals (such as benzene) and high volumes of
water and sand down the well under high pressure to create fractures in
the gas-bearing rock (New York Department of Environmental Conservation
2011, p. 1). The propping material holds the fractures open allowing
more gas to flow into the well. The hydraulic fracturing of the
Marcellus Shale will require large volumes of water to fracture the
rocks and produce natural gas. In 2008, oil and gas wells disgorged
approximately 9 million gallons of wastewater a day in Pennsylvania,
and water use is expected to increase to at least 19 million gallons
per day (Sapien 2009, p. 2).
The wastewater is a product of the hydraulic fracturing which pumps
about 1 million gallons of water mixed with sand and chemicals into
each well to withdraw the natural gas. When it comes back out, the
water contains toxins and dissolved solids. Wastewater contains enough
dissolved solids that the water can be five times as salty as sea
water. Recent research found methane contamination of drinking water in
Pennsylvania and New York from natural gas extraction on the Marcellus
Shale (Osborn et al. 2011, p. 2). In addition, water contamination has
been documented near drilling areas in Sublette County, Wyoming, and
Santa Fe, New Mexico; chemical spills of hydraulic fracturing chemicals
have occurred in Colorado (Lustgarten 2008, pp. 2-9).
The rate, timing, and location of water withdrawals could result in
negative impacts to streams, downstream riverine and riparian
resources, wetlands, and aquifer supplies where hydraulic fracturing to
mine natural gas occurs (New York Department of Environmental
Conservation 2009, p. 6-4). The draft environmental impact statement
for natural gas drilling in New York states, ``Water for hydraulic
fracturing may be obtained by withdrawing it from surface water bodies
away from the well site or through wells drilled into groundwater
aquifers'' (New York Department of Environmental Conservation 2009, p.
6-4). The existence and sustainability of wetland habitats directly
depend on the presence of water at or near the surface of the soil. The
functioning of a wetland is driven by the inflow and outflow of surface
water and groundwater. As a result, withdrawal of surface water or
groundwater for high volume hydraulic fracturing could impact wetland
resources and northern leopard frog habitat. These potential impacts
depend on the amount of water within the wetland, the amount of water
withdrawn from the catchment area of the wetland, and the dynamics of
water flowing into and out of the wetland. Even small changes in the
hydrology of the wetland can have significant impacts on the wetland
plant community and on the wildlife, such as the northern leopard frog,
that depend on the wetland. As discussed in the Biology section,
wintering northern leopard frogs are intolerant of freezing, and
withdrawals that reduce water depths in overwintering habitat could
lead to high levels of winter kill if water levels are reduced so much
that these areas freeze.
In summary, some northern leopard frog populations could be
impacted by oil and gas development activities through changes to water
quantity or quality (due to chemical pollution or increased salinity)
and through insufficient water flow to maintain wetland and stream
habitat. Natural gas drilling and hydraulic fracturing may occur across
the range of the northern leopard frog; however, the impacts are
expected to be localized population and habitat losses rather than
regional or species-level effects. Pennsylvania, Ohio, West Virginia,
Kentucky, Wyoming, Colorado, Montana, and New Mexico all have oil and
gas development occurring within their
[[Page 61917]]
boundaries; however, we have little to no information about oil and gas
development activities in northern leopard frog habitats throughout the
rest of the range of the species, notably the Midwestern United States
and Canada. Therefore, the best available scientific information
indicates that oil and gas development does not constitute a
significant threat to the northern leopard frog at the species level
now, nor do we have indication that it will in the future.
Roads
Roads have been shown to pose barriers to northern leopard frog
dispersal, to contribute to nonpoint source pollution, and to result in
direct mortality of northern leopard frogs (Smith 2003, pp. 27, 38;
Maxell 2000, p. 25; Fahrig et al. 1995, pp. 177-182). The movements of
adult northern leopard frogs to breeding habitats during spring rains
and the extensive dispersal of juveniles from breeding ponds in late
summer make this species vulnerable to highway traffic (Orr et al.
1998, p. 93; Langen et al. 2009, p. 111), and there are many reports of
large amounts of leopard frog road mortality (see references in Carr
and Fahrig 2001, p. 1075; Glista et al. 2008, pp. 81-82; Langen et al.
2009, p. 111). Road building is often tied to other activities such as
urban, agricultural, and oil and gas development, so roads may impact
leopard frogs directly and indirectly.
Bouchard et al. (2009, pp. 5-6) found that the northern leopard
frog's inability to avoid roads and their slow movement make them
particularly vulnerable to road mortality and that roads could thus
result in negative effects to local population abundance. Other studies
did not find any decreasing trends in abundance for amphibian roadside
populations (Mazerolle 2004, p. 51). Traffic density within 0.9 mi (1.5
km) of occupied northern leopard frog habitat may have negatively
affected local frog abundance, but it was unclear if results were due
to the observed road mortality, pollution (e.g., vehicle emissions,
road runoff), or increased urbanization (Carr and Fahrig 2001, p.
1074). Other studies have also documented smaller amphibian populations
in the vicinity of major roads and within landscapes with high road
densities than populations where roads are distant and few (Langen et
al. 2009, p. 104). ``Hotspots'' for northern leopard frog road
mortality tend to occur along causeways (road segments with water on
either side) with wetland sites within 328 ft (100 m) of the road
(Langen et al. 2009, p. 110).
In summary, although research indicates that roadside populations
of northern leopard frogs may be adversely impacted by roads and
evidence shows that individual frogs are certainly impacted through
road mortality, the information assessed indicates these impacts are
localized and result in effects to local frog abundance, not population
level impacts. While roads occur throughout the range of the northern
leopard frog, the best available information does not suggest that
roads constitute a significant threat to the northern leopard frog at
the species level now, nor do we have indication that they will in the
future.
Forest Management
The northern leopard frog is associated with forested as well as
grassland or open areas (Blomquist and Hunter 2009, p. 150). Based upon
broad land cover and use, forest management occurs in forested areas
throughout the range of the northern leopard frog (USDA NRCS 2001).
Timber harvest activities may impact northern leopard frog populations
in several ways. Clearcuts (areas where all trees are removed) at
breeding sites can result in enhanced tadpole development through
increased water temperatures and food production (Semlitsch et al.
2009, p. 859). However, clearcuts can also result in negative effects
to juvenile and adult northern leopard frog movement due to higher
surface temperatures (from canopy removal), and loss of soil-litter
moisture in upland habitats surrounding breeding ponds, which affects
the species' ability to move through these areas into post-breeding
habitat (Maxell 2000, pp. 12-14; Smith 2003, p. 29; Semlitsch et al.
2009, p. 860). Research on timber management and northern leopard frog
seasonal habitat requirements found that northern leopard frogs in the
late spring and summer used open, wet areas; frogs used unharvested
forest for longer movements (Blomquist and Hunter 2009, p. 153). Forest
management may affect local populations of northern leopard frogs by
fragmenting habitats and reducing landscape connectivity.
Forest management has the potential to impact northern leopard frog
breeding, dispersal, and foraging habitats in forested areas throughout
its range. However, the information we reviewed does not indicate that
forest management, clearcutting in particular, is occurring at a level
or extent that would result in impacts at the species level. Therefore,
the best available information indicates forest management is not a
significant threat to the northern leopard frog at the species level
now, nor do we have indication that it will in the future.
Groundwater Withdrawal
Throughout the range of the northern leopard frog, particularly in
the western United States and Canada, naturally geographically isolated
(or depressional) wetlands completely surrounded by upland plant
communities (such as the prairie pothole wetlands in the upper
Midwestern United States and Canada) and human-caused isolated wetlands
(such as natural wetlands that are no longer connected to streams due
to roads or other development) are important habitats for the northern
leopard frog. Many of these ``isolated'' wetlands appear to be
disconnected from other water sources, but are hydrologically connected
to other wetlands or waters through sub-surface or groundwater
connections (Tiner 2003, p. 495). Because of this hydrologic
connection, groundwater withdrawal can result in significant impacts to
wetland habitats and may result in decreased surface water, decreased
recharge, and reduced water levels in wetland and spring habitats
(Alley et al. 1999, pp. 33-44; Alberta Northern Leopard Frog Recovery
Plan 2005, p. 7; Wirt et al. 2005, pp. G1-11; Patten et al. 2008, p.
279). Specifically, groundwater withdrawal can result in loss of
northern leopard frog breeding ponds and spring- and riparian-
associated vegetation, and thus the loss or modification of northern
leopard frog habitat (Alberta Northern Leopard Frog Recovery Plan 2005,
p. 7; Patten et al. 2008, p. 286). In addition, decreased surface water
levels may reduce the water level in overwintering habitats, which may
result in the area freezing and an increased risk of mortality as
wintering northern leopard frogs are intolerant of freezing (see
Biology section).
Across the range of the northern leopard frog, these habitats occur
in the prairie potholes region (see above), the playas and springs of
the Southwest, the Sandhills wetlands in northern Nebraska, channeled
scablands in eastern Washington, woodland vernal pools of the
northeastern United States, and many other natural ponds throughout the
United States (Tiner 2003, p. 497). Within these areas, there is
regional and local information to indicate that current and proposed
groundwater pumping may result in reduced habitat for northern leopard
frogs, particularly in the arid West (Tiner 2003, p. 513; Deacon et al.
2007). Specifically, the BLM recently released the Draft Environmental
Impact Statement for the Clark, Lincoln, and White Pine Counties
Groundwater Development Project in Nevada (BLM
[[Page 61918]]
2011). Based upon the modeling analysis, the BLM predicts that northern
leopard frog habitat (for all life stages) will be reduced in currently
occupied areas of central-eastern Nevada as a result of the proposed
action (BLM 2011, p. 3.7-45). This information indicates that isolated
wetland habitats such as those in Spring Valley, Nevada, may be
significantly impacted by these proposed groundwater withdrawals.
Groundwater depletion has been a concern in the Southwest and High
Plains for many years due to the arid climate and a lack of water
resources; however, increased demands on groundwater resources have
overstressed aquifers in many areas of the United States (Bartolino and
Cunningham 2003, p. 2). The Southwest United States has experienced
rapid human population growth over the last two decades in conjunction
with long-term drought. This situation has resulted in increased demand
for water resulting in impacts to wetland and spring habitats from
groundwater pumping (Levick et al. 2008, pp. 70-71). Brussard et al.
(1998, pp. 505-542) found that pumping of groundwater from gold mines
impacted spring communities in the north-central region of Nevada.
Groundwater pumping by the City of Albuquerque, New Mexico, contributed
to the loss of wetland habitat in the Rio Grande valley as well (Bogan
1998, pp. 562-563). In addition, groundwater modeling studies indicate
that aquifers in eastern and southern Nevada that supply water to
springs currently occupied by northern leopard frogs may decline in
response to pumping in these areas to meet human water demands
(Schaefer and Harrill 1995, p. 46). However, streams and wetlands in
the Northeast, the High Plains, the Pacific Northwest, and other
regions of the United States have also been impacted by groundwater
pumping (Bartolino and Cunningham 2003, p. 2). Impacts have included
lowered water tables, reduced surface flows, desiccation of springs,
and decreased lengths of perennial streams as a result of groundwater
pumping (Bartolino and Cunningham 2003, pp. 2-4). Currently, there are
many ongoing discussions throughout the Southwest regarding water
supplies and how groundwater pumping may be used to meet human water
demands. While specific plans regarding how these future plans may
impact northern leopard frogs are limited at this time in many areas,
as described above, the recently proposed Clark, Lincoln, and White
Pine Counties Groundwater Development Project (Bureau of Land
Management 2011) is expected to reduce occupied northern leopard frog
habitat in Spring Valley, Nevada.
As described above in the Oil and Gas Development section, an
increase in natural gas mining (using hydraulic fracturing) may also
result in increases in groundwater pumping throughout Pennsylvania,
Ohio, West Virginia, Kentucky, Wyoming, Colorado, Montana, and New
Mexico (see Oil and Gas Development above for further discussion).
In summary, groundwater pumping has likely contributed to localized
and possibly regional declines of northern leopard frog habitat,
particularly in isolated wetlands and arid areas. However, in assessing
the impacts of groundwater pumping on current northern leopard frog
populations, impacts are most usually described as potential effects to
habitat availability. These impacts are further described as occurring
at local and regional, rather than species-wide, scales. Impacts to
isolated wetlands in particular are likely to be localized. Further,
impacts to water resources in the arid West cannot be extrapolated to
the eastern United States and eastern Canada due to differences in
climate and geography. Finally, there is little to no information about
groundwater withdrawals in Canada, and the northern leopard frog is
apparently still considered to be widespread and relatively common in
the eastern United States and eastern Canada. Therefore, the best
available information indicates groundwater withdrawal is not a
significant threat to the northern leopard frog at the species level
now, nor do we have indication that it will in the future.
Air Pollution
Acid precipitation may be affecting northern leopard frog habitat
in the western United States, including the Rocky Mountain region of
Colorado, New Mexico, and Wyoming. Acidic water is an environmental
stressor for northern leopard frogs (Simon et al. 2002, p. 697), and
leopard frog abundance may be reduced in areas where water
acidification has occurred (Pope et al. 2000, p. 2505). In the last few
decades, high-elevation aquatic habitats have become more acidic (Corn
and Vertucci 1992, p. 363; Simon et al. 2002, p. 697), which may be a
result of air pollution. The emissions of certain gases (principally
sulfur dioxide and nitrogen oxides) into the air may lead to acid
precipitation and the acidification of aquatic habitats. Acidification
of aquatic habitats may result in decreased reproductive capabilities
of adult northern leopard frogs, and mortality and developmental
abnormalities in northern leopard frog tadpoles (Simon et al. 2002, p.
697). In addition, acid precipitation can result in the direct
destruction of vegetation needed for habitat (Environmental Protection
Agency 2000, pp. 48699-48701; Jezouit 2004, pp. 423-445). 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;
Environmental Protection Agency 2005, p. 59594), can increase the
acidity of soils and aquatic ecosystems; may contribute to
eutrophication (a process whereby increased nutrients lead 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). However, effects from air pollution (in the form of acid
precipitation) are currently only a consideration in high-elevation
habitats in the western United States. Additionally, at this time, the
potential impacts are theoretical and have not been shown to result in
population-level impacts to the species. Therefore, the best available
information does not indicate that air pollution constitutes a
significant threat to northern leopard frogs at the species level now,
nor do we have indication that it will in the future.
Summary of Factor A
The northern leopard frog occupies a wide geographic range across
the United States and Canada. Because it occurs across such a large
area, the habitats it uses are subject to a number of impacts that
represent potential threats at various scales. As discussed above,
these factors generally have been historical in impact or are occurring
now and into the future at scales below the species level, both
individually and in combination. Further, while there have been
declines noted in portions of the range of the species, the frog is
apparently still considered to be widespread and relatively common in
the eastern United States and eastern Canada. Therefore, the best
available information indicates that the present or threatened
destruction, modification, or curtailment of its habitat or range is
not a significant threat to the northern leopard frog at the species
level now, nor do we have indication that it will in the future.
[[Page 61919]]
Factor B. Overutilization for Commercial, Recreational, Scientific, or
Educational Purposes
Overutilization of the northern leopard frog for commercial,
recreational, scientific, or educational purposes is not reported to be
a current threat to the species in most of its range (Woolington 2011,
pers. comm.; Smith 2003, p. 21; Arizona Game and Fish Department 2009,
p. 2); however, northern leopard frogs are harvested for bait and for
use in biology laboratories in some portions of its range (Smith 2003,
p. 21; Quinn 2009, pers. comm.; Minnesota Department of Natural
Resources 2011a, p. 2). Northern leopard frogs are collected for
commercial purposes in Nebraska, Minnesota, and Wisconsin, and
historical collection in other States likely contributed to long-term
population declines in some areas (Lannoo et al. 1994, p. 317; Moriarty
1998, p. 168; Smith 2003, p. 21). From 1995-1999, approximately 174,772
northern leopard frogs were collected in Nebraska to supply two
biological supply houses (Smith 2003, p. 21). Northern leopard frogs in
Minnesota have been heavily collected for fish bait and for the
biological supply trade, and there is little regulation on the
collection of frogs there (Moriarty 1998, p. 168). Other States that
have identified overutilization as a potential effect to the northern
leopard frog include Connecticut (Connecticut Department of
Environmental Protection 2005, p. 4-4-4-5), Maine (Maine Department of
Inland Fisheries and Wildlife 2005, p. 109), Massachusetts
(Massachusetts Department of Fish and Wildlife 2006, p. 407), and
Michigan (Eagle et al. 2005, Species of Greatest Conservation Need 152
of 242). However, other than naming collection as a potential concern
or including conservation measures to guard against overutilization in
their State wildlife action plans, we have no information regarding the
magnitude of the potential threat of collection in these States.
As noted earlier in the Status section, northern leopard frog
populations crashed in 1973 in Minnesota, which halted the commercial
collections for uses other than bait from 1974 to 1987. Harvest records
from the 1990s report collections of 1,000 to 2,000 pounds of frog per
year, compared to reports in the early 1970s that were in the 100,000-
pound-per-year range (Moriarty 1998, p. 168). According to North Dakota
Game and Fish Department records, 31,683 leopard frogs were collected
by wholesalers from 1996-2008. That is an average of 2,463 frogs per
year. The North Dakota Game and Fish Department does not believe that
this level of use has impacted the population (North Dakota Game and
Fish Department 2009, p. 2). There are no restrictions in South Dakota
regarding the collection of northern leopard frogs, and they are a
legal bait species (limit of 24 per day) (South Dakota Department of
Game, Fish, and Parks 2011, p. 23) and some South Dakota tribal members
collect and sell northern leopard frogs to educational suppliers in
Minnesota (Quinn 2009, pers. comm.). The northern leopard frog may also
be legally used for bait or other personal uses (typically with a
permit or license) in Iowa, Missouri, Nebraska, New Mexico, Illinois,
Indiana, Kentucky, Michigan, New York, Pennsylvania, and Vermont (as
identified in the Status section above).
In 1971, Gibbs et al. (p. 1027) described the frog trade and the
decline of northern leopard frogs throughout most of their range. Due
to the declines noted by Gibbs et al. (1971), many States began
establishing laws to prevent uncontrolled collecting. Today, many State
wildlife agencies, including those in the western United States, use
commercial and collection regulations to control human actions that may
harm wildlife populations, such as collection of amphibians (Adams et
al. 1995, p. 394; see also discussion in Status section describing
State collection laws and under Factor D describing regulatory
mechanisms).
Though many States have established regulations regarding the
collection of northern leopard frogs, wild-caught amphibians are still
traded on the global market, and there is some concern as to whether
the take of wild-caught individuals is biologically sustainable
(Schlaepfer et al. 2005, p. 257). Recent research found that millions
of individuals, millions of body parts and products, and more than
2,204,623 pounds (lbs) (1,000,000 kilograms (kg)) of amphibians and
reptiles are shipped across U.S. borders each year for commercial
purposes (Schlaepfer et al. 2005, p. 257). Greater than 2.5 million
whole, wild-caught amphibians and reptiles were imported into the
United States between 1998 and 2002, but these animals were not tracked
by species (Schlaepfer et al. 2005, p. 257). Information tracked by the
Service's Law Enforcement Management Information System indicates that
249,233 lbs (113,050 kg) of northern leopard frog were imported into
the United States between 1998 and 2002, for food and research
(Schlaepfer et al. 2005, p. 259). An additional 112,289 body parts and
products and 1,177,970 lbs (534,318 kg) of Lithobates frogs (not
identified to species), which likely consisted in part of wild-caught
northern leopard frogs, were imported into the United States during
this same timeframe. There were 361,858 Lithobates frogs imported or
exported from the United States with no species specific identification
(Schlaepfer et al. 2005, p. 261). We can conclude from this information
that the U.S. trade in amphibians and reptiles, which is a fraction of
the world trade in terms of wild-caught amphibians and reptiles
(Schlaepfer et al. 2005, p. 263), is importing large numbers of
northern leopard frogs from Canada. There are no data to indicate if
this trade in wild-caught northern leopard frogs is sustainable, and it
may partially explain why the frog continues to decline in Ontario and
other portions of eastern Canada. Schloegel et al. (2009, p. 1424)
found that an average of 5.1 million Ranid (= Lithobatid) frogs per
year, including live animals and their parts, were imported into the
United States between 2000 and 2005. However, based upon the reported
origin of the frogs (China and Taiwan), it is likely that most of these
imports were American bullfrogs. However, there is evidence that the
commercial trade in amphibians, particularly in American bullfrogs,
does result in the spread of disease (such as ranaviral disease and
Batrachochytrium dendrobatidis, which can cause the amphibian disease,
chytridiomycosis), and aids in the spread of invasive species (Fisher
and Garner 2007, pp. 3-4; Picco and Collins 2008, p. 1588; Schloegel et
al. 2009, pp. 1424-1425). In Arizona, northern leopard frogs do appear
in the pet trade, either in local pet stores or through on-line
suppliers (Arizona Game and Fish Department 2009, p. 3), and documented
releases of eastern northern leopard frogs into existing populations
have occurred (Hoffman and Blouin 2004a, pp. 150-151; Theimer et al.
2011, pp. 3, 30; O'Donnell et al. 2011, p. 3), which may have genetic
implications for the ongoing conservation of the species.
Summary of Factor B
Despite historic population and regional declines, we do not have
any evidence of impacts to northern leopard frogs at the species level
from overutilization for commercial, recreational, scientific, or
educational purposes, and we have no information that indicates this
factor will become a threat to the species in the future. The
significant declines and extirpations within the range of the species
have occurred in areas other than those that
[[Page 61920]]
have traditionally been subject to the highest collection pressures.
Further, the collections appear to be occurring in portions of the
range that have apparently stable populations. Therefore, the best
scientific and commercial information available indicates that
overutilization for commercial, recreational, scientific, or
educational purposes does not constitute a significant threat to the
northern leopard frog at the species level now, nor do we have
indication that it will in the future.
Factor C. Disease or Predation
Disease
Fungal, viral, and bacterial diseases may cause mass mortality and
contribute to population declines of northern leopard frogs (Rorabaugh
2005, pp. 575-577). Disease has caused mass mortality in ranid and
lithobatid frogs in almost every western State in the United States
(Bradley et al. 2002; Muths et al. 2003; Briggs et al. 2005). 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 (Johnson
et al. 2011, p. 564). Mortality from chytridiomycosis is reported for
several leopard frog species, including the northern leopard frog, in
Arizona, British Columbia, California, and Colorado (Bradley et al.
2002, pp. 206-212; Muths et al. 2003, p. 361; Briggs et al. 2005, p.
3149; Committee on the Status of Endangered Wildlife in Canada 2009, p.
26; Johnson et al. 2011, p. 564). 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 and is a possible contributing factor to the extensive
mortalities that occurred there (Carey et al. 1999, p. 461). This time
period is also when extensive declines of northern leopard frogs
occurred throughout the western United States and Canada, in places
such as Wisconsin, Alberta, Saskatchewan, and Manitoba. Longcore et al.
(2006, p. 440) found that Bd is widespread in the Northeast and the
highest prevalence of Bd in a Maine species was the northern leopard
frog. However, there was no observed decline in northern leopard frog
populations despite the significantly high infection rate (Longcore et
al. 2006, p. 441). It is possible that northern leopard frogs in the
eastern United States have developed some resistance to Bd, or that
thermoregulatory behavior (such as basking on a sunny day) may slow the
growth of the fungus (Longcore et al. 2006, pp. 441-442). It is
currently not known under what circumstances the northern leopard frog
is susceptible to the lethal effects of chytridiomycosis, but it
remains a concern as the fungus appears to be prevalent in the East and
in the West (Ellis 2011, pers. comm.; Van Stralen 2011, pers. comm.),
and mortality in wild frogs in British Columbia is thought to be the
result of chytridiomycosis.
Recent studies indicate that factors such as habitat degradation,
habitat fragmentation, and climate change may exacerbate the lethal
effects of chytridiomycosis 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
chytridiomycosis (Ouellet et al. 2005, p. 1437), and other stressors
such as water pollution may make northern leopard frogs more
susceptible to chytridiomycosis (Carey et al. 1999, pp. 459-472;
Kiesecker et al. 2004, p. 138).
Saprolegniasis, a water-borne fungal disease, may also affect
populations of northern leopard frogs (Faeh et al. 1998, p. 263).
However, this fungal disease is usually secondary to other stressors
such as bacterial infections or trauma (Faeh et al. 1998, p. 263).
Saprolegnia has been associated with embryonic die-offs of ranid frogs
in Oregon, and is found in Columbia spotted frog (Rana luteiventris)
eggs in Idaho and Montana (Patla and Keinath 2005, p. 43), but there is
no other information provided to indicate that this disease is
currently impacting northern leopard frogs.
Faeh et al. (1998, pp. 260-261) provided 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 introduction of bullfrogs and spread of tiger salamanders
throughout the U.S. range of the northern leopard frog may increase the
potential of ranavirus infection as both American bullfrogs and tiger
salamanders are hosts for the ranavirus (Picco and Collins 2008, p.
1588; Schloegel et al. 2009, p. 1424). Relatively recent mass mortality
events of northern leopard frog metamorphs resulting from ranavirus
have been documented in Ontario (Greer et al. 2005, p. 11).
Septicemia or ``red leg'' involves one or a combination of
hemolytic (destructive to blood cells) bacteria that enter the body via
wounds or abrasions (Faeh et al. 1998, p. 261). Septicemia often
results in death in individuals and often results in mass mortality.
Septicemia may also 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 United States and Canada
(McAllister et al. 1999, p. 19).
Significant mortality events of northern leopard frogs have been
attributable to disease (Rorabaugh 2005, p. 575). However, with the
exception of chytridiomycosis, impacts to northern leopard frogs
associated with these diseases appear to be localized. Chytridiomycosis
may be having significant effects to northern leopard frogs in the
West, but does not appear to be significantly affecting frogs in other
portions of its range as the frog is apparently still considered to be
widespread and stable in the eastern United States and eastern Canada.
Therefore, the best available information does not indicate that
disease is a significant threat to the northern leopard frog at the
species level now, nor do we have indication that it will in the
future.
Nonnative Species
The introduction of nonnative aquatic animals, particularly
American bullfrogs and predatory fishes, has resulted in the loss and
decline of northern leopard frogs throughout their range, but
particularly in the western United States and Canada (Merrell 1968, p.
275; Hine et al. 1981, p. 12; Hammerson 1982, pp. 115-116; Hayes and
Jennings 1986, p. 491; Hecnar and M'Closkey 1997, p. 126; Livo et al.
1998, p. 4; Orr et al. 1998, p. 92; Maxell 2000, p. 144; Hitchcock
2001, p. 63; Smith 2003, pp. 19-21; Alberta Northern Leopard Frog
Recovery Team 2005, p. 8; Rorabaugh 2005, p. 574; Smith and Keinath
2007,
[[Page 61921]]
p. 24; Committee on the Status of Endangered Wildlife in Canada 2009,
p. 35). Northern leopard frogs typically breed in waters without fish
or aquatic predators (Merrell 1977, p. 16; Hine et al. 1981, p. 12).
Nonnative animals (including crayfish, American bullfrogs, and fish)
displace northern leopard frogs by degrading habitat (e.g., destroying
emergent vegetation, increasing turbidity, reducing algal or
invertebrate populations) or through direct predation on eggs,
tadpoles, and adult leopard frogs (Green 1997, p. 300).
American bullfrogs, which compete with and prey on northern leopard
frogs, are thought to be a primary cause of the widespread decline of
northern leopard frogs throughout the western United States (Bury and
Luckenbach 1976, p. 10; Hammerson 1982, pp. 115-116; Kupferberg 1997,
p. 1749; Livo et al. 1998, p. 4). The American bullfrog is native to
the eastern and Midwestern United States and historically had a very
wide native distribution that excluded much of the western United
States. American bullfrogs currently are not present in most of eastern
Montana, North Dakota, South Dakota, southern Idaho, central and
western Wyoming, most of Utah, and a small portion of northern Arizona
and White Pine County, Nevada (Casper and Hendricks 2005, p. 541).
These areas where the American bullfrog has yet to invade coincide with
some areas where the northern leopard frog still occurs and, in some
cases, appears to be stable (such as Nebraska, North Dakota, South
Dakota, and eastern Montana). American bullfrogs have also been
introduced into British Columbia (Weller and Green 1997, p. 320).
As previously described, northern leopard frogs typically breed in
fishless waters (Merrell 1968, p. 275) and likely have little natural
defense against predation by introduced fish (Smith and Keinath 2007,
p. 25). In Canada, research shows that introduced predaceous fish
reduce the abundance and diversity of frog populations, including the
northern leopard frog (Hecnar and M'Closkey 1997, pp. 126-127). Common
carp (Cyprinus carpio) cause increased turbidity and the destruction of
emergent vegetation, which can displace northern leopard frogs by
modifying habitat, reducing invertebrates, and eliminating algae
(McAllister et al. 1999, pp. 6-7). Information from Bradford (2005, pp.
922-923) indicates that lithobatid frogs in the western United States
may be more adversely affected than lithobatid frogs in the eastern
United States due to their greater exposure to exotic, introduced
species. Because northern leopard frogs in the western United States
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). In addition, literature studying the habitat preferences
of northern leopard frogs from Ohio and Wisconsin indicates that across
the range of the northern leopard frog, successful breeding habitats
tend to be free of predaceous fish due to periodic drying (Merrell
1977, p. 16; Hine et al. 1981, p. 12). This implies that when nonnative
species are present, it is more likely that northern leopard frogs will
not successfully reproduce.
Invasive plants may also impact northern leopard frog habitat in
the western United States (Maxell 2000, pp. 21-22; Hitchcock 2001, pp.
5-6). Tamarisk and other nonnative aquatic and terrestrial plants 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 American bullfrogs (Adams et al. 2003, pp.
343-351; Maxell 2000, p. 21; Hitchcock 2001, pp. 5-6, 62-66).
Effects to northern leopard frogs from nonnative species are likely
significant in the western United States and Canada, but information we
reviewed does not indicate nonnative species are having significant
impacts on northern leopard frog populations in the eastern portion of
their range. Further, northern leopard frogs are apparently considered
to be widespread and relatively common in the eastern United States and
eastern Canada. Therefore, the best available information indicates
that impacts associated with nonnative species do not constitute a
significant threat to the northern leopard frog at the species level
now, nor do we have indication that it will in the future.
Summary of Factor C
Disease and predation have undoubtedly contributed to the loss of
northern leopard frog populations historically, particularly in the
western United States, and will likely continue to impact northern
leopard frogs in some portions of its range at local or regional
scales. However, despite these impacts, the frog is apparently still
considered to be widespread and relatively common in the eastern United
States and eastern Canada. Therefore, the best available information
indicates that impacts due to disease and predation do not constitute a
significant threat to the northern leopard frog at the species level
now, nor do we have indication that it will in the future.
Factor D. The Inadequacy of Existing Regulatory Mechanisms
Under this factor, we examine whether existing regulatory
mechanisms are inadequate to address the threats to the northern
leopard frog discussed under Factors A, B, C, and E. The Service
considers regulatory mechanisms to mean all regulatory and statutory
mechanisms that are related to a comprehensive regime designed to
maintain a conserved wildlife population. Section 4(b)(1)(A) of the Act
requires the Service to take into account, ``those efforts, if any,
being made by any State or foreign nation, or any political subdivision
of a State or foreign nation, to protect such species * * *.'' We
consider these efforts when developing our threat analyses under all
five factors, and in particular under Factor D. Therefore, under Factor
D we consider not only laws and regulations, but other mechanisms that
are part of a regulatory process, such as management plans, agreements,
and conservation practices.
Regulatory mechanisms, if they exist, may preclude the need for
listing if such mechanisms are judged to adequately address the threat
to the species such that listing is not warranted. Conversely, threats
are not ameliorated when not addressed by existing applicable
regulatory mechanisms, or when the existing mechanisms are not adequate
(or not adequately implemented or enforced). Within its distribution in
the United States, the northern leopard frog occurs on lands managed by
a myriad of Federal and State agencies, Native American tribes, and
private lands. In Canada, the northern leopard frog occurs on a similar
variety of jurisdictions. In this section, we review actions taken by
State and Federal entities that effectively reduce or remove threats to
the northern leopard frog.
Federal Laws and Regulations
The northern leopard frog is not specifically covered by the
provisions of any Federal law or regulation. However, there are Federal
agencies that manage lands occupied by northern leopard frogs and laws
that are applicable to the management and conservation of the species
and its habitat.
All Federal agencies are required to adhere to the National
Environmental Policy Act (NEPA) of 1969, as amended (42 U.S.C. 4321 et
seq.) for projects they fund, authorize, or carry out. The Council on
Environmental Quality's regulations for implementing NEPA (40
[[Page 61922]]
CFR parts 1500-1518) state that environmental impact statements shall
include a discussion on the environmental impacts of the various
project alternatives (including the proposed action), any adverse
environmental effects that cannot be avoided, and any irreversible or
irretrievable commitments of resources involved (40 CFR part 1502).
NEPA itself is a disclosure law that provides an opportunity for the
public to submit comments on the particular project and propose other
conservation measures that may directly benefit listed or sensitive
fish and wildlife species; however, it does not require subsequent
minimization or mitigation measures by the Federal agency involved.
Although Federal agencies may include conservation measures for listed
species as a result of the NEPA process, there is no requirement that
impacts to the northern leopard frog from action analyzed under NEPA
would be precluded. Any such measures are typically voluntary in nature
and are not required by the statute. Additionally, activities on non-
Federal lands are subject to NEPA if there is a Federal nexus, such as
permitting by the U.S. Army Corps of Engineers or the Federal Energy
Regulatory Commission.
The Environmental Protection Agency's mission is to protect human
health and the environment. The agency implements this mission by
setting standards for clean air, and regulating pesticide use, chemical
use, and water pollution, among other actions. There are a number of
laws that are central to this mission; however, the most important in
terms of preventing impacts to northern leopard frogs are likely the
Clean Air Act of 1970 (42 U.S.C. 7401 et seq.), the Clean Water Act of
1972 (33 U.S.C. 1251 et seq.), and the Safe Drinking Water Act of 1974
(42 U.S.C. 300f et seq.). However, as previously discussed, we have
determined that the adverse effects to habitat for the northern leopard
frog is not nor is likely to have a species-level impact.
The Clean Air Act is the Federal law that regulates air emissions
from stationary and mobile sources. Among other things, this law
authorizes the Environmental Protection Agency to establish National
Ambient Air Quality Standards to protect public health and public
welfare and to regulate emissions of hazardous air pollutants. The
Environmental Protection Agency is required under the Clean Air Act to
set National Ambient Air Quality Standards for six air pollutants
(ozone, particulate matter, carbon monoxide, nitrogen oxides, sulfur
dioxides, and lead). Evidence indicates that the National Ambient Air
Quality Standards for sulfur dioxide, which contributes to the
formation of acid precipitation, may not be adequate to protect aquatic
ecosystems from the impacts of acid precipitation and acidification
impacts, and continued acid precipitation may cause vegetation damage
under the current sulfur dioxide National Ambient Air Quality
Standards. Under the current National Ambient Air Quality Standards,
acid precipitation is likely to continue and may result in adverse
habitat effects from nitrogen deposition (Baron et al. 2000, p. 365;
Fenn et al. 2003, pp. 417-418).
The Clean Water Act establishes the basic structure for surface
water quality protection in the United States. The Environmental
Protection Agency employs a variety of regulatory and non-regulatory
tools to reduce direct pollutant discharges into waterways, finance
municipal wastewater treatment facilities, and manage polluted runoff.
The Clean Water Act made it unlawful to discharge any pollutant from a
point source into navigable waters, unless a permit was obtained. The
overall objective of the Clean Water Act is to restore and maintain the
chemical, physical, and biological integrity of the nation's waters so
that they can support ``the protection and propagation of fish,
shellfish, and wildlife and recreation in and on the water.''
The Safe Drinking Water Act is the main Federal law that ensures
the quality of Americans' drinking water. Under the Safe Drinking Water
Act, the Environmental Protection Agency sets standards for drinking
water quality and oversees the States, localities, and water suppliers
who implement those standards. Section 1421 of the Safe Drinking Water
Act tasks the Environmental Protection Agency with protecting
underground sources of drinking water for all current and future
drinking water supplies across the country.
The Service, Bureau of Land Management (BLM), National Park Service
(NPS), and U.S. Forest Service (Forest Service) are the primary Federal
agencies that manage lands that provide habitat for the northern
leopard frog.
The northern leopard frog occurs on the Service's National Wildlife
Refuges and Wetland Management Areas in States throughout the northern
leopard frog's U.S. range. The mission of the National Wildlife Refuge
System is to administer a national network of lands and waters for the
conservation, management, and, where appropriate, restoration of the
fish, wildlife, and plant resources and their habitats within the
United States for the benefit of present and future generations of
Americans. Management on these National Wildlife Refuges largely
results in the enhancement of northern leopard frog habitat (Hultberg
2009, pers. comm.; South Dakota Department of Game, Fish and Parks
2009, pp. 2-3).
The northern leopard frog occurs on BLM lands in Colorado, Idaho,
Montana, New Mexico, Nevada, and Wyoming, and may also inhabit BLM
lands in North Dakota and South Dakota. The frog has declined or is
absent from BLM lands in Arizona (Clarkson and Rorabaugh 1989, p. 534),
Idaho (Makela 1998, pp. 8-9), Montana (Maxell 2000, p. 144), Nevada
(Hitchcock 2001, p. 9), Washington (McAllister et al. 1999, pp. 1-4),
and Wyoming (Smith and Keinath 2004, p. 57), based upon current ranges.
BLM lists the northern leopard frog as a sensitive species in Colorado,
Nevada, Wyoming, and Montana; the species is not listed as sensitive on
BLM lands elsewhere.
The Federal Land Policy and Management Act of 1976 (FLPMA) (43
U.S.C. 1701 et seq.) is the primary Federal law governing most land
uses on BLM-administered lands. Section 102(a)(8) of FLPMA (43 U.S.C.
1701(a)(8)) specifically recognizes the public lands are to be managed
to provide food and habitat for fish and wildlife.
BLM Manual section 6840 guides the management of sensitive species
in a manner consistent with species and habitat management objectives
in land use and implementation plans to promote their conservation and
to minimize the likelihood and need for listing under the Act (BLM
2008, p. 05V). This manual also requires that resource management plans
(RMPs) should address sensitive species, and that implementation
``should consider all site-specific methods and procedures needed to
bring species and their habitats to the condition under which
management under the Bureau sensitive species policies would no longer
be necessary'' (BLM 2008, p. 2A1).
Where it has been designated as a sensitive species under BLM
Manual 6840, northern leopard frog conservation must be addressed in
the development and implementation of RMPs on BLM lands. RMPs are the
basis for all actions and authorizations involving BLM-administered
lands and resources. Resource management plans that include areas of
northern leopard frog habitat were completed beginning in the 1980s.
RMPs have been developed or amended to incorporate State or regionally
developed rangeland
[[Page 61923]]
health standards and guidelines, which BLM developed beginning in 1995
(60 FR 9894, February 22, 1995). Standards describe the specific
conditions needed for public land health, such as the presence of
streambank vegetation; guidelines are the rangeland management
techniques designed to achieve or maintain healthy public lands, as
defined by the standards. Standards and guidelines must be consistent
with the fundamentals of rangeland health, which include watersheds
that are in, or are making significant progress toward, properly
functioning physical condition, including their riparian-wetland and
aquatic components, and water quality that complies with State water
quality standards. Areas and activities are assessed to determine if
the standards are being achieved, and if not, actions must be taken
towards fulfilling the standards (43 CFR 4180.1).
The Service has no specific documentation of how implementation of
the rangeland health standards have maintained or improved riparian or
wetland conditions within northern leopard frog habitat on BLM-
administered lands. The latest Public Land Statistics report available
(2010) lists 23,618 acres (ac) (9,558 hectares (ha)) of wetlands either
in properly functioning condition or functioning-at-risk with an upward
trend, out of 49,764 total wetland ac (20,139 ha) on BLM lands in
Colorado, Idaho, Montana, Nevada, New Mexico, North and South Dakota,
and Wyoming. The same report lists 12,215 mi (19,658 km) of riparian
areas either in properly functioning condition or functioning-at-risk
with an upward trend, out of 19,759 total miles (31,799 km) on BLM
lands in the same States.
The BLM has regulatory authority for oil and gas leasing on Federal
lands and on private lands with a Federal mineral estate, as provided
at subpart 3100 (Onshore Oil and Gas Leasing: General) of Title 43 of
the CFR, and they are authorized to require stipulations as a condition
of issuing a lease. The BLM has developed best management practices to
reduce habitat fragmentation, loss, and degradation from energy
development. However, use of these conditions is discretionary, and the
Service does not have information as to how this authority has been
applied.
The NPS manages portions of habitat throughout the range of the
northern leopard frog. The NPS carries out its responsibilities in
parks and programs under the authority of the National Park Service
Organic Act of 1916 (16 U.S.C. 1 et seq.). As defined in the National
Park Service Organic Act, the purpose of national parks is to conserve
the scenery and the natural and historic objects and the wildlife
therein and to provide for the enjoyment of the same in such manner and
by such means as will leave them unimpaired for the enjoyment of future
generations.
The Forest Service manages habitat for northern leopard frogs in
the western United States on National Forests and National Grasslands
in several States, including Arizona, Colorado, Idaho, Minnesota,
Montana, New Mexico, North Dakota, South Dakota, Utah, and Wyoming.
Management of National Forest System lands is guided principally by the
National Forest Management Act (NFMA) (16 U.S.C. 1600 et seq.). The
NFMA specifies that all National Forests must have a Land and Resource
Management Plan (LRMP) (16 U.S.C. 1604) to guide and set standards for
all natural resource management activities on each National Forest or
National Grassland. The NFMA requires the Forest Service to incorporate
standards and guidelines into LRMPs (16 U.S.C. 1604(c)). The Forest
Service conducts NEPA analyses on its LRMPs, which include provisions
to manage plant and animal communities for diversity, based on the
suitability and capability of the specific land area in order to meet
overall multiple-use objectives. The Forest Service planning process is
similar to that of the BLM.
As described in the Status section, populations of northern leopard
frogs have declined across most of the western States on lands with
populations under Forest Service jurisdiction. The northern leopard
frog is designated a ``sensitive species'' in Forest Service Regions 1
(Northern Region--northern Idaho, Montana, North Dakota, and northwest
South Dakota), 2 (Rocky Mountain Region--Colorado, Nebraska, most of
South Dakota and Wyoming), 3 (Southwest Region--Arizona and New
Mexico), 5 (Pacific Southwest Region--California), and 6 (Pacific
Northwest--Oregon and Washington), but not in Regions 4 (Intermountain
Region--southern Idaho, Nevada, Utah, and western Wyoming) and 9
(Eastern Region--includes all eastern States and Minnesota). Sensitive
species status does not provide special protection but requires, ``an
analysis of the significance of adverse effects on the population, its
habitat, and on the viability of the species as a whole'' (Forest
Service's Manual at 2672.1).
Tribal Laws
Of the hundreds of tribal nations located throughout the range of
the northern leopard frog in the United States and Canada, we only
received information regarding the northern leopard frog from the
Navajo Nation (Arizona, New Mexico, and Utah), the Fort Peck Tribes
(Montana), the Confederated Salish and Kootenai Tribes of the Flathead
Nation (Montana), and the Sisseton-Wahpeton Oyate (South Dakota). The
Navajo Nation provided us with specific information regarding tribal
laws. We will continue to welcome any additional information regarding
the northern leopard frog from tribal nations.
Navajo Endangered Species List Group 2 species are protected under
Navajo Nation law. The Navajo Nation Code (17 Navajo Nation Code
section 507) makes it ``unlawful for any person to take, possess,
transport, export, process, sell or offer for sale or ship'' a Group 2
species. Under this Code, ``take'' means ``the hunting, capturing,
killing in any manner or the attempt to hunt, capture or kill in any
manner * * *.'' Habitat protection, per se, is not afforded under the
Navajo Nation Code.
The Navajo Nation government, pursuant to 2 Navajo Nation Code
section 164, reviews actions involving the use of natural resources for
compliance with Navajo Nation law, including the Navajo Endangered
Species Code. The Navajo Nation Fish and Wildlife Department, through
the section 164 review process, advises the tribal Resources Committee
and the Navajo Nation Council whether proposed natural resources
projects are in compliance with the Navajo Endangered Species Code. The
Resources Committee has the power to give final approval for any land
exchanges, non-mineral leases, right-of-ways, permits, and other
licenses and interests on Navajo land in accordance with applicable and
Federal and Navajo Nation laws. The Resources Committee recommends all
actions involving the approval of mineral agreements, land
acquisitions, and energy development agreements to the Navajo Nation
Council. Some protection for northern leopard frog habitat may be
provided through this review.
State Laws and Regulations
Only 1 of the 33 States assessed in the Status section above has
listed the northern leopard frog under a State wildlife conservation
law. In 2000, the Washington Department of Fish and Wildlife listed the
northern leopard frog as an endangered species under the Endangered,
Threatened, and Sensitive Species Classification (Washington
Administrative Code, Title 232, Chapter 12, Section 014). However,
because northern leopard frogs are currently
[[Page 61924]]
known from only two sites (Germaine and Hays 2009, p. 537) in
Washington State, this regulatory mechanism protects relatively few
individuals.
Arizona, California, Colorado, Connecticut, Idaho, Indiana,
Kentucky, Maine, Massachusetts, Michigan, Missouri, Montana, Nebraska,
Nevada, New Hampshire, New Mexico, Oregon, Pennsylvania, Rhode Island,
Utah, West Virginia, and Wyoming included the northern leopard frog
specifically as a species of greatest conservation need or species of
concern in their State wildlife action plans (designations vary by
State as described in Status section above); however, this designation
provides no regulatory protection to the species or its habitat. The
northern leopard frog is not considered a species of concern in
Illinois, Iowa, Minnesota, New York, North Dakota, Ohio, South Dakota,
Texas, Vermont, and Wisconsin.
Several States have laws that provide some protection of northern
leopard frogs in regards to collection, as discussed in the Status
section above. These laws and regulations generally preclude or limit
collection without a permit, but do not preclude impacts to habitat.
In summary, State wildlife conservation laws generally provide for
an inconsistent network of protections for the northern leopard frog.
While take is prohibited in some States, and the species is afforded
some management consideration in project planning, the laws generally
do not preclude impacts to habitat. However, 23 of the 33 States within
the range of the northern leopard frog have indicated commitment
through their State wildlife action plans to implementing conservation
actions and habitat enhancement projects to benefit the northern
leopard frog.
International Laws and Regulations
The northern leopard frog, Rocky Mountain population, is listed as
endangered under the Federal Species at Risk Act (Statues of Canada
2002, c.29) in Canada. The Species at Risk Act, passed December 12,
2002, is a commitment by the Canadian government to prevent the
extinction of wildlife and provide the necessary actions for the
recovery of the species deemed endangered. Wildlife species listed
under the Species at Risk Act are provided with legal protection to
avoid extinction resulting from human activities (Government of Canada
Species at Risk Public Registry 2011). The northern leopard frog is
also Red Listed as endangered under the British Columbia Wildlife Act
(Revised Statutes of British Columbia 1996, c. 488), which prohibits
the killing or collecting of amphibians or keeping them in captivity
without a permit. In British Columbia, the one remaining northern
leopard frog population is located in the Creston Valley Wildlife
Management Area (Committee on the Status of Endangered Wildlife in
Canada 2009, p. 42). The Creston Valley Wildlife Management area is
protected by the British Columbia government and by the Convention on
Wetlands of International Importance (``Ramsar Convention,'' Ramsar,
Iran 1971), where Creston Valley was designated a Wetland of
International Importance on February 21, 1994. The Convention on
Wetlands is an intergovernmental treaty that provides the framework for
national action and international cooperation for the conservation and
wise use of wetlands and their resources. In addition, other provincial
legislation, including the Fish Protection Act (Bill 25-1997), the
Creston Valley Wildlife Act (Revised Statutes of British Columbia 1996,
c. 84), the Integrated Pest Management Act (Statues of British Columbia
2003, c. 58), and the Riparian Areas Regulation (Fish Protection Act,
British Columbia Regulation 376/2004) provide habitat protection and
enhancement to the remaining northern leopard frog population
(Committee on the Status of Endangered Species in Canada 2009, p. vi).
The northern leopard frog was listed as threatened in Schedule 6 of
Alberta's Wildlife Act (Revised Statutes of Alberta 2000, Chapter W-
10), based on a decline in the number of populations, the fragmentation
of occupied habitats, and limited population dispersal capabilities of
the species (Alberta Northern Leopard Frog Recovery Team 2005, p. 1).
As a result of the listing, the Alberta Northern Leopard Frog Recovery
Plan was created and is currently being implemented (Alberta Northern
Leopard Frog Recovery Team 2005). In Saskatchewan, the northern leopard
frog is currently on the province's Interim Species at Risk List
(Wildlife Act 1998, Chapter W-13.12) and is protected in provincial and
national parks (Committee on the Status of Endangered Wildlife in
Canada 2009, p. vi). The national status of the western boreal and
prairie population (which includes Alberta, Saskatchewan, Manitoba, and
the Northwest Territories) was evaluated in 1998 and 2002, and the
northern leopard frog was designated a Species of Special Concern
(Committee on the Status of Endangered Wildlife in Canada 2004, p. 20).
As a result of the national designation, a management plan was required
to be developed for the western boreal and prairie population. Although
the northern leopard frog has no national or provincial status in
Eastern Canada, the species is protected on Federal lands managed by
Parks Canada (national parks and historic sites), Environment Canada
(national wildlife areas), and the Department of Defense (Committee on
the Status of Endangered Wildlife in Canada 2009, p. vi).
As noted in the BACKGROUND section above, the northern leopard frog
population in western Canada is small and fragmented, but as one
proceeds east, the number of northern leopard frog populations and
their known status, based on the best available information, improves.
Where the northern leopard frog has and likely continues to decline in
western Canada, there is no information to indicate that the species is
threatened by the inadequacy of existing regulatory mechanisms in
Canada.
Summary of Factor D
While northern leopard frog conservation has been addressed in some
State, Federal, and international plans, laws, regulations, and
policies, none of these have applicability throughout the range of the
northern leopard frog sufficient to provide effective population-level
conservation. However, we have found in the analysis of the other four
factors (A, B, C, and E) that there are no threats that currently rise
to a level such that they significantly impact the northern leopard
frog at the species level. Therefore, we conclude that the best
scientific and commercial information available indicates that the
inadequacy of existing regulatory mechanisms is not a significant
threat to the northern leopard frog at the species level now, nor do we
have indication that it will in the future.
Factor E. Other Natural or Manmade Factors Affecting Its Continued
Existence
Pesticides
Even at low levels, pesticides can contribute to local declines or
extirpation of northern leopard frog populations, particularly in areas
that are in close proximity to heavy or frequent pesticide use because
tadpole and larval stages are sensitive to even low-level pesticide
contamination (Berrill et al. 1997, p. 244). The effects to northern
leopard frogs from pesticides, including herbicides, piscicides
(chemical substances poisonous to fish), and insecticides, vary, but
information indicates that the species is negatively affected both
[[Page 61925]]
acutely and via sublethal symptoms by several pesticides and chemicals
(rotenone, Roundup, atrazine, malathion, copper sulfate, and fenthion)
that are commonly used in the United States (Stebbins and Cohen 1995,
pp. 215-216; Fordham 1999, p. 125; Hayes et al. 2002, pp. 895-896;
Beasley et al. 2005, p. 86; Patla 2005, p. 275; Relyea 2005, p. 353;
Rorabaugh 2005, p. 576). Pesticide contamination of surface waters in
the United States is extensive, and concentrations of pesticides are
frequently greater than water-quality benchmarks for aquatic life and
fish-eating wildlife (Gilliom et al. 2006, p. 8). Of the streams
analyzed as part of the National Water Quality Assessment Program, 57
percent contained one or more pesticides that exceeded at least one
aquatic life protection benchmark (Gilliom et al. 2006, p. 8), which
may result in decreased habitat quality, malformations, and decreased
fitness of northern leopard frogs (Rorabaugh 2005, p. 576).
While northern leopard frogs may be exposed to pesticides in a
number of ways, they are most significantly exposed to pesticides when
run-off from agricultural and urban areas reaches occupied habitats.
Exposure to pesticide run-off can influence parasitic community
structure and seasonal recruitment in northern leopard frogs (King et
al. 2008, p. 20). Berrill et al. (1997, p. 243) found that tadpoles
(including northern leopard frog tadpoles) are extremely sensitive
(i.e., they experience paralysis and death) to exposure of one
pesticide at a time; pesticides in combination likely have more severe
effects. Ouellet et al. (1997, p. 97) examined northern leopard frogs
in agricultural and non-agricultural ponds in Quebec and found that
frogs in the agricultural ponds had a variety of hind limb
malformations. The authors identified agricultural pesticides as a
potential causal agent. Pesticide exposure not only can cause
malformations in frogs (Lannoo 2008, pp. 142-144), but contact with
pesticides has been found to increase amphibians vulnerability to
Ribeiroia (trematode) and other parasitic infections, which are also
known to cause frog malformations (Kiesecker 2002, p. 9903; Lannoo
2008; Rohr et al. 2008, p. 1237). In addition, increased nitrates from
fertilizers can also result in adverse effects to amphibian development
and survival (Marco et al. 1999, p. 2837; Rouse et al. 1999, pp. 800-
802). Therefore, although northern leopard frogs were not specifically
tested for pesticides in the examples from Washington or Quebec, it is
plausible that the habitat alteration and subsequent contamination of
aquatic habitats with pesticides contributed to the decline of northern
leopard frogs in these areas. Agrichemical pollution is also thought to
be a factor in declining amphibian populations in Nebraska and Quebec
(Beasley et al. 2005, p. 86; McCleod 2005, p. 293; King et al. 2008, p.
20).
Based upon the above information, exposure to pesticides has likely
contributed to northern leopard frog population extirpations throughout
their range. While the magnitude of these impacts is conceivably high
in localized areas, pesticide use is not ubiquitous throughout the
range of the northern leopard frog; thus pesticide use is likely not
resulting in impacts at regional and species-level scales. Further,
despite ongoing exposure to pesticides, the northern leopard frog is
apparently still considered to be widespread and common in the eastern
United States and eastern Canada. Therefore, the best available
scientific information indicates that pesticide use does not constitute
a significant threat to the northern leopard frog at the species level
now, nor do we have indication that it will in the future.
Malformations
Within the last 15 to 20 years, malformed northern leopard frogs
have been reported with increasing frequency in the United States,
particularly in Minnesota, North Dakota, South Dakota, and Vermont
(Helgen et al. 1998, p. 288; Sessions 2003, p. 168; Johnson and Lunde
2005, p. 124; Rorabaugh 2005, p. 576). Malformations are also reported
from Colorado, Indiana, Iowa, Michigan, Missouri, Montana, Ohio,
Quebec, and Wisconsin (Converse et al. 2000, p. 163; Johnson and Lunde
2005, pp. 124-128; Rorabaugh 2005, p. 575; North American Center for
Reporting Amphibian Malformations 2006). Noted malformations have
included limb deformities, multiple or missing limbs, jaw deformities,
stunted growth, multiple eyes, missing eyes, and various other growths
(Helgen et al. 1998, pp. 288-297; Hoppe 2005, p. 104). Malformations
are believed to be caused by a variety of natural and manmade factors,
including trematode parasites, pesticides, ultraviolet-B radiation,
predation attempts, and water contamination (Helgen et al. 1998, pp.
294-297; Blaustein and Johnson 2003, pp. 87-91; Sessions 2003, p. 168;
Johnson and Lunde 2005, pp. 124-138;), but are generally linked to
human-induced changes in aquatic habitats (Meteyer et al. 2000, pp.
151-171; Johnson and Lunde 2005, pp. 130-136; Lannoo 2008, pp. 105-110,
197). These malformations typically lead to mortality as behavior and
physical mobility (such as swimming, hopping, and feeding) are
compromised to the point of affecting individual fitness (Helgen et al.
1998, p. 289; Hoppe 2005, pp. 105-108). Northern leopard frogs tend to
be one of the most common species found with malformations (Lannoo
2008, p. 207).
Malformations are a concern because they affect the ability of
individual and local populations of northern leopard frogs to survive,
and because they are a likely indicator of decreased water quality and
of decreased overall habitat quality. However, as stated above, there
are likely many causes of malformations in northern leopard frogs that
have to do with local, site-specific conditions and are likely not the
result of the same causal agent throughout the range of the northern
leopard frog (Lannoo 2008, p. 200). Further, the diversity of habitat
used by northern leopard frogs may provide some protection against the
variety of agents that seem to result in malformation at the local
scale. The rate of malformations in some local populations of northern
leopard frogs may result in significant effects to these populations;
however, the impact of malformations on the northern leopard frog at
the species level is not known to be significant. Therefore, based on
the best available information, we conclude that malformations are not
a significant threat to northern leopard frogs at the species level
now, nor do we have indication that it will in the future.
Climate Change
``Climate'' refers to an area's long-term average weather
statistics (typically for at least 20- or 30-year periods), including
the mean and variation of surface variables such as temperature,
precipitation, and wind, whereas ``climate change'' refers to a change
in the mean and/or variability of climate properties that persists for
an extended period (typically decades or longer), whether due to
natural processes or human activity (Intergovernmental Panel on Climate
Change (IPCC) 2007a, p. 78). Although changes in climate occur
continuously over geological time, changes are now occurring at an
accelerated rate. For example, at continental, regional and ocean basin
scales, recent observed changes in long-term trends include: A
substantial increase in precipitation in eastern parts of North
American and South America, northern Europe, and northern and central
Asia, and an increase in intense tropical cyclone activity in the North
Atlantic since about 1970 (IPCC 2007a,
[[Page 61926]]
p. 30); and an increase in annual average temperature of more than 2
[deg]F (1.1 [deg]C) across US since 1960 (Global Climate Change Impacts
in the United States (GCCIUS) 2009, p. 27). Examples of observed
changes in the physical environment include: An increase in global
average sea level, and declines in mountain glaciers and average snow
cover in both the northern and southern hemispheres (IPCC 2007a, p.
30); substantial and accelerating reductions in Arctic sea-ice (e.g.,
Comiso et al. 2008, p. 1), and a variety of changes in ecosystem
processes, the distribution of species, and the timing of seasonal
events (e.g., GCCIUS 2009, pp. 79-88).
The IPCC used Atmosphere-Ocean General Circulation Models and
various greenhouse gas emissions scenarios to make projections of
climate change globally and for broad regions through the 21st century
(Meehl et al. 2007, p. 753; Randall et al. 2007, pp. 596-599), and
reported these projections using a framework for characterizing
certainty (Solomon et al. 2007, pp. 22-23). Examples include: (1) It is
virtually certain there will be warmer and more frequent hot days and
nights over most of the earth's land areas; (2) it is very likely there
will be increased frequency of warm spells and heat waves over most
land areas, and the frequency of heavy precipitation events will
increase over most areas; and (3) it is likely that increases will
occur in the incidence of extreme high sea level (excludes tsunamis),
intense tropical cyclone activity, and the area affected by droughts
(IPCC 2007b, p. 8, Table SPM.2). More recent analyses using a different
global model and comparing other emissions scenarios resulted in
similar projections of global temperature change across the different
approaches (Prinn et al. 2011, pp. 527, 529).
All models (not just those involving climate change) have some
uncertainty associated with projections due to assumptions used, data
available, and features of the models; with regard to climate change
this includes factors such as assumptions related to emissions
scenarios, internal climate variability and differences among models.
Despite this, however, under all global models and emissions scenarios,
the overall projected trajectory of surface air temperature is one of
increased warming compared to current conditions (Meehl et al. 2007, p.
762; Prinn et al. 2011, p. 527). Climate models, emissions scenarios,
and associated assumptions, data, and analytical techniques will
continue to be refined, as will interpretations of projections, as more
information becomes available. For instance, some changes in conditions
are occurring more rapidly than initially projected, such as melting of
Arctic sea ice (Comiso et al. 2008, p. 1; Polyak et al. 2010, p. 1797),
and since 2000 the observed emissions of greenhouse gases, which are a
key influence on climate change, have been occurring at the mid- to
higher levels of the various emissions scenarios developed in the late
1990's and used by the IPPC for making projections (e.g., Raupach et
al. 2007, Figure 1, p. 10289; Manning et al. 2010, Figure 1, p. 377;
Pielke et al. 2008, entire). Also, the best scientific and commercial
data available indicates that average global surface air temperature is
increasing and several climate-related changes are occurring and will
continue for many decades even if emissions are stabilized soon (e.g.
Meehl et al. 2007, pp. 822-829; Church et al. 2010, pp. 411-412;
Gillett et al. 2011, entire).
Changes in climate can have a variety of direct and indirect
impacts on species, and can exacerbate the effects of other threats.
Rather than assessing ``climate change'' as a single threat in and of
itself, we examine the potential consequences to species and their
habitats that arise from changes in environmental conditions associated
with various aspects of climate change. For example, climate-related
changes to habitats, predator-prey relationships, disease and disease
vectors, or conditions that exceed the physiological tolerances of a
species, occurring individually or in combination, may affect the
status of a species. Vulnerability to climate change impacts is a
function of sensitivity to those changes, exposure to those changes,
and adaptive capacity (IPCC 2007, p. 89; Glick et al 2011, pp. 19-22).
As described above, in evaluating the status of a species, the Service
uses the best scientific and commercial data available, and this
includes consideration of direct and indirect effects of climate
change. As is the case with all potential threats, if a species is
currently affected or is expected to be affected by one or more
climate-related impacts, this does not necessarily mean the species is
a threatened or endangered species as defined under the Act. If a
species is listed as threatened or endangered, this knowledge regarding
its vulnerability to, and impacts from, climate-associated changes in
environmental conditions can be used to help devise appropriate
strategies for its recovery.
While projections from global climate model simulations are
informative and in some cases are the only or the best scientific
information available, various downscaling methods are being used to
provide higher-resolution projections that are more relevant to the
spatial scales used to assess impacts to a given species (see Glick et
al, 2011, pp. 58-61). With regard to the area of analysis for the
northern leopard frog, specific downscaled projections are not
available for all the parts of its range, but we do have more
generalized information. In North America, climate change is likely to
constrain already over-allocated water resources, resulting in
increased competition among agricultural, municipal, industrial, and
ecological uses of water (Bates et al. 2008, p. 102). Of particular
note are the expected changes in surface and groundwater hydrology. As
the rate of warming accelerates, the timing, volume, quality, and
spatial distribution of fresh water available to most areas in North
America will change (Bates et al. 2008, p. 102; Johnson et al. 2010, p.
138). These changes will likely affect the quality and quantity of
northern leopard frog habitat. Some areas, especially in the arid West,
will likely see decreases in habitat, while other areas may experience
stable or increasing available habitat. The freshwater wetland habitats
the northern leopard frog depends upon for breeding and overwintering,
particularly in the arid Southwest (Arizona, Colorado, New Mexico,
Nevada, and Utah) and the prairie potholes region (Alberta, Iowa,
Manitoba, Minnesota, Montana, North Dakota, Saskatchewan, and South
Dakota) are expected to be particularly sensitive to climate change
(Johnson et al. 2010, p. 128). Increases in drought and seasonal
precipitation may have profound impacts to habitat; however, we are
unable to reliably predict how changes in precipitation will affect
current and future northern leopard frog habitat throughout the
species' range.
Many experts expect that amphibians may be among the first
vertebrates to exhibit broad-scale changes in response to global
climate change (Reaser and Blaustein 2005, p. 61). The northern leopard
frog is at the upper limit of its physiological tolerance to
temperature and dryness throughout the arid and semi-arid habitats in
the western United States (Hammerson 1999, pp. 146-147; Hitchcock 2001,
pp. 18-19; Rorabaugh 2005, p. 577). As such, if the predictions for
temperature increases are realized, these arid areas may no longer
support the species. In addition, the northern leopard frog frequently
depends upon small, ephemeral wetlands for breeding habitats (Merrell
1968, p. 275), and due to habitat fragmentation, the presence of
nonnative aquatic species, and other
[[Page 61927]]
factors (such as agricultural and urban development, and roads), the
leopard frog is bounded by dispersal barriers throughout its range
(Rorabaugh 2005, p. 577). Species persistence is greater for species
occupying larger patches of their historical range (Channell and
Lomolino 2000, pp. 84-86). Because northern leopard frogs occupy
relatively small patches of habitat compared to their historical
distribution in some portions of their range, we may expect that
climate change could result in further fragmentation of those
populations in those portions of its range. In other words, the frogs
may exist in smaller and smaller patches that are more remote from the
core of their historical range.
As described above, changes in the quality and quantity of habitat
are likely to occur throughout the range of the northern leopard frog.
There are likely to be additional impacts to frogs in some portions of
it range because of these changes. Climate change impacts in the arid
and semi-arid areas could include earlier reproduction and more rapid
development of larva due to more a more advanced spring, decreased
mobility due to drier conditions, and shorter hibernation periods due
to longer ice-free periods in the winter (Carey and Alexander 2003, pp.
111-121; Patla and Keinath 2005, pp. 44-46; Johnson et al. 2010, p.
133). Higher summer temperatures may result in high egg mortality (in
response to freezing temperatures that may follow earlier breeding
times) and in drying of breeding habitats prior to metamorphosis (in
response to increased evaporation rate) (Smith 2003, p. 34). Climate
change may also cause frogs to experience increased physiological
stress and decreased immune system function, possibly leading to
disease outbreaks (Carey and Alexander 2003, pp. 111-121; Pounds et al.
2006, pp. 161-167). Northern leopard frog populations at lower
elevations are likely to show changes in phenology sooner than those at
higher elevations (Corn 2003, pp. 622-625). Based upon the extended
droughts in the Southwest and changes the Service has noted to northern
leopard frog habitats in Arizona and New Mexico (Service 2007, pp. 38-
41), it is likely that climate change may continue to reduce the amount
of habitat available for northern leopard frogs, particularly in the
western United States.
Climate change may result in significant impacts to some portions
of the range of the northern leopard frog and may synergistically
result in increased impacts from disease and other factors discussed
above. The overall impacts of climate change will likely be very
different across the range of the northern leopard frog, and it is
difficult to predict how these effects will manifest themselves in
terms of species-level impacts. There may be decreases in habitat in
some areas, and increases in other portions of the range. As a result,
it is possible that the species' range could expand, contract, or
shift. However, we do not know enough about the capacity of this
species to adapt to changing environmental conditions to make reliable
predictions about future large-scale range contractions or shifts in
response to climate change. In the arid West, it is likely that the
predictions for greater variability in temperature and precipitation
will result in further decreases in wetland habitats, which may
exacerbate the negative interactions of native and nonnative species
using wetted habitats. However, we expect that there may be portions of
the species' range that may experience more favorable conditions, such
as increased precipitation and temperature, that will positively affect
habitat for the northern leopard frog. In conclusion, although we
believe climate change will impact some northern leopard frog habitats
in the future, the information we reviewed does not indicate that
climate change will adversely impact northern leopard frogs at the
species level. Therefore, based on the best available information, we
conclude that climate change is not a significant threat individually
or in combination to the northern leopard frog at the species level
now, nor do we have indication that it will in the future.
Summary of Factor E
The northern leopard frog occupies a wide geographic range across
the United States and Canada. As we have stated earlier, because it
occurs across such a large area, the habitats it uses are subject to a
number of impacts from pesticide use and climate change, and the
species is subject to malformations that will impact local, and
possibly even regional, populations. However, the wide diversity of
wetland and upland habitats that are currently used by the northern
leopard frog across its range may provide some protection in the future
from changing climates and possibly from the variety of potential
agents that cause malformations. Therefore, the best available
information indicates that other natural and manmade factors do not
constitute a significant threat to the northern leopard frog at the
species level now, nor do we have indication that it will in the
future.
Finding
As required by the Act, we considered the five factors in assessing
whether the northern leopard frog is endangered or threatened
throughout all of its range (i.e., in danger of extinction now or in
the foreseeable future). We examined the best scientific and commercial
information available regarding the past, present, and future threats
faced by the northern leopard frog. We reviewed the petition,
information available in our files, and other available published and
unpublished information, and we consulted with other Federal, State,
and tribal agencies.
There have been historical impacts to the northern leopard frog, in
particular. The loss and degradation of wetland habitat, introduction
of nonnative species, and disease, have resulted in local and regional
extirpations of the species throughout its range, but particularly in
the western United States and Canada, as described in the Background
section above. Further, some of the threats discussed in this finding
work in concert with one another to cumulatively create situations that
potentially impact the northern leopard frog beyond the scope of each
individual threat. It is likely that for such a widespread species as
the northern leopard frog, causes of decline are dependent upon
multiple factors or causes. This is particularly true since the
northern leopard frog uses both terrestrial and aquatic habitats. For
example, as discussed under Factor A, degradation of wetland habitats,
resulting from agricultural use and the application of pesticides,
results in increased immunosuppression and risk of parasitic infection
in northern leopard frogs (Christin et al. 2003, pp. 1129-1130). These
factors can also enhance the potential for malformations, which can
result in decreased fitness, and subsequent declines of northern
leopard frog populations. Malformations (discussed under Factor E) are
likely the result of multiple causes. Lannoo (2008) describes the
search for ``the'' cause of amphibian malformations, but eloquently
determines in his comprehensive review that there is likely no one
cause, but many factors that can result in malformations. Similarly,
Thiemann and Wassersug (2000) found that the presence of predators and
parasites also increased the susceptibility of Rana (=Lithobates)
tadpoles to trematode infection by causing tadpoles to decrease their
activity levels. They found that the combination of such stressors as
increased predator loads (such as from
[[Page 61928]]
widespread predator introductions as discussed under Factor C),
parasite infection, and pesticide pollution may synergistically result
in increased impacts to tadpoles, which could be another factor in
declining populations. However, even where these factors may work
cumulatively to impact northern leopard frogs, the best available
information does not indicate that current populations are being
impacted significantly at scales above the population or regional
levels.
In summary, in order to determine that the northern leopard frog
warrants listing throughout its range, we must find that the best
available information indicates it is in danger of extinction now or in
the foreseeable future. The phrase ``in danger of extinction'' requires
a showing that the species is actually likely in danger of extinction
now, or likely to become so in the foreseeable future, not merely a
showing that the species is facing threats. We must show that the
threats are operative on the species such that the species meets the
definition of threatened or endangered (i.e., in danger of extinction
now or in the foreseeable future). The northern leopard frog occupies a
wide geographic range across the United States and Canada. Because it
occurs across such a large area, it is subject to a number of impacts
that represent potential threats at various scales. The number of
threats the species has faced and continues to face may appear
significant; however, as discussed above, the factors affecting the
northern leopard frog have generally been historical in impact or are
occurring now and into the future at scales below the species level as
indicated by the presence of apparently stable populations in large
areas of its range. Further, while there have been regional declines
noted in the range of the species, particularly in the western portions
of the United States and Canada, the frog is apparently still
considered to be widespread and relatively common in the eastern United
States and eastern Canada.
Based on our review of the best available scientific and commercial
information pertaining to the five factors, we find that threats, alone
or cumulatively, are not of sufficient magnitude at the species level
to indicate that the northern leopard frog is in danger of extinction,
or likely to become in danger of extinction within the foreseeable
future, throughout all of its range.
Significant Portion of Its Range
The Act defines ``endangered species'' as any species which is ``in
danger of extinction throughout all or a significant portion of its
range,'' and ``threatened species'' as any species which is ``likely to
become an endangered species within the foreseeable future throughout
all or a significant portion of its range.'' The definition of
``species'' is also relevant to this discussion. The Act defines the
term ``species'' as follows: ``The term `species' includes any
subspecies of fish or wildlife or plants, and any distinct population
segment of any species of vertebrate fish or wildlife which interbreeds
when mature.'' The phrase ``significant portion of its range'' is not
defined by the statute, and we have never addressed in our regulations:
(1) The consequences of a determination that a species is either
endangered or likely to become so throughout a significant portion of
its range, but not throughout all of its range; or (2) what qualifies a
portion of a range as ``significant.''
Two recent district court decisions have addressed whether the
``significant portion of its range'' language allows the Service to
list or protect less than all members of a defined ``species'':
Defenders of Wildlife v. Salazar, 729 F. Supp. 2d 1207 (D. Mont. 2010),
concerning the Service's delisting of the Northern Rocky Mountain gray
wolf (74 FR 15123, Apr. 2, 2009); and WildEarth Guardians v. Salazar,
2010 U.S. Dist. LEXIS 105253 (D. Ariz. Sept. 30, 2010), concerning the
Service's 2008 finding on a petition to list the Gunnison's prairie dog
(73 FR 6660, February 5, 2008). The Service had asserted in both of
these determinations that it had authority, in effect, to protect only
some members of a ``species,'' as defined by the Act (i.e., species,
subspecies, or DPS), under the Act. Both courts ruled that the
determinations were arbitrary and capricious on the grounds that this
approach violated the plain and unambiguous language of the Act. The
courts concluded that reading the ``significant portion of its range''
language to allow protecting only a portion of a species' range is
inconsistent with the Act's definition of ``species.'' The courts
concluded that once a determination is made that a species (i.e.,
species, subspecies, or DPS) meets the definition of ``endangered
species'' or ``threatened species,'' it must be placed on the list in
its entirety and the Act's protections applied consistently to all
members of that species (subject to modification of protections through
special rules under sections 4(d) and 10(j) of the Act).
Consistent with that interpretation, and for the purposes of this
finding, we interpret the phrase ``significant portion of its range''
in the Act's definitions of ``endangered species'' and ``threatened
species'' to provide an independent basis for listing; thus there are
two situations (or factual bases) under which a species would qualify
for listing: a species may be endangered or threatened throughout all
of its range; or a species may be endangered or threatened in only a
significant portion of its range. If a species is in danger of
extinction throughout a significant portion of its range, it, the
species, is an ``endangered species.'' The same analysis applies to
``threatened species.'' Therefore, the consequence of finding that a
species is endangered or threatened in only a significant portion of
its range is that the entire species will be listed as endangered or
threatened, respectively, and the Act's protections will be applied
across the species' entire range.
We conclude, for the purposes of this finding, that interpreting
the ``significant portion of its range'' phrase as providing an
independent basis for listing is the best interpretation of the Act
because it is consistent with the purposes and the plain meaning of the
key definitions of the Act; it does not conflict with established past
agency practice, as no consistent, long-term agency practice has been
established; and it is consistent with the judicial opinions that have
most closely examined this issue. Having concluded that the phrase
``significant portion of its range'' provides an independent basis for
listing and protecting the entire species, we next turn to the meaning
of ``significant'' to determine the threshold for when such an
independent basis for listing exists.
Although there are potentially many ways to determine whether a
portion of a species' range is ``significant,'' we conclude, for the
purposes of this finding, that the significance of the portion of the
range should be determined based on its biological contribution to the
conservation of the species. For this reason, we describe the threshold
for ``significant'' in terms of an increase in the risk of extinction
for the species. We conclude that a biologically based definition of
``significant'' best conforms to the purposes of the Act, is consistent
with judicial interpretations, and best ensures species' conservation.
Thus, for the purposes of this finding, a portion of the range of a
species is ``significant'' if its contribution to the viability of the
species is so important that, without that portion, the species would
be in danger of extinction.
We evaluate biological significance based on the principles of
conservation biology using the concepts of
[[Page 61929]]
redundancy, resiliency, and representation. Resiliency describes the
characteristics of a species that allow it to recover from periodic
disturbance. Redundancy (having multiple populations distributed across
the landscape) may be needed to provide a margin of safety for the
species to withstand catastrophic events. Representation (the range of
variation found in a species) ensures that the species' adaptive
capabilities are conserved. Redundancy, resiliency, and representation
are not independent of each other, and some characteristics of a
species or area may contribute to all three. For example, distribution
across a wide variety of habitats is an indicator of representation,
but it may also indicate a broad geographic distribution contributing
to redundancy (decreasing the chance that any one event affects the
entire species), and the likelihood that some habitat types are less
susceptible to certain threats, contributing to resiliency (the ability
of the species to recover from disturbance). None of these concepts is
intended to be mutually exclusive, and a portion of a species' range
may be determined to be ``significant'' due to its contributions under
any one of these concepts.
For the purposes of this finding, we determine if a portion's
biological contribution is so important that the portion qualifies as
``significant'' by asking whether, without that portion, the
representation, redundancy, or resiliency of the species would be so
impaired that the species would have an increased vulnerability to
threats to the point that the overall species would be in danger of
extinction (i.e., would be ``endangered''). Conversely, we would not
consider the portion of the range at issue to be ``significant'' if
there is sufficient resiliency, redundancy, and representation
elsewhere in the species' range that the species would not be in danger
of extinction throughout its range if the population in that portion of
the range in question became extirpated (extinct locally).
We recognize that this definition of ``significant'' establishes a
threshold that is relatively high. On the one hand, given that the
consequences of finding a species to be endangered or threatened in a
significant portion of its range would be listing the species
throughout its entire range, it is important to use a threshold for
``significant'' that is robust. It would not be meaningful or
appropriate to establish a very low threshold whereby a portion of the
range can be considered ``significant'' even if only a negligible
increase in extinction risk would result from its loss. Because nearly
any portion of a species' range can be said to contribute some
increment to a species' viability, use of such a low threshold would
require us to impose restrictions and expend conservation resources
disproportionately to conservation benefit: listing would be rangewide,
even if only a portion of the range of minor conservation importance to
the species is imperiled. On the other hand, it would be inappropriate
to establish a threshold for ``significant'' that is too high. This
would be the case if the standard were, for example, that a portion of
the range can be considered ``significant'' only if threats in that
portion result in the entire species' being currently endangered or
threatened. Such a high bar would not give the ``significant portion of
its range'' phrase independent meaning, as the Ninth Circuit held in
Defenders of Wildlife v. Norton, 258 F.3d 1136 (9th Cir. 2001).
The definition of ``significant'' used in this finding carefully
balances these concerns. By setting a relatively high threshold, we
minimize the degree to which restrictions will be imposed or resources
expended that do not contribute substantially to species conservation.
But we have not set the threshold so high that the phrase ``in a
significant portion of its range'' loses independent meaning.
Specifically, we have not set the threshold as high as it was under the
interpretation presented by the Service in the Defenders litigation.
Under that interpretation, the portion of the range would have to be so
important that current imperilment there would mean that the species
would be currently imperiled everywhere. Under the definition of
``significant'' used in this finding, the portion of the range need not
rise to such an exceptionally high level of biological significance. We
recognize that if the species is imperiled in a portion that rises to
that level of biological significance, then we should conclude that the
species is in fact imperiled throughout all of its range, and that we
would not need to rely on the ``significant portion of its range''
language for such a listing. Rather, under this interpretation we ask
whether the species would be in danger of extinction everywhere without
that portion, i.e., if that portion were completely extirpated.
The range of a species can theoretically be divided into portions
in an infinite number of ways. However, there is no purpose to
analyzing portions of the range that have no reasonable potential to be
significant or to analyzing portions of the range in which there is no
reasonable potential for the species to be endangered or threatened. To
identify only those portions that warrant further consideration, we
determine whether there is substantial information indicating that: (1)
The portions may be ``significant,'' and (2) the species may be in
danger of extinction there or likely to become so within the
foreseeable future. Depending on the biology of the species, its range,
and the threats it faces, it might be more efficient for us to address
the significance question first or the status question first. Thus, if
we determine that a portion of the range is not ``significant,'' we do
not need to determine whether the species is endangered or threatened
there; if we determine that the species is not endangered or threatened
in a portion of its range, we do not need to determine if that portion
is ``significant.'' In practice, a key part of the portion status
analysis is whether the threats are geographically concentrated in some
way. If the threats to the species are essentially uniform throughout
its range, no portion is likely to warrant further consideration.
Moreover, if any concentration of threats applies only to portions of
the species' range that clearly would not meet the biologically based
definition of ``significant,'' such portions will not warrant further
consideration.
After reviewing the potential threats throughout the range of the
northern leopard frog, we determine that there is a portion of the
range that could be considered to have concentrated threats. We defined
this area, which we are calling the westernmost portion, as including
the current range of the northern leopard frog within British Columbia
and Alberta, Canada, and Washington, eastern Oregon (if any native
populations remain), Idaho, California (if any native populations
remain), Nevada, Utah, Arizona, New Mexico, Colorado, and the portions
of Wyoming and Montana that are west of the Continental Divide. Below,
we outline the elevated threats found within this westernmost portion
of the northern leopard frog's range (see ``Summary of Information
Pertaining to the Five Factors'' for complete discussion). We then
assess whether this portion of the species' range may meet the
biologically based definition of ``significant,'' that is, whether the
contribution of this portion of the northern leopard frog's range to
the viability of the species is so important that without this
westernmost portion of the range, the species would be in danger of
extinction.
This westernmost portion of the northern leopard frog's range has
[[Page 61930]]
experienced significant declines and continues to experience impacts,
likely resulting from the influence of multiple contributing factors,
but primarily resulting from the combination of habitat loss, the
spread of American bullfrogs and predaceous fish into otherwise
suitable breeding habitats, disease, and increased variability in
temperature and precipitation (Rorabaugh 2005, pp. 575-577; Smith and
Keinath 2007, pp. 29-31; Committee on the Status of Endangered Species
in Canada 2009, pp. 31-35; Johnson et al. 2011, p. 557). As described
above in Species Information, the northern leopard frog depends upon a
landscape that includes breeding ponds, upland foraging areas,
overwintering aquatic habitats, and connectivity among habitats and
between populations (Pope et al. 2000, p. 2505; Smith 2003, pp. 6-15;
Rorabaugh 2005, pp. 571-575). The destruction and degradation of
wetland and riparian habitat is thought to represent the most
widespread impact to northern leopard frog populations in Arizona
(Arizona Game and Fish Department 2009, p. 1), Colorado (Colorado
Division of Wildlife 2009, p. 2), Idaho (Idaho Department of Fish and
Game 2005, Northern leopard frog species account), Montana (Montana
Fish Wildlife and Parks 2009, p. 2), Nevada (Nevada Department of
Wildlife 2009, p. 4), New Mexico (New Mexico Department of Game and
Fish 2009, p. 3), and Alberta, Canada (Alberta Northern Leopard Frog
Recovery Team 2005, p. 6). The loss of aquatic habitats has been
compounded by the spread of the American bullfrog and nonnative fish in
the West. These species predate on and compete with all life stages of
northern leopard frogs and have further stressed northern leopard frog
populations in this westernmost portion, likely contributing to
population declines. Based upon the extended droughts in the Southwest
and changes the Service has noted to northern leopard frog habitats in
Arizona and New Mexico (Service 2007, pp. 38-41), it is likely that
increased variability in temperature and precipitation will continue to
reduce the amount of breeding and wintering habitat available for
northern leopard frogs, particularly in the western United States.
After identifying elevated threats in the westernmost portion of
the range of the northern leopard frog, we next consider whether this
portion of the range should be considered a ``significant portion of
its range'' based on the framework laid out above. In order for the
westernmost portion of the range to be considered significant, we
consider whether there is sufficient resiliency, redundancy, and
representation in the remaining portion of the range (which includes
the species in the rest of its range; hereafter referred to as the
eastern portion of the range) such that the northern leopard frog would
not be in danger of extinction if the westernmost portion of the range
in question became extirpated (extinct locally). Our analysis,
described below, finds that the westernmost portion of the range does
not meet this definition of significant, because even without that
portion of the range the species, rangewide, would not be in danger of
extinction.
To determine whether or not the westernmost portion of the range is
``significant,'' we considered the species' resiliency, redundancy, and
representation in the remainder (i.e., the eastern portion) of its
range. For resiliency, we evaluated whether the eastern portion of the
range of the northern leopard frog, without the westernmost portion,
would maintain the characteristics necessary to allow the species to
recover from periodic disturbance. The eastern portion we refer to here
includes Saskatchewan, eastern Montana, and eastern Wyoming, and
continues east through Canada and the United States through the rest of
the range of the northern leopard frog. This area encompasses a large
proportion of the range of the species and contains a variety of
wetland and upland habitats necessary to provide breeding and
overwintering habitats, and habitat linkages. This area is also
sufficiently large as to provide a margin of safety for the species to
withstand disturbance events. We conclude that the eastern portion of
the range of the northern leopard frog is sufficiently resilient that
even without the westernmost portion of its range, the species would
not be in danger of extinction.
As part of our evaluation of redundancy, we evaluated whether the
eastern portion of the range of the northern leopard frog, without the
westernmost portion, would have enough populations sufficiently
distributed across the landscape to allow the species to withstand
catastrophic events. Based upon what we know of the current population
status in the eastern portion of the range, there are multiple areas
(such as South Dakota, North Dakota, Ohio, Ontario, Vermont, New York,
and Quebec) where the northern leopard frog is currently maintaining
stable, widespread populations. These areas are sufficient in size and
apparent distribution to serve as core areas from which northern
leopard frogs can recolonize areas that could be subject to
catastrophic future events (such as widespread flooding or drought). We
conclude that the eastern portion of the range of the northern leopard
frog is sufficiently redundant that even without the westernmost
portion of its range, the species would not be in danger of extinction.
In our evaluation of representation, we considered whether the
eastern portion of the range of the northern leopard frog, without the
westernmost portion, contains enough variation to ensure that the
species' adaptive capabilities are conserved (such that the genetic,
morphological, physiological, behavioral, or ecological diversity of
the species overall is maintained). Based upon our current knowledge of
the northern leopard frog, we do not have evidence of morphological,
physiological, or behavioral differences between individuals from the
westernmost portion of the range and individuals in the eastern portion
of the range. Although the westernmost portion of the range is located
on the periphery of the species' overall range, the eastern portion
contains large areas that represent an important genetic evolutionary
history between eastern and western northern leopard frogs (Hoffman and
Blouin 2004a, 2004b; Wilson et al. 2008). This important genetic
information is represented within the defined eastern area and would
not be lost if the westernmost portion of the range were extirpated. In
addition, although not well studied, there are likely broad ecological
differences between northern leopard frogs in the westernmost portion
of the range compared to those in the eastern portion of the range that
result from the geographical differences in habitat, climate, and
species interactions. We recognize the ecological importance of
conserving peripheral, as well as interior, populations of wide-ranging
species. However, due to the diversity of areas the northern leopard
frog occupies in the large eastern portion of its range, it is likely
that sufficient ecological adaptation potential would be maintained to
ensure ecological representation. We conclude that the eastern portion
of the range of the northern leopard frog is sufficiently
representative that even without the westernmost portion of its range,
the species would not be in danger of extinction.
Based on our analysis, we find that the eastern portion of the
range of the northern leopard frog contains sufficient redundancy,
resiliency, and
[[Page 61931]]
representation that, even without the contribution of the westernmost
portion of the species' range, the northern leopard frog would not be
in danger of extinction. Therefore, we find that the westernmost
portion of the northern leopard frog does not constitute a significant
portion of the species' range.
In conclusion, based on a review of the best available information,
we find the northern leopard frog is not in danger of extinction now or
in the foreseeable future throughout all or a significant portion of
its range and, therefore, does not warrant listing at this time.
We request that you submit any new information concerning the
distribution and status of, or threats to, the northern leopard frog to
our Arizona Ecological Services Office (see ADDRESSES) whenever it
becomes available. New information will help us monitor the northern
leopard frog and encourage its conservation. If an emergency situation
develops for the northern leopard frog or any other species, we will
act to provide immediate protection.
References Cited
A complete list of references cited is available on the Internet at
http://www.regulations.gov and upon request from the Arizona Ecological
Services Office (see ADDRESSES section).
Authors
The primary authors of this notice are the staff members of the
Arizona Ecological Services Office.
Authority
The authority for this section is section 4 of the Endangered
Species Act of 1973, as amended (16 U.S.C. 1531 et seq.).
Dated: September 26, 2011.
Gregory E. Siekaniec,
Acting Director, Fish and Wildlife Service.
[FR Doc. 2011-25498 Filed 10-4-11; 8:45 am]
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