Endangered and Threatened Wildlife and Plants; 12-Month Finding on a Petition to List the Amargosa Toad as Threatened or Endangered, 42040-42054 [2010-17647]
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Federal Register / Vol. 75, No. 138 / Tuesday, July 20, 2010 / Proposed Rules
Authority: The authority for this action is
the Endangered Species Act of 1973, as
amended (16 U.S.C. 1531 et seq.).
(TDD) may call the Federal Information
Relay Service (FIRS) at 800–877–8339.
SUPPLEMENTARY INFORMATION:
Dated:July 9, 2010
Wendi Weber,
Acting Director, U.S. Fish and Wildlife
Service.
Background
Section 4(b)(3)(B) of the Endangered
Species Act of 1973, as amended (Act)
(16 U.S.C. 1531 et seq.) requires that, for
any petition to revise the Federal Lists
of Endangered and Threatened Species
that contains substantial scientific or
commercial information that listing the
species may be warranted, we make a
finding within 12 months of the date of
receipt of the petition. In this finding,
we will determine that the petitioned
action is: (1) Not warranted, (2)
warranted, or (3) warranted, but the
immediate proposal of a regulation
implementing the petitioned action is
precluded by other pending proposals to
determine whether species are
threatened or endangered, and
expeditious progress is being made to
add or remove qualified species from
the Federal Lists of Endangered and
Threatened Species. 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.
[FR Doc. 2010–17650 Filed 7–19– 10; 8:45 am]
BILLING CODE S
DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[FWS–R8–ES–2009–0047]
[92210–1111–0000 B2]
Endangered and Threatened Wildlife
and Plants; 12-Month Finding on a
Petition to List the Amargosa Toad as
Threatened or Endangered
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AGENCY: Fish and Wildlife Service,
Interior.
ACTION: Notice of 12–month petition
finding.
SUMMARY: We, the U.S. Fish and
Wildlife Service (Service), announce a
12–month finding on a petition to list
the Amargosa toad (Anaxyrus nelsoni)
as threatened or endangered and to
designate critical habitat under the
Endangered Species Act of 1973, as
amended. After review of all available
scientific and commercial information,
we find that listing the Amargosa toad
is not warranted at this time. However,
we ask the public to submit to us any
new information that becomes available
concerning the threats to the Amargosa
toad or its habitat at any time.
DATES: The finding announced in this
document was made on July 20, 2010.
ADDRESSES: This finding is available on
the Internet at https://
www.regulations.gov at Docket Number
FWS–R8–ES–2009–0047. 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, Nevada Fish and
Wildlife Office, 4701 N. Torrey Pines
Dr., Las Vegas, NV. Please submit any
new information, materials, comments,
or questions concerning this finding to
the above address.
FOR FURTHER INFORMATION CONTACT:
Robert D. Williams, State Supervisor,
Nevada Fish and Wildlife Office; by
mail (see ADDRESSES); by telephone at
775–861–6300; or by facsimile at 775–
861–6301mailto:. Persons who use a
telecommunications device for the deaf
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Previous Federal Actions
On August 2, 1977, the Service
included the Amargosa toad on a list of
amphibians that we were reviewing to
determine whether those species should
be proposed for listing as endangered or
threatened (42 FR 39121). Subsequently,
we assigned the Amargosa toad as a
category 1 candidate species under the
Act in 1982 (47 FR 58454, December 30,
1982) and 1994 (59 FR 58982, November
15, 1994); and designated it as a
category 2 candidate in 1985 (50 FR
37958, September 18, 1985); 1989 (54
FR 554, January 6, 1989); and 1991 (56
FR 58804, November 21, 1991). A
category 1 species was a taxon for which
the Service has substantial information
on hand to support the biological
appropriateness of proposing to list as
endangered or threatened under the Act.
A category 2 species was a taxon for
which the Service has information
indicating that proposing to list the
species as endangered or threatened is
possibly appropriate, but that
information is not conclusive data on
biological vulnerability or threats that
would support a proposed listing.
On September 21, 1994, the Service
received a petition from the Biodiversity
Legal Foundation of Boulder, Colorado,
requesting emergency listing of the
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Amargosa toad as endangered. At the
time we received the petition, the
Amargosa toad was a category 1
candidate species. On March 23, 1995,
we announced our 90–day finding that
the petitioned action may be warranted
and initiated a status review of the
species (60 FR 15280). On July 26, 1995,
the Service recommended removal of
the Amargosa toad from category 1
candidate status based on information
we obtained during the status review.
On February 28, 1996 (61 FR 7596), we
removed the Amargosa toad from
candidate status. On March 1, 1996, we
announced our 12–month finding that
listing the Amargosa toad as endangered
or threatened was not warranted (61 FR
8018).
On February 27, 2008, we received a
petition from the Center for Biological
Diversity (CBD) and Public Employees
for Environmental Responsibility
(PEER), hereinafter referred to as
‘‘petitioners,’’ requesting that the
Amargosa toad be listed as endangered
or threatened and that critical habitat be
designated under the Act. The petition
clearly identified itself as such and
included the requisite identification
information for the petitioners, as
required in 50 CFR 424.14(a). In a letter
to the petitioners dated May 1, 2008, we
responded that we had reviewed the
petition and found that an emergency
listing was not warranted and we
anticipated making an initial finding on
the petition during Fiscal Year 2008. On
March 11, 2009, we received a 60–day
notice of intent to sue from CBD alleging
violations of the Act because we did not
publish our 12–month finding within 12
months of receiving the petition. On
September 10, 2009, we published a 90–
day finding stating the petition
contained substantial information to
indicate the petitioned action may be
warranted, and we announced the
initiation of a status review of the
species (74 FR 46551).
On April 26, 2010, CBD amended its
Complaint in Center for Biological
Diversity v. Salazar, U.S. Fish and
Wildlife Service, Case No.: 1:10–cv–
230–PLF (D.D.C.), adding an allegation
that the Service failed to issue its 12–
month petition finding on the Amargosa
toad within the mandatory statutory
timeframe. This notice constitutes the
12–month finding on the February 27,
2008, petition to list the Amargosa toad
as threatened or endangered with
critical habitat.
Species Information
In addition to the information
provided below, refer to the 90–day
finding (74 FR 46551) for additional
information on the Amargosa toad.
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Taxonomy and Species Description
The Amargosa toad is a member of the
family Bufonidae, which includes North
American true toads. Stejneger (1893,
cited in Lannoo 2005, p. 427) described
the Amargosa toad as Bufo boreas
nelsoni, a subspecies of the western toad
(Bufo boreas). Savage (1959, pp. 251–
254) was the first to refer to the
Amargosa toad as Bufo nelsoni in
accordance with the rules of the
International Code of Zoological
Nomenclature. Feder (1997, cited in
Lannoo 2005, p. 428) diagnosed Bufo
nelsoni by allozymic data and
concluded that the Amargosa toad
warrants species status. Mitochondrial
DNA analyses by Goebel (1996, cited in
Lannoo 2005, p. 429) are consistent with
species status for the Amargosa toad. In
2002, Bufo nelsoni was listed as a full
species in the Integrated Taxonomic
Information System database compiled
by the Smithsonian Institution, with the
highest credibility rating by their
Taxonomic Working Group (Lannoo
2005, p. 427). Frost et al. (2006) moved
North American toads from Bufo to
Anaxyrus (Tschudi 1845, cited in Frost
et al. 2006, p. 363), which was accepted
in 2008 by the Committee on Standard
and Scientific Names (Committee;
Crother 2008, pp. 2–4). The Committee,
sanctioned by the Society for the Study
of Amphibians and Reptiles, the
American Society of Ichthyologists and
Herpetologists, and The Herpetologists’
League, is tasked to develop standard
English names and publish a list of the
current scientific names of North
American herpetofauna. This is
considered the official list for those
societies.
Adult male Amargosa toads typically
have a snout-vent length of 1.6 to 2.7
inches (in.) (42 to 68 millimeters (mm));
for females it is typically 1.8 to 3.5 in.
(46 to 89 mm) (Nevada Department of
Wildlife (NDOW) 2000, p. A–2). The
dorsal body of the Amargosa toad has
three paired rows of wart-like skin
projections called tubercles. Their backs
have black speckling or asymmetrical
spots. Background coloration ranges
from almost black to brownish or pale
yellow-brown or olive, and may vary
considerably among individual toads in
the same population. A light mid-dorsal
stripe occurs along the backbone. The
large, wart-like parotid glands located
behind the eye are tawny to olive.
Underneath, the Amargosa toad is
whitish or pale olive, with scattered
black spots that merge above the legs to
form the appearance of ‘‘pants.’’
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Current and Historic Ranges
Amargosa toads are endemic to the
Amargosa River drainage in
southwestern Nevada (Goebel et al.
2009, p. 210). Available historic
accounts (Maciolek 1983a, p. 11) do not
provide any specific indication of wider
distribution. Toads that occur in
downstream reaches of the Amargosa
River corridor (e.g., Ash Meadows area)
anecdotally exhibit some taxonomic
similarities; however, they have not
been identified as Amargosa toads. The
area occupied by the Amargosa toad is
isolated, with no known or probable
connections to members of the western
toad complex (NDOW 2000, p. A–1).
The nearest known record for a western
toad is approximately 35 linear miles
(mi) (56 kilometers (km)) away at
Furnace Creek in Death Valley National
Park, California, where an introduced
population of western toad occurs. The
historical and current range of the
Amargosa toad occurs within Oasis
Valley, along an approximately 10-mi
(16–km) stretch of the Amargosa River
and nearby spring systems, roughly
between the towns of Springdale and
Beatty. Oasis Valley occurs along U.S.
Highway 95 between Bullfrog Hills and
the Nevada Test Site.
In 2007, the Amargosa Toad Working
Group (ATWG) prepared a map of all
known and potential habitat for the
species, including potential movement
corridors, and posted the map on the
Internet at: https://www.fws.gov/nevada/
nv_species/amargosa_toad.html. The
total amount of known and potential
Amargosa toad habitat delineated by the
ATWG is approximately 8,440 acres (ac)
(3,416 hectares (ha)).
Life History and Ecology
Amargosa toad habitat requirements
for breeding and population recruitment
include the presence of open, ponded,
or flowing water, with riparian
vegetative cover in an early-tointermediate successional stage to form
a partial canopy for shade with minimal
emergent vegetation at the water’s
edges. Immature (metamorphs or
toadlets) and adult Amargosa toads are
dependent upon the areas described
above, as well as areas they can use for
shelter, including burrows, debris piles,
spaces under logs or rocks, and areas of
dense vegetation (NDOW 2000, p. A–2).
Adult toads also require adjacent
vegetated uplands for nocturnal
foraging. Dense vegetation and
advanced successional stages of riparian
vegetation appear to limit habitat
suitability and occupancy by all life
stages, particularly where open water is
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not present (NDOW 2000, p. A–2).
Toads can be abundant in irrigated and
disturbed areas.
The breeding season for the Amargosa
toad begins in mid-February and may
extend into July, during which time
adults congregate at breeding sites. A
female toad may produce over 6,000
eggs in a single reproduction event
(Altig 1987, p. 277; Heinrich 1995, p. 2).
Amargosa toad tadpoles require
relatively open water that persists long
enough for the completion of
metamorphosis and development into
toadlets, which occur over
approximately 30 days. Predation and
early desiccation of wetlands needed for
breeding may destroy an entire breeding
effort. Although Amargosa toads
typically live 4 to 5 years, individual
toads are known to live up to 17 years
based on data from NDOW’s population
monitoring program (Hobbs 2010, p. 1.).
Population Status and Trends
In 1998, NDOW initiated a long-term
population monitoring program for the
Amargosa toad using mark-recapture
methods at 11 sites of the 18 known
sites occupied by toads. The 11 sites are
grouped into 4 spatial areas described
below (see distribution map available at
https://www.fws.gov/nevada/nv_species/
amargosa_toad.html). The monitoring
program was identified in the Amargosa
Toad Conservation Agreement and
Strategy (CAS) as an conservation action
(NDOW 2000, p. A–11) and involves
capture and marking (with implanted
tags) of all juvenile to adult age-class
Amargosa toads found that are 2 in. (50
mm) or greater in length. The NDOW
maintains a database on Amargosa toad
population monitoring data as
prescribed in the CAS (NDOW 2000, pp.
A–12 and 13). As of November 2009, a
total of 6,739 Amargosa toads had been
captured and tagged. In 2009, captures
increased 77 percent over 2008, with a
total of 768 toads captured and tagged,
519 of which were captured for the first
time. The 2009 population estimate for
monitored sites is 1,623, which is 13.6
percent less than the average of 1,826
for the period 1998 through 2008 (Hobbs
2009, p. 1). Unsuitable weather
conditions during the 2007 and 2008
surveys may have resulted in lower than
average toad activity (Figure 1; Hobbs
2009, p. 2). Habitat improvements and
disturbance of aquatic systems at
monitored sites have resulted in
increases in toad captures and
reproduction (Hobbs 2009, pp. 2–4;
Saving Toads thru Off-Road Racing,
Ranching, and Mining in Oasis Valley
(STORM–OV) 2009b, p. 1).
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Simandle (2006, p. 42) determined
that Amargosa toads meet the criteria
and expectations of metapopulations.
This means that occupied habitats,
unoccupied but suitable habitats, and
intervening habitat that may be
occasionally used during infrequent
migration events should all be
considered as conservation priorities.
Metapopulations can be expected to
have local extirpations in some patches,
resulting in the existence of empty but
suitable habitat that subsequently may
be recolonized in the future (Simandle
2006, p. 8). Events such as floods may
simultaneously destroy existing
occupied habitat, create new suitable
habitat, and facilitate infrequent
movement among different sites. Habitat
conditions and the number of toads that
occur at specific sites and
metapopulations change from year to
year, thus requiring site-specific
management strategies.
Population Groups
The 11 monitored sites occupied by
the Amargosa toad occur in three
groups: Harlan-Keal, Amargosa River,
and Spicer/Mullin/Torrance; and
Angel’s, a single site outside the three
groups. The sites associated with each
group are discussed below.
Harlan-Keal Group
The Harlan-Keal Group consists of
four sites: 5 ac (2 ha) of private land
(Harlan-Keal), including an irrigated
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garden area and 200-square foot (ft2)
(18.6-square meter (m2)) pond; a spring
and associated pond (Crystal Spring);
and two seeps named Trespass and
Wild Burro. Crystal Spring and the two
seeps occur on lands administered by
the BLM.
The Harlan-Keal pond was restored in
2003–2004, and has early successional
habitat where toad reproduction occurs
and may serve as a source population.
The 2009 population estimate for the
Harlan-Keal Group was 156, which was
22 percent below the 12–year average
for this group of sites (Hobbs 2009, p.
2). Because of its elevation, ambient air
temperatures at this site are always
cooler than at other sites. This will
likely affect the number of toads
captured during surveys.
The Crystal Spring site consists of a
spring, pond, and outflow on BLM land.
In 1995, a wild burro exclosure was
constructed around Crystal Spring to
reduce trampling and overuse of the
spring. This caused an increase in
emergent vegetation that has reduced
the extent of open water, which in turn
resulted in few toads remaining at the
site. Historically, this site was
maintained by ranchers and other
private efforts which removed sediment
and excess vegetation that maintained
open water in the pond. Planning is
under way to rehabilitate this site in
2010 to benefit Amargosa toads
(STORM–OV 2009a, pp. 1–3).
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Trespass Seep is a low-flow spring
site without any substantial ponded area
that has never supported many toads.
During surveys, the highest number of
toads captured at Trespass Seep was 12
in 1998. In August 2009, improvements
were made to Trespass Seep by a private
landowner that resulted in a substantial
increase in ponded surface water and
toad habitat. Within a few weeks after
improvements to the seep, Amargosa
tadpoles were observed at the site
(STORM–OV 2009b, p. 1).
Wild Burro seep consists of a lowflow spring, an excavation with
groundwater exposed, and wet meadow.
In 1998, 12 ac (4.9 ha) surrounding the
seep was fenced by BLM to exclude
wild burros that overused the site.
Currently this site provides little habitat
for the Amargosa toad, with only a few
toads documented at this site each year.
In November 2009, STORM–OV
submitted a plan to the BLM to create
and enhance toad habitat at this site
(STORM–OV, 2009c, pp. 1–6). STORM–
OV is a local nonprofit organization
representing the off-road, ranching, and
mining interests, dedicated to Amargosa
toad conservation projects.
Amargosa River Group
The Amargosa River consists of three
monitored segments characterized by
riparian vegetation interspersed with
flowing, open water. Amargosa toad
population monitoring occurs along a 2mi (3.2-km) section of the Amargosa
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River that is mostly perennial, from just
north of the Stagecoach Casino and
Hotel to the Narrows, south of Beatty,
Nevada (see distribution map available
at https://www.fws.gov/nevada/
nv_species/amargosa_toad.html). Land
ownership is a mosaic of private, local,
and Federal (BLM) lands. Most habitat
for the Amargosa toad exists along this
monitored section of the river, and most
toads are found along the river corridor
where perennial water occurs and
bullfrogs (Lithobates (=Rana)
catesbeiana) and crayfish (Procambarus
sp.) are few or absent. In a typical year,
tens or hundreds of thousands of
Amargosa toad tadpoles are produced
within the Amargosa River. The 2009
population estimate for this group was
14 percent lower than the 12–year
average (Hobbs 2009, p. 3). This lower
population estimate for the Amargosa
River may be the result of low
detectability of Amargosa toads due to
dense vegetation, no substantial habitat
improvements during the last few years,
and predation from bullfrogs and
crayfish.
Spicer/Mullin/Torrance Group
This group consists of three privately
held properties which include the
Spicer site (320 ac; 129 ha); Mullin site
(80 ac; 32 ha); and Torrance Ranch (130
ac; 52 ha). The Torrance Ranch was
purchased by The Nature Conservancy
(TNC) in 1999 to protect the Amargosa
toad and to provide a site for
experimental habitat management to
benefit the Amargosa toad. All three
sites are contiguous or in close
proximity to each other, which allows
movement of Amargosa toads among all
three sites. The 2009 population
estimate for this group was 86 percent
above the 12–year average for these
sites. All three property owners are
conservation partners with the Service
and NDOW, and have accomplished or
cooperated on numerous toad habitat
improvement projects.
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Angel’s Site
This 296-ac (120-ha) site consists of a
single location on private property. A
spring-fed, cement lined pond that has
an outflow to a wetland pasture
provides breeding and oviposition
habitat for the Amargosa toad. No
habitat changes have been observed in
at this site since monitoring efforts
began in the mid-1990s. The pond was
dry in 2007 and no evidence of
reproduction was observed in 2008. The
population estimate for this site
declined 33 percent in 2009 compared
to 2008, and 23 percent below the 12–
year average for this site (Hobbs 2009,
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p. 5). Crayfish and bullfrogs occur at
this site.
Other Sites
A 2.6 mi (4.2 km) stretch of the
Amargosa River north of the Stagecoach
Hotel and Casino, has intermittent and
perennial flow in sections, mostly
associated with spring outflow. Land
ownership is a mosaic of private and
BLM lands. Cursory surveys conducted
in this area by NDOW biologists have
detected Amargosa toads. Several
private properties are known to have
suitable Amargosa toad habitat. Surveys
have not been conducted on these
properties; however, anecdotal
observations of toads have been
reported (Maciolek 1983a, pp. 9–10;
1983b, pp. 4, A1–4). In 1993 and 1994,
Heinrich (1995, p. 8) documented toads
at eight sites, including the Manley
property (spring and outflow), Parker
Ranch (Ute Spring), and LaFleur Spring
site (Roberts Field). No population size
estimates or trends have been made for
these other sites. Amargosa toads at
these sites are not included in the
rangewide population estimates.
LaFleur Spring is a historic site for
Amargosa toads near the northern range
limit of the species. Altig (1987, p. 277)
found up to 74 toads at this site during
5 visits to the site in 1981. Altig further
concluded that the toad population at
the LaFleur site is small, with no
recruitment observed in 1980 or 1981.
No surveys have been conducted at this
site since the 1980s. The Springdale site
provides approximately 1 ac of (2.5 ha)
toad habitat; toads were reported to be
present in July and August 1983 by
Maciolek (1983a, p. 8). Habitat
improvements have occurred, including
the removal of salt cedar. The
Springdale site is not included in the
population monitoring program for
Amargosa toads.
Parker Ranch (24 ac; 212 ha) was
purchased by TNC in December 2000,
with assistance from the State of
Nevada, the National Fish and Wildlife
Foundation, and the U.S. Department of
Agriculture, Natural Resource
Conservation Service (NRCS), to protect
and restore unique biological resources,
including Amargosa toad habitat. Parker
Ranch is approximately 4 mi (6.4 km)
north of Beatty and includes Ute Spring.
Parker Ranch is currently being grazed
by 74 cattle by a local rancher to reduce
the amount of emergent wetland
vegetation to increase open water areas
(Moore 2010, p. 3). The spring source
was fenced off and outflow stream
channels were reconstructed in recent
years to prevent damage to stream banks
(Moore 2010, p. 3). The NRCS is
monitoring the vegetation condition to
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determine when cattle should be moved
to other properties in Oasis Valley. The
newly constructed stream channel and
toad pond system has been dry for
almost 2 years due to insufficient water
and overgrowth of emergent wetland
vegetation near the spring. Amargosa
toads continue to breed in the fencedoff spring and outflow channel on the 6ac (2.5-ha) private inholding. No
population estimates are available for
this area.
The Indian Springs Complex consists
of Upper, Middle, and Lower Indian
Springs. Lower Indian Spring consists of
two springs, Lower Indian and Cave
Springs. Upper Indian Spring is the
location of a municipal well that
provides water to the town of Beatty.
Middle Indian Spring is mostly dry,
with several mature cottonwood trees.
Little if any toad habitat currently
occurs at either Upper or Middle Indian
Springs. At Lower Indian Spring, an
approximate 10-ac (4-ha) wild burro/
livestock exclosure that surrounds two
springs was constructed by the BLM in
1994, along with a water pipe and
trough outside the exclosure to provide
water to burros, livestock, and wildlife.
Currently, this site is nearly dry, with
no water exiting the exclosure. Toads
have been captured at Lower Indian
Spring as recently as 1996. No
population estimates are available for
this area. Attempts to restore toad
habitat at this site in 1998 were
unsuccessful, but new techniques have
been developed, and the ATWG
proposed habitat rehabilitation in 2010.
Other private lands have been or
could be occupied by Amargosa toads.
Revert Spring (303 ac; 123 ha) is
privately owned by the owner of the
Stagecoach Hotel and Casino. Revert
Spring is an important water source for
Amargosa toad habitat in the river.
Although Maciolek (1983a, p. 10)
documented Amargosa toads at Revert
Spring in July and August 1983, the
current status of toads at the Revert
Spring site is unknown. Coffer Ranch
(900 ac; 364 ha) occurs at the
northernmost edge of the range of the
Amargosa toad and is owned and
managed by a cattle company. Maciolek
(1983b, p. A–1) reported that Amargosa
toads were present at the Coffer Ranch,
and suitable Amargosa toad habitat was
present. However, no population
estimates are available for these or other
privately owned lands where Amargosa
toads may occur.
Amargosa Toad Working Group (ATWG)
and Amargosa Toad Conservation
Agreement and Strategy (CAS)
In 1996, the ATWG was organized to
provide recommendations for
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management and conservation of the
Amargosa toad. The ATWG consists of
representatives of the Service, NDOW,
TNC, Nevada Department of
Conservation and Natural Resources,
Bureau of Land Management (BLM),
Nye County, Beatty Town Board, Beatty
Habitat Committee, The Amargosa
Conservancy, private landowners in the
Beatty community, the University of
Nevada at Reno, and others. The ATWG
meets semiannually to present and
exchange information on the toad and
its habitat, including the status of
habitat conditions and ongoing habitat
projects, potential threats to the toad,
and population monitoring data, and to
identify new conservation tasks.
In 2000, the ATWG completed the
Amargosa Toad CAS (NDOW 2000, pp.
1–12), which provides management and
conservation guidance for the Amargosa
toad. The CAS informs management of
the conservation needs of the toad,
prioritizes tasks, and provides an
implementation schedule. The ATWG is
currently updating the CAS to include
accomplishments and updated
conservation needs for the toad.
The CAS was developed to expedite
toad conservation over a period of 10
years by providing guidance and a
framework for implementation of
cooperative long-term conservation
actions to benefit the toad and cooccurring species. Signatories to the
CAS include NDOW, Nye County
Department of Natural Resources, the
Service, BLM, TNC, the Nevada Natural
Heritage Program, and the University of
Nevada at Reno. The signatories provide
representatives to the ATWG. The
signatories and ATWG are committed to
implementing specific conservation
actions (tasks) which identify, reduce,
or eliminate threats to the species, and
maintain and enhance a properly
functioning ecosystem for the Amargosa
toad and other indigenous species of
Oasis Valley. The ATWG meets
semiannually to plan Amargosa toad
conservation actions. Most conservation
actions in the CAS are implemented by
local private land owners, and land and
resource managers.
Many of the conservation actions
implemented by the ATWG and its
various partners are a direct result of the
commitments made in the CAS for the
Amargosa toad (NDOW 2000, pp. 1–12).
The goals of the CAS are to manage
threats, maintain habitats, monitor
populations, and test and evaluate
habitat manipulations. Completed
conservation actions identified in the
CAS have addressed threats identified
in Factors A, B, C, and E (see below).
We consider the CAS successful if
considerable progress is made towards
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achieving these goals. CAS
accomplishments that have contributed
towards success include 12 years of
population monitoring and maintaining
population data in a database; salt cedar
removal; habitat rehabilitation and
enhancement; research; public
education and outreach; and habitat
acquisition as discussed in Factor A.
Other CAS accomplishments include
control of predators through habitat
manipulation and work with the local
community to achieve conservation
such as an open space plan. The CAS
signatories and the ATWG, in
cooperation with local landowners,
have planned and initiated multiple
projects to protect, restore, and enhance
toad habitat, and create new habitat.
Overall success is measured by
population monitoring data that show
that rangewide, Amargosa toad
populations are relatively stable and
respond promptly and positively to
habitat improvements. Previous habitat
improvements on the Amargosa River,
Harlan-Keal, Mullin, and Spicer sites
have all resulted in substantial
population increases of toads. In 2005,
vegetation was removed by NDOT at the
U.S. 95 Highway bridge over the
Amargosa River in Beatty. This resulted
in a positive response by toads as shown
by a large reproductive event and a 2006
population estimate of 1,854 for the
river which was the highest on record
(ATWG 2005, p. 2; Wixson 2006, p. 3).
Again in 2005, vegetation was cleared
from the pond at the Harlan-Keal site
with funding from the Service and
NDOW which resulted in an estimated
90 percent increase in the population in
2006 over the 2005 estimate (Wixson
2006, p. 2).
The ATWG is in the process of
updating the CAS and anticipates a
revised CAS by the end of 2010. The
revised CAS will acknowledge
accomplishments and identify the
conservation needs of the toad for the
next 10 years. The revised CAS will
operate in a similar manner as the
existing one. The CAS has proven,
based on its 10 year track record, to be
an effective tool in furthering the longterm conservation of the species.
Summary of Information Pertaining to
the 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 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:
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(1) The present or threatened
destruction, modification, or
curtailment of its habitat or range; (2)
overutilization for commercial,
recreational, scientific, or educational
purposes; (3) disease or predation; (4)
the inadequacy of existing regulatory
mechanisms; or (5) other natural or
manmade factors affecting its continued
existence. In making this finding,
information pertaining to the Amargosa
toad in relation to the five factors
provided in section 4(a)(1) of the Act is
discussed below.
In making our 12–month finding on a
petition to list the Amargosa toad, we
considered and evaluated the best
available scientific and commercial
information. The analysis of potential
threats to the Amargosa toad discussed
below includes those identified in the
petition and those that we considered to
be substantial in our 90–day finding (74
FR 46551).
Factor A. The Present or Threatened
Destruction, Modification, or
Curtailment of Its Habitat or Range
Private Land Development
The petition identified several
potential residential or commercial
developments on private land that could
adversely affect the Amargosa toad or its
habitat. However, based on information
provided by TNC during our review
(Moore 2010, pp. 1–3), none of the
proposed developments appear to be
viable. Real estate and development
markets in nearby Pahrump and Las
Vegas influence markets in the Beatty
area, and each of these three areas have
experienced a downturn in both the
general economy and the housing
market. Plans for a shooting range across
from Torrance Ranch have been
abandoned and the property was
recently sold to an individual who plans
to build a home on the 40-ac (16-ha) site
(Moore 2010, p. 3). A geothermal project
at a hot spring on private lands
identified by CBD as a threat (2009, p.
2) has been abandoned (Moore 2010, pp.
1–3). Although development may occur
within the range of the Amargosa toad
over the near term, it is difficult to
predict the scope of that development
based on the available information.
Furthermore, humans and Amargosa
toads have coexisted in the Beatty area
since the early 1900s. Amargosa toads at
the Harlan-Keal site and other sites
where residential or commercial
development and toads co-occur
demonstrate that toad and human
interface can be compatible. Toads
occur in most disturbed and developed
areas with surface water and may be
locally abundant. During our review, we
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found no indication that the economic
growth of Beatty will change
substantially in the foreseeable future.
Due to the absence of potential
developments identified in the petition
and the ability of toads to coexist with
humans in developed and disturbed
areas, we conclude habitat loss as a
result of development on private land is
not a substantial threat to the Amargosa
toad now or in the foreseeable future.
Groundwater Development and
Extraction
The petitioners provided information
that claimed existing and future water
uses and developments are important
threats that reduce surface water
available for Amargosa toads in Oasis
Valley and that result in habitat loss.
The majority of water right allocations
within the basin are spring diversions
for irrigation and livestock watering.
Priority dates for groundwater rights,
including those of Beatty Water and
Sanitation District (BWSD), range from
the 1920s to 1996, with the majority
dating to the late 1980s or earlier. The
priority dates are the dates the
application are submitted and
determine the seniority of the water
right relative to other water rights in the
affected basin. Spring diversions are
located primarily along or near the
Amargosa River channel. Groundwater
rights are limited to approximately one
sixth of water right allocations in the
valley (by volume), 85 percent of which
are held by the BWSD as a source of
supply for homes and businesses in the
town of Beatty. The BWSD holds water
rights for three wells in the town of
Beatty and two wells several miles
northwest of town (including one at
Indian Springs), in addition to a
groundwater right at the Barrick Mine in
Amargosa Valley (Nevada Division of
Water Resources, https://water.nv.gov/).
Other groundwater rights in Oasis
Valley (a total of 8) are for irrigation,
recreation, livestock watering, and
minor commercial and mining
activities, most in the amount of 20
acre-feet per year (afy) or less.
Currently, TNC is negotiating
purchase of the water rights (500 afy) at
Revert Spring with the owner of the
Stagecoach Hotel and Casino to
establish long-term protection measures
for the water flowing from the spring
source into the Amargosa River.
Acquisition of this important water
source can reduce the threat of its use
for commercial purposes and enable
TNC to meet its commitment in the CAS
to work with private landowners to
pursue conservation actions such as
acquisitions and easements (NDOW
2000, p. A–20). However, we recognize
that this transaction has yet to be
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completed, and cannot be certain that
these rights will be secured.
Groundwater level records for Oasis
Valley, which are both recent and long
enough to assess trends (e.g., over the
last 10 years or more), are limited to
monthly and bimonthly measurements
collected by the U.S. Geological Survey
(USGS) for the U.S. Department of
Energy (USDOE) as part of the USDOE
Environmental Restoration Program
(USGS/U.S. DOE Cooperative Studies in
Nevada, https://nevada.usgs.gov/doe_nv/
). Specifically, groundwater level
measurements are available for seven
wells or nested wells along or near the
Amargosa River channel in Oasis Valley
and a number of additional wells to the
north and east within the valley and up
gradient basins for the period 1998 to
late 2009. The wells range in depth from
200 ft (61 m) or less in consolidated
sedimentary deposits to thousands of
feet in the volcanic rock aquifer. Trends
in groundwater levels along the
Amargosa River channel from 1998 to
2009 are mixed, some increasing
moderately, some decreasing
moderately, and some relatively
constant on an annual basis. Water
levels in two of the seven monitoring
wells located along or near the
Amargosa River channel (well ER–OV–
03 and the Beatty Wash Terrace Well)
decreased 1.3 to 1.5 ft (0.4 to 0.5 m)
from 2000 to late 2009. However, these
declines occurred in no clear relation to
permitted or certificated groundwater
rights (pumping at permitted supply
wells). Rather, they may be indicative of
local evapotranspiration responses.
Elsewhere along the river channel,
groundwater levels were unchanged, or
increased a few tenths of a foot from
2000 to late 2009 (ER–OV04a,
Springdale Upper Well, ER–OV–02, ER–
OV–05, and ER–OV–06a).
In areas to the north and east which
supply groundwater to the vicinity of
the Amargosa River channel and
Amargosa toad habitat in Oasis Valley,
specifically northeastern Oasis Valley
and the area of Pahute Mesa (the latter
located in the Gold Flat and Forty mile
Canyon-Buckboard Mesa basins)
(Laczniak et al. 1996, pp. 18–19; Reiner
et al. 2002, pp. 8–9; Fenelon et al. 2010,
pp. 22–23 and Plate 5), water levels in
USDOE Environment Restoration
Program wells increased a few tenths of
a foot to approximately 1.5 ft over this
same period.
No groundwater level data are
available for the vicinity of the BWSD
supply wells. As such, the effects of
BWSD pumping on surface water
resources cannot be evaluated at this
time except as they may be judged from
the results of biannual Amargosa toad
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surveys. This suggests that any
reduction in population is limited to the
area of Indian Springs. BWSD pumping
at the Indian Springs well has decreased
since the late 1990s, but Indian Springs
remains one of three primary supply
wells in Oasis Valley for the town of
Beatty. With respect to the potential for
additional groundwater pumping in
Oasis Valley, actual groundwater
withdrawals by the BWSD have been
limited to approximately 10 to 15
percent of their existing rights over most
of the last decade (Eng 2010, p. 1).
Whereas substantially more
groundwater could be pumped for
municipal purposes under existing
BWSD rights, their pumping within
Oasis Valley has been fairly constant.
Overall demand has decreased
approximately 25 percent (coupled with
a decrease in pumping at the Barrick
Mine) over this same period of time
based on pumping inventories provided
by the Nevada State Engineer (NSE).
Additionally, BWSD demand varies
seasonally, with demand at a minimum
from December through March, the
latter of which coincides with the
beginning of the Amargosa toad
breeding season. Moreover, the NSE has
ruled that the degree of hydraulic
connection between groundwater and
surface water in Oasis Valley is such
that they constitute a single source (NSE
Ruling 4669, 1998) and that no
unappropriated water existed in the
basin as of 1995 (NSE Ruling 4174,
1995), making additional allocations,
groundwater or surface water, unlikely.
Excessive groundwater withdrawals
have the potential to affect springs and
rivers that depend on groundwater for
recharge or base flows. Field
reconnaissance and Nevada Division of
Water Resources well drilling records
identified approximately 15 springs and
20 nonmunicipal wells that supply
water to individual homes and ranches
in Oasis Valley (Reiner et al. 2002, p.
33). A reasonable estimate of
groundwater withdrawal consumed
from each of these sources is 1 afy
(Reiner et al. 2002, p. 33). Based on this
consumption rate and the number of
supply sources, a reasonable estimate of
the nonmunicipal use of groundwater
from Oasis Valley is 35 afy. Estimates of
the total annual groundwater
withdrawal from Oasis Valley,
computed by combining municipal and
non-municipal estimates, declined from
440 afy in 1996, when Beatty’s human
population was 2,068, which was the
highest during the period 1991–2007
(Stantec 2009, p. 22), to 210 afy in 1999,
when Beatty’s population declined to
1,703.
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The population estimates for Beatty in
2007 indicate a resident base of
approximately 1,068 persons (Stantec
Consulting 2009, p. 22). This estimate
reflects a declining population trend
during the period 1991–2007. While the
future population size of Beatty is
unknown, we found no indication that
the human population will increase
beyond historic levels and we do not
anticipate an increase in use of
groundwater to support new residential
development. We conclude that future
human population effects on the
Amargosa toad are driven by the
economic status and growth of the
Beatty. Since there is no indication that
growth will increase, we conclude that
demand for groundwater is not likely to
rise.
The petitioners submitted comments
that identified a proposed solar energy
project in Amargosa Valley requiring
3,000 afy of groundwater for wet-cooling
and operation (CBD 2009, pp. 1–2). This
energy project remains proposed but has
been modified to use dry-cooling that
would reduce groundwater use to 400
afy. The 400 afy of groundwater
proposed for the project is currently
used for agriculture and, therefore this
level of groundwater use is not
anticipated to significantly affect
existing groundwater levels in the up
gradient areas where Amargosa toads
occur (Peterson 2010, p. 1).
The petitioners also identified 11
Department of Energy (DOE)
applications for water rights in Oasis
Valley as a potential threat to the toad
through groundwater withdrawal effects
(CBD 2009, p. 2). The DOE applications
were submitted for construction of a
railroad to a proposed nuclear waste
repository and were protested by the
petitioners and others. The Service
recommended that DOE transport water
needed for this project from sources
other than those associated with the
Amargosa toad, Ash Meadows, and
Devils Hole. In February 2010, DOE
withdrew their applications for water
rights in the Oasis Valley.
Based on the available information on
volume, timing, and location of
groundwater withdrawals, historic use
of groundwater, and water-level
measurements, we conclude that water
use and development in Oasis Valley is
not a substantial threat to the Amargosa
toad at this time or in the foreseeable
future. No declines in groundwater or
toad numbers have been observed at
monitored sites as a result of pumping.
The current and foreseeable demand for
groundwater in Oasis Valley remains
consistent with historical uses.
Inadequate Habitat Enhancement
Planning and Implementation
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The petitioners state that BLM failed
to initiate planning for habitat
enhancement projects including Wild
Burro Seep and Upper Cave Spring in
the Lower Indian Spring system (CBD
2009, p. 20). In fall 2009, STORM–OV,
in cooperation with BLM and the
ATWG, modified Wild Burro Seep and
greatly increased the extent of surface
water and toad habitat at the site.
STORM–OV and BLM developed plans
to restore Lower Indian Springs and
Crystal Spring in 2010 and 2011
(STORM–OV 2009a, pp. 1–3; Spicer
2009, pp. 1–5). Habitat enhancement is
a conservation action in the CAS
(NDOW 2000, p. A–11).
The Stagecoach Hotel and Casino
owner is a conservation partner with
TNC and the Service. In 2001, the
Service’s Partners for Fish and Wildlife
Program funded habitat improvements
in the vicinity of the Stagecoach to
benefit the Amargosa toad. The owner
and TNC continue to improve habitat
along the river behind the property,
which is part of a parcel identified as a
fee-title donation to TNC for
conservation purposes pursuant to
prescribed conservation actions in the
CAS. In addition, TNC and the Nevada
Department of Transportation (NDOT)
are working to remove debris from the
riverbank, which should improve
habitat for the Amargosa toad.
In 2007, 30 ac (12 ha) of nonnative
trees were removed from the Mullin site
and replaced with native willows and
cottonwoods as prescribed in the CAS
(NDOW 2000, p. A–11). During the 2009
survey, 137 Amargosa toads larger than
2 in (50 mm) were captured on the
Mullin site. This was the highest
number of captures for this site (Hobbs
2009, p. 4).
Three springs on the Spicer site have
been enhanced for the Amargosa toad by
the landowner. Surface water is
distributed on the Spicer site through a
system of pipes which provides most of
the water for toad habitat. Manipulation
of the distribution pipes provides a
habitat management tool to allow ponds
to be created, or dried to remove
crayfish and bullfrogs as prescribed in
the CAS (NDOW 2000, pp. A–11 and A–
12). Amargosa toads responded
positively to the habitat improvements
in 2009, increasing by 300 percent of
captured and marked toads since 2008
(Hobbs 2009, p. 4).
The Amargosa River Planning Team
was formed in October 2009 as a result
of a recommendation by the ATWG that
was included in the CAS (NDOW 2000,
p. A–14). The team consists of ATWG
representatives including the Service,
NDOW, Nye County, BLM, and TNC,
but also local landowners. The purpose
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of the team is to monitor habitat
conditions of the river, develop
management recommendations, and
coordinate habitat improvement with
landowners and managers on behalf of
the signatories of the CAS and the
ATWG.
The overall habitat suitability of
individual sites varies from year to year
depending on conditions and may
become unsuitable for toads. Because
the Amargosa toad occurs as
metapopulations, toads will move back
into these sites from neighboring sites
once the habitat becomes more suitable.
In the absence of natural disturbance
such as flood events and wildfires, toad
habitat will likely require periodic
manipulation or other forms of
disturbance such as burro or cattle use
to sustain toad populations. Based on
the metapopulation structure of the
toad, successful habitat projects and
disturbance by burros and cattle, we
anticipate that habitat planning and
implementation have resulted in
positive responses by toads. We expect
the Amargosa River Planning Team,
TNC, BLM, Service, and private
landowners to continue their efforts to
maintain and improve toad habitat into
the foreseeable future in accordance
with the CAS. We expect members of
the ATWG and private landowners to
continue their current efforts to
maintain and improve toad habitat, as
they have in the past, in accordance
with the CAS into the future. As a
result, we have determined that habitat
planning and implementation is not a
threat to the Amargosa toad now, nor is
it expected to be so in the foreseeable
future.
Vegetation Overgrowth
Overgrowth of vegetation in aquatic
habitats is an ongoing management
objective for the Amargosa toad as
specified in the CAS (NDOW 2000, pp.
A–11 and A–16). Habitat for Amargosa
toads at several spring sites including
Torrance Ranch, Lower Indian Spring,
and Crystal Spring, has degraded as a
result of overgrowth of emergent
vegetation and loss of open water.
Overgrowth of vegetation occurs mostly
at small spring sites and in the absence
of disturbance or management.
Although Lower Indian Spring and
Crystal Spring are small spring sites and
represent only a small fraction of the
species’ individuals and distribution,
the ATWG considers vegetation
management a priority for these sites.
Mechanical removal, controlled burns,
and grazing are proven tools to manage
vegetation in spring systems at HarlanKeal (ATWG 2004, p. 3) and Torrance
Ranch (ATWG 2007, attachment 1, p. 1).
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Spring-supplied ponds typically require
disturbance or periodic removal of
vegetation to maintain suitable habitat
conditions (e.g., open water) for the
Amargosa toad. Local ranchers
historically managed Crystal Spring and
other springs to maintain open water
(Spicer 2010, p. 1). Limited use by
livestock or feral burros provides
disturbance that benefits toads;
however, excessive use by livestock or
feral burros result in degradation of
habitat. Current and future habitat
projects at spring sites are designed to
minimize vegetation growth,
compensate for potential reductions in
spring flow due to overgrowth of
vegetation, and maintain proper habitat
conditions for the toad. Currently,
excess vegetation conditions occur at
Crystal and Lower Indian Springs, but
habitat modification proposed for 2010
and 2011 at these sites (STORM–OV
2009a, pp. 1–3; Spicer 2009, pp. 1–5) is
anticipated to substantially improve
habitat conditions for the toad. As stated
previously, we expect the efforts to
maintain and improve toad habitat
which includes control of vegetation to
continue in accordance with the CAS.
Therefore vegetation overgrowth is not a
significant threat to the Amargosa toad
now, nor is it expected to be so into the
foreseeable future.
Grazing and Trampling
The petitioners state that use of
springs by feral burros and cattle may
result in degraded habitat and reduced
numbers of Amargosa toads (CBD and
PEER 2008, pp. 17–18, 21 and 23–25).
The current level of burro occurrence in
Amargosa toad habitat varies by site and
ranges from zero to moderate with most
use along the Amargosa River. Cattle use
of Amargosa toad habitat is limited to
the northern sites where a cattle
operation is located (Coffer Ranch) and
sites targeted for vegetation reduction.
While burros and livestock (ungulates)
may trample Amargosa toad eggs and
larvae, light to moderate disturbance is
important to the Amargosa toad which
is a disturbance-dependant species
(ATWG 2005, p. 2). In the absence of
disturbance, vegetation grows
uncontrolled and reduces open areas
necessary for the toads. Intensive and
uncontrolled use of Amargosa toad
habitat by ungulates may threaten the
species by degrading habitat and killing
individual toads; however, light to
moderate use is known to be beneficial
to the Amargosa toad. Complete removal
of ungulates could lead to overgrowth of
vegetation, and may pose a more serious
threat to the Amargosa toad than
moderate ungulate use. Fencing
installed at the Crystal and Indian
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spring sites to exclude feral burros most
likely has contributed to declines in
toad populations at these sites by
reducing habitat disturbance. BLM
manages the burro population and
conducts burro ‘‘gathers’’ when the burro
numbers exceed the appropriate
management level for the area in
accordance with the CAS (NDOW 2000,
p. A–16). Most feral burro use of
monitored sites occurs along the river.
We conclude that light to moderate
ungulate use is not a substantial threat
to the toad and likely provides some
benefit to the Amargosa toad. Although
the number of feral burros fluctuates, we
do not anticipate the level of burro use
in Amargosa toad habitat to increase so
that it would affect toad populations in
the foreseeable future.
Recreation and Off-Highway Vehicle
(OHV) Activity
OHV activity affects Amargosa toads
most during the breeding season and
during the especially vulnerable egg and
tadpole stages of development. OHV
effects are only known to be a concern
along the Amargosa River near the
Stagecoach Hotel and Casino. TNC
biologists have observed small isolated
pools containing egg strands or tadpoles
in various stages of development that
were affected by OHVs in the riverbed
within the Town of Beatty. The local
nonprofit group, STORM–OV, is
attempting to educate the OHV users
about the need to avoid ponded water
during the toad breeding season, a
conservation action prescribed in the
CAS (NDOW 2000, p. A–18). In
addition, TNC plans to use its river
properties behind the Stagecoach Hotel
and Casino and northward in
educational opportunities. These two
groups propose to conduct town
meetings to inform Beatty residents of
the need to avoid damaging toad
breeding pools during the defined
breeding season. While localized OHV
use may cause a relatively small number
of eggs or tadpoles to be removed from
the affected population, this level of loss
is not substantial in the context of the
potentially tens or hundreds of
thousands of Amargosa toad eggs and
tadpoles produced in a typical year.
No landowners or managers have
identified, nor are we aware of any
spring sites that are substantially
affected by OHV activity. The
petitioners identified an OHV race that
passes near Crystal Spring as a potential
threat to the toad. In 2008, BLM chose
an alternate route away from toad
habitat for OHV events near Crystal
Spring and continues to consider the
toad during OHV permitting actions.
Due to the absence of substantial effects
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resulting from recreation or OHV use in
toad habitat and the location of many of
the spring sites on private land that
have no OHV use, we do not expect
effects from recreation and OHV use to
increase or become a threat to the toad
in the foreseeable future.
Invasive Plant Species
The petitioners assert that introduced
invasive trees have become established
along stretches of the Amargosa River
and springs, which may reduce prey
and microhabitat available for the
Amargosa toad (CBD and PEER 2008,
pp. 24 and 26).
Salt cedar is an exotic, invasive
species that grows in shrub form to
medium tree size and is native to
Eurasia. Removal of salt cedar is
identified as a conservation action in
the CAS (NDOW 2000, p. A–11). Native
aquatic and wetland herpetofauna may
be negatively impacted in areas where
salt cedar draws down surface water
(Shafroth et al. 2005, pp. 237–238).
Water-use studies indicate that
increases in water yield following salt
cedar control are likely to occur only
when a salt cedar stand containing high
leaf area is replaced by vegetation with
a lower leaf area (Shafroth et al. 2005,
pp. 237–238). The native vegetation in
Oasis Valley requires more water than is
provided by local rainfall. As a result of
high evapotranspiration rates during the
summer, these plants must rely on local
groundwater for sustenance (Reiner et
al. 2002, p. 42). Anderson et al. (2004,
cited in Shafroth et al. 2005, pp. 237–
238) present data from the lower
Colorado River suggesting that
abundances of several of the most
common insect families in riparian
areas occur in comparable or greater
abundance on salt cedar than on most
native vegetation. Efforts to remove salt
cedar and other nonnative, invasive
plants from the Amargosa River
watershed have occurred since 2003.
Replacing salt cedar with native
vegetation may result in lower
evapotranspiration rates. Eleven grants
provided $118,500 for salt cedar
removal from 11 private properties and
BLM, NDOT, and BWSD-managed land.
Salt cedar has been removed from
approximately 1,895 ac (767 ha) of
Amargosa toad habitat, and salt cedar
removal efforts will likely continue.
Amargosa toad population monitoring
data may be used to assess and measure
the effect of salt cedar removal on the
toad. We do not believe salt cedar is a
significant threat to the Amargosa toad
now or in the foreseeable future because
salt cedar has been removed from toad
habitat and those efforts continue in
accordance with the CAS.
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Failure of the CAS to Protect Toads and
Habitat
The petitioners claim that the CAS
failed to protect Amargosa toads and
increase toad populations. The CAS is a
voluntary, non-regulatory agreement.
The CAS was developed to expedite
Amargosa toad conservation over a
period of 10 years by providing
guidance and a framework for
implementation of cooperative longterm conservation actions to benefit the
toad and co-occurring species.
Signatories to the CAS include NDOW,
Nye County Department of Natural
Resources, the Service, BLM, TNC, the
Nevada Natural Heritage Program, and
the University of Nevada at Reno. The
signatories provide representatives to
the ATWG. The signatories and ATWG
are committed to implementing specific
conservation actions (tasks) which
identify, reduce, or eliminate threats to
the species, and maintain and enhance
a properly functioning ecosystem for the
Amargosa toad and other indigenous
species of Oasis Valley. The ATWG
meets semi-annually to assess the
conservation needs of the toad and plan
Amargosa toad conservation actions.
Most conservation actions in the CAS
are implemented by local private land
owners, and land and resource
managers.
Many of the conservation actions
implemented by the ATWG and its
various partners are a direct result of the
commitments made in the CAS for the
Amargosa toad (NDOW 2000, pp. 1–12).
The goals of the CAS are to manage
threats, maintain habitats, monitor
populations, and test and evaluate
habitat manipulations. Completed
conservation actions in the CAS have
addressed threats identified in Factors
A, C, and E. We consider the CAS
successful as considerable progress has
been made towards achieving these
goals. The CAS accomplishments that
have contributed towards success
include 12 years of population
monitoring and maintaining population
data in a database; burro management
through monitoring and gathers; salt
cedar removal; habitat rehabilitation
and enhancement; research; public
education and outreach; and habitat
acquisition as discussed above in this
factor. Other CAS accomplishments
include control of predators through
habitat manipulation and work with the
local community to achieve
conservation such as an open space
plan. The CAS signatories and the
ATWG in cooperation with local
landowners have planned and initiated
multiple projects to protect, restore, and
enhance toad habitat, and create new
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habitat. Overall success is measured by
population monitoring data that show
that rangewide, Amargosa toad
populations are relatively stable and
respond promptly and positively to
habitat improvements. Previous habitat
improvements on the Amargosa River,
Harlan-Keal, Mullin, and Spicer sites
have all resulted in substantial
population increases of toads. In 2005,
vegetation was removed by NDOT at the
U.S. 95 Highway bridge over the
Amargosa River in Beatty. This resulted
in a positive response by Amargosa
toads as shown by a large reproductive
event and a 2006 population estimate of
1,854 for the river which was the
highest on record (ATWG 2005, p. 2;
Wixson 2006, p. 3). In 2005, vegetation
was cleared from the pond at the
Harlan-Keal site with funding from the
Service and NDOW which resulted in
an estimated 90 percent increase in the
population in 2006 over the 2005
estimate (Wixson 2006, p. 2).
The ATWG is in the process of
updating the CAS and the group
anticipates a revised CAS by the end of
2010. The revised CAS will
acknowledge accomplishments and
identify the conservation needs of the
Amargosa toad for the next 10 years.
The existing CAS and revision will
function similarly. Although the CAS is
a voluntary, non-regulatory agreement,
we conclude that the CAS efforts have
been very successful in establishing a
coalition of partners, including State
and Federal agencies, local government,
private landowners, and conservation
organizations committed to reduce or
eliminate the threats to the species and
assure long-term conservation for the
Amargosa toad. In the absence of the
CAS, conservation progress would
proceed at a reduced rate but would not
result in the species becoming
threatened. Therefore, based on
implementation of various conservation
actions resulting from the CAS as
discussed in the factor above, we find
that the existence and implementation
of the CAS do not pose a threat to the
species.
Summary of Factor A
Development on private lands and use
of groundwater are not significant
threats to the Amargosa toad. Most
previously proposed developments have
been abandoned. With potential
development stalled, growth activity
within Beatty is not expected to change
substantially in the foreseeable future.
Groundwater use in the Beatty area has
decreased or remained constant, and
groundwater levels have fluctuated but
these fluctuations do not appear to
affect Amargosa toad numbers or
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distribution. Habitat has been improved
at several sites and improvements at
other sites are planned for 2010 and
2011. Although some sites are affected
by overgrowth of vegetation, past and
ongoing conservation and management
actions have improved toad habitat and
contributed to stable Amargosa toad
populations, as reflected in the 11 years
of population monitoring. In one
particular instance, a habitat
manipulation project was developed
and implemented, and was very
successful in transforming a small seep
into a new breeding site for toads
(STORM–OV 2009a, p. 1). Amargosa
toad population estimates are an
indication of habitat quality at a given
site, and in those areas where habitat
improvements have been conducted,
Amargosa toad populations have
increased substantially. Grazing by
cattle and feral burros may be locally
excessive, but moderate use provides
needed disturbance to the aquatic
systems that improves Amargosa toad
habitat. Some local areas are impacted
by OHV use but not to the extent that
population declines can be identified.
There has been no apparent reduction in
the current range of the Amargosa toad
compared to the historical range. As a
result of conservation efforts
accomplished by TNC through habitat
acquisition and improvements, and by
various groups through other habitat
improvement projects at Mullins,
Harlan-Keal, Spicer, and Torrance,
along the River, and at Parker Ranch
and Trespass Seep, there has been an
increase in habitat quality or quantity
for the Amargosa toad at these sites.
Additionally, private landowners have
recently become and remain involved in
conservation efforts. Salt cedar has been
substantially removed from private and
BLM land. Completed actions
prescribed in the CAS to conserve the
Amargosa toad have been shown to be
successful in meeting the objectives in
the CAS and reducing or eliminating the
threats to the Amargosa toad under
Factor A. We conclude that the present
or threatened destruction, modification,
or curtailment of the habitat or range of
the Amargosa toad is not a significant
threat to this species now or in the
foreseeable future, due to the limited
growth projected for Beatty, current and
anticipated groundwater use and levels;
completed and proposed habitat
improvements including removal of salt
cedar; continuing management of the
Amargosa River and adjacent habitat
under the direction of the Amargosa
River Planning Team, a subcommittee of
the ATWG; and continued
implementation of conservation
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measures in accordance with the revised
CAS.
Factor B. Overutilization for
Commercial, Recreational, Scientific, or
Educational Purposes
The petitioners provided no
information regarding threats under this
factor, nor do we have information on
the potential threat of overcollection or
overutilization for commercial,
recreational, scientific, or educational
purposes. There is no information to
indicate this factor will become a threat
to the species in the foreseeable future.
We find overutilization for commercial,
recreational, scientific, or educational
purposes does not threaten the
Amargosa toad. Based on a review of the
best available scientific and commercial
data, we find no indication that
overutilization for commercial,
recreational, scientific, or educational
purposes is a threat to the Amargosa
toad now or in the foreseeable future.
Factor C. Disease or Predation
Disease
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Chytridiomycosis is an infectious
disease of amphibians caused by the
chytrid fungus Batrachochytrium
dendrobatidis. Although the fungus has
been detected in bullfrogs in the Oasis
Valley, it has not been detected in
Amargosa toad populations. Chytrid
fungus has been identified in western
toad (Anaxyrus boreas) populations in
Colorado where western toad
occurrence is restricted to high
elevations (7,200 to 11,150 ft [2,200 to
3,400 m]; Muth et al. 2003, p. 358). The
Service and NDOW have no evidence
that chytrid or other diseases are
affecting or will affect the Amargosa
toad population. No sign of chytrid
fungus or other disease has been
observed in the hundreds of Amargosa
toads captured and inspected rangewide
every year since 1995. Further, no ill or
dying toads have been reported by
landowners or agency biologists.
Population monitoring data do not
indicate a decline in Amargosa toad
numbers. Therefore, we find disease is
not a threat to the Amargosa toad now
or in the foreseeable future.
Predation
Predation of all life stages of the
Amargosa toad by nonnative crayfish
and bullfrogs is a threat to the Amargosa
toad at the metapopulation level.
However, metapopulations of a species
allow for the coexistence of predators
and prey, or coexistence of competitors.
While local extinctions may occur, the
species may persist regionally if the
metapopulation structure ensures that
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predator and prey are not present in all
occupied patches all of the time
(Simandle 2006, p. 9).
Currently, the most promising
management tool for nonnative
predators involves manipulating and
enhancing habitat for Amargosa toads
while making habitat less suitable for
bullfrogs and crayfish, as prescribed in
the CAS (NDOW 2000, p. A–12). This is
accomplished by drawing down ponded
areas that contain nonnative predators
and allowing them to be dry for a period
of time long enough to kill the
nonnative predators and cause toads to
move to nearby sites. Recently
completed and proposed habitat
projects have incorporated the
capability of adding or removing water
to allow sites to dry to remove or reduce
numbers of bullfrogs and crayfish, and
are designed to provide an advantage to
Amargosa toads including substrate
selection and water depth. One of the
goals of the CAS is to manage threats to
the Amargosa toad. We consider the
CAS successful as considerable progress
has been made towards achieving this
goal and addressing threats to the
Amargosa toad under Factor C.
The life history of the toads further
reduces the threat of nonnative
predators. Under average conditions,
toads produce tens or hundreds of
thousands of eggs, larvae, and toadlets
each year, most of which will not
survive to adults with or without
predatory pressure.
Although bullfrogs are known to
occur at 10 of 18 sites occupied by
Amargosa toads, the monitoring data do
not indicate a declining toad population
trend. We have documented Amargosa
toads in the stomach contents of
bullfrogs (ATWG 2003, p. 2). While
there is no coordinated control effort,
bullfrogs are removed from the
Amargosa River and other sites
occupied by Amargosa toads during
population surveys. All toad habitat
improvement projects consider the
needs of the toad and select against
bullfrogs. Bullfrogs generally require
deeper, impounded perennial waters,
which are more limited than shallow
stream and spring outflow habitat in
Oasis Valley. Observation and removal
of bullfrogs from stream and spring
outflows can be very effective in
controlling bullfrog numbers.
Since their introduction in the mid1980s, nonnative crayfish have become
established along most of the Amargosa
River and at seven spring sites occupied
by the Amargosa toad. We have no
Amargosa toad population data prior to
the introduction of crayfish, bullfrogs,
or other nonnative Amargosa toad
predators into Oasis Valley; therefore,
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42049
we cannot assess the potential impact of
predators on the Amargosa toad
population. However, we do have
Amargosa toad survey data collected
since 1998 for sites occupied and
unoccupied by bullfrogs and crayfish.
Population numbers at sites with
predators and without predators have
fluctuated in a similar manner, which
indicates there is no population level of
effect that can be attributed to
predation. This is consistent with the
way in which a metapopulation
structure of interconnected populations
functions; thus, in certain areas
Amargosa toads may become extirpated,
but repopulate those areas at a later
time. The capability of toads to move
among these sites in response to threats
and habitat condition allows toads to
coexist with nonnative predators. For
instance, the population estimate for the
Spicer property in 2009 increased from
53 to 167, even though it is a site where
crayfish and bullfrogs are abundant. The
increase in Amargosa toad numbers in
2009 at the Spicer site is most likely a
result of habitat improvements, which
demonstrates the success of habitat
condition. We are unaware of any
extirpations that can be attributed to
crayfish or bullfrogs, but Amargosa
toads have been extirpated or nearly
extirpated from Lower Indian Spring
and Crystal Spring as a result of poor
habitat conditions mostly due to
overgrowth of vegetation.
In 2009, NDOW, TNC World Wide
Office, and Arizona Game and Fish
Department provided funding to TNC to
develop crayfish removal strategies
which included habitat characterization,
crayfish distribution, and control
techniques in a five-state effort (AZ,
NM, CA, UT, and NV). These studies are
currently under contract; the first phase
is to be completed by June 30, 2010.
We expect the current level of
predation by crayfish and bullfrogs to
continue into the foreseeable future, but
do not consider this level of predation
a significant threat due to the life
history characteristics of the Amargosa
toad and their ability to coexist with
nonnative predators and move among
metapopulations. This determination is
based on the Amargosa toad
metapopulation structure; habitat
projects that select for toads; the life
history of the toad; and 12 years of toad
population monitoring data that shows
toads can coexist with nonnative
predators.
Predation by Fish Species
The majority of habitats in Oasis
Valley supporting Amargosa toad
populations are not structurally capable
of supporting the large-bodied predatory
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fish that would be capable of significant
predation on Amargosa toads (NDOW
2009, p. 4). Largemouth bass
(Micropterus salmoides) are known to
occur in at least one pond on private
property in Oasis Valley, but Amargosa
toads are not a primary component of
their diet. Black bullhead catfish
(Ictalurus melas) and Amargosa toads
have co-occurred at one pond on private
land at the Harlan-Keal site for at least
10 years; however, the pond dried
during the summer 2009, and catfish are
not expected to persist at this site.
Therefore, we do not consider
largemouth bass or catfish to be a
significant threat to the Amargosa toad
now or in the foreseeable future.
Mosquito fish (Gambusia affinis) have
been introduced into waters of Oasis
Valley and occur at most sites occupied
by toads. Mosquito fish have been
observed to prey on eggs of the arroyo
toad (Anaxyrus (=Bufo) californicus;
Lannoo 2005, p. 399) and may also prey
on Amargosa toad eggs. During our
review of the status of the Amargosa
toad, no information was available that
suggests mosquito fish are important
predators of toad eggs. No observations
of mosquito fish preying on toad eggs
have been reported during the 12 years
of population monitoring. NDOW is
actively working with a variety of
partners, including Nye County, to limit
the use and distribution of mosquito
fish in the Oasis Valley and to develop
alternative vector control strategies that
do not use mosquito fish as the control
agent. We have no information to
indicate that the presence of, or
predation by, mosquito fish is a
significant threat to the Amargosa toad
or that such predation will become a
threat in the foreseeable future.
Summary of Factor C
Based on a review of the best
available scientific and commercial
data, we find no indication of a
potential threat of disease. We have no
reason to conclude disease is currently
or will become a threat to the species in
the foreseeable future, due to an absence
of sign of disease in Amargosa toads.
Predation by bullfrogs, crayfish, and
mosquito fish continues to affect
Amargosa toad populations but not to
an extent that threatens the species.
Largemouth bass do generally occur in
waters occupied by toads and do not
substantially affect the toad. Based on
the best scientific information available,
there is no indication that predation is
resulting in negative population wide
effects. Completed actions prescribed in
the CAS to conserve the Amargosa toad
have been shown to be successful in
meeting the objectives in the CAS and
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reducing or eliminating the threats to
the Amargosa toad under Factor C.
Therefore, after a review of the best
scientific and commercial information,
we conclude disease and predation are
not significant threats to the Amargosa
toad and are not likely to become
significant threats in the foreseeable
future. This determination is based on
the absence of signs of disease;
Amargosa toad metapopulation
structure; habitat projects that select for
toads; the life history of the toad; and 12
years of toad population monitoring
data that shows toads can coexist with
nonnative predators.
Factor D. The Inadequacy of Existing
Regulatory Mechanisms
The petitioners claim the existing
regulatory mechanisms, including
Nevada State law protections, have been
ineffective in preventing the decline of
and mitigating the principal threats to
the species. The petitioners claim that
the State of Nevada fails to provide
adequate protection for the Amargosa
toad through existing statutes,
particularly regarding permit
exemptions for residential groundwater
use up to 1,800 gallons per day (CBD
and PEER 2008, pp. 20 and 28).
Generally, domestic wells that draw less
than 1,800 gallons per day do not
require a permit (NRS 534.180).
However, the NSE may require the
registration of domestic wells in certain
groundwater basins that it designates
and may limit the amount of
groundwater extracted from a permitted
well to an amount below the full
permitted amount under certain
conditions. No declines in groundwater
levels or toad numbers have been
observed at monitored sites as a result
of groundwater pumping. In our review
in Factor A, we concluded that
Amargosa toad populations have not
been affected and are not likely to
become affected by groundwater
extraction. Groundwater use is currently
consistent with historic use and will not
likely increase due to lack of growth in
the area.
The Amargosa toad was classified as
a protected amphibian by the State of
Nevada through an action of the Nevada
Board of Wildlife Commissioners in
1998, under authority of NAC 503.075,
and NAC 503.090 provides that no open
season shall be designated for species of
resident wildlife classified as protected
which includes collection or possession.
Through NDOW, the State plays an
important role in ensuring conservation
actions are achieved for this species
under these and other authorities.
The Amargosa toad is designated by
the BLM Nevada State Director as a
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BLM sensitive species. This requires
BLM to ensure that actions they
authorize, fund, or carry out do not
contribute to the need to list the species
as threatened or endangered (BLM
Manual section 6840.06 C). The BLM’s
Tonopah Resource Management Plan
and Record of Decision (RMP)
determined that habitat for BLM
sensitive species be managed to
maintain or increase current
populations of these species (BLM 1997,
p. 9).
The petitioners identified privately
owned Amargosa toad habitat and the
lack of a final master plan for the Oasis
Valley as potential threats to the toad.
Considering the limited extent and use
of private lands in Oasis Valley, a
master plan would likely be
unnecessary to guide development.
However, on November 3, 2009, the Nye
County Board of County Commissioners
approved the Beatty Open Space Plan
(Stantec Consulting 2009, pp. 1–45 plus
appendices). This final plan provides
the framework by which the County
may pursue more specific actions to
preserve BLM land for the benefit of the
Town of Beatty and private land for the
preservation of Amargosa toad habitat
and a walking trail along the Amargosa
River. Open space in the plan is defined
as land that is not intensively developed
for residential, commercial, industrial,
or institutional use. The plan identifies
26,778 ac (10,837 ha) of land
administered by the BLM as open space,
which includes most of the range of the
Amargosa toad (Stantec Consulting
2009, Appendix A). The broad goals for
the Beatty Open Space Plan as defined
by the stakeholders include: Install
signage and implement a communitywide education program on the
importance of staying out of the
riverbed, particularly with ATVs, to
protect the toad habitat; protect
sensitive habitats; and identify
appropriate activities in Amargosa toad
habitat (Stantec Consulting 2009, p. 24).
As a signatory to the CAS, Nye County
committed to coordinate conservation
with the local community such as
development of the open space plan
(NDOW 2000, p. A–15). We conclude
that the completion of a final open
space plan is an important conservation
achievement that demonstrates the
cooperative relationship and strong
partnership among all levels of
government, Beatty landowners, and the
Beatty community. Adoption of an open
space plan and BLM’s protection of
Amargosa toad habitat through
implementation of the Tonopah RMP
provide some mechanisms that reduce
the potential threats to the species.
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Summary of Factor D
We have reviewed the best available
scientific and commercial information,
and conclude that the Amargosa toad is
not threatened by the existence of
inadequate regulatory mechanisms.
There are no significant threats to the
species, and Amargosa toad populations
are stable based on annual population
estimates.
Factor E. Other Natural or Manmade
Factors Affecting Its Continued
Existence
In our 90–day finding, we concluded
that natural or manmade factors,
particularly small populations, small
range size, and environmental changes
due to climate change, could exacerbate
threats identified under Factor A. In this
12–month finding, we determined that
no significant threats were found under
Factor A.
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Small Range and Population Size
The range of the Amargosa toad is
approximately 8,440 ac (3,416 ha) and
the rangewide total number of adult
toads is estimated at 2,500 to 4,000
toads. No reductions in the range of the
Amargosa toad have been documented.
Although no historic estimates of
population size are known (NDOW
2009, p. 1), there is also no indication
that historical population levels were
significantly higher than current levels.
Population data collected over the past
12 years show 5 years of population
increases, 6 years of declines, and data
for 2000 was essentially the same as
1999; no declines occurred over any
consecutive 3–year period (Hobbs 2009,
p. 2). Amargosa toad data collected by
NDOW as prescribed in the CAS
(NDOW 2000, p. A–13), and as part of
the mark-recapture program document
individual toad movements among
metapopulations and across dry desert
uplands to remote Trespass Seep and
from the Harlan-Keal site to the river
south of Beatty (approximately 8 mi (13
km)). Amargosa toad metapopulations
are mostly limited by habitat conditions.
Amargosa toads disperse among sites
when habitat conditions are suitable,
and Amargosa toad numbers at any
given site can range from historic lows
to record highs in one year (Hobbs 2009,
pp. 1–6). Small population and small
range sizes are not necessarily threats to
a species. With the ability to move
across large expanses of unsuitable
habitat, and recolonize suitable habitat
patches, the Amargosa toad exhibits a
classic and strong metapopulation
structure. This allows the Amargosa
toad to take advantage of newly
available resources, or quickly rebound
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after localized population extirpations.
Therefore, we conclude that the small
range and population size of the species
is not a significant threat to the species,
nor do we expect the range or
population size to decrease in the
foreseeable future due for the reasons
stated above.
Climate Change
The Intergovernmental Panel on
Climate Change (IPCC) has high
confidence in predictions that extreme
weather events, warmer temperatures,
and regional drought are very likely to
increase in the northern hemisphere as
a result of climate change (IPCC 2007,
pp. 15–16). Climate models show the
southwestern United States has
transitioned into a more arid climate of
drought that is predicted to continue
into the next century (Seager et al. 2007,
p. 1181). In the past 60 years, the
frequency of storms with extreme
precipitation has increased in Nevada
by 29 percent (Madsen and Figdor 2007,
p. 37). Changes in local southern
Nevada climatic patterns cannot be
definitively tied to global climate
change; however, they appear to be
consistent with IPCC-predicted patterns
of extreme precipitation, warmer than
average temperatures, and drought.
Information on specific effects from
climate change to the Amargosa toad
and to individual habitats and aquatic
systems is not available, and effects are
difficult to predict and likely to vary
from site to site over time. However, as
detailed under Factor A, previous
habitat improvements on the Amargosa
River, Harlan-Keal, Mullin, and Spicer
sites have all resulted in substantial
positive responses by Amargosa toads.
To meet objectives under the CAS,
Amargosa toad conservation partners
have implemented design strategies and
are continuing to develop and
implement appropriate strategies that
build resiliency into habitat projects.
We conclude that continuing to
maintain and actively manage the
matrix of habitats that support the
population of the Amargosa toad
reduces the potential threat of climate
change to the toad to the extent that
Amargosa toads will continue to occupy
most sites currently occupied by the
species which will continue into the
foreseeable future. In the absence of
active management, several spring sites
may become degraded; however, the
river and larger spring sites are expected
to maintain their function to provide the
ecological needs for the species.
Stochastic Events
The petitioners claim stochastic
events such as drought, floods, and fires
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are threats to the Amargosa toad because
of the limited distribution of the toad.
Major flood events have occurred in the
Amargosa River; however, Amargosa
toads continue to occur in the river and
may benefit from the disturbance
created by such events. Although floods
may result in short-term adverse effects
to the Amargosa toad, the disturbance
created by flooding events may scour
dense emergent vegetation and create
and increase open water pools that are
preferred by the species.
Some studies suggest that amphibian
responses to fire and associated habitat
alteration are species-specific,
incompletely understood, and variable
among habitats and regions (Pilliod et
al. 2003, p. 165). We found no
information that any wildfire occurred
in Amargosa toad habitat in recent
history. However, controlled burns on
TNC properties have resulted in positive
responses by toads by reducing
emergent aquatic vegetation and
providing open water (ATWG 2009, p.
3) that is beneficial to the species.
The metapopulation structure of the
Amargosa toad allows local extirpations
and recolonization following stochastic
events. Such fluctuation in Amargosa
toad numbers has been observed after
prescribed burns and habitat
improvement projects that resulted in
disturbance to Amargosa toad habitat.
Drought effects on the Amargosa toad
may include a reduction of surface
water, prey, and wetland habitat;
however, we found no evidence of longterm effects to the Amargosa toad as a
result of drought. We expect stochastic
events to occur periodically in the
future; however toads may benefit from
the disturbance. If the number of toads
at a given site is reduced or toads
become extirpated from a site, we
expect recolonization to occur from
other metapopulations. Therefore, we
do not expect stochastic events to be a
threat to the toad in the foreseeable
future.
Contaminants
Radiation poisoning through
groundwater contamination from atomic
testing on the Nevada Test Site (NTS)
was cited as a threat by the petitioners
(CBD and PEER 2008, p. 21). The
movement of radiation in groundwater
in Oasis Valley is currently being
studied. Geologic faults allow alluvial
groundwater connection between the
Amargosa River and the Pahute Mesa
aquifer, which includes areas used for
atomic testing (Reiner et al. 2002, p. 61).
There have been no reports of abnormal
toads, reduced reproduction, or death of
multiple toads at any given site that
would suggest radiation or contaminant
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effects. In 2006, DOE contracted
sampling of nine wells and three springs
in Oasis Valley wells for radioactivity
(tritium) in groundwater (DOE 2006, pp.
4.1–4.30). The investigators concluded
that no groundwater (wells or springs)
sampled downgradient of the NTS,
including Oasis Valley where Amargosa
toads occur, had been impacted by NTS
nuclear test operations as of 2006. In all
cases, measured tritium levels in wells
and springs sampled in Oasis Valley
were below or just above the laboratory
detection limit, and three orders of
magnitude less than the U.S.
Environmental Protection Agency
established maximum contaminant level
for drinking water. Because the Town of
Beatty uses groundwater from the Oasis
Valley, monitoring for potential
contaminants in groundwater will
continue for human health. Based on
the available information, there is no
indication that radioactive groundwater
is a concern for the Amargosa toad, or
that radioactive groundwater from the
Pahute Mesa aquifer will become a
threat to the toad in the foreseeable
future.
The petitioners also assert that
pollution of unknown levels on private
land is a threat to the Amargosa toad
(CBD and PEER 2008, p. 25). During
monitoring of toad populations from
1998 to 2009 as prescribed in the CAS,
no environmental evidence was
observed to suggest that contaminants
from private lands are affecting
Amargosa toads. Although Amargosa
toads have not been examined to assess
contaminant levels, no Amargosa toad
developmental anomalies or die-offs
have been reported. Due to the high
level of monitoring and close proximity
to residents who consistently
communicate with the Service on the
Amargosa toad, we believe any
detrimental environmental effects
would be observed and reported.
Therefore, we conclude that
contaminants are not a threat to the
toad. We do not anticipate that
contaminants will become a threat to
the toad in the foreseeable future due to
our expectation that the metapopulation
structure will persist and monitoring
will continue which would detect any
effects of contaminants at the level of
the individual or population.
The petitioners claim that the CAS
failed to protect Amargosa toads and
increase toad populations. The CAS is a
voluntary and non-regulatory
agreement. As discussed above, the CAS
has proven to be an effective tool in
furthering the long term conservation of
the species, as well as reducing or
eliminating the threats to the species.
Please see our discussion for specific
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information regarding the CAS in the
background section of this finding.
Based on implementation of various
conservation actions resulting from the
CAS as discussed in the factors above,
we find that the existence and
implementation of the CAS do not pose
a threat to the species.
Summary of Factor E
We have reviewed the best available
scientific and commercial information
and find that small range and
population size, climate change,
stochastic events, or contaminants are
not significant threats to the species.
While we have no Amargosa toad
population estimates prior to the mid1990s, the best available information
indicates that the historic range of the
toad approximates its current range.
Based on 12 years of population
monitoring data, toad populations
estimates are stable. The range and
population numbers will not decrease in
the foreseeable future in consideration
of the habitat improvements identified
in Factor A and overall absence of
significant threats to the species. While
climate change effects are mostly
uncertain, we conclude that sufficient
resiliency has been provided to the toad
through project that established of a
matrix of habitats and metapopulations.
Stochastic events will continue but will
benefit the toads by providing
disturbance or result in recolonization
from adjacent populations. Monitoring
and oversight by the signatories of the
CAS, ATWG, and local landowners will
continue and detect any impacts to the
toad that may result from contaminants.
Therefore, we conclude that other
natural or manmade factors are not
affecting the continued existence of the
Amargosa toad, now or in the
foreseeable future.
Finding
As required by the Act, we considered
the five factors in assessing whether the
Amargosa toad is threatened or
endangered throughout all or a
significant portion of its range. We
examined the best scientific and
commercial information available
regarding the past, present, and future
threats faced by the Amargosa toad. We
reviewed the petition, information
available in our files and other available
published and unpublished
information, and we consulted with
recognized Amargosa toad experts and
other Federal, State, local agencies, and
nongovernment organizations. In
considering what factors might
constitute threats, we must look beyond
the mere exposure of the species to the
factor to determine whether the species
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responds to the factor in a way that
causes actual impacts to the species. If
there is exposure to a factor, but no
response, or only a positive response,
that factor is not a threat. If there is
exposure and the species responds
negatively, the factor may be a threat
and we then attempt to determine how
significant a threat it is. If the threat is
significant, it may drive or contribute to
the risk of extinction of the species such
that the species warrants listing as
threatened or endangered as those terms
are defined by the Act. This does not
necessarily require empirical proof of a
threat. The combination of exposure and
some corroborating evidence of how the
species is likely impacted could suffice.
The identification of factors that could
impact a species negatively is not
sufficient to compel a finding that
listing is appropriate; we require
evidence that these factors are operative
threats that act on the species to the
point that the species meets the
definition of threatened or endangered
under the Act.
We analyzed the potential threats to
the Amargosa toad including: Private
land development resulting in habitat
loss and water use; groundwater
development/extraction; habitat
degradation including overgrowth of
vegetation; grazing and trampling by
livestock; recreation and OHV activity;
invasive plants species; disease;
predation by nonnative bullfrogs,
crayfish, and fishes; lack of regulatory
control of residential groundwater
withdrawal; inadequate protection on
privately owned land including lack of
a final master plan for the Oasis Valley;
small range and population size; climate
change; stochastic events; and
contaminants.
We found that habitat loss as a result
of development on private land is not a
substantial threat to the Amargosa toad,
and we do not believe that the toad
population is declining rangewide. In
addition, we found no indication that
the human population will increase
beyond historic levels, and we do not
anticipate an increase in future use of
groundwater to support new residential
development in the Town of Beatty and
Oasis Valley. Based on the volume,
timing, and location of groundwater
withdrawal; historic use of
groundwater, and water-level
measurements, we concluded that water
use and development in Oasis Valley
are not a substantial threat to the
Amargosa toad. Overgrowth of
vegetation in aquatic habitats is an
ongoing management concern for the
Amargosa toad because it can result in
degraded habitat. However, various
tools, such as habitat improvement and
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enhancement projects, have been and
continue to be implemented to manage
this potential threat to the Amargosa
toad. Continued implementation of
conservation actions as outlined in the
CAS by regulatory agencies and a
coalition of partners has reduced and
continues to minimize threats to the
Amargosa toad. Light to moderate
ungulate grazing and trampling are not
a substantial threat to the toad and
likely provide some benefit to the
habitat for the Amargosa toad. Excessive
ungulate grazing in Amargosa toad
habitat is localized and mostly occurs in
the Amargosa River channel south of
Beatty. Use by OHVs, particularly in wet
areas (along the Amargosa River), can be
an issue, especially when Amargosa
toad eggs and tadpoles are present.
However, efforts have been undertaken
(e.g., rerouting of OHV races out of
habitat) or are proposed to reduce OHV
use in these areas so that OHV use is not
a significant threat to the species. In
addition, no spring sites have been
identified that are substantially affected
by OHV activity. Efforts to remove salt
cedar and other nonnative, invasive
plants from the Amargosa River
watershed have occurred since 2003.
Efforts will continue to remove salt
cedar and replace it with native shrubs
and trees, which may improve toad
habitat and increase toad numbers. We
conclude that the present or threatened
destruction, modification, or
curtailment of toad habitat or its range
is not a significant threat to the
Amargosa toad now or in the foreseeable
future.
We found no information that
overcollection or overutilization for
commercial, recreational, scientific, or
educational purposes is a threat or will
become a threat to the species in the
future. Therefore, we find
overutilization for commercial,
recreational, scientific, or educational
purposes does not threaten the
Amargosa toad now or in the foreseeable
future.
We also found no evidence that
chytrid or other diseases are affecting
the Amargosa toad population, and
therefore, disease does not threaten the
Amargosa toad. Predation by nonnative
species has affected, and will continue
to affect Amargosa toad populations;
however, metapopulations are allowing
the coexistence of the Amargosa toad
with predators and competitors.
Amargosa toad populations appear to be
generally stable over the long-term,
including sites where toads coexist with
nonnative predators and competitors.
Habitat projects have been designed and
constructed to provide an advantage to
Amargosa toads and reduce numbers of
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nonnative predators. Therefore, we
conclude that disease or predation are
not significant threats to the Amargosa
toad now or in the foreseeable future.
The Amargosa toad is classified as a
protected amphibian by the State of
Nevada under authority of NAC
503.075, and it is also designated as a
BLM sensitive species in Nevada.
Completion of a final open space plan
for the Oasis Valley, approved by the
Nye County Board of Commissioners,
indicates a cooperative conservation
effort among all levels of government,
Beatty landowners, and the Beatty
community to protect Amargosa toad
habitat.
The current range of the Amargosa
toad is approximately the same, and
possibly larger, than its historical range
as a result of conservation efforts
accomplished by the various entities
working to ensure long-term
conservation of the Amargosa toad. In
summary, we concluded that inadequate
regulatory mechanisms are not a threat
to the Amargosa toad now or in the
foreseeable future.
The range and small population size
of the toad have characterized the
species during modern times with no
significant changes. Current monitoring
efforts will continue and inform the
ATWG and others of any habitat
improvement needs for the species.
Climate change is likely to continue for
the foreseeable future, but there is
substantial uncertainty as to how
climate change will affect the Amargosa
toad and its habitat. We found no
information to suggest that climate
change will result in an altered
landscape to the extent that it will
negatively affect Amargosa toads.
Stochastic events (such as floods, fire
and drought) have occurred on the
landscape where Amargosa toads occur
in Oasis Valley. The metapopulation
structure of the Amargosa toad would
allow local extirpations as a result of
these stochastic events, but also
recolonization following the events.
Controlled burns have resulted in
positive responses by Amargosa toads
by reducing vegetation and providing
open water. By maintaining and actively
managing the matrix of habitats that
support the population of the Amargosa
toad, the uncertainties and threats of
climate change and stochastic events
should be reduced. The ability to
modify site conditions where Amargosa
toads occur in response to
environmental changes has been
demonstrated as a significant
management tool for Amargosa toad
conservation efforts to address various
threats, including stochastic events and
invasive species, as well as possible
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42053
changed conditions from climate change
in the future. No environmental
evidence has been observed to suggest
that contaminants from private lands are
affecting Amargosa toads. We believe
any detrimental environmental effects
would be observed and reported to the
Service or NDOW. Continued
implementation of conservation actions
as outlined in the 2000 CAS by NDOW,
other signatories, and a coalition of
partners has reduced and continues to
minimize threats to the Amargosa toad.
We conclude that other natural or
manmade factors are not significant
threats to the Amargosa toad now or in
the foreseeable future.
Based on our review of the best
available scientific and commercial
information pertaining to the five
factors, we find that the threats are not
of sufficient imminence, intensity, or
magnitude to indicate that the Amargosa
toad is in danger of extinction
(endangered), or likely to become
endangered within the foreseeable
future (threatened). Therefore, we find
that listing the Amargosa toad as a
threatened or endangered species is not
warranted.
Evaluation of Distinct Population
Segment (DPS)
Having determined that the Amargosa
toad does not meet the definition of a
threatened or endangered species, we
must next consider whether there are
any segments within the population that
meet the Service’s DPS policy. Under
the DPS policy (61 FR 4722; February 7,
1996), three elements are considered in
the decision concerning the
establishment and classification of a
possible DPS. These are applied
similarly for additions to or removal
from the Federal List of Endangered and
Threatened Wildlife. These elements
include:
(1) The discreteness of a population 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, delisting, or
reclassification (i.e., is the population
segment endangered or threatened).
Under the DPS Policy, we must first
determine whether the population
qualifies as a DPS; this requires a
finding that the population is both: (1)
Discrete in relation to the remainder of
the species to which it belongs; and (2)
biologically and ecologically significant
to the species to which it belongs. If the
population meets the first two criteria
under the DPS policy, we then proceed
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to the third element in the process,
which is to evaluate the population
segment’s conservation status in relation
to the Act’s standards for listing as an
endangered or threatened species. The
DPS evaluation in this finding concerns
the Amargosa toad that we were
petitioned to list as threatened or
endangered.
Discreteness
Under the DPS Policy, a population
segment of a vertebrate taxon may be
considered discrete if it satisfies either
one of the following conditions:
(1) It is markedly separated from other
populations of the same taxon as a
consequence of physical, physiological,
ecological, or behavioral factors.
Quantitative measures of genetic or
morphological discontinuity may
provide evidence of this separation. (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.
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Markedly Separated From Other
Populations of the Taxon
As described previously (see Species
Information above), the Amargosa toad
is characterized by metapopulations
across its range. Individual Amargosa
toads move among these
metapopulations, and there is no
indication that physical, physiological,
ecological, or behavioral barriers exist
that would render any portions of the
species’ range markedly separate from
other portions. Furthermore, we have no
quantitative data such as genetic
information to suggest any portions of
the species to be markedly separate from
others. Therefore, we conclude there are
no portions of the species’ range that
meet the discreteness criterion of the
Service’s DPS policy. Since both
discreteness and significance are
required to satisfy the DPS policy, we
have determined that there are no
populations of the Amargosa toad that
qualify as a DPS under our policy. As
a result, no further analysis under the
DPS policy is necessary.
Significant Portion of the Range
Having determined that the Amargosa
toad does not meet the definition of a
threatened or endangered species, we
must next consider whether there are
any significant portions of the range
where the Amargosa toad is in danger of
extinction or is likely to become
endangered in the foreseeable future.
We considered whether any portions
of the Amargosa toad’s range warrant
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further consideration. We found that
there is no area within the range of the
Amargosa toad where the potential
threat of development or groundwater
withdrawal is significantly concentrated
or may be substantially greater than in
other portions of the range. Some sites
including Crystal and Lower Indian
Springs may become overgrown with
vegetation and cause the site to become
unsuitable and require rehabilitation.
Cattle and feral burros may provide the
necessary disturbance to improve and
maintain Amargosa toad habitat but may
cause short-term overuse of some sites.
Use by OHVs may cause localized
impacts but we do not anticipate these
effects to result in population declines.
Although nonnative toad predators such
as crayfish, bullfrogs, and mosquito fish
occur throughout much of the range of
the toad and likely impact the toad to
some extent, we have found that toads
have, and will continue to coexist with
these predators. There is no indication
that stochastic events, climate change,
or environmental contaminants
differentially affect any given site.
On the basis of our review, we found
no areas within the species’ range where
threats are geographically concentrated.
The species is characterized by
metapopulations across its range which
allows for an individual site to be
extirpated and become repopulated
from neighboring populations. The
factors affecting the species are
essentially uniform throughout its
range, indicating that no portion of the
Amargosa toad’s range warrants further
consideration of possible threatened or
endangered status.
We do not find that the Amargosa
toad is in danger of extinction now, nor
is it likely to become endangered within
the foreseeable future throughout all or
a significant portion of its range.
Therefore, listing the Amargosa toad as
threatened or endangered under the Act
is not warranted throughout all or a
significant portion of its range at this
time.
We request that you submit any new
information concerning the status of, or
threats to, the Armargosa toad to our
Nevada Fish and Wildlife Office (see
ADDRESSES section) whenever it
becomes available. New information
will help us monitor the Amargosa toad
and encourage its conservation. If an
emergency situation develops for the
Amargosa toad, we will act to provide
immediate protection.
References Cited
A complete list of references cited is
available on the Internet at https://
www.regulations.gov and upon request
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from the Nevada Fish and Wildlife
Office (see ADDRESSES section).
Author(s)
The primary authors of this notice are
staff with the Nevada Fish and Wildlife
Office, Las Vegas.
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: July 9, 2010
Wendi Weber,
Acting Director, Fish and Wildlife Service.
[FR Doc. 2010–17647 Filed 7–19– 10; 8:45 am]
BILLING CODE S
DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS–R8–ES–2009–0073]
[92210–1117–0000–B4]
RIN 1018–AW54
Endangered and Threatened Wildlife
and Plants; Revised Critical Habitat for
Brodiaea filifolia (Thread-leaved
Brodiaea)
AGENCY: Fish and Wildlife Service,
Interior.
ACTION: Proposed rule; reopening of
comment period.
SUMMARY: We, the U.S. Fish and
Wildlife Service (Service), announce the
reopening of the public comment period
on our December 8, 2009, proposed
revised designation of critical habitat for
Brodiaea filifolia (thread-leaved
brodiaea) under the Endangered Species
Act of 1973, as amended. We also
announce the availability of a draft
economic analysis (DEA) and an
amended required determinations
section of the proposal. We are
reopening the comment period for an
additional 30 days to allow all
interested parties an opportunity to
comment on all of the above. If you
submitted comments previously, you do
not need to resubmit them because we
have already incorporated them into the
public record and will fully consider
them in our final determination.
DATES: We will consider public
comments received on or before August
19, 2010. Any comments that we receive
after the closing date may not be
considered in the final decision on this
action.
ADDRESSES: You may submit comments
by one of the following methods:
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Agencies
[Federal Register Volume 75, Number 138 (Tuesday, July 20, 2010)]
[Proposed Rules]
[Pages 42040-42054]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2010-17647]
-----------------------------------------------------------------------
DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[FWS-R8-ES-2009-0047]
[92210-1111-0000 B2]
Endangered and Threatened Wildlife and Plants; 12-Month Finding
on a Petition to List the Amargosa Toad as Threatened or Endangered
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Notice of 12-month petition finding.
-----------------------------------------------------------------------
SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a
12-month finding on a petition to list the Amargosa toad (Anaxyrus
nelsoni) as threatened or endangered and to designate critical habitat
under the Endangered Species Act of 1973, as amended. After review of
all available scientific and commercial information, we find that
listing the Amargosa toad is not warranted at this time. However, we
ask the public to submit to us any new information that becomes
available concerning the threats to the Amargosa toad or its habitat at
any time.
DATES: The finding announced in this document was made on July 20,
2010.
ADDRESSES: This finding is available on the Internet at https://www.regulations.gov at Docket Number FWS-R8-ES-2009-0047. 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, Nevada Fish and Wildlife Office, 4701 N.
Torrey Pines Dr., Las Vegas, NV. Please submit any new information,
materials, comments, or questions concerning this finding to the above
address.
FOR FURTHER INFORMATION CONTACT: Robert D. Williams, State Supervisor,
Nevada Fish and Wildlife Office; by mail (see ADDRESSES); by telephone
at 775-861-6300; or by facsimile at 775-861-6301mailto:. Persons who
use a telecommunications device for the deaf (TDD) may call the Federal
Information Relay Service (FIRS) at 800-877-8339.
SUPPLEMENTARY INFORMATION:
Background
Section 4(b)(3)(B) of the Endangered Species Act of 1973, as
amended (Act) (16 U.S.C. 1531 et seq.) requires that, for any petition
to revise the Federal Lists of Endangered and Threatened Species that
contains substantial scientific or commercial information that listing
the species may be warranted, we make a finding within 12 months of the
date of receipt of the petition. In this finding, we will determine
that the petitioned action is: (1) Not warranted, (2) warranted, or (3)
warranted, but the immediate proposal of a regulation implementing the
petitioned action is precluded by other pending proposals to determine
whether species are threatened or endangered, and expeditious progress
is being made to add or remove qualified species from the Federal Lists
of Endangered and Threatened Species. 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 August 2, 1977, the Service included the Amargosa toad on a list
of amphibians that we were reviewing to determine whether those species
should be proposed for listing as endangered or threatened (42 FR
39121). Subsequently, we assigned the Amargosa toad as a category 1
candidate species under the Act in 1982 (47 FR 58454, December 30,
1982) and 1994 (59 FR 58982, November 15, 1994); and designated it as a
category 2 candidate in 1985 (50 FR 37958, September 18, 1985); 1989
(54 FR 554, January 6, 1989); and 1991 (56 FR 58804, November 21,
1991). A category 1 species was a taxon for which the Service has
substantial information on hand to support the biological
appropriateness of proposing to list as endangered or threatened under
the Act. A category 2 species was a taxon for which the Service has
information indicating that proposing to list the species as endangered
or threatened is possibly appropriate, but that information is not
conclusive data on biological vulnerability or threats that would
support a proposed listing.
On September 21, 1994, the Service received a petition from the
Biodiversity Legal Foundation of Boulder, Colorado, requesting
emergency listing of the Amargosa toad as endangered. At the time we
received the petition, the Amargosa toad was a category 1 candidate
species. On March 23, 1995, we announced our 90-day finding that the
petitioned action may be warranted and initiated a status review of the
species (60 FR 15280). On July 26, 1995, the Service recommended
removal of the Amargosa toad from category 1 candidate status based on
information we obtained during the status review. On February 28, 1996
(61 FR 7596), we removed the Amargosa toad from candidate status. On
March 1, 1996, we announced our 12-month finding that listing the
Amargosa toad as endangered or threatened was not warranted (61 FR
8018).
On February 27, 2008, we received a petition from the Center for
Biological Diversity (CBD) and Public Employees for Environmental
Responsibility (PEER), hereinafter referred to as ``petitioners,''
requesting that the Amargosa toad be listed as endangered or threatened
and that critical habitat be designated under the Act. The petition
clearly identified itself as such and included the requisite
identification information for the petitioners, as required in 50 CFR
424.14(a). In a letter to the petitioners dated May 1, 2008, we
responded that we had reviewed the petition and found that an emergency
listing was not warranted and we anticipated making an initial finding
on the petition during Fiscal Year 2008. On March 11, 2009, we received
a 60-day notice of intent to sue from CBD alleging violations of the
Act because we did not publish our 12-month finding within 12 months of
receiving the petition. On September 10, 2009, we published a 90-day
finding stating the petition contained substantial information to
indicate the petitioned action may be warranted, and we announced the
initiation of a status review of the species (74 FR 46551).
On April 26, 2010, CBD amended its Complaint in Center for
Biological Diversity v. Salazar, U.S. Fish and Wildlife Service, Case
No.: 1:10-cv-230-PLF (D.D.C.), adding an allegation that the Service
failed to issue its 12-month petition finding on the Amargosa toad
within the mandatory statutory timeframe. This notice constitutes the
12-month finding on the February 27, 2008, petition to list the
Amargosa toad as threatened or endangered with critical habitat.
Species Information
In addition to the information provided below, refer to the 90-day
finding (74 FR 46551) for additional information on the Amargosa toad.
[[Page 42041]]
Taxonomy and Species Description
The Amargosa toad is a member of the family Bufonidae, which
includes North American true toads. Stejneger (1893, cited in Lannoo
2005, p. 427) described the Amargosa toad as Bufo boreas nelsoni, a
subspecies of the western toad (Bufo boreas). Savage (1959, pp. 251-
254) was the first to refer to the Amargosa toad as Bufo nelsoni in
accordance with the rules of the International Code of Zoological
Nomenclature. Feder (1997, cited in Lannoo 2005, p. 428) diagnosed Bufo
nelsoni by allozymic data and concluded that the Amargosa toad warrants
species status. Mitochondrial DNA analyses by Goebel (1996, cited in
Lannoo 2005, p. 429) are consistent with species status for the
Amargosa toad. In 2002, Bufo nelsoni was listed as a full species in
the Integrated Taxonomic Information System database compiled by the
Smithsonian Institution, with the highest credibility rating by their
Taxonomic Working Group (Lannoo 2005, p. 427). Frost et al. (2006)
moved North American toads from Bufo to Anaxyrus (Tschudi 1845, cited
in Frost et al. 2006, p. 363), which was accepted in 2008 by the
Committee on Standard and Scientific Names (Committee; Crother 2008,
pp. 2-4). The Committee, sanctioned by the Society for the Study of
Amphibians and Reptiles, the American Society of Ichthyologists and
Herpetologists, and The Herpetologists' League, is tasked to develop
standard English names and publish a list of the current scientific
names of North American herpetofauna. This is considered the official
list for those societies.
Adult male Amargosa toads typically have a snout-vent length of 1.6
to 2.7 inches (in.) (42 to 68 millimeters (mm)); for females it is
typically 1.8 to 3.5 in. (46 to 89 mm) (Nevada Department of Wildlife
(NDOW) 2000, p. A-2). The dorsal body of the Amargosa toad has three
paired rows of wart-like skin projections called tubercles. Their backs
have black speckling or asymmetrical spots. Background coloration
ranges from almost black to brownish or pale yellow-brown or olive, and
may vary considerably among individual toads in the same population. A
light mid-dorsal stripe occurs along the backbone. The large, wart-like
parotid glands located behind the eye are tawny to olive. Underneath,
the Amargosa toad is whitish or pale olive, with scattered black spots
that merge above the legs to form the appearance of ``pants.''
Current and Historic Ranges
Amargosa toads are endemic to the Amargosa River drainage in
southwestern Nevada (Goebel et al. 2009, p. 210). Available historic
accounts (Maciolek 1983a, p. 11) do not provide any specific indication
of wider distribution. Toads that occur in downstream reaches of the
Amargosa River corridor (e.g., Ash Meadows area) anecdotally exhibit
some taxonomic similarities; however, they have not been identified as
Amargosa toads. The area occupied by the Amargosa toad is isolated,
with no known or probable connections to members of the western toad
complex (NDOW 2000, p. A-1). The nearest known record for a western
toad is approximately 35 linear miles (mi) (56 kilometers (km)) away at
Furnace Creek in Death Valley National Park, California, where an
introduced population of western toad occurs. The historical and
current range of the Amargosa toad occurs within Oasis Valley, along an
approximately 10-mi (16-km) stretch of the Amargosa River and nearby
spring systems, roughly between the towns of Springdale and Beatty.
Oasis Valley occurs along U.S. Highway 95 between Bullfrog Hills and
the Nevada Test Site.
In 2007, the Amargosa Toad Working Group (ATWG) prepared a map of
all known and potential habitat for the species, including potential
movement corridors, and posted the map on the Internet at: https://www.fws.gov/nevada/nv_species/amargosa_toad.html. The total amount of
known and potential Amargosa toad habitat delineated by the ATWG is
approximately 8,440 acres (ac) (3,416 hectares (ha)).
Life History and Ecology
Amargosa toad habitat requirements for breeding and population
recruitment include the presence of open, ponded, or flowing water,
with riparian vegetative cover in an early-to-intermediate successional
stage to form a partial canopy for shade with minimal emergent
vegetation at the water's edges. Immature (metamorphs or toadlets) and
adult Amargosa toads are dependent upon the areas described above, as
well as areas they can use for shelter, including burrows, debris
piles, spaces under logs or rocks, and areas of dense vegetation (NDOW
2000, p. A-2). Adult toads also require adjacent vegetated uplands for
nocturnal foraging. Dense vegetation and advanced successional stages
of riparian vegetation appear to limit habitat suitability and
occupancy by all life stages, particularly where open water is not
present (NDOW 2000, p. A-2). Toads can be abundant in irrigated and
disturbed areas.
The breeding season for the Amargosa toad begins in mid-February
and may extend into July, during which time adults congregate at
breeding sites. A female toad may produce over 6,000 eggs in a single
reproduction event (Altig 1987, p. 277; Heinrich 1995, p. 2). Amargosa
toad tadpoles require relatively open water that persists long enough
for the completion of metamorphosis and development into toadlets,
which occur over approximately 30 days. Predation and early desiccation
of wetlands needed for breeding may destroy an entire breeding effort.
Although Amargosa toads typically live 4 to 5 years, individual toads
are known to live up to 17 years based on data from NDOW's population
monitoring program (Hobbs 2010, p. 1.).
Population Status and Trends
In 1998, NDOW initiated a long-term population monitoring program
for the Amargosa toad using mark-recapture methods at 11 sites of the
18 known sites occupied by toads. The 11 sites are grouped into 4
spatial areas described below (see distribution map available at https://www.fws.gov/nevada/nv_species/amargosa_toad.html). The monitoring
program was identified in the Amargosa Toad Conservation Agreement and
Strategy (CAS) as an conservation action (NDOW 2000, p. A-11) and
involves capture and marking (with implanted tags) of all juvenile to
adult age-class Amargosa toads found that are 2 in. (50 mm) or greater
in length. The NDOW maintains a database on Amargosa toad population
monitoring data as prescribed in the CAS (NDOW 2000, pp. A-12 and 13).
As of November 2009, a total of 6,739 Amargosa toads had been captured
and tagged. In 2009, captures increased 77 percent over 2008, with a
total of 768 toads captured and tagged, 519 of which were captured for
the first time. The 2009 population estimate for monitored sites is
1,623, which is 13.6 percent less than the average of 1,826 for the
period 1998 through 2008 (Hobbs 2009, p. 1). Unsuitable weather
conditions during the 2007 and 2008 surveys may have resulted in lower
than average toad activity (Figure 1; Hobbs 2009, p. 2). Habitat
improvements and disturbance of aquatic systems at monitored sites have
resulted in increases in toad captures and reproduction (Hobbs 2009,
pp. 2-4; Saving Toads thru Off-Road Racing, Ranching, and Mining in
Oasis Valley (STORM-OV) 2009b, p. 1).
[[Page 42042]]
[GRAPHIC] [TIFF OMITTED] TP20JY10.020
Simandle (2006, p. 42) determined that Amargosa toads meet the
criteria and expectations of metapopulations. This means that occupied
habitats, unoccupied but suitable habitats, and intervening habitat
that may be occasionally used during infrequent migration events should
all be considered as conservation priorities. Metapopulations can be
expected to have local extirpations in some patches, resulting in the
existence of empty but suitable habitat that subsequently may be
recolonized in the future (Simandle 2006, p. 8). Events such as floods
may simultaneously destroy existing occupied habitat, create new
suitable habitat, and facilitate infrequent movement among different
sites. Habitat conditions and the number of toads that occur at
specific sites and metapopulations change from year to year, thus
requiring site-specific management strategies.
Population Groups
The 11 monitored sites occupied by the Amargosa toad occur in three
groups: Harlan-Keal, Amargosa River, and Spicer/Mullin/Torrance; and
Angel's, a single site outside the three groups. The sites associated
with each group are discussed below.
Harlan-Keal Group
The Harlan-Keal Group consists of four sites: 5 ac (2 ha) of
private land (Harlan-Keal), including an irrigated garden area and 200-
square foot (ft\2\) (18.6-square meter (m\2\)) pond; a spring and
associated pond (Crystal Spring); and two seeps named Trespass and Wild
Burro. Crystal Spring and the two seeps occur on lands administered by
the BLM.
The Harlan-Keal pond was restored in 2003-2004, and has early
successional habitat where toad reproduction occurs and may serve as a
source population. The 2009 population estimate for the Harlan-Keal
Group was 156, which was 22 percent below the 12-year average for this
group of sites (Hobbs 2009, p. 2). Because of its elevation, ambient
air temperatures at this site are always cooler than at other sites.
This will likely affect the number of toads captured during surveys.
The Crystal Spring site consists of a spring, pond, and outflow on
BLM land. In 1995, a wild burro exclosure was constructed around
Crystal Spring to reduce trampling and overuse of the spring. This
caused an increase in emergent vegetation that has reduced the extent
of open water, which in turn resulted in few toads remaining at the
site. Historically, this site was maintained by ranchers and other
private efforts which removed sediment and excess vegetation that
maintained open water in the pond. Planning is under way to
rehabilitate this site in 2010 to benefit Amargosa toads (STORM-OV
2009a, pp. 1-3).
Trespass Seep is a low-flow spring site without any substantial
ponded area that has never supported many toads. During surveys, the
highest number of toads captured at Trespass Seep was 12 in 1998. In
August 2009, improvements were made to Trespass Seep by a private
landowner that resulted in a substantial increase in ponded surface
water and toad habitat. Within a few weeks after improvements to the
seep, Amargosa tadpoles were observed at the site (STORM-OV 2009b, p.
1).
Wild Burro seep consists of a low-flow spring, an excavation with
groundwater exposed, and wet meadow. In 1998, 12 ac (4.9 ha)
surrounding the seep was fenced by BLM to exclude wild burros that
overused the site. Currently this site provides little habitat for the
Amargosa toad, with only a few toads documented at this site each year.
In November 2009, STORM-OV submitted a plan to the BLM to create and
enhance toad habitat at this site (STORM-OV, 2009c, pp. 1-6). STORM-OV
is a local nonprofit organization representing the off-road, ranching,
and mining interests, dedicated to Amargosa toad conservation projects.
Amargosa River Group
The Amargosa River consists of three monitored segments
characterized by riparian vegetation interspersed with flowing, open
water. Amargosa toad population monitoring occurs along a 2-mi (3.2-km)
section of the Amargosa
[[Page 42043]]
River that is mostly perennial, from just north of the Stagecoach
Casino and Hotel to the Narrows, south of Beatty, Nevada (see
distribution map available at https://www.fws.gov/nevada/nv_species/amargosa_toad.html). Land ownership is a mosaic of private, local, and
Federal (BLM) lands. Most habitat for the Amargosa toad exists along
this monitored section of the river, and most toads are found along the
river corridor where perennial water occurs and bullfrogs (Lithobates
(=Rana) catesbeiana) and crayfish (Procambarus sp.) are few or absent.
In a typical year, tens or hundreds of thousands of Amargosa toad
tadpoles are produced within the Amargosa River. The 2009 population
estimate for this group was 14 percent lower than the 12-year average
(Hobbs 2009, p. 3). This lower population estimate for the Amargosa
River may be the result of low detectability of Amargosa toads due to
dense vegetation, no substantial habitat improvements during the last
few years, and predation from bullfrogs and crayfish.
Spicer/Mullin/Torrance Group
This group consists of three privately held properties which
include the Spicer site (320 ac; 129 ha); Mullin site (80 ac; 32 ha);
and Torrance Ranch (130 ac; 52 ha). The Torrance Ranch was purchased by
The Nature Conservancy (TNC) in 1999 to protect the Amargosa toad and
to provide a site for experimental habitat management to benefit the
Amargosa toad. All three sites are contiguous or in close proximity to
each other, which allows movement of Amargosa toads among all three
sites. The 2009 population estimate for this group was 86 percent above
the 12-year average for these sites. All three property owners are
conservation partners with the Service and NDOW, and have accomplished
or cooperated on numerous toad habitat improvement projects.
Angel's Site
This 296-ac (120-ha) site consists of a single location on private
property. A spring-fed, cement lined pond that has an outflow to a
wetland pasture provides breeding and oviposition habitat for the
Amargosa toad. No habitat changes have been observed in at this site
since monitoring efforts began in the mid-1990s. The pond was dry in
2007 and no evidence of reproduction was observed in 2008. The
population estimate for this site declined 33 percent in 2009 compared
to 2008, and 23 percent below the 12-year average for this site (Hobbs
2009, p. 5). Crayfish and bullfrogs occur at this site.
Other Sites
A 2.6 mi (4.2 km) stretch of the Amargosa River north of the
Stagecoach Hotel and Casino, has intermittent and perennial flow in
sections, mostly associated with spring outflow. Land ownership is a
mosaic of private and BLM lands. Cursory surveys conducted in this area
by NDOW biologists have detected Amargosa toads. Several private
properties are known to have suitable Amargosa toad habitat. Surveys
have not been conducted on these properties; however, anecdotal
observations of toads have been reported (Maciolek 1983a, pp. 9-10;
1983b, pp. 4, A1-4). In 1993 and 1994, Heinrich (1995, p. 8) documented
toads at eight sites, including the Manley property (spring and
outflow), Parker Ranch (Ute Spring), and LaFleur Spring site (Roberts
Field). No population size estimates or trends have been made for these
other sites. Amargosa toads at these sites are not included in the
rangewide population estimates.
LaFleur Spring is a historic site for Amargosa toads near the
northern range limit of the species. Altig (1987, p. 277) found up to
74 toads at this site during 5 visits to the site in 1981. Altig
further concluded that the toad population at the LaFleur site is
small, with no recruitment observed in 1980 or 1981. No surveys have
been conducted at this site since the 1980s. The Springdale site
provides approximately 1 ac of (2.5 ha) toad habitat; toads were
reported to be present in July and August 1983 by Maciolek (1983a, p.
8). Habitat improvements have occurred, including the removal of salt
cedar. The Springdale site is not included in the population monitoring
program for Amargosa toads.
Parker Ranch (24 ac; 212 ha) was purchased by TNC in December 2000,
with assistance from the State of Nevada, the National Fish and
Wildlife Foundation, and the U.S. Department of Agriculture, Natural
Resource Conservation Service (NRCS), to protect and restore unique
biological resources, including Amargosa toad habitat. Parker Ranch is
approximately 4 mi (6.4 km) north of Beatty and includes Ute Spring.
Parker Ranch is currently being grazed by 74 cattle by a local rancher
to reduce the amount of emergent wetland vegetation to increase open
water areas (Moore 2010, p. 3). The spring source was fenced off and
outflow stream channels were reconstructed in recent years to prevent
damage to stream banks (Moore 2010, p. 3). The NRCS is monitoring the
vegetation condition to determine when cattle should be moved to other
properties in Oasis Valley. The newly constructed stream channel and
toad pond system has been dry for almost 2 years due to insufficient
water and overgrowth of emergent wetland vegetation near the spring.
Amargosa toads continue to breed in the fenced-off spring and outflow
channel on the 6-ac (2.5-ha) private inholding. No population estimates
are available for this area.
The Indian Springs Complex consists of Upper, Middle, and Lower
Indian Springs. Lower Indian Spring consists of two springs, Lower
Indian and Cave Springs. Upper Indian Spring is the location of a
municipal well that provides water to the town of Beatty. Middle Indian
Spring is mostly dry, with several mature cottonwood trees. Little if
any toad habitat currently occurs at either Upper or Middle Indian
Springs. At Lower Indian Spring, an approximate 10-ac (4-ha) wild
burro/livestock exclosure that surrounds two springs was constructed by
the BLM in 1994, along with a water pipe and trough outside the
exclosure to provide water to burros, livestock, and wildlife.
Currently, this site is nearly dry, with no water exiting the
exclosure. Toads have been captured at Lower Indian Spring as recently
as 1996. No population estimates are available for this area. Attempts
to restore toad habitat at this site in 1998 were unsuccessful, but new
techniques have been developed, and the ATWG proposed habitat
rehabilitation in 2010.
Other private lands have been or could be occupied by Amargosa
toads. Revert Spring (303 ac; 123 ha) is privately owned by the owner
of the Stagecoach Hotel and Casino. Revert Spring is an important water
source for Amargosa toad habitat in the river. Although Maciolek
(1983a, p. 10) documented Amargosa toads at Revert Spring in July and
August 1983, the current status of toads at the Revert Spring site is
unknown. Coffer Ranch (900 ac; 364 ha) occurs at the northernmost edge
of the range of the Amargosa toad and is owned and managed by a cattle
company. Maciolek (1983b, p. A-1) reported that Amargosa toads were
present at the Coffer Ranch, and suitable Amargosa toad habitat was
present. However, no population estimates are available for these or
other privately owned lands where Amargosa toads may occur.
Amargosa Toad Working Group (ATWG) and Amargosa Toad Conservation
Agreement and Strategy (CAS)
In 1996, the ATWG was organized to provide recommendations for
[[Page 42044]]
management and conservation of the Amargosa toad. The ATWG consists of
representatives of the Service, NDOW, TNC, Nevada Department of
Conservation and Natural Resources, Bureau of Land Management (BLM),
Nye County, Beatty Town Board, Beatty Habitat Committee, The Amargosa
Conservancy, private landowners in the Beatty community, the University
of Nevada at Reno, and others. The ATWG meets semiannually to present
and exchange information on the toad and its habitat, including the
status of habitat conditions and ongoing habitat projects, potential
threats to the toad, and population monitoring data, and to identify
new conservation tasks.
In 2000, the ATWG completed the Amargosa Toad CAS (NDOW 2000, pp.
1-12), which provides management and conservation guidance for the
Amargosa toad. The CAS informs management of the conservation needs of
the toad, prioritizes tasks, and provides an implementation schedule.
The ATWG is currently updating the CAS to include accomplishments and
updated conservation needs for the toad.
The CAS was developed to expedite toad conservation over a period
of 10 years by providing guidance and a framework for implementation of
cooperative long-term conservation actions to benefit the toad and co-
occurring species. Signatories to the CAS include NDOW, Nye County
Department of Natural Resources, the Service, BLM, TNC, the Nevada
Natural Heritage Program, and the University of Nevada at Reno. The
signatories provide representatives to the ATWG. The signatories and
ATWG are committed to implementing specific conservation actions
(tasks) which identify, reduce, or eliminate threats to the species,
and maintain and enhance a properly functioning ecosystem for the
Amargosa toad and other indigenous species of Oasis Valley. The ATWG
meets semiannually to plan Amargosa toad conservation actions. Most
conservation actions in the CAS are implemented by local private land
owners, and land and resource managers.
Many of the conservation actions implemented by the ATWG and its
various partners are a direct result of the commitments made in the CAS
for the Amargosa toad (NDOW 2000, pp. 1-12). The goals of the CAS are
to manage threats, maintain habitats, monitor populations, and test and
evaluate habitat manipulations. Completed conservation actions
identified in the CAS have addressed threats identified in Factors A,
B, C, and E (see below). We consider the CAS successful if considerable
progress is made towards achieving these goals. CAS accomplishments
that have contributed towards success include 12 years of population
monitoring and maintaining population data in a database; salt cedar
removal; habitat rehabilitation and enhancement; research; public
education and outreach; and habitat acquisition as discussed in Factor
A. Other CAS accomplishments include control of predators through
habitat manipulation and work with the local community to achieve
conservation such as an open space plan. The CAS signatories and the
ATWG, in cooperation with local landowners, have planned and initiated
multiple projects to protect, restore, and enhance toad habitat, and
create new habitat. Overall success is measured by population
monitoring data that show that rangewide, Amargosa toad populations are
relatively stable and respond promptly and positively to habitat
improvements. Previous habitat improvements on the Amargosa River,
Harlan-Keal, Mullin, and Spicer sites have all resulted in substantial
population increases of toads. In 2005, vegetation was removed by NDOT
at the U.S. 95 Highway bridge over the Amargosa River in Beatty. This
resulted in a positive response by toads as shown by a large
reproductive event and a 2006 population estimate of 1,854 for the
river which was the highest on record (ATWG 2005, p. 2; Wixson 2006, p.
3). Again in 2005, vegetation was cleared from the pond at the Harlan-
Keal site with funding from the Service and NDOW which resulted in an
estimated 90 percent increase in the population in 2006 over the 2005
estimate (Wixson 2006, p. 2).
The ATWG is in the process of updating the CAS and anticipates a
revised CAS by the end of 2010. The revised CAS will acknowledge
accomplishments and identify the conservation needs of the toad for the
next 10 years. The revised CAS will operate in a similar manner as the
existing one. The CAS has proven, based on its 10 year track record, to
be an effective tool in furthering the long-term conservation of the
species.
Summary of Information Pertaining to the 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 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:
(1) The present or threatened destruction, modification, or
curtailment of its habitat or range; (2) overutilization for
commercial, recreational, scientific, or educational purposes; (3)
disease or predation; (4) the inadequacy of existing regulatory
mechanisms; or (5) other natural or manmade factors affecting its
continued existence. In making this finding, information pertaining to
the Amargosa toad in relation to the five factors provided in section
4(a)(1) of the Act is discussed below.
In making our 12-month finding on a petition to list the Amargosa
toad, we considered and evaluated the best available scientific and
commercial information. The analysis of potential threats to the
Amargosa toad discussed below includes those identified in the petition
and those that we considered to be substantial in our 90-day finding
(74 FR 46551).
Factor A. The Present or Threatened Destruction, Modification, or
Curtailment of Its Habitat or Range
Private Land Development
The petition identified several potential residential or commercial
developments on private land that could adversely affect the Amargosa
toad or its habitat. However, based on information provided by TNC
during our review (Moore 2010, pp. 1-3), none of the proposed
developments appear to be viable. Real estate and development markets
in nearby Pahrump and Las Vegas influence markets in the Beatty area,
and each of these three areas have experienced a downturn in both the
general economy and the housing market. Plans for a shooting range
across from Torrance Ranch have been abandoned and the property was
recently sold to an individual who plans to build a home on the 40-ac
(16-ha) site (Moore 2010, p. 3). A geothermal project at a hot spring
on private lands identified by CBD as a threat (2009, p. 2) has been
abandoned (Moore 2010, pp. 1-3). Although development may occur within
the range of the Amargosa toad over the near term, it is difficult to
predict the scope of that development based on the available
information. Furthermore, humans and Amargosa toads have coexisted in
the Beatty area since the early 1900s. Amargosa toads at the Harlan-
Keal site and other sites where residential or commercial development
and toads co-occur demonstrate that toad and human interface can be
compatible. Toads occur in most disturbed and developed areas with
surface water and may be locally abundant. During our review, we
[[Page 42045]]
found no indication that the economic growth of Beatty will change
substantially in the foreseeable future. Due to the absence of
potential developments identified in the petition and the ability of
toads to coexist with humans in developed and disturbed areas, we
conclude habitat loss as a result of development on private land is not
a substantial threat to the Amargosa toad now or in the foreseeable
future.
Groundwater Development and Extraction
The petitioners provided information that claimed existing and
future water uses and developments are important threats that reduce
surface water available for Amargosa toads in Oasis Valley and that
result in habitat loss. The majority of water right allocations within
the basin are spring diversions for irrigation and livestock watering.
Priority dates for groundwater rights, including those of Beatty Water
and Sanitation District (BWSD), range from the 1920s to 1996, with the
majority dating to the late 1980s or earlier. The priority dates are
the dates the application are submitted and determine the seniority of
the water right relative to other water rights in the affected basin.
Spring diversions are located primarily along or near the Amargosa
River channel. Groundwater rights are limited to approximately one
sixth of water right allocations in the valley (by volume), 85 percent
of which are held by the BWSD as a source of supply for homes and
businesses in the town of Beatty. The BWSD holds water rights for three
wells in the town of Beatty and two wells several miles northwest of
town (including one at Indian Springs), in addition to a groundwater
right at the Barrick Mine in Amargosa Valley (Nevada Division of Water
Resources, https://water.nv.gov/). Other groundwater rights in Oasis
Valley (a total of 8) are for irrigation, recreation, livestock
watering, and minor commercial and mining activities, most in the
amount of 20 acre-feet per year (afy) or less.
Currently, TNC is negotiating purchase of the water rights (500
afy) at Revert Spring with the owner of the Stagecoach Hotel and Casino
to establish long-term protection measures for the water flowing from
the spring source into the Amargosa River. Acquisition of this
important water source can reduce the threat of its use for commercial
purposes and enable TNC to meet its commitment in the CAS to work with
private landowners to pursue conservation actions such as acquisitions
and easements (NDOW 2000, p. A-20). However, we recognize that this
transaction has yet to be completed, and cannot be certain that these
rights will be secured.
Groundwater level records for Oasis Valley, which are both recent
and long enough to assess trends (e.g., over the last 10 years or
more), are limited to monthly and bimonthly measurements collected by
the U.S. Geological Survey (USGS) for the U.S. Department of Energy
(USDOE) as part of the USDOE Environmental Restoration Program (USGS/
U.S. DOE Cooperative Studies in Nevada, https://nevada.usgs.gov/doe_nv/
). Specifically, groundwater level measurements are available for seven
wells or nested wells along or near the Amargosa River channel in Oasis
Valley and a number of additional wells to the north and east within
the valley and up gradient basins for the period 1998 to late 2009. The
wells range in depth from 200 ft (61 m) or less in consolidated
sedimentary deposits to thousands of feet in the volcanic rock aquifer.
Trends in groundwater levels along the Amargosa River channel from 1998
to 2009 are mixed, some increasing moderately, some decreasing
moderately, and some relatively constant on an annual basis. Water
levels in two of the seven monitoring wells located along or near the
Amargosa River channel (well ER-OV-03 and the Beatty Wash Terrace Well)
decreased 1.3 to 1.5 ft (0.4 to 0.5 m) from 2000 to late 2009. However,
these declines occurred in no clear relation to permitted or
certificated groundwater rights (pumping at permitted supply wells).
Rather, they may be indicative of local evapotranspiration responses.
Elsewhere along the river channel, groundwater levels were unchanged,
or increased a few tenths of a foot from 2000 to late 2009 (ER-OV04a,
Springdale Upper Well, ER-OV-02, ER-OV-05, and ER-OV-06a).
In areas to the north and east which supply groundwater to the
vicinity of the Amargosa River channel and Amargosa toad habitat in
Oasis Valley, specifically northeastern Oasis Valley and the area of
Pahute Mesa (the latter located in the Gold Flat and Forty mile Canyon-
Buckboard Mesa basins) (Laczniak et al. 1996, pp. 18-19; Reiner et al.
2002, pp. 8-9; Fenelon et al. 2010, pp. 22-23 and Plate 5), water
levels in USDOE Environment Restoration Program wells increased a few
tenths of a foot to approximately 1.5 ft over this same period.
No groundwater level data are available for the vicinity of the
BWSD supply wells. As such, the effects of BWSD pumping on surface
water resources cannot be evaluated at this time except as they may be
judged from the results of biannual Amargosa toad surveys. This
suggests that any reduction in population is limited to the area of
Indian Springs. BWSD pumping at the Indian Springs well has decreased
since the late 1990s, but Indian Springs remains one of three primary
supply wells in Oasis Valley for the town of Beatty. With respect to
the potential for additional groundwater pumping in Oasis Valley,
actual groundwater withdrawals by the BWSD have been limited to
approximately 10 to 15 percent of their existing rights over most of
the last decade (Eng 2010, p. 1). Whereas substantially more
groundwater could be pumped for municipal purposes under existing BWSD
rights, their pumping within Oasis Valley has been fairly constant.
Overall demand has decreased approximately 25 percent (coupled with a
decrease in pumping at the Barrick Mine) over this same period of time
based on pumping inventories provided by the Nevada State Engineer
(NSE). Additionally, BWSD demand varies seasonally, with demand at a
minimum from December through March, the latter of which coincides with
the beginning of the Amargosa toad breeding season. Moreover, the NSE
has ruled that the degree of hydraulic connection between groundwater
and surface water in Oasis Valley is such that they constitute a single
source (NSE Ruling 4669, 1998) and that no unappropriated water existed
in the basin as of 1995 (NSE Ruling 4174, 1995), making additional
allocations, groundwater or surface water, unlikely.
Excessive groundwater withdrawals have the potential to affect
springs and rivers that depend on groundwater for recharge or base
flows. Field reconnaissance and Nevada Division of Water Resources well
drilling records identified approximately 15 springs and 20
nonmunicipal wells that supply water to individual homes and ranches in
Oasis Valley (Reiner et al. 2002, p. 33). A reasonable estimate of
groundwater withdrawal consumed from each of these sources is 1 afy
(Reiner et al. 2002, p. 33). Based on this consumption rate and the
number of supply sources, a reasonable estimate of the nonmunicipal use
of groundwater from Oasis Valley is 35 afy. Estimates of the total
annual groundwater withdrawal from Oasis Valley, computed by combining
municipal and non-municipal estimates, declined from 440 afy in 1996,
when Beatty's human population was 2,068, which was the highest during
the period 1991-2007 (Stantec 2009, p. 22), to 210 afy in 1999, when
Beatty's population declined to 1,703.
[[Page 42046]]
The population estimates for Beatty in 2007 indicate a resident
base of approximately 1,068 persons (Stantec Consulting 2009, p. 22).
This estimate reflects a declining population trend during the period
1991-2007. While the future population size of Beatty is unknown, we
found no indication that the human population will increase beyond
historic levels and we do not anticipate an increase in use of
groundwater to support new residential development. We conclude that
future human population effects on the Amargosa toad are driven by the
economic status and growth of the Beatty. Since there is no indication
that growth will increase, we conclude that demand for groundwater is
not likely to rise.
The petitioners submitted comments that identified a proposed solar
energy project in Amargosa Valley requiring 3,000 afy of groundwater
for wet-cooling and operation (CBD 2009, pp. 1-2). This energy project
remains proposed but has been modified to use dry-cooling that would
reduce groundwater use to 400 afy. The 400 afy of groundwater proposed
for the project is currently used for agriculture and, therefore this
level of groundwater use is not anticipated to significantly affect
existing groundwater levels in the up gradient areas where Amargosa
toads occur (Peterson 2010, p. 1).
The petitioners also identified 11 Department of Energy (DOE)
applications for water rights in Oasis Valley as a potential threat to
the toad through groundwater withdrawal effects (CBD 2009, p. 2). The
DOE applications were submitted for construction of a railroad to a
proposed nuclear waste repository and were protested by the petitioners
and others. The Service recommended that DOE transport water needed for
this project from sources other than those associated with the Amargosa
toad, Ash Meadows, and Devils Hole. In February 2010, DOE withdrew
their applications for water rights in the Oasis Valley.
Based on the available information on volume, timing, and location
of groundwater withdrawals, historic use of groundwater, and water-
level measurements, we conclude that water use and development in Oasis
Valley is not a substantial threat to the Amargosa toad at this time or
in the foreseeable future. No declines in groundwater or toad numbers
have been observed at monitored sites as a result of pumping. The
current and foreseeable demand for groundwater in Oasis Valley remains
consistent with historical uses.
Inadequate Habitat Enhancement Planning and Implementation
The petitioners state that BLM failed to initiate planning for
habitat enhancement projects including Wild Burro Seep and Upper Cave
Spring in the Lower Indian Spring system (CBD 2009, p. 20). In fall
2009, STORM-OV, in cooperation with BLM and the ATWG, modified Wild
Burro Seep and greatly increased the extent of surface water and toad
habitat at the site. STORM-OV and BLM developed plans to restore Lower
Indian Springs and Crystal Spring in 2010 and 2011 (STORM-OV 2009a, pp.
1-3; Spicer 2009, pp. 1-5). Habitat enhancement is a conservation
action in the CAS (NDOW 2000, p. A-11).
The Stagecoach Hotel and Casino owner is a conservation partner
with TNC and the Service. In 2001, the Service's Partners for Fish and
Wildlife Program funded habitat improvements in the vicinity of the
Stagecoach to benefit the Amargosa toad. The owner and TNC continue to
improve habitat along the river behind the property, which is part of a
parcel identified as a fee-title donation to TNC for conservation
purposes pursuant to prescribed conservation actions in the CAS. In
addition, TNC and the Nevada Department of Transportation (NDOT) are
working to remove debris from the riverbank, which should improve
habitat for the Amargosa toad.
In 2007, 30 ac (12 ha) of nonnative trees were removed from the
Mullin site and replaced with native willows and cottonwoods as
prescribed in the CAS (NDOW 2000, p. A-11). During the 2009 survey, 137
Amargosa toads larger than 2 in (50 mm) were captured on the Mullin
site. This was the highest number of captures for this site (Hobbs
2009, p. 4).
Three springs on the Spicer site have been enhanced for the
Amargosa toad by the landowner. Surface water is distributed on the
Spicer site through a system of pipes which provides most of the water
for toad habitat. Manipulation of the distribution pipes provides a
habitat management tool to allow ponds to be created, or dried to
remove crayfish and bullfrogs as prescribed in the CAS (NDOW 2000, pp.
A-11 and A-12). Amargosa toads responded positively to the habitat
improvements in 2009, increasing by 300 percent of captured and marked
toads since 2008 (Hobbs 2009, p. 4).
The Amargosa River Planning Team was formed in October 2009 as a
result of a recommendation by the ATWG that was included in the CAS
(NDOW 2000, p. A-14). The team consists of ATWG representatives
including the Service, NDOW, Nye County, BLM, and TNC, but also local
landowners. The purpose of the team is to monitor habitat conditions of
the river, develop management recommendations, and coordinate habitat
improvement with landowners and managers on behalf of the signatories
of the CAS and the ATWG.
The overall habitat suitability of individual sites varies from
year to year depending on conditions and may become unsuitable for
toads. Because the Amargosa toad occurs as metapopulations, toads will
move back into these sites from neighboring sites once the habitat
becomes more suitable. In the absence of natural disturbance such as
flood events and wildfires, toad habitat will likely require periodic
manipulation or other forms of disturbance such as burro or cattle use
to sustain toad populations. Based on the metapopulation structure of
the toad, successful habitat projects and disturbance by burros and
cattle, we anticipate that habitat planning and implementation have
resulted in positive responses by toads. We expect the Amargosa River
Planning Team, TNC, BLM, Service, and private landowners to continue
their efforts to maintain and improve toad habitat into the foreseeable
future in accordance with the CAS. We expect members of the ATWG and
private landowners to continue their current efforts to maintain and
improve toad habitat, as they have in the past, in accordance with the
CAS into the future. As a result, we have determined that habitat
planning and implementation is not a threat to the Amargosa toad now,
nor is it expected to be so in the foreseeable future.
Vegetation Overgrowth
Overgrowth of vegetation in aquatic habitats is an ongoing
management objective for the Amargosa toad as specified in the CAS
(NDOW 2000, pp. A-11 and A-16). Habitat for Amargosa toads at several
spring sites including Torrance Ranch, Lower Indian Spring, and Crystal
Spring, has degraded as a result of overgrowth of emergent vegetation
and loss of open water. Overgrowth of vegetation occurs mostly at small
spring sites and in the absence of disturbance or management. Although
Lower Indian Spring and Crystal Spring are small spring sites and
represent only a small fraction of the species' individuals and
distribution, the ATWG considers vegetation management a priority for
these sites. Mechanical removal, controlled burns, and grazing are
proven tools to manage vegetation in spring systems at Harlan-Keal
(ATWG 2004, p. 3) and Torrance Ranch (ATWG 2007, attachment 1, p. 1).
[[Page 42047]]
Spring-supplied ponds typically require disturbance or periodic removal
of vegetation to maintain suitable habitat conditions (e.g., open
water) for the Amargosa toad. Local ranchers historically managed
Crystal Spring and other springs to maintain open water (Spicer 2010,
p. 1). Limited use by livestock or feral burros provides disturbance
that benefits toads; however, excessive use by livestock or feral
burros result in degradation of habitat. Current and future habitat
projects at spring sites are designed to minimize vegetation growth,
compensate for potential reductions in spring flow due to overgrowth of
vegetation, and maintain proper habitat conditions for the toad.
Currently, excess vegetation conditions occur at Crystal and Lower
Indian Springs, but habitat modification proposed for 2010 and 2011 at
these sites (STORM-OV 2009a, pp. 1-3; Spicer 2009, pp. 1-5) is
anticipated to substantially improve habitat conditions for the toad.
As stated previously, we expect the efforts to maintain and improve
toad habitat which includes control of vegetation to continue in
accordance with the CAS. Therefore vegetation overgrowth is not a
significant threat to the Amargosa toad now, nor is it expected to be
so into the foreseeable future.
Grazing and Trampling
The petitioners state that use of springs by feral burros and
cattle may result in degraded habitat and reduced numbers of Amargosa
toads (CBD and PEER 2008, pp. 17-18, 21 and 23-25). The current level
of burro occurrence in Amargosa toad habitat varies by site and ranges
from zero to moderate with most use along the Amargosa River. Cattle
use of Amargosa toad habitat is limited to the northern sites where a
cattle operation is located (Coffer Ranch) and sites targeted for
vegetation reduction. While burros and livestock (ungulates) may
trample Amargosa toad eggs and larvae, light to moderate disturbance is
important to the Amargosa toad which is a disturbance-dependant species
(ATWG 2005, p. 2). In the absence of disturbance, vegetation grows
uncontrolled and reduces open areas necessary for the toads. Intensive
and uncontrolled use of Amargosa toad habitat by ungulates may threaten
the species by degrading habitat and killing individual toads; however,
light to moderate use is known to be beneficial to the Amargosa toad.
Complete removal of ungulates could lead to overgrowth of vegetation,
and may pose a more serious threat to the Amargosa toad than moderate
ungulate use. Fencing installed at the Crystal and Indian spring sites
to exclude feral burros most likely has contributed to declines in toad
populations at these sites by reducing habitat disturbance. BLM manages
the burro population and conducts burro ``gathers'' when the burro
numbers exceed the appropriate management level for the area in
accordance with the CAS (NDOW 2000, p. A-16). Most feral burro use of
monitored sites occurs along the river. We conclude that light to
moderate ungulate use is not a substantial threat to the toad and
likely provides some benefit to the Amargosa toad. Although the number
of feral burros fluctuates, we do not anticipate the level of burro use
in Amargosa toad habitat to increase so that it would affect toad
populations in the foreseeable future.
Recreation and Off-Highway Vehicle (OHV) Activity
OHV activity affects Amargosa toads most during the breeding season
and during the especially vulnerable egg and tadpole stages of
development. OHV effects are only known to be a concern along the
Amargosa River near the Stagecoach Hotel and Casino. TNC biologists
have observed small isolated pools containing egg strands or tadpoles
in various stages of development that were affected by OHVs in the
riverbed within the Town of Beatty. The local nonprofit group, STORM-
OV, is attempting to educate the OHV users about the need to avoid
ponded water during the toad breeding season, a conservation action
prescribed in the CAS (NDOW 2000, p. A-18). In addition, TNC plans to
use its river properties behind the Stagecoach Hotel and Casino and
northward in educational opportunities. These two groups propose to
conduct town meetings to inform Beatty residents of the need to avoid
damaging toad breeding pools during the defined breeding season. While
localized OHV use may cause a relatively small number of eggs or
tadpoles to be removed from the affected population, this level of loss
is not substantial in the context of the potentially tens or hundreds
of thousands of Amargosa toad eggs and tadpoles produced in a typical
year.
No landowners or managers have identified, nor are we aware of any
spring sites that are substantially affected by OHV activity. The
petitioners identified an OHV race that passes near Crystal Spring as a
potential threat to the toad. In 2008, BLM chose an alternate route
away from toad habitat for OHV events near Crystal Spring and continues
to consider the toad during OHV permitting actions. Due to the absence
of substantial effects resulting from recreation or OHV use in toad
habitat and the location of many of the spring sites on private land
that have no OHV use, we do not expect effects from recreation and OHV
use to increase or become a threat to the toad in the foreseeable
future.
Invasive Plant Species
The petitioners assert that introduced invasive trees have become
established along stretches of the Amargosa River and springs, which
may reduce prey and microhabitat available for the Amargosa toad (CBD
and PEER 2008, pp. 24 and 26).
Salt cedar is an exotic, invasive species that grows in shrub form
to medium tree size and is native to Eurasia. Removal of salt cedar is
identified as a conservation action in the CAS (NDOW 2000, p. A-11).
Native aquatic and wetland herpetofauna may be negatively impacted in
areas where salt cedar draws down surface water (Shafroth et al. 2005,
pp. 237-238). Water-use studies indicate that increases in water yield
following salt cedar control are likely to occur only when a salt cedar
stand containing high leaf area is replaced by vegetation with a lower
leaf area (Shafroth et al. 2005, pp. 237-238). The native vegetation in
Oasis Valley requires more water than is provided by local rainfall. As
a result of high evapotranspiration rates during the summer, these
plants must rely on local groundwater for sustenance (Reiner et al.
2002, p. 42). Anderson et al. (2004, cited in Shafroth et al. 2005, pp.
237-238) present data from the lower Colorado River suggesting that
abundances of several of the most common insect families in riparian
areas occur in comparable or greater abundance on salt cedar than on
most native vegetation. Efforts to remove salt cedar and other
nonnative, invasive plants from the Amargosa River watershed have
occurred since 2003. Replacing salt cedar with native vegetation may
result in lower evapotranspiration rates. Eleven grants provided
$118,500 for salt cedar removal from 11 private properties and BLM,
NDOT, and BWSD-managed land. Salt cedar has been removed from
approximately 1,895 ac (767 ha) of Amargosa toad habitat, and salt
cedar removal efforts will likely continue. Amargosa toad population
monitoring data may be used to assess and measure the effect of salt
cedar removal on the toad. We do not believe salt cedar is a
significant threat to the Amargosa toad now or in the foreseeable
future because salt cedar has been removed from toad habitat and those
efforts continue in accordance with the CAS.
[[Page 42048]]
Failure of the CAS to Protect Toads and Habitat
The petitioners claim that the CAS failed to protect Amargosa toads
and increase toad populations. The CAS is a voluntary, non-regulatory
agreement. The CAS was developed to expedite Amargosa toad conservation
over a period of 10 years by providing guidance and a framework for
implementation of cooperative long-term conservation actions to benefit
the toad and co-occurring species. Signatories to the CAS include NDOW,
Nye County Department of Natural Resources, the Service, BLM, TNC, the
Nevada Natural Heritage Program, and the University of Nevada at Reno.
The signatories provide representatives to the ATWG. The signatories
and ATWG are committed to implementing specific conservation actions
(tasks) which identify, reduce, or eliminate threats to the species,
and maintain and enhance a properly functioning ecosystem for the
Amargosa toad and other indigenous species of Oasis Valley. The ATWG
meets semi-annually to assess the conservation needs of the toad and
plan Amargosa toad conservation actions. Most conservation actions in
the CAS are implemented by local private land owners, and land and
resource managers.
Many of the conservation actions implemented by the ATWG and its
various partners are a direct result of the commitments made in the CAS
for the Amargosa toad (NDOW 2000, pp. 1-12). The goals of the CAS are
to manage threats, maintain habitats, monitor populations, and test and
evaluate habitat manipulations. Completed conservation actions in the
CAS have addressed threats identified in Factors A, C, and E. We
consider the CAS successful as considerable progress has been made
towards achieving these goals. The CAS accomplishments that have
contributed towards success include 12 years of population monitoring
and maintaining population data in a database; burro management through
monitoring and gathers; salt cedar removal; habitat rehabilitation and
enhancement; research; public education and outreach; and habitat
acquisition as discussed above in this factor. Other CAS
accomplishments include control of predators through habitat
manipulation and work with the local community to achieve conservation
such as an open space plan. The CAS signatories and the ATWG in
cooperation with local landowners have planned and initiated multiple
projects to protect, restore, and enhance toad habitat, and create new
habitat. Overall success is measured by population monitoring data that
show that rangewide, Amargosa toad populations are relatively stable
and respond promptly and positively to habitat improvements. Previous
habitat improvements on the Amargosa River, Harlan-Keal, Mullin, and
Spicer sites have all resulted in substantial population increases of
toads. In 2005, vegetation was removed by NDOT at the U.S. 95 Highway
bridge over the Amargosa River in Beatty. This resulted in a positive
response by Amargosa toads as shown by a large reproductive event and a
2006 population estimate of 1,854 for the river which was the highest
on record (ATWG 2005, p. 2; Wixson 2006, p. 3). In 2005, vegetation was
cleared from the pond at the Harlan-Keal site with funding from the
Service and NDOW which resulted in an estimated 90 percent increase in
the population in 2006 over the 2005 estimate (Wixson 2006, p. 2).
The ATWG is in the process of updating the CAS and the group
anticipates a revised CAS by the end of 2010. The revised CAS will
acknowledge accomplishments and identify the conservation needs of the
Amargosa toad for the next 10 years. The existing CAS and revision will
function similarly. Although the CAS is a voluntary, non-regulatory
agreement, we conclude that the CAS efforts have been very successful
in establishing a coalition of partners, including State and Federal
agencies, local government, private landowners, and conservation
organizations committed to reduce or eliminate the threats to the
species and assure long-term conservation for the Amargosa toad. In the
absence of the CAS, conservation progress would proceed at a reduced
rate but would not result in the species becoming threatened.
Therefore, based on implementation of various conservation actions
resulting from the CAS as discussed in the factor above, we find that
the existence and implementation of the CAS do not pose a threat to the
species.
Summary of Factor A
Development on private lands and use of groundwater are not
significant threats to the Amargosa toad. Most previously proposed
developments have been abandoned. With potential development stalled,
growth activity within Beatty is not expected to change substantially
in the foreseeable future. Groundwater use in the Beatty area has
decreased or remained constant, and groundwater levels have fluctuated
but these fluctuations do not appear to affect Amargosa toad numbers or
distribution. Habitat has been improved at several sites and
improvements at other sites are planned for 2010 and 2011. Although
some sites are affected by overgrowth of vegetation, past and ongoing
conservation and management actions have improved toad habitat and
contributed to stable Amargosa toad populations, as reflected in the 11
years of population monitoring. In one particular instance, a habitat
manipulation project was developed and implemented, and was very
successful in transforming a small seep into a new breeding site for
toads (STORM-OV 2009a, p. 1). Amargosa toad population estimates are an
indication of habitat quality at a given site, and in those areas where
habitat improvements have been conducted, Amargosa toad populations
have increased substantially. Grazing by cattle and feral burros may be
locally excessive, but moderate use provides needed disturbance to the
aquatic systems that improves Amargosa toad habitat. Some local areas
are impacted by OHV use but not to the extent that population declines
can be identified. There has been no apparent reduction in the current
range of the Amargosa toad compared to the historical range. As a
result of conservation efforts accomplished by TNC through habitat
acquisition and improvements, and by various groups through other
habitat improvement projects at Mullins, Harlan-Keal, Spicer, and
Torrance, along the River, and at Parker Ranch and Trespass Seep, there
has been an increase in habitat quality or quantity for the Amargosa
toad at these sites. Additionally, private landowners have recently
become and remain involved in conservation efforts. Salt cedar has been
substantially removed from private and BLM land. Completed actions
prescribed in the CAS to conserve the Amargosa toad have been shown to
be successful in meeting the objectives in the CAS and reducing or
eliminating the threats to the Amargosa toad under Factor A. We
conclude that the present or threatened destruction, modification, or
curtailment of the habitat or range of the Amargosa toad is not a
significant threat to this species now or in the foreseeable future,
due to the limited growth projected for Beatty, current and anticipated
groundwater use and levels; completed and proposed habitat improvements
including removal of salt cedar; continuing management of the Amargosa
River and adjacent habitat under the direction of the Amargosa River
Planning Team, a subcommittee of the ATWG; and continued implementation
of conservation
[[Page 42049]]
measures in accordance with the revised CAS.
Factor B. Overutilization for Commercial, Recreational, Scientific, or
Educational Purposes
The petitioners provided no information regarding threats under
this factor, nor do we have information on the potential threat of
overcollection or overutilization for commercial, recreational,
scientific, or educational purposes. There is no information to
indicate this factor will become a threat to the species in the
foreseeable future. We find overutilization for commercial,
recreational, scientific, or educational purposes does not threaten the
Amargosa toad. Based on a review of the best available scientific and
commercial data, we find no indication that overutilization for
commercial, recreational, scientific, or educational purposes is a
threat to the Amargosa toad now or in the foreseeable future.
Factor C. Disease or Predation
Disease
Chytridiomycosis is an infectious disease of amphibians caused by
the chytrid fungus Batrachochytrium dendrobatidis. Although the fungus
has been detected in bullfrogs in the Oasis Valley, it has not been
detected in Amargosa toad populations. Chytrid fungus has been
identified in western toad (Anaxyrus boreas) populations in Colorado
where western toad occurrence is restricted to high elevations (7,200
to 11,150 ft [2,200 to 3,400 m]; Muth et al. 2003, p. 358). The Service
and NDOW have no evidence that chytrid or other diseases are affecting
or will affect the Amargosa toad population. No sign of chytr