[Federal Register Volume 65, Number 198 (Thursday, October 12, 2000)]
[Proposed Rules]
[Pages 60603-60605]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-26179]
[[Page 60603]]
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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
Endangered and Threatened Wildlife and Plants: 90-Day Finding on
a Petition To List the Mountain Yellow-legged Frog as Endangered
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Notice of 90-day petition finding.
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SUMMARY: The U.S. Fish and Wildlife Service (Service) announces a 90-
day finding on a petition to list the mountain yellow-legged frog (Rana
muscosa) as endangered, under the Endangered Species Act (Act) of 1973,
as amended (16 U.S.C. 1531 et seq.). We believe that the petition
presents substantial information indicating that listing the species
may be warranted. A status review is initiated.
DATES: The finding announced in this document was made on October 5,
2000. To be considered in the 12-month finding for this petition,
comments and information should be submitted to the Service by December
11, 2000.
ADDRESSES: Data, information, comments, or questions concerning this
petition should be submitted to the Field Supervisor; Sacramento Fish
and Wildlife Office; Sacramento Fish and Wildlife Office; 2800 Cottage
Way, Room W-2605; Sacramento, California 95825. The petition finding,
supporting data and comments are available for public inspection, by
appointment, during normal business hours at the above address.
FOR FURTHER INFORMATION CONTACT: Jason Davis or Maria Boroja at the
Sacramento Fish and Wildlife Office (see ADDRESSES section above), or
at (916) 414-6600.
SUPPLEMENTARY INFORMATION:
Background
Section 4(b)(3)(A) of the Endangered Species Act (Act) of 1973, as
amended (16 U.S.C. 1531 et seq.), requires that the Service make a
finding on whether a petition to list, delist, or reclassify a species
presents substantial information indicating that the petitioned action
may be warranted. To the maximum extent practicable, this finding is to
be made within 90 days of the receipt of the petition, and the finding
is to be published promptly in the Federal Register. If the finding is
that substantial information was presented, the Service will commence a
review of the status of the involved species. This finding is based on
information contained in the petition, supporting information submitted
with the petition, and otherwise available to the Service at the time
the finding was made.
The processing of this petition conforms with our final listing
priority guidance published in the Federal Register on October 22, 1999
(64 FR 57114). The guidance clarifies the order in which we will
process rulemakings. Highest priority is processing emergency listing
rules for any species determined to face a significant and imminent
risk to its well-being (Priority 1). Second priority (Priority 2) is
processing final determinations on proposed additions to the lists of
endangered and threatened wildlife and plants. Third priority (Priority
3) is processing new proposals to add species to the lists. The
processing of administrative petition findings (petitions filed under
section 4 of the Act) is the fourth priority. The processing of
critical habitat determinations (prudency and determinability
decisions) and proposed or final designations of critical habitat will
be funded separately from other section 4 listing actions and will no
longer be subject to prioritization under the listing priority
guidance. The processing of this petition finding is a Priority 4
action.
We have made a 90-day finding on a petition to list the mountain
yellow-legged frog (Rana muscosa) as an endangered species. On February
10, 2000, we received a petition, dated February 8, 2000, to list the
Sierra Nevada Mountain population of the mountain yellow-legged frog as
an endangered species. The petition was submitted by the Center for
Biological Diversity and Pacific Rivers Council. The letter clearly
identified itself as a petition, and contained the names, signatures,
and addresses of the two parties submitting the petition. The
petitioners argued that the ``Sierra Nevada population of the mountain
yellow-legged frog'' qualifies for listing under our Distinct
Vertebrate Population Segment Policy (61 FR 4722). Included in the
petition was supporting information relating to the species' taxonomy
and ecology, adequacy of existing regulatory mechanisms for the
species, and the historic and present distribution, current status, and
potential causes of decline. This notice constitutes the 90-day finding
for the February 10, 2000, petition.
On July 10, 1995, we were petitioned to list the southern
California population of the mountain yellow-legged frog a distinct
population segment (DPS) of the mountain yellow-legged frog. The
southern California population is isolated from the main part of the
species' range, in the Sierra Nevada Mountains, by the Tehachapi
Mountains and a distance of 225 kilometers (km) (140 miles(mi)). On
December 22, 1999, we published a proposed rule to list the Southern
California DPS of the mountain yellow-legged frog as an endangered
species (64 FR 71714). In the proposed rule we recognized the southern
population according to our policy on distinct vertebrate population
segments (61 FR 4722). On March 20, 2000, we published a notice in the
Federal Register to reopen the comment period on the proposal to list
the southern California DPS of the mountain yellow-legged frog as
endangered for a 30-day period.
As the present petition (and this finding) addresses the remainder
of the species' range, in the Sierra Nevada from Tulare County,
California, in the south to Plumas County, California, in the north, we
find no reason to recognize mountain yellow-legged frogs that occur in
the Sierra Nevada as a DPS. Throughout the rest of this finding we
refer to the petitioned entity, all mountain yellow-legged frogs that
occur north of the Tehachapi Mountains in the Sierra Nevada, as the
mountain yellow-legged frog.
The petition and accompanying documentation state that the species
qualifies for listing pursuant to the Act due to potential habitat
destruction and modification, the presence of disease in combination
with natural predation, the inadequacy of existing regulatory
mechanisms, and other natural or human-caused factors affecting its
continued existence. The petitioners contend that natural and human-
induced changes to mountain yellow-legged frog habitats, including (1)
non-native fish introductions, (2) contaminant introductions, (3)
livestock grazing, (4) acidification from atmospheric deposition, (5)
nitrate deposition, (6) ultraviolet radiation, (7) drought, and (8)
other factors, separately and in combination are responsible for an
estimated 70 to 90 percent decline in mountain yellow-legged frog
populations throughout the historic range of the species in the Sierra
Nevada Mountains.
The introduction of nonnative fish, including rainbow trout
(Oncorhynchus mykiss), is one the best documented causes of decline of
Sierra Nevada Mountain populations of mountain yellow-legged frogs.
Careful study of the distributions of introduced trout and mountain
yellow-legged frogs for several years has shown conclusively that
[[Page 60604]]
introduced trout have had negative impacts on mountain yellow-legged
frogs over much of the Sierra Nevada Mountains (Bradford 1989; Knapp
1996). Bradford (1989) and Bradford et al. (1994) concluded that
introduced trout have eliminated many populations of mountain yellow-
legged frogs. In addition, the presence of trout in intervening streams
sufficiently isolates other frog populations so recolonization after
stochastic (random, naturally occurring) local extinctions is
essentially impossible. This mechanism is sufficient to explain the
elimination of mountain yellow-legged frogs from the majority of sites
they once inhabited in the Sierra Nevada Mountains.
Several studies have shown that significant levels of contaminants
have been deposited in high Sierran aquatic ecosystems from pesticide
drift, acid precipitation, and smog drift (Seiber et al. 1998; Aston
and Seiber 1997; Cahill et al. 1996; Miller 1996; Byron and Goldman
1991; Nikolaidis 1991; Laird et al. 1986). The petitioners present
general evidence that the presence of contaminants in water, sediment,
and aquatic vegetation can harm frog populations through lethal and
sublethal effects including delayed metamorphosis, reduced breeding and
feeding activity (Berrill et al. 1993, 1994, 1995, 1998; Boyer and Grue
1995; Beaties and Tyler-Jones 1992; Corn and Vertucci 1992; Hall and
Henry 1992). In addition, contaminant introduction may weaken the
immune systems of frogs rendering them more susceptible to disease such
as chytrid fungus and red-legged disease (Carey et al. 1993, 1995,
1999; Jennings 1996; Drost and Fellers 1996; Sherman and Morton 1993).
The petitioners cite recent work by Carlos Davidson (U.C. Davis,
unpublished manuscript) that shows a positive relationship between
amphibian declines in the Sierra Nevada Mountains that occur upwind
from areas in California's Central Valley that apply large amounts of
wind-borne agrochemicals. In particular, Davidson found agricultural
land use to be twice as high downwind of sites where mountain yellow-
legged frogs had disappeared compared to sites where the species is
still present (Davidson, unpublished manuscript).
Livestock grazing can directly impact mountain yellow-legged frogs
through trampling of individuals. Indirectly, livestock can have a
significant effect on frog populations by: (1) Altering the hydrology
and morphology of high mountain streams and ponds, (2) trampling of
cover and vegetation along the periphery of wetland systems that are
important egg laying and larval rearing areas, and (3) introducing
nitrates into breeding areas resulting in elevated levels of bacteria
(Armour et al. 1994; Duff 1977; Bohn and Buckhouse 1985; Kauffman and
Krueger 1984; Kauffman et al. 1983; Marlow and Pogacnik 1985; Meehan
and Platts 1978; Stephenson and Street 1978; U.S. Forest Service 2000).
Acidification, nitrate deposition, and ultraviolet radiation have
been implicated as other factors that may contribute to the range wide
decline of mountain yellow-legged frogs. The petitioners state these
factors may have negative effects on mountain yellow-legged frogs that
include reduced growth rates, reduced feeding activity, disequilibrium,
physical abnormalities, paralysis, embryonic failure, and even death
among tadpoles and young frogs (Blaustein et al. 1994, Bradford and
Gordon 1993, Carey et al. 1999, Clark and LaZerte 1985, Freda 1990,
Marco et al. 1999, Marco and Blaustein 1999).
During periods of prolonged drought, amphibians find refugial
habitat in deeper, permanent sources of water which are also suited for
fish. These refugial habitats allow for repopulation of more peripheral
areas during wetter years (Bradford et al. 1993; Knapp 1996; Drost and
Fellers 1996). The presence of nonnative fish has eliminated many of
the permanent sources of refugial habitat from the mountain yellow-
legged frog, thus rendering frog populations more vulnerable to
drought-related extinction events (Bradford et al. 1993; Knapp 1996;
Drost and Fellers 1996).
The petitioners state that disease likely plays a significant role
in the widespread decline of mountain yellow-legged frogs. Two diseases
potentially affecting mountain yellow-legged frogs are red-legged
disease (Aeromonas hydrophila), which is caused by a freshwater
bacteria, and chytrid fungus. The petitioners cite an article by
Bradford (1991) reporting the loss of a mountain yellow-legged frog
population in the Sierra Nevada due to red-legged frog disease and
predation by Brewer's blackbirds (Euphagus cyanocephalus). In addition,
they cite studies reporting mortality of adult Yosemite toads (Bufo
canorus) in the Sierra Nevada and boreal toads (Bufo boreas boreas) in
the Rocky Mountains due to red-legged disease (Sherman and Morton 1993;
Carey 1993). Chytrid fungus, an aquatic pathogen discovered after 1993,
has led to the mortality of many amphibian species in the United States
and worldwide. The chytrid fungus attacks the mouthparts of tadpoles
affecting their ability to feed. Chytrids have recently been discovered
in larval mountain yellow-legged frogs in the Sierra Nevada (Gary
Fellers, U.S. Geologic Survey, pers. comm. 1999). Roland Knapp (Sierra
Nevada Aquatic Research Lab, pers. comm. 2000) reported a significant
decline of mountain yellow-legged frogs at Dry Creek near Mono Lake, a
site that had thriving population in 1998. He attributed the population
crash to the chytrid fungus after detecting deformed mouthparts in
several tadpoles at the site. The petitioners also cite a personal
communication with Vance Vredenburg (University of California,
Berkeley, Museum of Vertebrate Zoology, pers. comm. 2000) who reported
the complete loss of another mountain yellow-legged frog population in
the Emigrant Wilderness due to the chytrid fungus. There have been
reports of chytrid fungus attacking other Sierra Nevada amphibians,
including the Yosemite toad. An investigation of museum specimens of
Yosemite toads collected by Sherman and Morton at Tioga Pass during a
1977-1978 die-off found those toads to be infected with chytrid fungus
(Carey et al. 1999). The petitioners state that there is significant
information yet to be discovered regarding aquatic pathogens and their
relationship to the ecology of mountain yellow-legged frogs. Should
evidence indicate that mountain yellow-legged frogs have evolved with
aquatic pathogens, then other stressors including contaminant
introductions and UV-radiation may be reducing the ability of frogs to
fight off infection from these pathogens (Sherman and Morton 1993;
Drost and Fellers 1996; Carey et al. 1993, 1995, 1999; Jennings 1996;
Taylor et al. 1999).
Up to the 1960s, the mountain yellow-legged frog was widely
distributed and abundant across the Sierra Nevada (Zwefel 1955; Cory et
al. 1970, Jennings and Hayes 1994). Since then, however, the overall
population has declined dramatically. The most pronounced declines have
occurred within the northernmost 125 km (78 mi) of the range, north of
Lake Tahoe, and the southernmost 50 km (31 mi) of the range, below
Sequoia and Kings Canyon National Parks, where only a few populations
remain (Jennings and Hayes 1994; Fellers 1999). Jennings and Hayes
(1994) noted a 50 percent decline in the species across the Sierra
Nevada based on sampling historic mountain yellow-legged frog locations
conducted before the 1970s. Knapp and Matthews (2000) noted that the 50
percent decline may be conservative, as the sampling conducted by
Jennings and Hayes took place in Sequoia and Kings Canyon National
Parks, where mountain yellow-
[[Page 60605]]
legged frog populations are larger and more abundant compared to
populations north of the Sierra National Forest.
However, even in the protected areas of Sequoia and Kings Canyon
National Parks, mountain yellow-legged frog populations have undergone
significant declines. Bradford et al. (1994) published results of two
separate studies which resurveyed historic sites where mountain yellow-
legged frogs were documented between 1959 and 1979 in Sequoia and Kings
Canyon National Parks. They found mountain yellow-legged frogs at only
12 of 49 sites surveyed in 1989 and 1990. In addition, mountain yellow-
legged frogs had disappeared from one of these 12 sites by 1991.
Outside of Sequoia and Kings Canyon National Parks, Bradford et al.
(1994) reported the absence of mountain yellow-legged frogs at 21 of 24
historic sites. In another study, Drost and Fellers (1996) resurveyed
14 sites originally surveyed in 1915 by Grinnell and Storer (1924), and
found only two now occupied by the mountain yellow-legged frog. These
surveys all strongly suggest that the mountain yellow-legged frog has
systematically declined throughout its range.
We have reviewed the petition and other information available in
the Service's files. Based upon this review, we believe that
substantial evidence exists that listing the mountain yellow-legged
frog as endangered may be warranted. When we make a positive finding,
we also are required to promptly commence a review of the status of the
species. Based upon available and any newly obtained information, we
will issue a 12-month finding as required by section 4(b)(3)(B) of the
Act. Petitioners also requested that critical habitat be designated for
the Sierra Nevada population of the mountain yellow-legged frog. The
12-month finding will address this issue.
Public Information Requested
The Service hereby announces its formal review of the species'
status pursuant to this 90-day petition finding. We request any
additional data, comments, and suggestions from the public, other
concerned government agencies, the scientific community, industry, and
any other interested parties concerning the status of the mountain
yellow-legged frog. Of particular interest is information regarding:
(1) The existence and status of additional subpopulations, (2) the
impact of nonnative fish introductions, contaminants, livestock
grazing, acidification from atmospheric deposition, nitrate deposition,
ultraviolet radiation, drought, disease, and other factors that may be
responsible for the range-wide decline of the species, (3) the
implementation of any actions that are benefitting the species, and (4)
genetic variability in known subpopulations.
If you wish to comment, you may submit your comments and materials
concerning this finding to the Field Supervisor, Sacramento Fish and
Wildlife Office (see ADDRESSES section). Our practice is to make
comments, including names and home addresses of respondents, available
for public review during regular business hours. Respondents may
request that we withhold their home address, which we will honor to the
extent allowable by law. There also may be circumstances in which we
would withhold a respondent's identity, as allowable by law. If you
wish us to withhold your name and/or address, you must state this
request prominently at the beginning of your comment. However, we will
not consider anonymous comments. To the extent consistent with
applicable law, we will make all submissions from organizations or
businesses, and from individuals identifying themselves as
representatives or officials of organizations or businesses, available
for public inspection in their entirety. Comments and materials
received will be available for public inspection, by appointment,
during normal business hours at the above address.
References Cited
A complete list of all references cited herein is available on
request from the Sacramento Fish and Wildlife Office, (See ADDRESSES
section).
Author: The primary author of this document is Jason Davis,
Sacramento Fish and Wildlife Office (see ADDRESSES section).
Authority
The authority for this action is the Endangered Species Act of
1973, as amended (16 U.S.C. 1531 et seq.).
Dated: October 5, 2000.
Jamie Rappaport Clark,
Director, Fish and Wildlife Service.
[FR Doc. 00-26179 Filed 10-11-00; 8:45 am]
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