AGENDA
Chair: David Bradford,
US EPA.
Local Committee: Cherie Briggs, Vance Vredenburg, Lara Rachowicz,
UC Berkeley
Sponsor: California Biodiversity Center (Mary Power, Director;
http://cbc.berkeley.edu/)
Thursday, January 13, 2005
8:45-10:00 am Room
open.
10:00-10:10 am Introduction
and Announcements. David Bradford, Landscape Ecology
Branch, US Environmental Protection Agency, Las Vegas, NV
KEYNOTE ADDRESS
10:10-10:55 am Amphibian
Declines: a 15-year Retrospective. Where Are We Heading?
David B. Wake, Department of Integrative Biology and Museum
of Vertebrate Zoology, University of California, Berkeley, CA.
VARIOUS TAXA
AND TOPICS
10:55-11:15 am Malformations
and Parasite Infection: An Emerging Problem in Amphibian Conservation.
Pieter Johnson, Center for Limnology, University of Wisconsin,
Madison, WI. (20 min)
11:15-11:30 am Creating
Pond Habitat for Columbia Spotted Frogs in the Reese River Drainage,
Central Nevada. Chad Mellison1* and Jim Harvey.2
1US Fish and Wildlife Service, Reno, NV; 2US Forest Service.
(15 min)
11:30-11:50 am Complementary
Resource Use and Migration Potential of the Cascades Frog (Rana
cascadae): a Case Study in the Trinity Alps Wilderness, California.
Justin Garwood, Redwood Sciences Laboratory, US Forest Service,
and Humboldt State University, Arcata, CA. (20 min)
11:50-12:00 pm Amphibian
Conservation Strategies for 5 Sierra Nevada Frog Species.
Cathy Brown1* and Diane Macfarlane.2 1PSW Research Station,
US Forest Service, Berkeley, CA; 2 Threatened, Endangered, and
Sensitive Species Program, US Forest Service, Vallejo, CA. (10
min)
12:00-1:30 pm Lunch
Moderator: Cherie
Briggs, Department of Integrative Biology, University of California,
Berkeley, CA
1:30-1:50 pm Projected
Effects of Upland Habitat Loss on California Tiger Salamander
Populations - Lessons for Conservation Planning.
Peter Trenham, Davis, CA. (20 min)
1:50-2:05 pm Implications
of the Discovery of Rana yavapaiensis in the Western Grand Canyon
to the Conservation Strategy for Rana onca. Jef
Jaeger,1* David Bradford,2 Charles Drost,3 and Lisa Gelczis.3
1Department of Biological Sciences, University of Nevada Las
Vegas, NV; 2Landscape Ecology Branch, US Environmental Protection
Agency, Las Vegas, NV; 3Southwest Biological Science Center,
US Geological Survey, Flagstaff, AZ. (15 min)
2:05-2:20 pm The
Response of Amargosa Toad Populations to Habitat Change at Selected
Sites.
Brian Hobbs, Nevada Department of Wildlife, Las Vegas, NV.
(15 min)
2:20-2:40 pm Life
History of Post-metamorphic Tailed Frogs in North Coastal California.
Laura Burkholder1* and Lowell Diller. 2 1Humboldt State University,
Arcata, CA; 2Green Diamond Resource Company, Korbel, CA. (20
min)
2:40-3:00 pm The
Relationship of Cold-water Tributaries to Landscape-scale Attributes
in a Northern California Watershed: Implications for the Conservation
of Cold-water Adapted Amphibians.
Hart Welsh* and Garth Hodgson. Redwood Sciences Laboratory,
US Forest Service, Arcata, CA. (20 min)
3:00-3:45 pm Break
Moderator: Vance
Vredenburg, Department of Integrative Biology, University of
California, Berkeley, CA
3:45-4:00 pm Calaveras
Frogs Are Making a ‘Celebrated’ Comeback.
Robert Stack,1 Mark Jennings,2* and Marc Hayes.3 1Jumping Frog
Research Institute, Angels Camp, CA; 2Rana Resources, Davis,
CA; 3Washington Department of Fish and Wildlife. (15 min.)
LEGAL ISSUES
4:00-4:20 pm 2004
Year in Review: Legal and Policy Developments Affecting
Amphibians in California & Nevada. Deanna Spooner,
Pacific Rivers Council, Eugene, OR. (20 min)
HIGH MOUNTAIN LAKE PROJECTS – CALIF. DEPT. FISH
& GAME
4:20-4:35 pm High
Mountain Lakes Database. Mitch Lockhart, California
Department of Fish & Game, Bishop, CA. (15 min)
4:35-4:50 pm Management
of Native Fauna and Introduced Fisheries in Sierra Nevada Lakes.
Curtis Milliron, California Department of Fish & Game, Bishop,
CA. (15 min)
4:50-5:05 pm High
Mountain Lake Rana muscosa Habitat Restoration.
Phillip Kiddoo, California Department of Fish & Game, Bishop,
CA. (15 min)
5:05-5:20 pm General
Discussion. Above speakers plus Dawne Becker, California
Department of Fish & Game, Bishop, CA. (15 min)
POSTERS
All Day, Thurs-Fri:
Balancing the Operations
and Maintenance Requirements of the State Water Project with
the Habitat Needs of the Federally Threatened California Red-legged
Frog. Jennifer Hogan, California Department of
Water Resources, Sacramento, CA.
All Day, Thurs-Fri:
Antipredator
Response and Palatability of Yosemite Toad Larvae to Nonnative
Brook Trout in the Sierra Nevada Mountains of California.
Robert Grasso,1* Ronald Coleman,1 and Carlos Davidson.2 1California
State University, Sacramento, Department of Biological Sciences,
Sacramento, CA; 2California State University, Sacramento, Department
of Environmental Studies, Sacramento, CA.
All Day, Thurs-Fri:
Mountain Yellow-legged Frog (Rana muscosa) Habitat Restoration
in the Gable Lakes Basin. Rick Ziegler, California
Department of Fish and Game.
All Day, Thurs-Fri:
www.AmphibiaWeb.org: An Information System for Amphibian
Conservation Biology. Rebecca A. Doubledee, Tate Tunstall,
Vance T. Vredenburg, Joyce Gross, Meridith J. Mahoney, Arie
Van der Meijen, and David Wake. Museum of Vertebrate Zoology,
Dept. of Integrative Biology, and Dept. of Computer Science
(JG), University of California, Berkeley.
All Day, Thurs-Fri:
Amphibian Conservation
Through Integrated Data Management: the ARMI (Amphibian Research
and Monitoring Initiative) Model. Chris W. Brown,1
Jang Byun,2 Alisa Gallant,3 Carlton J. Rochester,1 Stacie A.
Hathaway,1 and Robert N. Fisher.1 1US Geological Survey, Western
Ecological Research Center, San Diego, CA; 2US Geological Survey,
Patuxent Wildlife Research Center, Laurel, MD; 3US Geological
Survey, EROS Data Center, Sioux Falls, SD.
Friday, January 14, 2005
7:30-8:30 am Room
open.
8:30-8:35 am Introduction.
David Bradford, Landscape Ecology Branch, US Environmental Protection
Agency, Las Vegas, NV.
KEYNOTE ADDRESS
8:35-9:20 am From
Silent Spring to Silent Night: Pesticides and What Our Canary
Is Trying to Tell Us. Tyrone Hayes, Department of Integrative
Biology, University of California, Berkeley, CA.
RANA BOYLII
AND R. MUSCOSA
9:20-9:40 am Status,
Decline, and Phylogeography
of Rana boylii: Implications for Conservation of Frogs and Rivers.
Amy Lind,1* Carlos Davidson,2 A. Borisenko,3 Brad Shaffer,4
and Gary Fellers.5 1Sierra Nevada Research Center, US Forest
Service, Sacramento, CA; 2Dept. of Environmental Studies, California
State University, Sacramento, CA; 3Oregon Department of Environmental
Quality, Portland, OR; 4Section of Evolution and Ecology, University
of California, Davis, CA; 5Biological Resources Division, US
Geological Survey, Point Reyes, CA. (20 min)
9:40-10:00 am Mating
System and Strategy of the Foothill Yellow-legged Frog (Rana
boylii). Clara Wheeler, Redwood Sciences Laboratory,
US Forest Service, Arcata, C
10:45-11:05 am Seasonal
Movements of the Foothill Yellow-legged Frog (Rana boylii) in
Tehama County, California. Ryan Bourque and Sharyn
Marks , Humboldt State University, Arcata, CA. (20 minutes)
11:05-11:25 am Habitat
Variability Observed at Foothill Yellow-legged Frog (Rana boylii)
Breeding Locations in Several Large River Drainages along the
West Slope of the Sierra Nevada: Implications for Developing
Survey Strategies. Craig Seltenrich1* and Alicia
Pool.2 1ECORP Consulting, Roseville, CA; 2PG&E, San Ramon,
CA. (20 min.)
11:25-11:45 am The
Sierra Nevada Amphibian Monitoring Program: A Long-Term Bioregional
Approach. Cathy Brown, PSW Research Station, US
Forest Service, Berkeley. (20 min)
11:45-12:00 pm Update
on the Mountain Yellow-legged Frog Restoration Project in Sequoia
and Kings Canyon National Parks. Danny Boiano,
Sequoia and Kings Canyon National Parks, Three Rivers, CA. (15
minutes)
12:00-1:30 pm Lunch
Moderator: Lara Rachowicz,
Department of Integrative Biology, University of California,
Berkeley, CA
1:30-1:50 pm A
Skeletochronological Study of the Longevity and Age Structure
of the Mountain Yellow-legged Frog, Rana muscosa, in the Sierra
Nevada, California.
Kathleen R. Matthews1* and Claud Miaud.2 1Sierra Nevada
Research Center, US Forest Service, Berkeley, CA. (20 min.)
PESTICIDES
AND AMPHIBIANS
1:50-2:10 pm Pesticide
Impacts on Amphibian Populations in the Sierra Nevada Mountains:
Results of Field Studies and Laboratory Experiments.
Gary Fellers,1* Patrick Kleeman,1 and Donald Sparling.2 1Biological
Resources Division, US Geological Survey, Point Reyes, CA; 2Cooperative
Wildlife Research Laboratory, Southern Illinois University,
Carbondale, IL. (20 min)
2:10-2:30 pm Fish,
Pesticides and the Decline of Mountain Yellow-legged Frogs.
Carlos Davidson1* and Roland Knapp.2 1Department of Environmental
Studies, California State University, Sacramento, CA; 2University
of California, Sierra Nevada Aquatic Research Laboratory, Mammoth
Lakes, CA. (20 min)
2:30-2:50 pm Current
Studies, Regulation and Legal Case Developments Regarding Pesticides
That May Be Affecting Amphibians in California. Michael
Graf, El Cerrito, CA. (20 min).
RETURN TO
RANA BOYLII
2:50-3:05 pm Crayfish
Predation on Foothill Yellow-legged Frog (Rana boylii) Egg Masses
in the Northern Sierra Nevada. Joe Drennan, Ron
Jackman, Karla Marlow, Kevin Wiseman, Jason Minton, and Jane
Kim, Garcia and Associates (GANDA), San Francisco, CA. (15 min)
3:05-3:35 pm Break
Moderator: Mark Jennings,
Rana Resources, Davis, CA
CHYTRIDIOMYCOSIS
3:35-3:55 pm Host-Pathogen
Population Dynamics of Chytridiomycosis in Mountain Yellow-legged
Frogs in the Sierra Nevada Mountains, California. Cherie
Briggs, Department of Integrative Biology, University of California,
Berkeley, CA. (20 min)
3:55-4:15 pm How
Useful Is Tadpole Mouthpart Depigmentation as an Indicator of
Chytridiomycosis? Roland Knapp, University of California,
Sierra Nevada Aquatic Research Laboratory, Mammoth Lakes, CA.
(20 min)
4:15-4:35 pm Can
Batrachochytrium dendrobatidis Survive in the Environment Without
an Amphibian Host? Preliminary Results from a Field Experiment
with Rana muscosa. Vance Vredenburg, Department
of Integrative Biology, University of California, Berkeley,
CA. (20 min)
SOUTHERN
CALIFORNIA AMPHIBIANS
4:35-4:55 pm Fires
and Other Burning Issues from Southern California in Frog/Toad
Conservation. Robert Fisher, Biological Resources Division,
US Geological Survey, San Diego, CA. (20 min)
4:55-5:00 pm Wrap-up.
ABSTRACTS
BOIANO,
DANNY
Sequoia
& Kings Canyon National Parks, Division of Natural Resources,
47050 General Highway, Three Rivers, CA, 93271; E-mail: danny_boiano@nps.gov
Update
on the Mountain Yellow-legged Frog Restoration Project in Sequoia
and Kings Canyon National Parks
To help reverse the
decline of the mountain yellow-legged frog (Rana muscosa), Sequoia
and Kings Canyon National Parks began removing introduced trout
in 2001 from six lakes and adjacent streams using gill nets
and backpack electrofishers. We also began restoring a seventh
lake in 2004. In total we have removed more than 11,000 trout
and eradicated three populations, and expect to eradicate two
additional populations in 2005. We also conducted multiple shoreline
surveys per season in the restoration lakes to assess frog recovery.
By 2004 we measured large increases in mountain yellow-legged
frog abundance in five of the restoration lakes; one lake showed
an increase of 77 times in the average number of individuals
detected per survey in 2004 versus 2001. Furthermore, in several
of the restoration lakes we observed increased densities of
aquatic invertebrates, birds and snakes, indicating that many
components of the ecosystem may be responding favorably to trout
eradication.
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BOURQUE,
RYAN M*.
MARKS, SHARYN B.
Department of Biological Sciences, Humboldt State University,
Arcata, CA 95521; rmb32@humboldt.edu
Seasonal
Movements of the Foothill Yellow-legged Frog in Tehama County,
California
Complementary resources
for amphibians (e.g., breeding, foraging, and refugia) change
with time and are separated in space. Understanding the extent
and frequency of seasonal movements between these resources
is important for the development of successful conservation
plans. Radio-telemetry was used to study the movements and habitat
use of the foothill yellow-legged frog (Rana boylii) in Tehama,
County, California. Sixty frogs (11 males and 49 females) occupying
habitat along Red Bank Creek were opportunistically captured,
fitted with radio-transmitters, and tracked to describe seasonal
movements. Females were tracked during two study periods (spring
and autumn), while males were only tracked in the spring. Movements
were mapped and habitat use analyzed using global positioning
and geographic information systems. Site-specific environmental
conditions were monitored to determine if movements were correlated
with weather conditions. Patterns of spatial use, determined
from 879 tracking observations, indicated that frogs rarely
ventured far from the stream channel. Males and females displayed
different movement patterns. The greatest cumulative seasonal
distances traveled by a male and female frog were 0.65 km and
7.03 km, respectively; these distances were traveled during
the spring season. Males had smaller home ranges than females,
and there was no difference between female home ranges across
seasons. These results and other preliminary findings useful
for management of this species will be discussed.
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BRIGGS,
CHERYL J.
Department of Integrative Biology, University of California,
Berkeley, CA 94720-3140; cbriggs@socrates.berkeley.edu
Update
on Chytridiomycosis in Rana muscosa
I will give an update
of our current work studying the effects of the disease, chytridiomycosis
(caused by the chytrid fungus Batrachochytrium dendrobatidis),
on mountain yellow-legged frogs. I will discuss the use of swabbing
and real time PCR to detect and quantify the fungus on live
frogs in the field and laboratory. I will discuss our recent
observations on the spread of the disease through a watershed,
and its impact on frog populations. Finally, I will talk about
our ongoing efforts to compare the disease dynamics at sites
at which we are observing frog die-offs due to chytridiomycosis,
versus sites at which the frog populations appear to be persisting
with the disease.
GO BACK
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BROWN,
CATHY
USDA Forest Service, Stanislaus National Forest, PSW Research
Station, PO Box 245, Berkeley, CA 94701; cathybrown@fs.fed.us
The
Sierra Nevada Amphibian Monitoring Program: A Long-Term Bioregional
Approach
In 2002, the USDA
Forest Service initiated a long-term, bioregional monitoring
program for two aquatic frog species, the mountain yellow-legged
frog (Rana muscosa) and Yosemite toad (Bufo canorus), in the
Sierra Nevada, CA. Both species are USFWS candidate species
and recent assessments indicate they have disappeared from a
large proportion of their historic localities. The Sierra Nevada
Amphibian Monitoring Program assesses the status and change
of populations and habitat for these two species. The monitoring
is designed to make inferences at the scale of the species’
ranges in the Sierra Nevada and to provide information for the
10-year Forest Service planning cycle. The monitoring combines
extensive and intensive components in one integrated design.
Extensively, for each species, 130 small watersheds (2-4 km2)
will be surveyed throughout the range of each species over a
5-year cycle, with 20% revisited annually. Population trends
are measured by breeding occupancy (number of occupied watersheds,
number of occupied sites/watershed). Habitat trends are measured
by attributes that assess hydrologic condition, habitat matrix,
cover, water temperature, disturbance, and general characterization.
Intensively, we will select three small watersheds for each
species and collect more detailed abundance, life history, and
habitat data. For both components, we survey all lentic and
a sample of lotic sites within each watershed. The extensive
component was initiated during 2002 and approximately 70 watersheds
were surveyed over the past three years, with 18 re-surveyed
for at least two years. Results from this monitoring will help
determine whether USDA Forest Service management practices are
promoting desired conditions for these species’ populations
and habitat throughout their ranges in the Sierra Nevada, increase
our knowledge of population dynamics and habitat requirements,
and provide information for making more informed management
decisions.
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BROWN,
CATHY*
USDA Forest Service, Stanislaus National Forest, PSW Research
Station, PO Box 245, Berkeley, CA 94701; cathybrown@fs.fed.us
MACFARLANE,
DIANE
USDA Forest Service, Regional Office, Vallejo, CA; dmacfarlane@fs.fed.us
Amphibian
Conservation Strategies for 5 Sierra Nevada Frog Species
As part of the Sierra
Nevada Forest Plan Amendment (SNFPA) Record of Decision (ROD),
the U.S. Forest Service committed to completing conservation
assessments for five aquatic frog species, the mountain yellow-legged
frog (Rana muscosa), Yosemite toad (Bufo canorus), foothill
yellow-legged frog (Rana boylii), Cascades frog (Rana cascadae),
and northern leopard frog (Rana pipiens). These are in progress
in cooperation with other federal agencies, state agencies,
universities, and research scientists. The conservation assessments
are intended to be the first phase in a three-phase process
that includes the conservation assessments, conservation strategies,
and conservation agreements. The assessments provide the information
base and scientific foundation for the conservation strategies.
The strategies would recommend specific conservation actions,
which would lead to conservation agreements among various agencies
and partners. Working groups comprised of interagency specialists
and species experts were formed for each species. Work began
in December, 2001, and is scheduled to be completed in 2005.
Currently, the assessments are approximately 75% complete. The
next drafts to be presented to the working teams are scheduled
for completion in March, 2005. The final product, which will
be peer reviewed by scientists and key management disciplines,
is intended for publication.
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BROWN, CHRIS W.
Western Ecological Research Center, San Diego Field Station,
San Diego, California
BYUN, JANG
Patuxent Wildlife Research Center, Laurel, Maryland
GALLANT,
ALISA
EROS Data Center, Sioux Falls, South Dakota
ROCHESTER,
CARLTON J.
HATHAWAY, STACIE A.
FISHER, ROBERT N.
Western Ecological Research Center, San Diego Field Station,
San Diego, California
Amphibian
Conservation Through Integrated Data Management: The ARMI (Amphibian
Research and Monitoring Initiative) Model
Successful management
of herpetofauna relies on integrated management of ecological
and physiological research data. In southern California, the
Western Ecological Research Center of the US Geological Survey
(USGS) is working with researchers, city, county, state and
Federal resource agencies to develop strategies to supply data
that meets these management needs. Land managers and regulators
rely on access to the most current and applicable research data
available in making sound decisions to conserve amphibian diversity
in perpetuity. Integrated data management allows researchers,
agencies and consultants to share non sensitive information
regarding their independent research, inventory and monitoring
projects. Several data management strategies ranging from local
and regional partners to Federal partners including Departments
of Interior, Defense and Agriculture that are collaborating
in the national USGS program Amphibian Research and Monitoring
Initiative (ARMI) were examined to determine how to meet needs
of the managers. Federal and university researchers and statisticians
also contributed greatly to impart study design needs and capabilities
and to insure data of highest value. Together, these concepts
provided a base on which a strategy could be developed. To develop
the data management strategy that is currently being tested
by USGS, several goals needed to be accomplished. Stringent
database development has provided a backbone structure that
can meet the needs of the managers and still provide flexibility
for the researchers. Networking solutions have been developed
to allow secure access to managers and researchers whether centrally
located or at remote locations. Multiple data entry and recall
tools have been developed to meet the demands of different study
designs, including full digital data collection utilizing hand
held computers with standardized forms, queries and reports.
Coupled with sound science, this strategy of integrated data
management will be of great benefit to the researchers and an
invaluable tool to land mangers.
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BURKHOLDER,
LAURA L.*
Humboldt State University, Wildlife Department, Arcata, CA 95521;
lburkholder@greendiamond.com
DILLER,
LOWELL V.
Green Diamond Resource Company, PO Box 68, Korbel, CA 95550
Life
History of Post-metamorphic Tailed Frogs in North Coastal California
The tailed frog (Ascaphus
truei) is potentially sensitive to habitat alterations often
associated with timber harvest practices, such as increased
sediment load in streams and increases in water temperatures.
Understanding the ecology of tailed frogs is critical for effective
management of this species. Most research on tailed frogs has
focused on the larvae, because they are easier to sample and
are presumed to be more susceptible to timber harvest impacts
compared to adults. Therefore, little is known about the life
history and ecology of post-metamorphic populations of tailed
frogs. We conducted nocturnal surveys of post-metamorphic tailed
frogs on six streams from 2002-04 using mark-recapture to determine
sizes of age classes, site fidelity, seasonal activity, reproductive
chronology, and growth rates. Tailed frogs in these streams
exhibited little within channel movement (mean = 9.5 m). However,
movements were highly variable ranging from 0-106 m. Frogs were
active within the channel and riparian zone from March to November
with peak activity from July-September for adults and from May-August
for immatures. Most captures of reproductive adults occurred
from March to August, with significantly more captures in the
spring than the summer. This suggests that breeding occurs primarily
in the spring. Tailed frogs grew year-round with faster summer
(1.22 mm/month) than winter (0.89mm/month) growth. Females grew
significantly faster and to a larger maximum size than males.
Growth curves indicated that following metamorphosis, females
may reach sexual maturity in three years whiles males may become
reproductive in two years.
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DAVIDSON,
CARLOS*
Department of Environmental Studies, California State University,
Sacramento, 6000 J Street,
Sacramento, CA 95819-6001; cdavidson@csus.edu
KNAPP,
ROLAND A.
Sierra Nevada Aquatic Research Laboratory, University of California,
Star Route 1, Box 198, Mammoth Lakes, CA 93546; knapp@lifesci.ucsb.edu
Fish,
Pesticides and the Decline of Mountain Yellow-legged Frogs
Introduced fish and
pesticides have both been implicated as contributing to population
declines of a number of California amphibians. However, to date
the fish and pesticides explanations for amphibian declines
have not been assessed together within a single study. We examined
the impact of fish and upwind pesticide use on population status
of the mountain yellow-legged frog (Rana muscosa) at close to
7,000 water-bodies in California’s Sierra Nevada, including
almost all water-bodies in Yosemite and Sequoia-Kings Canyon
National Parks and part of the John Muir Wilderness. At each
site we collected information on presence/absence of R. muscosa
and introduced fish, water-body depth, elevation, substrate
composition and number of nearby water-bodies. Upwind pesticide
use from 1991 to 2000 was determined based on predominate wind
directions and Department of Pesticide Regulation pesticide
application records. To examine the possibility of topography
sheltering sites from windborne pesticides, for each site we
calculated the difference between the prevailing wind direction,
and water-body drainage orientation. Using generalized additive
model regression we found that introduced fish, upwind pesticide
use and topographic sheltering were all significant predictors
of R. muscosa presence, along with covariates for spatial location,
depth, elevation, and number of surrounding water bodies. The
impact of fish was consistent with earlier observational and
experimental studies of fish effects on R. muscosa. We found
a steep near linear decline in the probability of frog presence
with increasing upwind pesticide use, with an almost complete
absence of frogs at water-bodies with high upwind pesticide
use.
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DRENNAN,
JOSEPH E.
JACKMAN, RONALD E.
MARLOW, KARLA R.
WISEMAN, KEVIN D.*
MINTON, JASON S.
KIM, JANE J.
Garcia and Associates (GANDA), San Francisco, CA; kwiseman@garciaandassociates.com
Crayfish
Predation on Foothill Yellow-legged Frog (Rana boylii) Egg Masses
in the Northern Sierra Nevada
As part of ongoing
monitoring of foothill yellow-legged frog (Rana boylii) populations
on the North Fork Feather River (Butte Co., CA) for Pacific
Gas and Electric's FERC relicensing project, we employed an
underwater video camera system to investigate the fate of R.
boylii egg masses and tadpoles. A total of four egg masses and
one tadpole group were monitored using an Aqua-Vu® underwater
video system during two consecutive field seasons (2003-2004).
Analysis of 442.5 hours of video revealed that the introduced
signal crayfish (Pacifasticus leniusculus) prey upon R. boylii
egg masses and contribute to premature detachment of egg masses
from rocky substrates. Nine other species were observed near
egg masses and tadpole groups, none of which were found to be
significant predators of R. boylii during video monitoring.
Visual encounter survey results suggest that signal crayfish
also prey upon larval stages of R. boylii, based upon observations
of tail injuries. Signal crayfish are present in large numbers
in this drainage and have been observed in other systems where
R. boylii are found, including the Pit and Stanislaus Rivers.
Introduced crayfish may present a significant threat to Sierran
R. boylii populations, where the species lacks evolutionary
experience with crayfish predation. Future studies should address:
1) the extent of crayfish predation pressure 2) area of sympatry,
and 3) developmental and behavioral effects of introduced crayfish
on R. boylii populations.
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FELLERS,
GARY M.*
KLEEMAN, PATRICK
Western Ecological Research Center, USGS, Point Reyes National
Seashore, Point Reyes, CA 94956; gary_fellers@usgs.gov.
SPARLING,
DONALD W.
Cooperative Wildlife Research Center, Southern Illinois University,
Carbondale, IL 62901.
Pesticide
Impacts on Amphibian Populations in the Sierra Nevada Mountains:
Results of Field Studies and Laboratory Experiments
When an experimental
translocation of R. muscosa in 1994 to 1995 was deemed unsuccessful
in 1997, the last 20 translocated frogs were collected from
the release site, and pesticide concentrations were measured
at both the release site and a control site. DDE concentration
in frog tissue was one to two orders of magnitude higher than
the other organochlorines. Both g-chlordane and trans-nonachlor
were found in significantly greater concentrations in frog tissue
from the release site. Organophosphate insecticides, chlorpyrifos,
and diazinon were observed primarily in surface water with higher
concentrations at the release site. No contaminants were significantly
higher in our control samples. Subsequent laboratory experiments
using Hyla regilla and Rana boylii tadpoles have examined both
acute toxicity and chronic effects of endosulfan and chlorpyrifos
on growth and metamorphosis. Endosulfan was more toxic than
chlorpyrifos, and endosulfan was more toxic to R. boylii than
H. regilla. This work demonstrates that environmentally realistic
concentrations of commonly used pesticides can have a impact
on native amphibians in the Sierra Nevada Mountains.
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GARWOOD,
JUSTIN M.*
Humboldt State University, Department of Wildlife Management,
and U.S. Forest Service, Redwood Sciences Laboratory, 1700 Bayview
Drive, Arcata, CA 95521; jg18@humboldt.edu
WELSH,
HARTWELL H., Jr.
U.S. Forest Service, Redwood Sciences Laboratory 1700 Bayview
Drive, Arcata, CA 95521
Complementary
Resource Use and Migration Potential of Cascades Frogs (Rana
cascadae): A Case Study in the Trinity Alps Wilderness, California
Ranid frogs of western
North America are among the most seriously impacted of all amphibian
species. In light of investigations documenting rapid declines
of Cascades frogs (Rana cascadae), renewed attention has been
placed on their conservation. Rana cascadae require at least
three major complementary resources for annual activities: reproduction,
foraging, and hibernation. As with many high elevation temperate
anurans, R. cascadae are subjected to move seasonally because
some or all of these resources are spatially and temporally
separated, requiring migrations among and between habitat patches.
In a high-elevation (2200m) basin within the Trinity Alps Wilderness,
California, we used radio transmitters and PIT tags to characterize
movements among and within habitat patches for all post-metamorphic
life stages. Movements were documented across the entire activity
period (June-September) for two years. We conducted 21 basin
wide mark-recapture censuses which resulted in and 3726 captures
for post-metamorphic frogs. Adult frogs moved more on average
(425.7 " 37m SE ), than juveniles (265.2 " 23.7m).
We collected 972 individual radio telemetry locations for 35
adult frogs. Mean 95% fixed kernel home range size was 1.14
" 0.27 ha. Migrations occurred quickly between habitat
patches and were not limited to aquatic corridors. Frogs occupied
an array of aquatic habitats, but appeared to be selecting different
types based on seasonal life history requirements.
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GRASSO,
ROBERT L.
COLEMAN, RONALD M.
Department of Biological Sciences, California State University,
Sacramento, CA; rgrasso@lycos.com
DAVIDSON,
CARLOS
Department of Environmental Studies, California State University,
Sacramento, CA
Antipredator
Response and Palatability of Yosemite Toad Larvae to Nonnative
Brook Trout in the Sierra Nevada Mountains of California (poster)
Introduction of non-native
trout into fishless lakes in the Sierra Nevada Mountains of
California has been shown to adversely affect some native frog
populations through predation. The Yosemite toad (Bufo canorus),
is also declining throughout its range in the Sierra; however,
many tadpoles of the genus Bufo possess chemical toxins and
are thought to be unpalatable to fish. Understanding the role
of trout predation is critical to the proper management of this
species.
To determine the effect of trout on Yosemite toads, I performed
two experiments. In the first experiment, the antipredator behavior
of Yosemite toad tadpoles in response to brook trout (Salvelinus
fontinalis) chemical cues was measured by change in tadpole
activity levels using a gravitational flow-through system. I
predicted that if Yosemite toad larvae were susceptible to trout
predation they would be able to detect trout chemical cues and
respond through reduced activity levels along with increased
refuge use. I found that Yosemite toad tadpole activity and
refuge use did not differ significantly from controls.
In the second experiment,
palatability of Yosemite toad larvae to brook trout was assessed
by conducting choice experiments in which Yosemite toad and
Pacific treefrog (Hyla regilla, a known palatable species) tadpoles
were offered to starved trout. No Yosemite toad tadpoles were
consumed by trout during the experimental trials, while trout
consumed treefrog tadpoles readily. These preliminary results
suggest that Yosemite toad larvae have retained chemical defenses
even though they evolved in absence of fish predators. Although
tadpoles were not consumed, there may be sublethal effects from
trout “sampling” or mouthing and ejecting tadpoles,
which was observed during trials.
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HOBBS,
BRIAN
Nevada Department of Wildlife, 4747 Vegas Drive, Las Vegas,
NV 89108; bhobbs@ndow.org
The
Response of Amargosa Toad Populations to Habitat Change at Selected
Sites
One of the key issues
facing the Amargosa toad is vegetation growth. Spring pools
and outflows that once harbored many toads have become choked
with vegetation which has reduced reproduction, prevented toadlet
migration from the springs, and provided ideal habitat for the
colonization of nonnative predators. Vegetation has increased
because of recently excluded grazing at spring sites, poor flood
control measures, and water development. Habitat restorations
in 2003 and 2004 have already yielded results at one site. The
success of future actions at sites throughout the valley will
depend on how long the newly restored habitats continue to function
and how much human intervention will be needed to maintain proper
function.
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HOGAN,
JENNIFER
California Department of Water Resources, Division of Environmental
Services, Environmental Compliance and Evaluation Branch, Sacramento,
CA 95816; jhogan@water.ca.gov
Balancing
the Operations and Maintenance Requirements of the State Water
Project with the Habitat Needs of the Federally Threatened California
Red-legged Frog: Can California Red-legged Frogs and DWR Operations
and Maintenance Activities Co-exist? (poster)
In 1996 the California
red-legged frog was listed as federally threatened, and all
maintenance removals of sediment and vegetation in drainages
flowing under the California and South Bay aqueducts within
DWR’s Delta Field Division ceased in order to prevent
"take" of a listed species. Since all maintenance
activities stopped, sediment load and vegetation growth within
these drainages increased. Several permits needed to be obtained
in order to proceed with the maintenance work at sites known
or believed to contain these frogs. After receiving the permits,
including a Biological Opinion from the U. S. Fish and Wildlife
Service and a 1601 Programmatic Stream Alteration Agreement
from the Department of Fish and Game, modified maintenance activities
are now past their second year. The poster describes the maintenance
activities and shows preliminary results of monitoring to determine
whether or not these activities benefit the resident California
red-legged frog populations.
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JAEGER,
JEF*
Department of Biological Sciences, University of Nevada, Las
Vegas, 4505 Maryland Pkwy., Las Vegas, NV 89154; jaeger@ccmail.nevada.edu
BRADFORD,
DAVID F.
Landscape Ecology Branch, US Environmental Protection Agency,
944 E. Harmon Ave., Las Vegas, NV 89119
DROST,
CHARLES
Southwest Biological Science Center, US Geological Survey, 2255
N. Gemini Dr., Flagstaff, AZ 86001
GELCZIS,
LISA
Southwest Biological Science Center, US Geological Survey, 2255
N. Gemini Dr., Flagstaff, AZ 86001
Implications
of the Discovery of Rana yavapaiensis in the Western Grand Canyon
to the Conservation Strategy for Rana onca
The minimum historical
range of the relict leopard frog, Rana onca, comprises the drainages
of the Virgin and Colorado rivers from the vicinity of Hurricane,
Utah, to Black Canyon below Lake Mead, in Nevada and Arizona.
Extant populations are known near only the Black Canyon and
Overton Arm of Lake Mead. One adjacent area that may contain
extant populations remains largely unsurveyed. This is the Colorado
River and tributary drainages upstream from the confluence with
the Virgin River (part of Lake Mead) in the western portion
of the Grand Canyon. A few sites in this area were recently
surveyed and a population of frogs physically similar to R.
onca was found in Surprise Canyon (a tributary drainage). A
mitochondrial DNA sequence analysis of several specimens showed
that these individuals were more closely related to the lowland
leopard frog, Rana yavapaiensis, than to R. onca. Surprise Canyon
is situated within the Potential Management Zone (PMZ) for R.
onca, as identified in the draft Conservation Assessment and
Strategy (CAS). Discovery of the Surprise Canyon frogs within
the PMZ has raised new concerns about the potential for hybridization.
This threat impedes the primary recovery mechanism for R. onca
identified in the draft CAS, i.e., to establish a number of
new populations within the PMZ. Translocation sites are critically
needed, but the majority of potential sites observed to date
appear to be severely degraded. The western Grand Canyon was
viewed as a promising area for establishing populations. Without
further information, however, the threat of hybridization with
the Surprise Canyon frogs renders questionable the suitability
of this portion of the PMZ. The uncertainty is acute because
the extent and identity of ranid frogs within the western Grand
Canyon remains mostly unknown.
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JOHNSON,
PIETER T. J.
Center for Limnology, University of Wisconsin, 680 North Park
Street, Madison, WI 53706-1492; ptjohnson2@wisc.edu
Malformations and Parasite Infection:
An Emerging Problem in Amphibian Conservation
Although malformed amphibians have been observed sporadically
since at least the 1700s, reports of population-level, “mass
malformations” have become increasingly common only since
the mid-1990s. Here I present an overview of field and laboratory
investigations into the causes and consequences of amphibian
limb deformities. Field surveys throughout the western and midwestern
USA indicate that trematode parasite (Ribeiroia ondatrae) infection
is significantly associated with greater-than-baseline levels
of malformations. Experimental exposures of frogs, toads and
salamanders with realistic numbers of Ribeiroia cercariae demonstrate
that infection causes malformations identical to those observed
in field surveys, including supernumerary limbs (up to six extra),
missing limbs, skin webbings, and bony triangles. Combinations
of re-survey data, voucher specimen examinations, and interview
data indicate that, while Ribeiroia infection is not a new cause
of amphibian deformities, it may be on the rise. Current research
is focused on secondary factors that interact with parasite
infection to elevate the frequency of deformities. Field data
suggest that wetland eutrophication (excess nutrient runoff)
promotes infection and deformities through its effects on algal
production and rams horn snails – the first intermediate
host of Ribeiroia ondatrae. Although field and experimental
data indicate that parasite infection and malformations increase
mortality, there is as yet no research dedicated to long-term
interactions between amphibian population declines and deformities.
I argue that Ribeiroia infection and malformations will grow
in conservation importance as natural wetlands and amphibian
breeding areas are continually destroyed, forcing amphibians
into suboptimal habitats conducive to the parasite’s life
cycle.
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KIDDOO,
PHILL
California Department of Fish & Game, Bishop, CA.
California
Department of Fish & Game High Mountain Lake Rana muscosa
Habitat Restoration
In the late summer
of 1999 CDFG began their first high mountain lake non-native
trout removal project to recover native amphibians specifically,
Rana muscosa, in the Big Pine Basin, Inyo County. This pilot
project was funded as an experiment to determine the feasibility
of fish removal in high mountain lakes using non-chemical methods.
Upon successful trout eradication and amphibian resurgence in
2001, CDFG proposed additional vital native species restoration
sites in an attempt at recovery of extant R. muscosa populations.
To date, CDFG (Eastern
Sierra Inland Desert Region 6) has initiated native species
restoration projects at 19 lakes. These 19 lakes will aid recovery
of 9 R. muscosa populations. Of these 19 lakes, all but 2 have
and/or are currently having non-native trout mechanically removed.
Four management plans (Mt. Tom, Bishop Creek, Middle Fork San
Joaquin, and West Walker) pending approval, propose another
20 native species restoration areas, in all tallying 70 lakes.
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KNAPP,
ROLAND A.
University of California, Sierra Nevada Aquatic Research Laboratory,
Crowley Lake, CA 93546; knapp@lifesci.ucsb.edu
How
Useful Is Tadpole Mouthpart Depigmentation as an Indicator of
Chytridiomycosis?
Chytridiomycosis
is a disease caused by the amphibian chytrid fungus, Batrachochytrium
dendrobatidis. This disease has been implicated in the decline
or extinction of many amphibian populations worldwide and as
a consequence, there is considerable interest in inexpensive
methods for accurately determining the chytrid status of amphibians.
Depigmentation of tadpole mouthparts (i.e., jaw sheaths and
toothrows) is a commonly cited outcome of chytridiomycosis,
but no effort has yet been made to determine the accuracy of
mouthpart depigmentation as an indicator of chytridiomycosis.
We conducted such an analysis using mountain yellow-legged frog
(Rana muscosa) tadpoles collected in California’s Sierra
Nevada. For 118 tadpoles whose mouthparts spanned the complete
range of depigmentation (from fully pigmented to completely
depigmented), we determined actual chytrid status of individuals
using PCR tests. Depigmentation of jaw sheaths and toothrows
were both related to tadpole chytrid status, and this relationship
was particularly strong for upper jaw sheaths. Of the 64 tadpoles
that showed any depigmentation of the upper jaw sheath, 54 (84%)
were chytrid-positive. Of the 52 tadpoles that had fully pigmented
upper jaw sheaths, 46 (88%) were chytrid-negative. Based on
these results, we suggest that inspection of tadpole mouthparts
for evidence of depigmentation is an easy and accurate method
of determining the chytrid status of R. muscosa populations.
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LIND, AMY J.*
Dept. of Evolution and Ecology, University of California, Davis,
and USDA Forest Service – Sierra Nevada Research Center,
2121 Second St., Suite A-101, Davis, CA 95616; alind@fs.fed.us
DAVIDSON,
C. D.
Department of Environmental Studies, California State University,
Sacramento, 6000 J Street,
Sacramento, California 95819
BORISENKO,
A
Oregon Department of Environmental Quality, Laboratory Division
- Northwest Region,
Watershed Assessment Section, Portland, Oregon.
SHAFFER,
H.B.
Department of Evolution and Ecology, One Shields Ave., University
of California, Davis 95616
FELLERS,
G.M.
Western Ecological Research Center, U.S. Geological Survey,
Point Reyes National Seashore, Point Reyes, CA 94956.
Status,
Decline, and Phylogeography of Rana boylii: Implications for
Conservation of Frogs and Rivers
The foothill yellow-legged
frog (Rana boylii) is a stream-associated frog that is declining
over much of its historic range in California and Oregon. This
paper summarizes recent research on likely decline factors and
provides the first range-wide phylogenetic and population genetic
analyses for this species. For analysis of decline factors,
we used univariate and multivariate analyses to examine the
spatial relationship between the current status of R. boylii
(present or absent) at historic localities relative to: geographic
characteristics (e.g. elevation and latitude), land use impacts,
wind-borne toxins and pollutants, climatic factors, and proximity
and size of dams. Climatic affects were the strongest of any
individual variable as well as showing strong influence in multivariate
models. Specifically, mean annual precipitation was positively
related to presence and variability of precipitation and percent
of dry years were negatively related to presence. We also discovered
evidence for interactions, especially that negative effects
of dams appear to be exacerbated in areas with low precipitation.
It appears that R. boylii is responding to recent climate changes
and thus conservation efforts must consider the implications
of this factor in the future. For genetic analyses, we used
1525 total base pairs from sequences of two mtDNA fragments
(Cytochrome B and ND2) for 77 individuals from 34 localities.
Our results demonstrated that several well-supported geographically
congruent clades exist within R. boylii. While genetic variation
was low among populations in the largest, most inclusive clade,
individuals from several localities demonstrated substantial
genetic divergence. Hydrologic regions, which represent likely
dispersal corridors for R. boylii, show promise in explaining
historic patterns of genetic variation and may be the appropriate
units for conservation as well.
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LOCKHART,
MITCH
California Department of Fish & Game, Bishop, CA
California
Department of Fish & Game High Mountain Lakes Database
California Department
of Fish & Game (CDFG) has completed its fourth year of the
High Mountain Lakes (HML) project. The project’s goals
are to inventory all mapped water bodies and unmapped water
bodies with biological resources in the high country of the
Sierra Nevada excluding lakes within National Park boundaries.
Data collected at each water body included habitat characterization,
a census of frog and toad species present, and a gill net sample
of fish populations present. Currently, out of an estimated
10,750 lakes to be surveyed, 7607 have been inventoried. Significant
amphibian findings include 558 sites with Rana muscosa, 267
of which supported larvae, and 161 sites with Bufo canorus.
That out of the 558 sites with R. muscosa only 81 are known
to coexist with fish is particularly poignant to the recovery
of the species. Lakes inventory data is used to develop Aquatic
Biodiversity Management Plans for each watershed that establishes
management directions for recreational angling, amphibians and
other native species.
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MATTHEWS,
KATHLEEN R.*
US Forest Service Pacific Southwest Research Station Box 245
Berkeley, Ca 94701;
kmatthews@fs.fed.us
MIAUD,
CLAUDE
CNRS 5553, Laboratory Biology of Alpine Populations, University
of Savoie, France 73376 Le Bourget du Lac; claude.miaud@univ-savoie.fr
A
Skeletochronological Study of the Longevity and Age Structure
of the Mountain Yellow-Legged Frog, Rana muscosa, in the Sierra
Nevada, California
We used skeletochronology to age 149 (67 females, 44 males,
and 38 metamorphs) mountain yellow-legged frogs, Rana muscosa,
from 13 locations throughout their current range in the Sierra
Nevada. Lines of arrested growth (LAGs) from excised toe bones
were distinct in these high elevation frogs and each LAG was
assumed to represent one year of age. Females ranged in age
from 0-10 years (mean = 4.4 years) and males from 0-8 years
(mean = 4.0 yrs). The skeletochronological age was that of the
adult frog, and did not include the tadpole stage. Mountain
yellow-legged frogs spend 3-4 years as tadpoles, thus, their
total ages including both tadpoles and adult stages ranged up
to 14 years. Ages from sample sites at higher elevations (n=5
sites >3000 m) had the broadest range up to 10 years. In
comparison, ages from sample sites at lower elevations (n=8
sites <3000 m) ranged up to 7 years. However at lower elevations,
length and weight at age was higher. Mean masses and lengths
of frogs were greater from those sampled < 3000 m (n= 83,
mean mass = 29.8 g, mean length = 60.4 mm) compared to those
> 3000 m (n=66, mean mass = 14.8 g, mean length 47 mm). Compared
to other ranid species, mountain yellow-legged frogs were found
to be relatively long-lived and which has implications for restoration
and recovery plans. We found that location (elevation and location
within the northern-southern Sierra Nevada range) was an important
variable in the relationship between length and age.
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MELLISON,
CHAD*
U.S. Fish and Wildlife Service, 1340 Financial Blvd, Ste 234,
Reno, Nevada 89502; chad_mellison@fws.gov
HARVEY,
JIM
U.S. Forest Service, Humboldt-Toiyabe National Forest, 1200
Franklin Way, Sparks, Nevada; jimharvey@fs.fed.us
Creating
pond habitat for Columbia spotted frogs in the Reese River drainage,
Central Nevada
A conservation agreement
and strategy (CAS) was signed in September 2003 for Columbia
spotted frog (Rana luteiventris) populations in Nevada. One
of the objectives of the CAS states that viable populations
and their habitats are managed and enhanced to ensure the continued
existence of Columbia spotted frogs throughout their historic
range in Nevada. During the summer and fall of 2004, a multi
agency effort began to monitor populations of Columbia spotted
frogs in the Reese River drainage. In addition to the monitoring
effort, pond habitat was created and/or enhanced along a tributary
to the Reese River. Effectiveness monitoring will begin in 2005
to assess the desired outcomes of the project.
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MILLIRON, CURTIS
California Department of Fish & Game, Bishop, CA; cmilliro@dfg.ca.gov
California
Department of Fish & Game Management of Native Fauna and
Introduced Fisheries in Sierra Nevada Lakes
Using comprehensive
and current data on fish and herpetofauna distributions within
watershed-based management units, the California Department
of Fish and Game is developing management plans to restore native
aquatic faunal assemblages while meeting reasonable expectations
for recreational angling. Native fauna restoration projects
focus on key amphibian species, usually the mountain yellow-legged
frog, Rana muscosa, with the measure of success being the reestablishment
of large naturally functioning ecosystems that provide habitats
for the continued evolutionary development of native fauna.
Native species restoration projects, usually in the form of
fish removals, are being proposed and implemented across the
Sierra Nevada where feasible from biological, physical and political
perspectives. Where recreational angling is identified as the
management direction, fisheries managers utilize new and traditional
means, including aerial fish stocking, to meet management objectives.
Interestingly, fish removal projects and fisheries management
activities have been funded through Federal Sport Fish Restoration
Act and other state and federal funding sources.
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SELTENRICH,
CRAIG P.*
ECORP Consulting, Inc., 2260 Douglas Blvd., Roseville, CA, 95661;
cseltenrich@ecorpconsulting.com
POOL, ALICIA
C.
Pacific Gas & Electric Company, San Ramon, CA, 94583; acpa@pge.com
Habitat
Variability Observed at Foothill Yellow-legged Frog (Rana boylii)
Breeding Locations in Several Large River Drainages along the
West Slope of the Sierra Nevada: Implications for Developing
Survey Strategies
Available literature
on habitat preferences of foothill yellow-legged frog (Rana
boylii) in large river systems in Northern California has been
derived primarily from research on coastal rivers. These studies
have documented R. boylii utilizing wide, shallow reaches with
cobble and boulder river bars and/or side channels for breeding.
Until recently, very little information on R. boylii habitat
was available for Sierra Nevada populations. However, within
the last five years, numerous hydroelectric relicensing projects
along the west slopes of the Sierra Nevada have required detailed
studies to evaluate R. boylii populations relative to project
operations. As a result, extensive surveys have been conducted
on several large river systems in the Sierras including the
Mokelumne, Stanislaus, American, and Feather rivers. Results
of these studies indicate that R. boylii populations in the
Sierras appear to utilize a wide variety of habitats for breeding.
Drainage specific differences in channel morphology and substrate
composition can significantly affect the types of habitat utilized
by this species. R. boylii appear to be highly adaptable to
a variety of habitat types when “traditional” habitats
(e.g., cobble/boulder bars, side channels) are not available,
or in response to altered flow regimes on regulated rivers.
Consequently, when designing studies in the Sierras, the selection
of survey sites should include a relatively wide array of habitat
types, especially if traditional breeding habitat is in limited
supply, or if the seasonal flow regime is altered or regulated
by dams or hydroelectric projects.
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STACK,
ROBERT
Jumping Frog Research Institute, PO Box 1416, Angels Camp, CA
95222; jumpingfrog@earthlink.net
JENNINGS,
MARK*
Rana Resources, 39913 Sharon Avenue, Davis, CA 95616
HAYES,
MARC
Washington Department of Fish and Wildlife, 600 Capitol Way
North, Olympia, Washington 98501
Calaveras
Red-legged Frogs Make A “Celebrated” Comeback
In late 2003 on a
ranch in Calaveras County, two small children playing near an
isolated pool along an intermittent creek discovered a population
of California red-legged frogs (Rana draytonii). The Jumping
Frog Research Institute (JFRI) preliminarily identified the
species in October 2003, and biologists from the US Fish and
Wildlife Service (USFWS) subsequently confirmed the find with
a night-time survey that revealed three adults.
Through 2004, the
children, who were enlisted as “junior biologists”in
the effort, actively surveyed and monitored the site. Breeding
was documented in an upstream in-channel pool in March 2004,
but non-native green sunfish (Lepomis cyanellus) threatened
to rapidly consume the entire complement of larvae resulting
from the only egg mass found. Approval was sought and granted
by the USFWS to begin an active seining and gill netting program
to reduce or eliminate the fish from the creek reach up- and
downstream of the known tadpole locations.
By late Summer 2004,
recruitment of over 50 juvenile California red-legged frogs
had been documented, and the landowner has voluntarily agreed
to undertake a series of habitat improvements suggested by JFRI
and the USFWS that should further enhance the survival and recovery
of what is widely believed to be Mark Twain’s “Celebrated
Jumping Frog of Calaveras County.”
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TRENHAM,
PETE
Independent Researcher, 3325 Monterey Ave., Davis, CA 95616;
ptrenham@yahoo.com
Projected
Effects of Upland Habitat Loss on California Tiger Salamander
Populations - Lessons for Conservation Planning
Many amphibians breed
in wetland habitats, and spend the vast majority of their lives
in nearby upland habitats. However, for most species the spatial
distribution of individuals in upland habitat is poorly understood.
To estimate the upland distribution of subadult and adult California
tiger salamanders (Ambystoma californiense), we used a novel
trapping approach that allowed us to model the spatial variation
in capture rates in the landscape surrounding an isolated breeding
pond. As expected, we found that captures of adults declined
with distance from the breeding pond. However, captures of subadults
climbed steadily from 10 to 400 m from the breeding site, but
declined to zero at 800 m. A negative exponential function fit
to the adult capture data suggested that 50, 90, and 95% were
within 150, 490, 620 m of the pond, respectively. For subadults,
the quadratic function fit to the data similarly suggested that
95% were within 630 m of the pond, but that 85% of this life
stage was concentrated between 200 and 600 m from the pond.
To investigate the population-level consequences of reducing
the amount of suitable upland habitat around breeding ponds,
we used a stage-based stochastic population model with subadult
and adult survival parameters modified according to our empirical
observations of upland distribution. Model simulations suggested
that substantial reductions in population size are less likely
if upland habitats extending at least 600 m from the pond edge
are maintained. Model elasticities indicated that quasi-extinction
probabilities are more sensitive to reductions in subadult and
adult survivorship than reproductive parameters. Understanding
the upland ecology of pond-breeding amphibians, especially the
distribution and survivorship of subadults is critical for designing
protective reserves and land use plans.
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VREDENBURG,
VANCE
Department of Integrative Biology, University of California,
Berkeley, CA; vancev@socrates.berkeley.edu
Can
Batrachochytrium dendrobatidis Survive in the Environment Without
an Amphibian Host? Preliminary Results from a Field Experiment
with Rana muscosa
Amphibian declines
are occurring worldwide and many potential causes have been
identified, yet there is still little known about the relative
importance of various factors in population declines. In the
Sierra Nevada, California, the mountain yellow-legged frog (Rana
muscosa) has suffered large declines, and several factors may
be affecting populations. Recently, an emerging infectious disease,
chytridiomycosis, caused by the chytrid fungus Batrachochytrium
dendrobatidis has been identified in wild populations. In the
past 3 years, B. dendrobatidis has spread in R. muscosa in the
Sierra Nevada, and many infected populations have gone locally
extinct. This study examined whether the persistence of B. dendrobatidis
outside its host, R. muscosa, would preclude frog re-introductions
to these sites. In order to understand whether B. dendrobatidis
can survive without the host, we introduced uninfected tadpoles
into host extinction sites associated with chytridiomycosis.
Tadpoles from two uninfected source populations were re-introduced
into 5 sites, each site contained two large cages (2m x 1m x
1m) with 30 tadpoles. We had one positive control (uninfected
tadpoles added to a lake with an ongoing infection) and two
negative controls (uninfected tadpoles transported and placed
back into source lake inside cages). We collected the tadpoles
after 10 weeks of exposure and used real-time PCR to determine
if they were infected with B. dendrobatidis. At this time, about
70% of the samples have been analyzed, and so far, tadpoles
from extinction sites (n=5) did not become infected. Our negative
controls (n=2) were all uninfected; however, in our positive
control (n=1 site; 60 tadpoles) all but one tadpole was infected.
These results suggest that B. dendrobatidis may become extinct
in the absence of a host.
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WELSH,
HARTWELL H., Jr.*
GARTH R. HODGSON
USFS-PSW Redwood Sciences Laboratory, 1700 Bayview Dr., Arcata,
CA 95521; hwelsh@fs.fed.us
The
Relationship of Cold-water Tributaries to Landscape-scale Attributes
in a Northern California Watershed: Implications for the Conservation
of Cold-water Adapted Amphibians
We examined relationships
between stream temperatures and environmental attributes, including
forest cover, in the Mattole watershed of northwestern California.
We characterized temperature regimes of 40 tributaries by determining
the highest maximum weekly maximum temperature (MWMT) using
measurements recorded every hour throughout the summer. Multi-year
sampling established a link between cold-water tributaries (MWMT
<18 oC) and the presence of two headwater amphibian species
of special concern, the tailed frog and southern torrent salamander,
and the threatened coho salmon. While our analysis indicated
that stream temperature was the best predictor of the presence
of these cold-water-adapted species, the best predictor of stream
temperature regimes was a landscape-scale model consisting of
three variables: aspect, catchment area, and proportion of non-forested
habitat (R2 = 0.69). Temperature regimes in the warmest tributaries
containing these species, combined with historic and current
watershed conditions which affect stream temperatures, suggest
that strategies to restore and conserve cold-water species in
this and similar watersheds, should focus on managing for lower
stream temperatures. According to our model, the best variable
available to effect a particular water temperature regime is
the amount of intact forest cover. Sensitivity analyses based
on this model indicated that if the objective is to provide
summer stream temperatures suitable for tailed frogs, torrent
salamanders, or coho salmon in a north-facing basin of 400 ha,
forest cover should be maintained at >85%.
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WHEELER,
CLARA
Clara Wheeler, Redwood Sciences Laboratory, US Forest Service,
Arcata, CA.
Mating
System and Strategy of the Foothill Yellow-legged Frog (Rana
boylii).
Due to recent declines
across its historic range the foothill yellow-legged frog (Rana
boylii) is currently the subject of many ongoing research projects.
However, aspects of the species natural history are still largely
unknown. Our objective was to obtain information about the species
mating strategy by studying a breeding population in a natural
and static breeding location. Understanding the mating strategy
provides information on effective population size and genetic
diversity of a breeding population. We monitored breeding activity
and collected data on observations during three breeding seasons.
Our recapture data indicate that individuals have site fidelity
to breeding areas. Daily sex ratios were highly male-skewed.
Breeding season sex ratios were female-skewed. We found a negative
association between male size and arrival time to the breeding
area in 2002 and 2003 (Pearson, r=-0.66 and r=-0.38, respectively).
We found no relationship between male size and site tenure in
2002 or 2003 (Pearson, r=0.09 and r=-0.12, respectively). Our
2003 data suggests that there is no size-assortative mating
(Pearson, r=0.13, P =0.53), however females may be selecting
larger males (T-test, T=2.35, df=27, P=0.03). Our observations
indicate that male frogs are maintaining and aggressively defending
territories within the breeding area. Males arriving earlier
to the breeding site maintained smaller territories (Pearson,
r = 0.51), males maintaining larger territories are more aggressive
(linear regression, r2=0.37), and aggressive males have a higher
frequency of calling (Pearson, r=0.47). These results indicate
that this breeding population exhibits a complex mating system
and social structure.
* Denotes speaker in multi-authored presentations
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