I am a Scientist Emeritus at the USGS Forest and Rangeland Ecosystem Science Center. My research focuses on amphibians and reptiles.
My research interests include ecology of aquatic and forest ecosystems, conservation biology of amphibians and reptiles, the effects of perturbations on animal populations, biological invasions, and inventorying and monitoring.
Education and Certifications
Ph.D. Zoology from University of California-Berkeley
MSc. Life Sciences from Calif. State Univ.-Sacramento
BSc. Biology from Humboldt State University
Science and Products
If you are unable to access or download a product, email fresc_outreach@usgs.gov a request, including the full citation, or call (541) 750-1030.
Resource partitioning in two stream salamanders, Dicamptodon tenebrosus and Rhyacotriton cascadae, from the Oregon Cascade Mountains
A history of herpetologists and herpetology in the U.S. Department of the Interior
Modifications of traps to reduce bycatch of freshwater turtles
The "peer" in "peer review"
Western pond turtle: Biology, sampling techniques, inventory and monitoring, conservation, and management: Northwest Fauna No. 7
Using multilevel spatial models to understand salamander site occupancy patterns after wildfire
Range and habitats of the desert tortoise
Low thermal tolerances of stream amphibians in the Pacific Northwest: Implications for riparian and forest management
Science Review for the Scott Bar Salamander (Plethodon asupak) and the Siskiyou Mountains Salamander (P. stormi): Biology, Taxonomy, Habitat, and Detection Probabilities/Occupancy
Natural history, field ecology, conservation biology and wildlife management: Time to connect the dots
Trachemys scripta elegans (Red-eared Slider). Reproduction
Ecology and Conservation of Sensitive Herpetofauna Species
Science and Products
- Publications
If you are unable to access or download a product, email fresc_outreach@usgs.gov a request, including the full citation, or call (541) 750-1030.
Filter Total Items: 52Resource partitioning in two stream salamanders, Dicamptodon tenebrosus and Rhyacotriton cascadae, from the Oregon Cascade Mountains
We investigated the potential for resource partitioning between the Coastal giant salamander (Dicamptodon tenebrosus) and the Cascade torrent salamander (Rhyacotriton cascadae) by examining their diet and microhabitats in forest streams. Larval D. tenebrosus and R. cascadae fed primarily upon aquatic insect larvae. We found similar foods in larval and adult R. cascadae and combined these results.A history of herpetologists and herpetology in the U.S. Department of the Interior
The U.S. Department of the Interior (DOI) has a long and distinguished history of employing herpetologists to conduct basic and applied research to better manage amphibian and reptile populations on public lands and even outside the boundaries of the United States. This history extends back over 125 years with roots in the U.S. Biological Survey, the Fish and Wildlife Service, the Bureau of Land MModifications of traps to reduce bycatch of freshwater turtles
Mortality of freshwater turtles varies among types and deployments of traps. There are few or no losses in hoop or fyke traps set where turtles may reach air, including placement in shallows, addition of floats on traps, and tying traps securely to a stake or to shore. Turtle mortality occurs when traps are set deep, traps are checked at intervals >1 day, and when turtles are captured as bycatch.The "peer" in "peer review"
No abstract available.Western pond turtle: Biology, sampling techniques, inventory and monitoring, conservation, and management: Northwest Fauna No. 7
One of only two native, freshwater turtle species in the western United States, western pond turtles are declining in portions of their original range. Declines are mostly due to habitat loss, introduction of non-native species, pollution, and lack of connectivity among populations. USGS zoologist R. Bruce Bury and colleagues from the U.S. Forest Service, California State University, and other ageUsing multilevel spatial models to understand salamander site occupancy patterns after wildfire
Studies of the distribution of elusive forest wildlife have suffered from the confounding of true presence with the uncertainty of detection. Occupancy modeling, which incorporates probabilities of species detection conditional on presence, is an emerging approach for reducing observation bias. However, the current likelihood modeling framework is restrictive for handling unexplained sources of vaRange and habitats of the desert tortoise
We determined the current range of the desert tortoise (Gopherus agassizii) based on the available latest data from government agencies, the literature, and our experience. We developed the first detailed range map of this species and summarized information about habitat preferences. New records of occurrences were incorporated, and some peripheral localities of questionable authenticity were deleLow thermal tolerances of stream amphibians in the Pacific Northwest: Implications for riparian and forest management
Temperature has a profound effect on survival and ecology of amphibians. In the Pacific Northwest, timber harvest is known to increase peak stream temperatures to 24??C or higher, which has potential to negatively impact cold-water stream amphibians. I determined the Critical Thermal Maxima (CT max) for two salamanders that are endemic to the Pacific Northwest. Rhyacotriton variegatus larvae accliScience Review for the Scott Bar Salamander (Plethodon asupak) and the Siskiyou Mountains Salamander (P. stormi): Biology, Taxonomy, Habitat, and Detection Probabilities/Occupancy
The Plethodon elongatus Complex in the Klamath-Siskiyou Ecoregion of southern Oregon and northern California includes three species: the Del Norte salamander, Plethodon elongatus; the Siskiyou Mountains salamander, P. stormi; and the Scott Bar salamander, P. asupak. This review aims to summarize the current literature and information available on select topics for P. stormi and P. asupak. These arNatural history, field ecology, conservation biology and wildlife management: Time to connect the dots
Natural history and field ecology are essential building blocks for successful conservation and management of herpetofauna. Thus, natural history and field ecology merit major infusions of funding and increased recognition of their importance in science and management. Others have stated matters well: (1) Academic training in natural history should receive high priority; (2) we need to integrate oTrachemys scripta elegans (Red-eared Slider). Reproduction
The natural range of Trachemys scripta elegans is centered in the south-central United States, from Illinois to the Gulf of Mexico. Because of its prominence in the international pet trade, the species now can be found over much of the United States, and its introduction has been documented throughout the world (Ernst et al. 1994. Turtles of the United States and Canada. Smithsonian Institution Pr - Science
Ecology and Conservation of Sensitive Herpetofauna Species
Many species of amphibians and reptiles are declining or facing population threats in the West related to habitat loss, habitat alteration, introduction of non-native species, and other factors. Our work focuses on the status and trends of resident herpetofauna and how to better manage their habitats. Much of the effort is undertaken with cooperators, particularly with other agencies in the...