Christopher A Pearl
I am a Wildlife Biologist at the USGS Forest and Rangeland Ecosystem Science Center in Corvallis, OR.
I work on research and monitoring studies for a variety of aquatic and terrestrial species in the Pacific Northwest. I am particularly interested in restoration of wetland and riparian systems, herpetology, and interactions between native and invasive species.
Professional Experience
2001-Present: Wildlife Biologist, USGS Forest and Rangeland Ecosystem Science Center, Corvallis, OR
The Nature Conservancy
Faculty Research Associate, Oregon State University, Corvallis, OR
Education and Certifications
M.S., Environmental Studies, University of Oregon (1999)
B.S., Community Forestry and Horticulture, University of Vermont, Burlington, VT (1988)
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.
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.
Invasive crayfish in the Pacific Northwest
Non-native species impacts on pond occupancy by an anuran
Non-native species impacts on pond occupancy by an anuran
Columbia spotted frog (Rana luteiventris) in southeastern Oregon: A survey of historical localities, 2009
Using occupancy models to understand the distribution of an amphibian pathogen, Batrachochytrium dendrobatidis
An 11 000-year-long record of fire and vegetation history at Beaver Lake, Oregon, central Willamette Valley
Surveys for presence of Oregon spotted frog (Rana pretiosa): background information and field methods
Short-term effect of cattle exclosures on Columbia Spotted Frog (Rana luteiventris) populations and habitat in northeastern Oregon
Widespread occurrence of the chytrid fungus batrachochytrium dendrobatidis on oregon spotted frogs (rana pretiosa)
A Protocol for Aging Anurans Using Skeletochronology
Demography and movement in a relocated population of Oregon Spotted Frogs (Rana pretiosa): Influence of season and gender
Range-wide phylogeographic analysis of the spotted frog complex (Rana luteiventris and Rana pretiosa) in northwestern North America
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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: 18No Result Found - 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: 67Invasive crayfish in the Pacific Northwest
Invasive species directly threaten freshwater biodiversity, particularly in regions of high aquatic richness like the Pacific Northwest (PNW). Crayfish are among the most impactful of aquatic invasive species. Invasive crayfish are considered ecosystem engineers due to their ability to alter basic wetland properties, such as reducing vegetation and bank integrity and increasing turbidity. In areasAuthorsChristopher A. Pearl, Brome McCreary, Michael AdamsNon-native species impacts on pond occupancy by an anuran
Non‐native fish and bullfrogs (Lithobates catesbeianus) are frequently cited as contributing to the decline of ranid frogs in the western United States, so we hypothesized that non‐native species, habitat, or a combination of these relate to the probability of local extinction for northern red‐legged frogs (Rana aurora) in Oregon, USA. We also hypothesized that the probability of colonization relaAuthorsM. J. Adams, Christopher A. Pearl, Stephanie Galvan, Brome McCrearyNon-native species impacts on pond occupancy by an anuran
Non-native fish and bullfrogs (Lithobates catesbeianus) are frequently cited as contributing to the decline of ranid frogs in the western United States, so we hypothesized that non-native species, habitat, or a combination of these relate to the probability of local extinction for northern red-legged frogs (Rana aurora) in Oregon, USA. We also hypothesized that the probability of colonization relaAuthorsMichael J. Adams, Christopher Pearl, Stephanie Galvan, Brome McCrearyColumbia spotted frog (Rana luteiventris) in southeastern Oregon: A survey of historical localities, 2009
The Columbia spotted frog (Rana luteiventris) occupies a large range in western North America and is comprised of at least three genetic units. Concern exists regarding the status of the Great Basin populations in Oregon, Idaho, and Nevada. We surveyed target and nearby alternate sites on public lands in southeastern Oregon where there was evidence that Columbia spotted frogs were historically preAuthorsChistopher A. Pearl, Stephanie K. Galvan, M. J. Adams, Brome McCrearyUsing occupancy models to understand the distribution of an amphibian pathogen, Batrachochytrium dendrobatidis
Batrachochytrium dendrobatidis is a fungal pathogen that is receiving attention around the world for its role in amphibian declines. Study of its occurrence patterns is hampered by false negatives: the failure to detect the pathogen when it is present. Occupancy models are a useful but currently underutilized tool for analyzing detection data when the probability of detecting a species is <1. We uAuthorsM. J. Adams, Nathan Chelgren, David M. Reinitz, Rebecca A. Cole, L.J. Rachowicz, Stephanie Galvan, Brome McCreary, Christopher A. Pearl, Larissa L. Bailey, Jamie B. Bettaso, Evelyn L. Bull, Matthias LeuAn 11 000-year-long record of fire and vegetation history at Beaver Lake, Oregon, central Willamette Valley
High-resolution macroscopic charcoal and pollen analysis were used to reconstruct an 11??000-year-long record of fire and vegetation history from Beaver Lake, Oregon, the first complete Holocene paleoecological record from the floor of the Willamette Valley. In the early Holocene (ca 11??000-7500 calendar years before present [cal??yr??BP]), warmer, drier summers than at present led to the establiAuthorsMegan K. Walsh, Christopher A. Pearl, Cathy Whitlock, Patrick J. Bartlein, Marc A. WoronaSurveys for presence of Oregon spotted frog (Rana pretiosa): background information and field methods
The Oregon spotted frog (Rana pretiosa) is the most aquatic of the native frogs in the Pacific Northwest. The common name derives from the pattern of black, ragged-edged spots set against a brown or red ground color on the dorsum of adult frogs. Oregon spotted frogs are generally associated with wetland complexes that have several aquatic habitat types and sizeable coverage of emergent vegetation.AuthorsChristopher A. Pearl, David Clayton, Lauri TurnerShort-term effect of cattle exclosures on Columbia Spotted Frog (Rana luteiventris) populations and habitat in northeastern Oregon
Livestock grazing is a common land use across the western United States, but concerns have been raised regarding its potential to affect amphibian populations. We studied the short-term effects of full and partial livestock grazing exclosures on Rana luteiventris (Columbia Spotted Frog) populations using a controlled manipulative field experiment with pre- and posttreatment data (2002–2006). DespiAuthorsM. J. Adams, Christopher Pearl, Brome McCreary, Stephanie Galvan, Stephanie J. Wessell, Wendy Wente, Chauncey W. Anderson, Allison B. KuehlWidespread occurrence of the chytrid fungus batrachochytrium dendrobatidis on oregon spotted frogs (rana pretiosa)
The pathogen Batrachochytrium dendrobatidis (Bd) has been associated with amphibian declines in multiple continents, including western North America. We investigated Bd prevalence in Oregon spotted frog (Rana pretiosa), a species that has declined across its range in the Pacific Northwest. Polymerase chain reaction analysis of skin swabs indicated that Bd was prevalent within populations (420 of 6AuthorsC.A. Pearl, J. Bowerman, M.J. Adams, N.D. ChelgrenA Protocol for Aging Anurans Using Skeletochronology
Age distribution information can be an important part of understanding the biology of any population. Age estimates collected from the annual growth rings found in tooth and bone cross sections, often referred to as Lines of Arrested Growth (LAGs), have been used in the study of various animals. In this manual, we describe in detail all necessary steps required to obtain estimates of age from anurAuthorsBrome McCreary, Christopher A. Pearl, M. J. AdamsDemography and movement in a relocated population of Oregon Spotted Frogs (Rana pretiosa): Influence of season and gender
We used five years of recapture data and Bayesian estimation to assess seasonal survival, movement, and growth of Oregon Spotted Frogs (Rana pretiosa) relocated into created ponds at Dilman Meadow in Oregon, USA. We evaluate hypotheses specific to the relocation and elucidate aspects of R. pretiosa life history that are poorly known. The odds of survival of relocated individuals during the first yAuthorsN.D. Chelgren, C.A. Pearl, M.J. Adams, J. BowermanRange-wide phylogeographic analysis of the spotted frog complex (Rana luteiventris and Rana pretiosa) in northwestern North America
The dynamic geological and climatic history of northwestern North America has made it a focal region for phylogeography. We conducted a range-wide phylogeographic analysis of the spotted frog complex (Rana luteiventris and Rana pretiosa) across its range in northwestern North America to understand its evolutionary history and the distribution of clades to inform conservation of R. pretiosa and GreAuthorsW.C. Funk, C.A. Pearl, H.M. Draheim, M.J. Adams, T.D. Mullins, S. M. Haig - News