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.
Filter Total Items: 68
Independent and interactive effects of disease and methylmercury on demographic rates across multiple amphibian populations Independent and interactive effects of disease and methylmercury on demographic rates across multiple amphibian populations
Disease, alone or combined with other stressors such as habitat loss and contaminants, affects wildlife populations worldwide. However, interactions among stressors and how they affect demography and populations remain poorly understood. The amphibian chytrid fungus (Batrachochytrium dendrobatidis; Bd) is a sometimes-lethal pathogen linked with population declines and extirpations of...
Authors
Morgan P. Kain, Blake R. Hossack, Kelly Smalling, Brian J. Halstead, Daniel A. Grear, David A. Miller, Michael J. Adams, Adam R. Backlin, William Barichivich, Collin A. Eagles-Smith, Colleen Emery, Jillian Elizabeth Fleming, Robert N. Fisher, Elizabeth Gallegos, Duoa J. Lor, Patrick M. Kleeman, Erin L. Muths, Ty Pan, Christopher Pearl, Charles W. Robinson, Caitlin Teresa Rumrill, Brian J. Tornabene, J. Hardin Waddle, Susan Walls, Evan H. Campbell Grant
Pan-amphibia distribution of the fungal parasite Batrachochytrium dendrobatidis varies with species and temperature Pan-amphibia distribution of the fungal parasite Batrachochytrium dendrobatidis varies with species and temperature
Batrachochytrium dendrobatidis (Bd) is a globally distributed fungal pathogen of amphibians that has contributed to one of the largest disease-related biodiversity losses in wildlife. Bd is regularly viewed through the lens of a global wildlife epizootic because the spread of highly virulent genetic lineages has resulted in well-documented declines and extinctions of multiple amphibian...
Authors
Daniel A. Grear, Michael J. Adams, Adam R. Backlin, William Barichivich, Adrianne Brand, Gary M. Bucciarelli, Daniel L. Calhoun, Tara Chestnut, Jon D Davenport, Andrew E Dietrich, Graziella V. DiRenzo, Robert N. Fisher, Brad Glorioso, Evan H. Campbell Grant, Brian J. Halstead, Marc P Hayes, Blake R. Hossack, Morgan Kain, Patrick M. Kleeman, Jeffrey M. Lorch, Brome McCreary, David A.W. Miller, Brittany A. Mosher, Erin L. Muths, Christopher Pearl, Charles H. Robinson, Mark Roth, Jennifer Rowe, Walter Sadinski, Brent H. Sigafus, Iga Stasiak, Samuel Sweet, Hardin Waddle, Susan Walls, Gregory J Watkins-Colwell, Lori A Williams, Megan Winzeler
Bayesian networks facilitate updating of species distribution and habitat suitability models Bayesian networks facilitate updating of species distribution and habitat suitability models
Managers often rely on predictions of species distributions and habitat suitability to inform conservation and management decisions. Although numerous approaches are available to develop models to make these predictions, few approaches exist to update existing models as new data accumulate. There is a need for updatable models to ensure good modeling practices in an aim to keep pace with...
Authors
Adam Duarte, Robert S. Spaan, James Peterson, Christopher Pearl, Michael J. Adams
Broad-scale assessment of methylmercury in adult amphibians Broad-scale assessment of methylmercury in adult amphibians
Mercury (Hg) is a toxic contaminant that has been mobilized and distributed worldwide and is a threat to many wildlife species. Amphibians are facing unprecedented global declines due to many threats including contaminants. While the biphasic life history of many amphibians creates a potential nexus for methylmercury (MeHg) exposure in aquatic habitats and subsequent health effects, the...
Authors
Brian J. Tornabene, Blake R. Hossack, Brian J. Halstead, Collin A. Eagles-Smith, Michael J. Adams, Adam R. Backlin, Adrianne Brand, Colleen Emery, Robert N. Fisher, Jillian Elizabeth Fleming, Brad Glorioso, Daniel A. Grear, Evan H. Campbell Grant, Patrick M. Kleeman, David Miller, Erin L. Muths, Christopher Pearl, Jennifer Rowe, Caitlin Teresa Rumrill, J. Hardin Waddle, Megan Winzeler, Kelly L. Smalling
By
Ecosystems Mission Area, Water Resources Mission Area, Contaminant Biology, Toxic Substances Hydrology, Eastern Ecological Science Center, Forest and Rangeland Ecosystem Science Center, Fort Collins Science Center, National Wildlife Health Center, New Jersey Water Science Center, Northern Rocky Mountain Science Center, Western Ecological Research Center (WERC), Wetland and Aquatic Research Center
Population dynamics of the threatened Oregon spotted frog before and after drought mitigation Population dynamics of the threatened Oregon spotted frog before and after drought mitigation
Amphibians are among the most sensitive taxa to climate change, and species inhabiting arid and semiarid landscapes at the extremes of their range are especially vulnerable to drought. The Jack Creek, Oregon, USA, population of Oregon spotted frogs (Rana pretiosa) faces unique challenges because it occupies the highest elevation site in the species' extant range and one that has been...
Authors
Jennifer Rowe, Christopher Pearl, Adam Duarte, Brome McCreary, Michael J. Adams
Adjacent and downstream effects of forest harvest on the distribution and abundance of larval headwater stream amphibians in the Oregon Coast Range Adjacent and downstream effects of forest harvest on the distribution and abundance of larval headwater stream amphibians in the Oregon Coast Range
Forest harvest is a primary landscape-scale management action affecting riparian forests. Although concerns about impacts of forest harvest on stream amphibians is generally limited to areas adjacent to harvest, there is a paucity of information regarding potential downstream effects of forest harvest on these species. We designed a before-after, control-impact (BACI) experiment to...
Authors
Adam Duarte, Nathan Chelgren, Jennifer Rowe, Christopher Pearl, Sherri L Johnson, Michael J. Adams
Herpetological Research Team (FRESC)
The Herpetological Research Team focuses on issues related to conservation and management of amphibians and other aquatic and semi-aquatic species. Among our current studies are effects of invasive species, disease, and land use change on the dynamics of amphibian communities to inform conservation and management decision making.
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: 19
Oregon spotted frog (Rana pretiosa) captures before and after drought mitigation at Jack Creek, Oregon 2009-2021 Oregon spotted frog (Rana pretiosa) captures before and after drought mitigation at Jack Creek, Oregon 2009-2021
Amphibians are among the most sensitive taxa to climate change, and species inhabiting arid and semiarid landscapes at the extremes of their range are especially vulnerable to periods of drought. The Jack Creek, Oregon, USA population of Oregon spotted frogs (Rana pretiosa) faces unique challenges occupying the highest elevation site in the species’ extant range and one that has been
Mercury concentrations in amphibian tissues across the United States, 2016-2021 Mercury concentrations in amphibian tissues across the United States, 2016-2021
Comma-separated values (.csv) file containing data related to amphibian sampling across the United States between 2016 and 2021. Data files contain mercury concentrations in amphibian and dragonfly tissues, mercury concentrations in sediment, as well as amphibian morphometrics, and habitat and climate characteristics where the samples were collected.
Larval headwater stream amphibian captures from the Trask River Watershed Experimental Study of forest harvest impacts, 2008-2016 Larval headwater stream amphibian captures from the Trask River Watershed Experimental Study of forest harvest impacts, 2008-2016
Forest harvest is one of the primary landscape-scale management actions affecting riparian forests of the Pacific Northwest, U.S, yet the effect of harvest on headwater steam amphibians is largely understudied. Existing information is often limited because of the difficulty separating movement and emigration processes from occupancy and abundance estimates. We designed a before-after...
Cascade torrent salamander (Rhyacotriton cascadae) surveys in Oregon and Washington 2022 Cascade torrent salamander (Rhyacotriton cascadae) surveys in Oregon and Washington 2022
The US Fish and Wildlife Service (USFWS) is evaluating the status of the Cascade torrent salamander (Rhyacotriton cascadae) across its range to determine whether the species merits listing under the Endangered Species Act. The USGS conducted visual surveys for Rhyacotriton cascadae at 65 sites in Oregon and Washington that were historically occupied by the species. Sites were selected...
Oregon spotted frog (Rana pretiosa) telemetry and habitat use at Crane Prairie Reservoir in Oregon, USA Oregon spotted frog (Rana pretiosa) telemetry and habitat use at Crane Prairie Reservoir in Oregon, USA
We used radio-telemetry to study late-season movement and habitat use by Oregon spotted frogs (Rana pretiosa) at Crane Prairie Reservoir in Oregon. This dataset includes individual frog location data and habitat use during each tracking event that occurred roughly weekly between September and late November of 2018.
Oregon spotted frog (Rana pretiosa) observations in Oregon (ver. 6.0, March 2025) Oregon spotted frog (Rana pretiosa) observations in Oregon (ver. 6.0, March 2025)
This dataset contains information from surveys conducted 2016-2024 by USGS as part of an ongoing Oregon spotted frog (Rana pretiosa) monitoring effort in Oregon. USGS research activities 2016-2024 were divided into seven study design categories: breeding (egg mass counts), mid-level (visual encounter surveys for occupancy monitoring), apex (mark-recapture), telemetry, trapping, water...
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.
Filter Total Items: 68
Independent and interactive effects of disease and methylmercury on demographic rates across multiple amphibian populations Independent and interactive effects of disease and methylmercury on demographic rates across multiple amphibian populations
Disease, alone or combined with other stressors such as habitat loss and contaminants, affects wildlife populations worldwide. However, interactions among stressors and how they affect demography and populations remain poorly understood. The amphibian chytrid fungus (Batrachochytrium dendrobatidis; Bd) is a sometimes-lethal pathogen linked with population declines and extirpations of...
Authors
Morgan P. Kain, Blake R. Hossack, Kelly Smalling, Brian J. Halstead, Daniel A. Grear, David A. Miller, Michael J. Adams, Adam R. Backlin, William Barichivich, Collin A. Eagles-Smith, Colleen Emery, Jillian Elizabeth Fleming, Robert N. Fisher, Elizabeth Gallegos, Duoa J. Lor, Patrick M. Kleeman, Erin L. Muths, Ty Pan, Christopher Pearl, Charles W. Robinson, Caitlin Teresa Rumrill, Brian J. Tornabene, J. Hardin Waddle, Susan Walls, Evan H. Campbell Grant
Pan-amphibia distribution of the fungal parasite Batrachochytrium dendrobatidis varies with species and temperature Pan-amphibia distribution of the fungal parasite Batrachochytrium dendrobatidis varies with species and temperature
Batrachochytrium dendrobatidis (Bd) is a globally distributed fungal pathogen of amphibians that has contributed to one of the largest disease-related biodiversity losses in wildlife. Bd is regularly viewed through the lens of a global wildlife epizootic because the spread of highly virulent genetic lineages has resulted in well-documented declines and extinctions of multiple amphibian...
Authors
Daniel A. Grear, Michael J. Adams, Adam R. Backlin, William Barichivich, Adrianne Brand, Gary M. Bucciarelli, Daniel L. Calhoun, Tara Chestnut, Jon D Davenport, Andrew E Dietrich, Graziella V. DiRenzo, Robert N. Fisher, Brad Glorioso, Evan H. Campbell Grant, Brian J. Halstead, Marc P Hayes, Blake R. Hossack, Morgan Kain, Patrick M. Kleeman, Jeffrey M. Lorch, Brome McCreary, David A.W. Miller, Brittany A. Mosher, Erin L. Muths, Christopher Pearl, Charles H. Robinson, Mark Roth, Jennifer Rowe, Walter Sadinski, Brent H. Sigafus, Iga Stasiak, Samuel Sweet, Hardin Waddle, Susan Walls, Gregory J Watkins-Colwell, Lori A Williams, Megan Winzeler
Bayesian networks facilitate updating of species distribution and habitat suitability models Bayesian networks facilitate updating of species distribution and habitat suitability models
Managers often rely on predictions of species distributions and habitat suitability to inform conservation and management decisions. Although numerous approaches are available to develop models to make these predictions, few approaches exist to update existing models as new data accumulate. There is a need for updatable models to ensure good modeling practices in an aim to keep pace with...
Authors
Adam Duarte, Robert S. Spaan, James Peterson, Christopher Pearl, Michael J. Adams
Broad-scale assessment of methylmercury in adult amphibians Broad-scale assessment of methylmercury in adult amphibians
Mercury (Hg) is a toxic contaminant that has been mobilized and distributed worldwide and is a threat to many wildlife species. Amphibians are facing unprecedented global declines due to many threats including contaminants. While the biphasic life history of many amphibians creates a potential nexus for methylmercury (MeHg) exposure in aquatic habitats and subsequent health effects, the...
Authors
Brian J. Tornabene, Blake R. Hossack, Brian J. Halstead, Collin A. Eagles-Smith, Michael J. Adams, Adam R. Backlin, Adrianne Brand, Colleen Emery, Robert N. Fisher, Jillian Elizabeth Fleming, Brad Glorioso, Daniel A. Grear, Evan H. Campbell Grant, Patrick M. Kleeman, David Miller, Erin L. Muths, Christopher Pearl, Jennifer Rowe, Caitlin Teresa Rumrill, J. Hardin Waddle, Megan Winzeler, Kelly L. Smalling
By
Ecosystems Mission Area, Water Resources Mission Area, Contaminant Biology, Toxic Substances Hydrology, Eastern Ecological Science Center, Forest and Rangeland Ecosystem Science Center, Fort Collins Science Center, National Wildlife Health Center, New Jersey Water Science Center, Northern Rocky Mountain Science Center, Western Ecological Research Center (WERC), Wetland and Aquatic Research Center
Population dynamics of the threatened Oregon spotted frog before and after drought mitigation Population dynamics of the threatened Oregon spotted frog before and after drought mitigation
Amphibians are among the most sensitive taxa to climate change, and species inhabiting arid and semiarid landscapes at the extremes of their range are especially vulnerable to drought. The Jack Creek, Oregon, USA, population of Oregon spotted frogs (Rana pretiosa) faces unique challenges because it occupies the highest elevation site in the species' extant range and one that has been...
Authors
Jennifer Rowe, Christopher Pearl, Adam Duarte, Brome McCreary, Michael J. Adams
Adjacent and downstream effects of forest harvest on the distribution and abundance of larval headwater stream amphibians in the Oregon Coast Range Adjacent and downstream effects of forest harvest on the distribution and abundance of larval headwater stream amphibians in the Oregon Coast Range
Forest harvest is a primary landscape-scale management action affecting riparian forests. Although concerns about impacts of forest harvest on stream amphibians is generally limited to areas adjacent to harvest, there is a paucity of information regarding potential downstream effects of forest harvest on these species. We designed a before-after, control-impact (BACI) experiment to...
Authors
Adam Duarte, Nathan Chelgren, Jennifer Rowe, Christopher Pearl, Sherri L Johnson, Michael J. Adams
Herpetological Research Team (FRESC)
The Herpetological Research Team focuses on issues related to conservation and management of amphibians and other aquatic and semi-aquatic species. Among our current studies are effects of invasive species, disease, and land use change on the dynamics of amphibian communities to inform conservation and management decision making.
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: 19
Oregon spotted frog (Rana pretiosa) captures before and after drought mitigation at Jack Creek, Oregon 2009-2021 Oregon spotted frog (Rana pretiosa) captures before and after drought mitigation at Jack Creek, Oregon 2009-2021
Amphibians are among the most sensitive taxa to climate change, and species inhabiting arid and semiarid landscapes at the extremes of their range are especially vulnerable to periods of drought. The Jack Creek, Oregon, USA population of Oregon spotted frogs (Rana pretiosa) faces unique challenges occupying the highest elevation site in the species’ extant range and one that has been
Mercury concentrations in amphibian tissues across the United States, 2016-2021 Mercury concentrations in amphibian tissues across the United States, 2016-2021
Comma-separated values (.csv) file containing data related to amphibian sampling across the United States between 2016 and 2021. Data files contain mercury concentrations in amphibian and dragonfly tissues, mercury concentrations in sediment, as well as amphibian morphometrics, and habitat and climate characteristics where the samples were collected.
Larval headwater stream amphibian captures from the Trask River Watershed Experimental Study of forest harvest impacts, 2008-2016 Larval headwater stream amphibian captures from the Trask River Watershed Experimental Study of forest harvest impacts, 2008-2016
Forest harvest is one of the primary landscape-scale management actions affecting riparian forests of the Pacific Northwest, U.S, yet the effect of harvest on headwater steam amphibians is largely understudied. Existing information is often limited because of the difficulty separating movement and emigration processes from occupancy and abundance estimates. We designed a before-after...
Cascade torrent salamander (Rhyacotriton cascadae) surveys in Oregon and Washington 2022 Cascade torrent salamander (Rhyacotriton cascadae) surveys in Oregon and Washington 2022
The US Fish and Wildlife Service (USFWS) is evaluating the status of the Cascade torrent salamander (Rhyacotriton cascadae) across its range to determine whether the species merits listing under the Endangered Species Act. The USGS conducted visual surveys for Rhyacotriton cascadae at 65 sites in Oregon and Washington that were historically occupied by the species. Sites were selected...
Oregon spotted frog (Rana pretiosa) telemetry and habitat use at Crane Prairie Reservoir in Oregon, USA Oregon spotted frog (Rana pretiosa) telemetry and habitat use at Crane Prairie Reservoir in Oregon, USA
We used radio-telemetry to study late-season movement and habitat use by Oregon spotted frogs (Rana pretiosa) at Crane Prairie Reservoir in Oregon. This dataset includes individual frog location data and habitat use during each tracking event that occurred roughly weekly between September and late November of 2018.
Oregon spotted frog (Rana pretiosa) observations in Oregon (ver. 6.0, March 2025) Oregon spotted frog (Rana pretiosa) observations in Oregon (ver. 6.0, March 2025)
This dataset contains information from surveys conducted 2016-2024 by USGS as part of an ongoing Oregon spotted frog (Rana pretiosa) monitoring effort in Oregon. USGS research activities 2016-2024 were divided into seven study design categories: breeding (egg mass counts), mid-level (visual encounter surveys for occupancy monitoring), apex (mark-recapture), telemetry, trapping, water...