Karen Thorne, Ph.D.
Dr. Karen Thorne is a Research Ecologist with the USGS Western Ecological Research Center,
Her research focus is on climate change impacts to coastal ecosystems. In particular, her work has included assessing sea-level rise and storm impacts to coastal ecosystems, wetland ecology, restoration, and blue carbon. She received her Ph.D. and MS from the University of California, Davis.
Dr. Thorne's interests lie in conservation and management issues surrounding climate-related research that assess changes to ecosystems. Her current focus is assessing how sea-level rise and storms impact tidal wetland ecosystems in the U.S. and island habitats. She conducts research to inform climate adaptation and planning to help managers mitigate impacts and conduct restoration. Her research is based on field data collection methods that can be developed into climate change impact models using ArcGIS and other remote sensing tools.
RESEARCH INTERESTS
- Global Change Biology
- Coastal Ecosystems
- Wetland Ecology
- Restoration
- Threatened & Endangered Species
- Blue Carbon
- Landscape Ecology
- Ecological Response Modeling
- Storm Monitoring
- Sea-level Rise Planning & Decision Support
Professional Experience
Research Ecologist, USGS, Western Ecological Research Center, Davis Field Station, 2012 - present
Biologist, USGS, Western Ecological Research Center, San Francisco Bay Estuary Field Station, 2005 to 2012
Research Associate, U.S. Fish & Wildlife Service, Fairbanks, AK, 2002 to 2005
Education and Certifications
PhD, Geography, Global Change, University of California, Davis, 2012
MSc, Geography, Environmental Studies, University of California, Davis, 2008
BS, Wildlife, Fish, & Conservation Biology, University of California, Davis 2000
Affiliations and Memberships*
California Landscape Conservation Cooperative Science Team
Science and Products
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Short-term impact of sediment addition on plants and invertebrates in a southern California salt marsh
The implementation and monitoring of management strategies is integral to protect coastal marshes from increased inundation and submergence under sea-level rise. Sediment addition is one such strategy in which sediment is added to marshes to raise relative elevations, decrease tidal inundation, and enhance ecosystem processes. This study looked at the plant and invertebrate community...
Authors
Kaelin J McAtee, Karen M. Thorne, Christine R. Whitcraft
Salinity and inundation effects on productivity of brackish tidal marsh plants in the San Francisco Bay-Delta Estuary
Plant productivity is central to numerous ecosystem functions in tidal wetlands. We examined how productivity of brackish marsh plants in northern California responded to abiotic stress gradients of inundation and salinity using two experimental approaches. In a greenhouse study with varying salinity, shoot production and biomass of Juncus balticus, Schoenoplectus acutus and S...
Authors
Christopher Janousek, Bruce D. Dugger, Brandon M Drucker, Karen M. Thorne
Testing the interactive effects of flooding and salinity on tidal marsh plant productivity
Tidal wetlands support plant communities that facilitate carbon storage, accrete soil, and provide habitat for terrestrial and aquatic species. Climate change is likely to alter estuaries through sea-level rise and changing precipitation patterns, although the ecological responses are uncertain. We were interested in plant responses to physiological stress induced by elevated water...
Authors
Kevin Buffington, Arianna Goodman, Chase M. Freeman, Karen M. Thorne
Spatiotemporal patterns of mineral and organic matter deposition across two San Francisco Bay-Delta tidal marshes
Sediment deposition in tidal wetlands is a critical process that determines whether vertical growth will keep pace with sea-level rise. However, more information is needed on how sediment deposition varies spatially and temporally across wetlands, including the effects of elevation, tidal inundation, vegetation, and weather. We investigated variation in sediment deposition due to season...
Authors
Kevin Buffington, Christopher Janousek, Karen M. Thorne, Bruce D. Dugger
Effects of elevated sea levels and waves on southern California estuaries during the 2015–2016 El Niño
The 2015–2016 El Niño provided insight into how low-inflow estuaries might respond to future climate regimes, including high sea levels and more intense waves. High waves and water levels coupled with low rainfall along the Southern California coastline provided the opportunity to examine how extreme ocean forcing impacts estuaries independently from fluvial events. From November 2015 to...
Authors
Madeleine Harvey, Sarah N Giddings, Eric D. Stein, Jeffrey A Crooks, Christine R. Whitcraft, Timu W. Gallien, John L. Largier, Liesl Tiefenthaler, Hallee Meltzer, Geno Pawlak, Karen M. Thorne, Karina Johnston, Richard F. Ambrose, Stephen C Schroeter, Henry M. Page, Hany Elwany
Habitat of the endangered salt marsh harvest mouse (Reithrodontomys raviventris) in San Francisco Bay
Understanding habitat associations is vital for conservation of at‐risk marsh‐endemic wildlife species, particularly those under threat from sea level rise. We modeled environmental and habitat associations of the marsh‐endemic, Federally endangered salt marsh harvest mouse (Reithrodontomys raviventris, RERA) and co‐occurrence with eight associated small mammal species from annual trap...
Authors
Bruce G. Marcot, Isa Woo PR, Karen M. Thorne, Chase M. Freeman, Glenn Guntenspergen
Understanding tidal marsh trajectories: Evaluation of multiple indicators of marsh persistence
Robust assessments of ecosystem stability are critical for informing conservation and management decisions. Tidal marsh ecosystems provide vital services, yet are globally threatened by anthropogenic alterations to physical and biological processes. A variety of monitoring and modeling approaches have been undertaken to determine which tidal marshes are likely to persist into the future...
Authors
Kerstin Wasson, Neil Kamal Ganju, Zafer Defne, Charlie Endris, Tracy Elsey-Quirk, Karen M. Thorne, Chase M. Freeman, Glenn Guntenspergen, Daniel J. Nowacki, Kenneth B. Raposa
Thin-layer sediment addition to an existing salt marsh to combat sea-level rise and improve endangered species habitat in California, USA
Current tidal marsh elevations and their accretion rates are important predictors of vulnerability to sea-level rise. When tidal marshes are at risk, adaptation measures, such as sediment addition to increase elevations, can be implemented to prevent degradation and loss. In 2016, wildlife managers prescribed a thin-layer sediment addition of locally sourced dredged material from Anaheim...
Authors
Karen M. Thorne, Chase M. Freeman, Jordan Rosencranz, Neil Kamal Ganju, Glenn Guntenspergen
Flooding regimes increase avian predation on wildlife prey in tidal marsh ecosystems
Within isolated and fragmented populations, species interactions such as predation can cause shifts in community structure and demographics in tidal marsh ecosystems. It is critical to incorporate species interactions into our understanding when evaluating the effects of sea‐level rise and storm surges on tidal marshes. In this study, we hypothesize that avian predators will increase...
Authors
Karen M. Thorne, Kyle A. Spragens, Kevin Buffington, Jordan Rosencranz, John Y. Takekawa
Rising tides: Assessing habitat vulnerability for an endangered salt marsh-dependent species with sea-level rise
Salt marsh-dependent species are vulnerable to impacts of sea-level rise (SLR). Site-specific differences in ecogeomorphic processes result in different SLR vulnerabilities. SLR impacts to Ridgway’s rail (Rallus obsoletus) of Southern California (SC) and San Francisco Bay (SF), U.S.A. could foreshadow SLR effects on other coastal endemic species. Salt marsh vulnerabilities to SLR were...
Authors
Jordan Rosencranz, Karen M. Thorne, Kevin Buffington, Cory T. Overton, John Y. Takekawa, Michael L. Casazza, Jennifer McBroom, Julian K. Wood, Nadav Nur, Richard L. Zembal, Glen M. MacDonald, Richard F. Ambrose
El Niño increases high‐tide flooding in tidal wetlands along the U.S. Pacific coast.
Periodic oscillations between El Niño and La Niña conditions in the Pacific Basin affect oceanographic and meteorological phenomena globally, with impacts on the abundance and distribution of marine species. However, El Niño effects on estuarine hydrology and tidal wetland processes have seldom been examined rigorously. We used detailed wetland elevation and local inundation data from 10...
Authors
Arianna Goodman, Karen M. Thorne, Kevin Buffington, Chase M. Freeman, Christopher Janousek
Sea‐level rise, habitat loss, and potential extirpation of a salt marsh specialist bird in urbanized landscapes
Sea‐level rise (SLR) impacts on intertidal habitat depend on coastal topology, accretion, and constraints from surrounding development. Such habitat changes might affect species like Belding's savannah sparrows (Passerculus sandwichensis beldingi; BSSP), which live in high‐elevation salt marsh in the Southern California Bight. To predict how BSSP habitat might change under various SLR...
Authors
Jordan Rosencranz, Karen M. Thorne, Kevin Buffington, John Y. Takekawa, Ryan F. Hechinger, Tara E. Stewart, Richard F. Ambrose, Glen M. MacDonald, Mark A. Holmgren, Jeff A. Crooks, Robert T. Patton, Kevin D. Lafferty
Science and Products
Filter Total Items: 36
Filter Total Items: 30
No Result Found
Filter Total Items: 70
Short-term impact of sediment addition on plants and invertebrates in a southern California salt marsh
The implementation and monitoring of management strategies is integral to protect coastal marshes from increased inundation and submergence under sea-level rise. Sediment addition is one such strategy in which sediment is added to marshes to raise relative elevations, decrease tidal inundation, and enhance ecosystem processes. This study looked at the plant and invertebrate community...
Authors
Kaelin J McAtee, Karen M. Thorne, Christine R. Whitcraft
Salinity and inundation effects on productivity of brackish tidal marsh plants in the San Francisco Bay-Delta Estuary
Plant productivity is central to numerous ecosystem functions in tidal wetlands. We examined how productivity of brackish marsh plants in northern California responded to abiotic stress gradients of inundation and salinity using two experimental approaches. In a greenhouse study with varying salinity, shoot production and biomass of Juncus balticus, Schoenoplectus acutus and S...
Authors
Christopher Janousek, Bruce D. Dugger, Brandon M Drucker, Karen M. Thorne
Testing the interactive effects of flooding and salinity on tidal marsh plant productivity
Tidal wetlands support plant communities that facilitate carbon storage, accrete soil, and provide habitat for terrestrial and aquatic species. Climate change is likely to alter estuaries through sea-level rise and changing precipitation patterns, although the ecological responses are uncertain. We were interested in plant responses to physiological stress induced by elevated water...
Authors
Kevin Buffington, Arianna Goodman, Chase M. Freeman, Karen M. Thorne
Spatiotemporal patterns of mineral and organic matter deposition across two San Francisco Bay-Delta tidal marshes
Sediment deposition in tidal wetlands is a critical process that determines whether vertical growth will keep pace with sea-level rise. However, more information is needed on how sediment deposition varies spatially and temporally across wetlands, including the effects of elevation, tidal inundation, vegetation, and weather. We investigated variation in sediment deposition due to season...
Authors
Kevin Buffington, Christopher Janousek, Karen M. Thorne, Bruce D. Dugger
Effects of elevated sea levels and waves on southern California estuaries during the 2015–2016 El Niño
The 2015–2016 El Niño provided insight into how low-inflow estuaries might respond to future climate regimes, including high sea levels and more intense waves. High waves and water levels coupled with low rainfall along the Southern California coastline provided the opportunity to examine how extreme ocean forcing impacts estuaries independently from fluvial events. From November 2015 to...
Authors
Madeleine Harvey, Sarah N Giddings, Eric D. Stein, Jeffrey A Crooks, Christine R. Whitcraft, Timu W. Gallien, John L. Largier, Liesl Tiefenthaler, Hallee Meltzer, Geno Pawlak, Karen M. Thorne, Karina Johnston, Richard F. Ambrose, Stephen C Schroeter, Henry M. Page, Hany Elwany
Habitat of the endangered salt marsh harvest mouse (Reithrodontomys raviventris) in San Francisco Bay
Understanding habitat associations is vital for conservation of at‐risk marsh‐endemic wildlife species, particularly those under threat from sea level rise. We modeled environmental and habitat associations of the marsh‐endemic, Federally endangered salt marsh harvest mouse (Reithrodontomys raviventris, RERA) and co‐occurrence with eight associated small mammal species from annual trap...
Authors
Bruce G. Marcot, Isa Woo PR, Karen M. Thorne, Chase M. Freeman, Glenn Guntenspergen
Understanding tidal marsh trajectories: Evaluation of multiple indicators of marsh persistence
Robust assessments of ecosystem stability are critical for informing conservation and management decisions. Tidal marsh ecosystems provide vital services, yet are globally threatened by anthropogenic alterations to physical and biological processes. A variety of monitoring and modeling approaches have been undertaken to determine which tidal marshes are likely to persist into the future...
Authors
Kerstin Wasson, Neil Kamal Ganju, Zafer Defne, Charlie Endris, Tracy Elsey-Quirk, Karen M. Thorne, Chase M. Freeman, Glenn Guntenspergen, Daniel J. Nowacki, Kenneth B. Raposa
Thin-layer sediment addition to an existing salt marsh to combat sea-level rise and improve endangered species habitat in California, USA
Current tidal marsh elevations and their accretion rates are important predictors of vulnerability to sea-level rise. When tidal marshes are at risk, adaptation measures, such as sediment addition to increase elevations, can be implemented to prevent degradation and loss. In 2016, wildlife managers prescribed a thin-layer sediment addition of locally sourced dredged material from Anaheim...
Authors
Karen M. Thorne, Chase M. Freeman, Jordan Rosencranz, Neil Kamal Ganju, Glenn Guntenspergen
Flooding regimes increase avian predation on wildlife prey in tidal marsh ecosystems
Within isolated and fragmented populations, species interactions such as predation can cause shifts in community structure and demographics in tidal marsh ecosystems. It is critical to incorporate species interactions into our understanding when evaluating the effects of sea‐level rise and storm surges on tidal marshes. In this study, we hypothesize that avian predators will increase...
Authors
Karen M. Thorne, Kyle A. Spragens, Kevin Buffington, Jordan Rosencranz, John Y. Takekawa
Rising tides: Assessing habitat vulnerability for an endangered salt marsh-dependent species with sea-level rise
Salt marsh-dependent species are vulnerable to impacts of sea-level rise (SLR). Site-specific differences in ecogeomorphic processes result in different SLR vulnerabilities. SLR impacts to Ridgway’s rail (Rallus obsoletus) of Southern California (SC) and San Francisco Bay (SF), U.S.A. could foreshadow SLR effects on other coastal endemic species. Salt marsh vulnerabilities to SLR were...
Authors
Jordan Rosencranz, Karen M. Thorne, Kevin Buffington, Cory T. Overton, John Y. Takekawa, Michael L. Casazza, Jennifer McBroom, Julian K. Wood, Nadav Nur, Richard L. Zembal, Glen M. MacDonald, Richard F. Ambrose
El Niño increases high‐tide flooding in tidal wetlands along the U.S. Pacific coast.
Periodic oscillations between El Niño and La Niña conditions in the Pacific Basin affect oceanographic and meteorological phenomena globally, with impacts on the abundance and distribution of marine species. However, El Niño effects on estuarine hydrology and tidal wetland processes have seldom been examined rigorously. We used detailed wetland elevation and local inundation data from 10...
Authors
Arianna Goodman, Karen M. Thorne, Kevin Buffington, Chase M. Freeman, Christopher Janousek
Sea‐level rise, habitat loss, and potential extirpation of a salt marsh specialist bird in urbanized landscapes
Sea‐level rise (SLR) impacts on intertidal habitat depend on coastal topology, accretion, and constraints from surrounding development. Such habitat changes might affect species like Belding's savannah sparrows (Passerculus sandwichensis beldingi; BSSP), which live in high‐elevation salt marsh in the Southern California Bight. To predict how BSSP habitat might change under various SLR...
Authors
Jordan Rosencranz, Karen M. Thorne, Kevin Buffington, John Y. Takekawa, Ryan F. Hechinger, Tara E. Stewart, Richard F. Ambrose, Glen M. MacDonald, Mark A. Holmgren, Jeff A. Crooks, Robert T. Patton, Kevin D. Lafferty
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government