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
Foundations of modeling resilience of tidal saline wetlands to sea-level rise along the U.S. Pacific Coast
Spatially explicit models of seed availability improve predictions of conifer regeneration following the 2018 Carr Fire in northern California
Future marsh evolution due to tidal changes induced by human adaptation to sea level rise
Phenotypic trait differences between Iris pseudacorus in native and introduced ranges support greater capacity of invasive populations to withstand sea level rise
A summary of water-quality and salt marsh monitoring, Humboldt Bay, California
Multi-decadal simulation of marsh topography evolution under sea level rise and episodic sediment loads
Constraints on the adjustment of tidal marshes to accelerating sea level rise
Assessing small-mammal trapping design using spatially explicit capture recapture (SECR) modeling on long-term monitoring data
Migration and transformation of coastal wetlands in response to rising seas
Atmospheric river storm flooding influences tidal marsh elevation building processes
Elevations of mangrove forests of Pohnpei, Micronesia
Seasonal impoundment management reduces nitrogen cycling but not resilience to surface fire in a tidal wetland
Developing a Pacific Mangrove Monitoring Network (PACMAN) in Response to Sea Level Rise
Wetland Carbon Working Group: Improving Methodologies and Estimates of Carbon and Greenhouse Gas Flux in Wetlands
Sea-level Rise Vulnerability of Mangrove Forests in Micronesia and the Pacific
The Response of Coastal Wetlands to Sea-level Rise: Understanding how Macroscale Drivers Influence Local Processes and Feedbacks
The response of coastal wetlands to sea-level rise: Understanding how macroscale drivers influence local processes and feedbacks
Science to Inform the Management of Mangrove Ecosystems Undergoing Sea Level Rise at Ding Darling National Wildlife Refuge, Sanibel Island, Florida
The Impact of Sea-Level Rise on Coral Reef and Mangrove Interactions and the Resulting Coastal Flooding Hazards
Webinar: Sea-Level Rise, El Niño, and Storm Effects on Coastal Tidal Marshes
Using Drone Imagery to Assess Impacts of the 2018 Carr Fire
The Future Resiliency of Mangrove Forests to Sea-Level Rise in the Western Pacific: Initiating a National Assessment Approach
Coon Island Marsh
Fagan Marsh
Data Describing Site Characteristics Including Conifer Regeneration Following the 2018 Carr Fire in Whiskeytown National Recreation Area
Sediment deposition and accretion data from a tidal salt marsh in South San Francisco Bay, California 2021-2022
Elevation and Mangrove Cover Projections under Sea-Level Rise Scenarios at J.N. Ding Darling National Wildlife Refuge, Sanibel Island, Florida, 2020-2100
Bias-Corrected Topobathymetric Elevation Model for South Florida, 2018
Potential landward migration of coastal wetlands in response to sea-level rise within estuarine drainage areas and coastal states of the conterminous United States
Estuarine drainage area boundaries for the conterminous United States
Salt marsh monitoring during water years 2013 to 2019, Humboldt Bay, CA – water levels, surface deposition, elevation change, and carbon storage
Surface Elevation Table Measurements at Five Tidal Marshes Across the San Francisco Bay-Delta (2016-2019)
Elevation Survey Across Southwest Florida Coastal Wetlands, 2021
Antioch Dunes evening primrose (Oenothera deltoides subsp. howellii) juvenile and adult abundance across the known range, California, USA (2019)
Tidal Wetland Elevation Projections for Five San Francisco Bay Delta Regions Using WARMER-2, 2000-2100
Soil, Plant, and Elevation Characteristics of Tidal and Managed Impounded Wetlands in Suisun Marsh, California, USA (2018-2019)
Science and Products
- Publications
Filter Total Items: 56
Foundations of modeling resilience of tidal saline wetlands to sea-level rise along the U.S. Pacific Coast
Context Tidal saline wetlands (TSWs) are highly threatened from climate-change effects of sea-level rise. Studies of TSWs along the East Coast U.S. and elsewhere suggest significant likely losses over coming decades but needed are analytic tools gauged to Pacific Coast U.S. wetlands.Objectives We predict the impacts of sea-level rise (SLR) on the elevation capital (vertical) and migration potentiaAuthorsBruce G. Marcot, Karen M. Thorne, Joel A. Carr, Glenn R. GuntenspergenSpatially explicit models of seed availability improve predictions of conifer regeneration following the 2018 Carr Fire in northern California
For many conifer species in dry conifer forests of North America, seeds must be present for postfire regeneration to occur, suggesting that seed dispersal from surviving trees plays a critical role in postfire forest recovery. However, the application of tree fecundity and spatial arrangement to postfire conifer recovery predictions have only recently become more common, and is often included at rAuthorsMicah C. Wright, Phillip J. van Mantgem, Kevin J. Buffington, Karen M. Thorne, Eamon Engber, Sean SmithFuture marsh evolution due to tidal changes induced by human adaptation to sea level rise
With sea level rise threatening coastal development, decision-makers are beginning to act by modifying shorelines. Previous research has shown that hardening or softening shorelines may change the tidal range under future sea level rise. Tidal range can also be changed by natural factors. Coastal marshes, which humans increasingly depend on for shoreline protection, are ecologically sensitive to tAuthorsCelina Balderas-Guzman, Kevin J. Buffington, Karen M. Thorne, Glenn R. Guntenspergen, Michelle A. Hummel, Mark T. StaceyPhenotypic trait differences between Iris pseudacorus in native and introduced ranges support greater capacity of invasive populations to withstand sea level rise
AimTidal wetlands are greatly impacted by climate change, and by the invasion of alien plant species that are being exposed to salinity changes and longer inundation periods resulting from sea level rise. To explore the capacity for the invasion of Iris pseudacorus to persist with sea level rise, we initiated an intercontinental study along estuarine gradients in the invaded North American range aAuthorsBrenda J. Grewell, Blanca Gallego-Tévar, Gael Bárcenas-Moreno, Christine R. Whitcraft, Karen M. Thorne, Kevin J. Buffington, Jesus M. CastilloA summary of water-quality and salt marsh monitoring, Humboldt Bay, California
This report summarizes data-collection activities associated with the U.S. Geological Survey Humboldt Bay Water-Quality and Salt Marsh Monitoring Project. This work was undertaken to gain a comprehensive understanding of water-quality conditions, salt marsh accretion processes, marsh-edge erosion, and soil-carbon storage in Humboldt Bay, California. Multiparameter sondes recorded water temperatureAuthorsJennifer A. Curtis, Karen M. Thorne, Chase M. Freeman, Kevin J. Buffington, Judith Z. DrexlerMulti-decadal simulation of marsh topography evolution under sea level rise and episodic sediment loads
Coastal marsh within Mediterranean climate zones is exposed to episodic watershed runoff and sediment loads that occur during storm events. Simulating future marsh accretion under sea level rise calls for attention to: (a) physical processes acting over the time scale of storm events and (b) biophysical processes acting over time scales longer than storm events. Using the upper Newport Bay in SoutAuthorsM W Brand, Kevin J. Buffington, J B Rogers, Karen M. Thorne, E D Stein, B F SandersConstraints on the adjustment of tidal marshes to accelerating sea level rise
Much uncertainty exists about the vulnerability of valuable tidal marsh ecosystems to relative sea level rise. Previous assessments of resilience to sea level rise, to which marshes can adjust by sediment accretion and elevation gain, revealed contrasting results, depending on contemporary or Holocene geological data. By analyzing globally distributed contemporary data, we found that marsh sedimenAuthorsNeil Saintilan, Katya E. Kovalenko, Glenn R. Guntenspergen, Kerrylee Rogers, James C. Lynch, Donald Cahoon, Catherine E. Lovelock, Daniel A. Friess, Erica Ashe, Ken Krauss, Nicole Cormier, Tom Spencer, Janine Adams, Jacqueline Raw, Carles Ibanez, Francesco Scarton, Stijn Temmerman, Patrick Meire, Tom Maris, Karen M. Thorne, John Brazner, Gail L. Chmura, Tony Bowron, Vishmie Palepitiya Gamage, Kimberly Cressman, Charlie Endris, Christina Marconi, Pamela Marcum, Kari St. Laurent, William G. Reay, Kenneth B. Raposa, Jason A. Garwood, Nicole KahnAssessing small-mammal trapping design using spatially explicit capture recapture (SECR) modeling on long-term monitoring data
Few studies have evaluated the optimal sampling design for tracking small mammal population trends, especially for rare or difficult to detect species. Spatially explicit capture-recapture (SECR) models present an advancement over non-spatial models by accounting for individual movement when estimating density. The salt marsh harvest mouse (SMHM; Reithrodontomys raviventris) is a federal and CalifAuthorsChase M. Freeman, Laureen Barthman-Thompson, Robert C. Klinger, Isa Woo, Karen M. ThorneMigration and transformation of coastal wetlands in response to rising seas
Coastal wetlands are not only among the world’s most valued ecosystems but also among the most threatened by high greenhouse gas emissions that lead to accelerated sea level rise. There is intense debate regarding the extent to which landward migration of wetlands might compensate for seaward wetland losses. By integrating data from 166 estuaries across the conterminous United States, we show thatAuthorsMichael Osland, Bogdan Chivoiu, Nicholas Enwright, Karen M. Thorne, Glenn R. Guntenspergen, James Grace, Leah Dale, William Brooks, Nathaniel Herold, John W. Day, Fred H. Sklar, Christopher M. SwarzenskiByEcosystems Mission Area, Water Resources Mission Area, Climate Research and Development Program, Land Management Research Program, Eastern Ecological Science Center, Lower Mississippi-Gulf Water Science Center, Western Ecological Research Center (WERC), Wetland and Aquatic Research Center , Gulf of MexicoAtmospheric river storm flooding influences tidal marsh elevation building processes
Disturbances are a key component of ecological processes in coastal ecosystems. Investigating factors that affect tidal marsh accretion and elevation change is important, largely due to accelerating sea-level rise and the ecological and economic value of wetlands. Sediment accumulation rates, elevation change, and flooding were examined at five marshes along a riverine-tidal gradient in the northeAuthorsKaren M. Thorne, Scott Jones, Chase M. Freeman, Kevin J. Buffington, Christopher N. Janousek, Glenn R. GuntenspergenElevations of mangrove forests of Pohnpei, Micronesia
Mangrove surface elevation is the crux of mangrove vulnerability to sea level rise. Local topography influences critical periods of tidal inundation that govern distributions of mangrove species and dictates future distributions. This study surveyed ground surface elevations of the extensive mangroves of Pohnpei, Federated States of Micronesia, integrating four survey technologies to solve issuesAuthorsJoanna C Ellison, Kevin J. Buffington, Karen M. Thorne, Dean B. Gesch, Jeffrey Irwin, Jeffrey J. DanielsonSeasonal impoundment management reduces nitrogen cycling but not resilience to surface fire in a tidal wetland
Hydrology and salinity regimes of many impounded wetlands are manipulated to provide seasonal habitats for migratory waterfowl, with little-known consequences for ecosystem structure and function. Managed hydrology can alter ecosystems by directly changing soil properties and processes and by influencing plant community dynamics. Additionally, management history may influence ecosystem response toAuthorsScott Jones, Charles A Schutte, Brian J Roberts, Karen M. Thorne - Science
Filter Total Items: 34
Developing a Pacific Mangrove Monitoring Network (PACMAN) in Response to Sea Level Rise
Continued sea-level rise from a changing climate is expected to result in the loss of many coastal mangrove trees, which, will strongly affect human populations on isolated Western Pacific islands as they rely heavily on mangrove forests for food (fish, shrimp, and crabs), building materials, and firewood. Mangroves also protect local communities from tsunamis and cyclones and are important for clWetland Carbon Working Group: Improving Methodologies and Estimates of Carbon and Greenhouse Gas Flux in Wetlands
WARC researchers are working to quantify the impacts of future climate and land use/land cover change on greenhouse gas emissions and reductions.Sea-level Rise Vulnerability of Mangrove Forests in Micronesia and the Pacific
The USGS and partners are studying how mangrove forests in the Federated States of Micronesia may respond to sea-level rise over the coming century. Their projections will help Micronesian communities plan for the future.The Response of Coastal Wetlands to Sea-level Rise: Understanding how Macroscale Drivers Influence Local Processes and Feedbacks
The purpose of this work is to advance our understanding of how coastal wetland responses to sea-level rise (SLR) within the conterminous United States are likely to vary as a function of local, regional, and macroscale drivers, including climate. Based on our interactions with managers and decision makers, as well as our knowledge of the current state of the science, we propose to: (a) conduct a...The response of coastal wetlands to sea-level rise: Understanding how macroscale drivers influence local processes and feedbacks
The purpose of this work is to advance our understanding of how coastal wetland responses to SLR within the conterminous United States are likely to vary as a function of local, regional, and macroscale drivers, including climate. Based on our interactions with managers and decision makers, as well as our knowledge of the current state of the science, we propose to (a) conduct a national synoptic...Science to Inform the Management of Mangrove Ecosystems Undergoing Sea Level Rise at Ding Darling National Wildlife Refuge, Sanibel Island, Florida
Mangroves are forested tidal wetlands that occur in tropical, sub-tropical, and warm temperate coastal regions around the world. Mangroves occupy a significant area of coastlines globally and provide important ecosystem services to humans and wildlife. These services include aesthetic value, storm protection, food provisioning, recreation, critical wildlife habitat, and biological carbon sequestraThe Impact of Sea-Level Rise on Coral Reef and Mangrove Interactions and the Resulting Coastal Flooding Hazards
Ecosystems such as coral reefs and mangroves provide an effective first line of defense against coastal hazards and represent a promising nature-based solution to adapt to sea-level rise. In many areas, coral reefs cause waves to break and lose energy, allowing for sediment to accumulate on the inshore portion of reef flats (i.e. the shallowest, flattest part of a reef) and mangroves to establish.Webinar: Sea-Level Rise, El Niño, and Storm Effects on Coastal Tidal Marshes
View this webinar to learn how climate change may affect El Niño events and extreme storms on coastal wetlands.Using Drone Imagery to Assess Impacts of the 2018 Carr Fire
USGS WERC’s Dr. Karen Thorne and her research team are using drone imagery to understand how the 2018 Carr Fire affected ecosystems and cultural resources. The study, a collaboration with the National Park Service (NPS), focuses on Whiskeytown National Recreation Area in northern California. The drone images will help the WERC researchers identify changes in topography, cultural sites, debris...The Future Resiliency of Mangrove Forests to Sea-Level Rise in the Western Pacific: Initiating a National Assessment Approach
Sea-level rise will eventually flood and kill many coastal mangrove trees. The loss of mangrove forests will strongly affect human populations on isolated western Pacific islands as they rely heavily on mangroves for food, such as fish, shrimp, and crabs; building materials; and fire wood. Mangroves also shelter coastal communities from the impacts of tsunamis and cyclones, are home to endangeredCoon Island Marsh
Coon Island marsh is located along the Napa River and covers 99 hectares. We surveyed 799 elevation points and 364 vegetation plots to determine baseline conditions of the marsh. Water level loggers deployed in 2010 were used to characterize the tidal inundation patterns throughout the year. Sediment accretion rates from soil cores were used as input for the WARMER sea-level rise response model...Fagan Marsh
Fagan marsh is located along the Napa River and covers 68 hectares. We surveyed 481 elevation points and 241 vegetation plots to determine baseline conditions of the marsh. Water level loggers deployed in 2010 were used to characterize the tidal inundation patterns throughout the year. Sediment accretion rates from soil cores at Coon Island marsh were extrapolated to Fagan marsh and used as input... - Data
Filter Total Items: 23
Data Describing Site Characteristics Including Conifer Regeneration Following the 2018 Carr Fire in Whiskeytown National Recreation Area
This dataset provides seedling density and site characteristics for 131 plots in Whiskeytown National Recreation Area in California, USA. Site characteristics include modeled seed availability and terrain indices calculated using a 1 meter resolution digital elevation model (DEM).Sediment deposition and accretion data from a tidal salt marsh in South San Francisco Bay, California 2021-2022
The U.S. Geological Survey, Western Ecological Research Center collected sediment and accretion data at a wave-exposed tidal salt marsh in South San Francisco Bay, California. Sediment traps and feldspar marker horizons (MH) were deployed along transects of increasing distance from the sediment source, at primary, secondary and tertiary marsh channels/bay. Data were collected bi-monthly over two mElevation and Mangrove Cover Projections under Sea-Level Rise Scenarios at J.N. Ding Darling National Wildlife Refuge, Sanibel Island, Florida, 2020-2100
Elevation projections from the WARMER-Mangroves model for J N. "Ding" Darling National Wildlife Refuge across a range of sea-level rise scenarios (53, 115, and 183 cm by 2100). The model was calibrated using dated soil cores sampled from the basin hydrologic zone. These data support the following publication: Buffington, K.J., Thorne, K.M., Krauss, K.W., Conrad, J.K., Drexler, J.Z., and Zhu, Z.,Bias-Corrected Topobathymetric Elevation Model for South Florida, 2018
Accurate elevation data in coastal ecosystems are crucial for understanding vulnerability to sea-level rise. Lidar has become increasingly available; however, in tidal wetlands such as mangroves and salt marsh, vertical bias from dense vegetation reduces accuracy of the delivered 'base earth' products. To increase accuracy of elevation models across south Florida, we applied the LEAN technique toPotential landward migration of coastal wetlands in response to sea-level rise within estuarine drainage areas and coastal states of the conterminous United States
We quantified the potential area available for landward migration of tidal saline wetlands and freshwater wetlands due to sea-level rise (SLR) at the estuary scale for 166 estuarine drainage areas and at the state scale for 22 coastal states and District of Columbia. We used 2016 Coastal Change Analysis Program (C-CAP) data in combination with the future wetland migration data under the 1.5 m globEstuarine drainage area boundaries for the conterminous United States
To quantify the potential for landward migration at the estuary level, we developed a geospatial dataset for the conterminous United States (CONUS) that identifies the boundaries for estuarine drainage areas. Nine estuarine drainage areas in south Florida were delineated using data developed by the South Florida Water Management District (SFWMD 2018). For the rest of CONUS, we used information conSalt marsh monitoring during water years 2013 to 2019, Humboldt Bay, CA – water levels, surface deposition, elevation change, and carbon storage
This data release includes montorting data collected by the U.S. Geological Survey (USGS) Humboldt Bay Water Quality and Salt Marsh Monitoring Project. The datasets include continuous water levels collected at a 6-minute timestep collected in two study marshes (Mad River and Hookton). Surface deposition, elevation changes and carbon storage (in marsh edge environments) measured in five USGS studySurface Elevation Table Measurements at Five Tidal Marshes Across the San Francisco Bay-Delta (2016-2019)
Surface elevation tables with marker horizons (SET-MH) measure millimeter-scale changes in elevation over time. A combination of pin measurements (elevation change) and surface deposition measurements (marker horizon) is used to distinguish elevation changes due to belowground and aboveground processes. SET-MHs were installed in 2016 and were measured quarterly across five tidal marshes (PetalumaElevation Survey Across Southwest Florida Coastal Wetlands, 2021
Accurate elevation data in coastal wetlands is crucial for planning for sea-level rise. Elevation surveys were conducted across southwest Florida wetlands to provide ground validation of LiDAR as well as target long-term monitoring stations (surface elevation tables). Surveys were conducted in June 2021 across Ding Darling National Wildlife Refuge, Clam Bay, Rookery Bay National Estuarine ResearchAntioch Dunes evening primrose (Oenothera deltoides subsp. howellii) juvenile and adult abundance across the known range, California, USA (2019)
These datasets provide information on total plant cover, Normalized Difference Vegetation Index, and Antioch Dunes evening primrose (Oenothera deltoides subsp. howellii) abundance within grids across the subspecies' extant range in California. These data support the following publication: Jones, S.F., Kennedy, A., Freeman, C.M. et al. Intensity of grass invasion negatively correlated with pTidal Wetland Elevation Projections for Five San Francisco Bay Delta Regions Using WARMER-2, 2000-2100
Projections of marsh elevation change with WARMER-2 across five regions of the San Francisco Bay Delta (Cache Yolo, South Delta, North Delta, Central Delta, and Suisun). The model was run across a range of initial elevations for each region and for scenarios of sea-level rise (30, 61, 91, 122, 152, 183, 305 cm by 2100), sediment availability (historic, constant, declining, and increase), and withSoil, Plant, and Elevation Characteristics of Tidal and Managed Impounded Wetlands in Suisun Marsh, California, USA (2018-2019)
These datasets provide information on soil properties, plant species cover, and soil surface elevation in a tidal wetland and a managed impounded wetland in northern Suisun Marsh, California, USA. These data support the following publication: Jones, S.F., Schutte, C.A., Roberts, B.J. and Thorne, K.M., 2022. Seasonal impoundment management reduces nitrogen cycling but not resilience to surfa - Multimedia
- News
*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