Tabitha Graves, Ph.D.
I answer applied research questions at the intersection of wildlife biology, landscape ecology, and statistics.
Research Interests
My work falls under three broad themes: (1) understand the influence of humans and associated land use impacts on wildlife distributions, densities, and related processes at local and landscape scales, (2) develop new analytical tools that address the influence of landscape features on animals at the sub-population and population scales, and (3) improve efficiency of research and monitoring through optimal study design. I have >15 years experience studying grizzly bears, bighorn sheep, elk, and the development of novel and integrated analyses of habitat use, connectivity, migration, and genetics, all very applied work. I have also assisted with projects studying black bears, wolverines, mountain goats, wolves, lynx, kinkajou, loons, hawks, owls, riparian vegetation, pika, and sugar pine.
Current projects
- Chronic wasting disease- evaluating changes in density and contacts across multiple cervid populations
- Assessing current and changing forage for elk and mule deer with climate change
- Assessing connectivity and migration in and around Glacier National Park (GNP)
- Optimal monitoring of wildlife with occupancy models
- Pollinator communities and Western bumble bee assessment on BLM lands in Montana and the Dakotas, in GNP, and across the west
- Mountain goat and bighorn sheep abundance, trend, population structure, and habitat
- Spatial capture recapture approaches
- Water to Wildlife: Connecting changes in water to vegetation to wildlife across 3 northwest parks
- Evaluating potential impacts of climate change on berry plant abundance and production
Professional Experience
Research Ecologist, USGS Northern Rocky Mountain Science Center: 2/10/14-present
David H. Smith Post-doctoral Conservation Research Fellow: 7/12 – 2/14
Education and Certifications
PhD. 2012. Northern Arizona University. Dissertation Title: Spatial ecology of grizzly bears in northwestern Montana and estimating resistance to gene flow
M.S. Wildlife Biology. 2002. University of Montana
Honors B.A. German Literature with distinction. 1995. University of Wisconsin-Madison
Science and Products
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U.S. Geological Survey science for the Wyoming Landscape Conservation Initiative—2017 annual report
The Wyoming Landscape Conservation Initiative (WLCI) was established in 2008 to address the scientific and conservation questions associated with land use changes because of energy development and other factors in southwest Wyoming. Over the past decade, partners from U.S. Geological Survey (USGS), State and Federal land management agencies, universities, and the public have collaborated to implem
Authors
Linda Zeigenfuss, Ellen Aikens, Cameron L. Aldridge, Patrick J. Anderson, Timothy J. Assal, Zachary H. Bowen, Anna D. Chalfoun, Geneva W. Chong, Cheryl A. Eddy-Miller, Stephen S. Germaine, Tabitha Graves, Collin G. Homer, Christopher Huber, Aaron N. Johnston, Matthew J. Kauffman, Daniel J. Manier, Ryan R. McShane, Kirk A. Miller, Adrian P. Monroe, Anna Ortega, Annika W. Walters, Teal B. Wyckoff
Keeping the crown of the continent connected: An interagency US2 connectivity workshop report
At over 2.5 million acres, Glacier National Park and the Bob Marshall Wilderness complex form one of the largest protected areas in the continental United States. Straddling the Continental Divide, these two areas form a vital linkage between vast areas of public land to the south towards Yellowstone, and contiguous protected areas north of the US-Canada border. However, US Highway 2 (US2) and the
Authors
John S. Waller, Tabitha Graves
Trade-offs and efficiencies in optimal budget-constrained multispecies corridor networks
Conservation biologists recognize that a system of isolated protected areas will be necessary but insufficient to meet biodiversity objectives. Current approaches to connecting core conservation areas through corridors consider optimal corridor placement based on a single optimization goal: commonly, maximizing the movement for a target species across a network of protected areas. We show that des
Authors
Bistra Dilkina, Rachel Houtman, Carla P. Gomes, Claire A. Montgomery, Kevin McKelvey, Katherine Kendall, Tabitha A. Graves, Richard Bernstein, Michael K. Schwartz
Community for Data Integration 2015 annual report
The Community for Data Integration (CDI) continued to experience success in fiscal year 2015. The CDI community members have been sharing, learning, and collaborating through monthly forums, workshops, working groups, and funded projects. In fiscal year 2015, CDI coordinated 10 monthly forums with 16 different speakers from the U.S. Geological Survey and external partners; funded 11 collaborative
Authors
Madison L. Langseth, Michelle Y. Chang, Jennifer Carlino, J. Ryan Bellmore, Daniella D. Birch, Joshua Bradley, R. Sky Bristol, Daniel D. Buscombe, Jeffrey J. Duda, Anthony L. Everette, Tabitha A. Graves, Michelle M. Greenwood, David L. Govoni, Heather S. Henkel, Vivian B. Hutchison, Brenda K. Jones, Tim Kern, Jennifer Lacey, Rynn M. Lamb, Frances L. Lightsom, John L. Long, Ra'ad A. Saleh, Stan W. Smith, Christopher E. Soulard, Roland J. Viger, Jonathan A. Warrick, Katherine E. Wesenberg, Daniel J. Wieferich, Luke A. Winslow
Demographic mechanisms underpinning genetic assimilation of remnant groups of a large carnivore
Current range expansions of large terrestrial carnivores are occurring following human-induced range contraction. Contractions are often incomplete, leaving small remnant groups in refugia throughout the former range. Little is known about the underlying ecological and evolutionary processes that influence how remnant groups are affected during range expansion. We used data from a spatially explic
Authors
Nathaniel Mikle, Tabitha A. Graves, Ryan P. Kovach, Katherine C. Kendall, Amy C. Macleod
Density, distribution, and genetic structure of grizzly bears in the Cabinet-Yaak Ecosystem
The conservation status of the 2 threatened grizzly bear (Ursus arctos) populations in the Cabinet-Yaak Ecosystem (CYE) of northern Montana and Idaho had remained unchanged since designation in 1975; however, the current demographic status of these populations was uncertain. No rigorous data on population density and distribution or analysis of recent population genetic structure were available to
Authors
Katherine C. Kendall, Amy C. Macleod, Kristina L. Boyd, John Boulanger, J. Andrew Royle, Wayne F. Kasworm, David Paetkau, Michael F. Proctor, Tabitha A. Graves, Kim Annis
Nature vs. nurture: Evidence for social learning of conflict behaviour in grizzly bears
The propensity for a grizzly bear to develop conflict behaviours might be a result of social learning between mothers and cubs, genetic inheritance, or both learning and inheritance. Using non-invasive genetic sampling, we collected grizzly bear hair samples during 2011–2014 across southwestern Alberta, Canada. We targeted private agricultural lands for hair samples at grizzly bear incident sites,
Authors
Andrea T. Morehouse, Tabitha A. Graves, Nathaniel Mikle, Mark S. Boyce
Estimating landscape resistance to dispersal
Dispersal is an inherently spatial process that can be affected by habitat conditions in sites encountered by dispersers. Understanding landscape resistance to dispersal is important in connectivity studies and reserve design, but most existing methods use resistance functions with cost parameters that are subjectively chosen by the investigator. We develop an analytic approach allowing for direct
Authors
Tabitha A. Graves, Richard B. Chandler, J. Andrew Royle, Paul Beier, Katherine C. Kendall
Spatial capture-recapture models for jointly estimating population density and landscape connectivity
Population size and landscape connectivity are key determinants of population viability, yet no methods exist for simultaneously estimating density and connectivity parameters. Recently developed spatial capture–recapture (SCR) models provide a framework for estimating density of animal populations but thus far have not been used to study connectivity. Rather, all applications of SCR models have u
Authors
J. Andrew Royle, Richard B. Chandler, Kimberly D. Gazenski, Tabitha A. Graves
Balancing precision and risk: should multiple detection methods be analyzed separately in N-mixture models?
Using multiple detection methods can increase the number, kind, and distribution of individuals sampled, which may increase accuracy and precision and reduce cost of population abundance estimates. However, when variables influencing abundance are of interest, if individuals detected via different methods are influenced by the landscape differently, separate analysis of multiple detection methods
Authors
Tabitha A. Graves, J. Andrew Royle, Katherine C. Kendall, Paul Beier, Jeffrey B. Stetz, Amy C. Macleod
Linking landscape characteristics to local grizzly bear abundance using multiple detection methods in a hierarchical model
Few studies link habitat to grizzly bear Ursus arctos abundance and these have not accounted for the variation in detection or spatial autocorrelation. We collected and genotyped bear hair in and around Glacier National Park in northwestern Montana during the summer of 2000. We developed a hierarchical Markov chain Monte Carlo model that extends the existing occupancy and count models by accountin
Authors
T.A. Graves, Katherine C. Kendall, J. Andrew Royle, J.B. Stetz, A.C. Macleod
Non-USGS Publications**
Graves, T.A., S. Farley, M. Goldstein, and C.Servheen. 2007. Identification of functional corridors with movement characteristics of brown bears on the Kenai Peninsula, Alaska. Landscape Ecology.
Graves, T.A., S. Farley, and C.Servheen. 2006. Frequency and distribution of highway crossings by Kenai Peninsula brown bears. Wildlife Society Bulletin. 34: 800-808.
Graves, T.A. and J. Waller. 2006. Identification of causes of missed fixes in GPS collar on animals. Journal of Wildlife Management. 70: 844-851.
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
Filter Total Items: 16
Filter Total Items: 23
No Result Found
Filter Total Items: 35
U.S. Geological Survey science for the Wyoming Landscape Conservation Initiative—2017 annual report
The Wyoming Landscape Conservation Initiative (WLCI) was established in 2008 to address the scientific and conservation questions associated with land use changes because of energy development and other factors in southwest Wyoming. Over the past decade, partners from U.S. Geological Survey (USGS), State and Federal land management agencies, universities, and the public have collaborated to implem
Authors
Linda Zeigenfuss, Ellen Aikens, Cameron L. Aldridge, Patrick J. Anderson, Timothy J. Assal, Zachary H. Bowen, Anna D. Chalfoun, Geneva W. Chong, Cheryl A. Eddy-Miller, Stephen S. Germaine, Tabitha Graves, Collin G. Homer, Christopher Huber, Aaron N. Johnston, Matthew J. Kauffman, Daniel J. Manier, Ryan R. McShane, Kirk A. Miller, Adrian P. Monroe, Anna Ortega, Annika W. Walters, Teal B. Wyckoff
Keeping the crown of the continent connected: An interagency US2 connectivity workshop report
At over 2.5 million acres, Glacier National Park and the Bob Marshall Wilderness complex form one of the largest protected areas in the continental United States. Straddling the Continental Divide, these two areas form a vital linkage between vast areas of public land to the south towards Yellowstone, and contiguous protected areas north of the US-Canada border. However, US Highway 2 (US2) and the
Authors
John S. Waller, Tabitha Graves
Trade-offs and efficiencies in optimal budget-constrained multispecies corridor networks
Conservation biologists recognize that a system of isolated protected areas will be necessary but insufficient to meet biodiversity objectives. Current approaches to connecting core conservation areas through corridors consider optimal corridor placement based on a single optimization goal: commonly, maximizing the movement for a target species across a network of protected areas. We show that des
Authors
Bistra Dilkina, Rachel Houtman, Carla P. Gomes, Claire A. Montgomery, Kevin McKelvey, Katherine Kendall, Tabitha A. Graves, Richard Bernstein, Michael K. Schwartz
Community for Data Integration 2015 annual report
The Community for Data Integration (CDI) continued to experience success in fiscal year 2015. The CDI community members have been sharing, learning, and collaborating through monthly forums, workshops, working groups, and funded projects. In fiscal year 2015, CDI coordinated 10 monthly forums with 16 different speakers from the U.S. Geological Survey and external partners; funded 11 collaborative
Authors
Madison L. Langseth, Michelle Y. Chang, Jennifer Carlino, J. Ryan Bellmore, Daniella D. Birch, Joshua Bradley, R. Sky Bristol, Daniel D. Buscombe, Jeffrey J. Duda, Anthony L. Everette, Tabitha A. Graves, Michelle M. Greenwood, David L. Govoni, Heather S. Henkel, Vivian B. Hutchison, Brenda K. Jones, Tim Kern, Jennifer Lacey, Rynn M. Lamb, Frances L. Lightsom, John L. Long, Ra'ad A. Saleh, Stan W. Smith, Christopher E. Soulard, Roland J. Viger, Jonathan A. Warrick, Katherine E. Wesenberg, Daniel J. Wieferich, Luke A. Winslow
Demographic mechanisms underpinning genetic assimilation of remnant groups of a large carnivore
Current range expansions of large terrestrial carnivores are occurring following human-induced range contraction. Contractions are often incomplete, leaving small remnant groups in refugia throughout the former range. Little is known about the underlying ecological and evolutionary processes that influence how remnant groups are affected during range expansion. We used data from a spatially explic
Authors
Nathaniel Mikle, Tabitha A. Graves, Ryan P. Kovach, Katherine C. Kendall, Amy C. Macleod
Density, distribution, and genetic structure of grizzly bears in the Cabinet-Yaak Ecosystem
The conservation status of the 2 threatened grizzly bear (Ursus arctos) populations in the Cabinet-Yaak Ecosystem (CYE) of northern Montana and Idaho had remained unchanged since designation in 1975; however, the current demographic status of these populations was uncertain. No rigorous data on population density and distribution or analysis of recent population genetic structure were available to
Authors
Katherine C. Kendall, Amy C. Macleod, Kristina L. Boyd, John Boulanger, J. Andrew Royle, Wayne F. Kasworm, David Paetkau, Michael F. Proctor, Tabitha A. Graves, Kim Annis
Nature vs. nurture: Evidence for social learning of conflict behaviour in grizzly bears
The propensity for a grizzly bear to develop conflict behaviours might be a result of social learning between mothers and cubs, genetic inheritance, or both learning and inheritance. Using non-invasive genetic sampling, we collected grizzly bear hair samples during 2011–2014 across southwestern Alberta, Canada. We targeted private agricultural lands for hair samples at grizzly bear incident sites,
Authors
Andrea T. Morehouse, Tabitha A. Graves, Nathaniel Mikle, Mark S. Boyce
Estimating landscape resistance to dispersal
Dispersal is an inherently spatial process that can be affected by habitat conditions in sites encountered by dispersers. Understanding landscape resistance to dispersal is important in connectivity studies and reserve design, but most existing methods use resistance functions with cost parameters that are subjectively chosen by the investigator. We develop an analytic approach allowing for direct
Authors
Tabitha A. Graves, Richard B. Chandler, J. Andrew Royle, Paul Beier, Katherine C. Kendall
Spatial capture-recapture models for jointly estimating population density and landscape connectivity
Population size and landscape connectivity are key determinants of population viability, yet no methods exist for simultaneously estimating density and connectivity parameters. Recently developed spatial capture–recapture (SCR) models provide a framework for estimating density of animal populations but thus far have not been used to study connectivity. Rather, all applications of SCR models have u
Authors
J. Andrew Royle, Richard B. Chandler, Kimberly D. Gazenski, Tabitha A. Graves
Balancing precision and risk: should multiple detection methods be analyzed separately in N-mixture models?
Using multiple detection methods can increase the number, kind, and distribution of individuals sampled, which may increase accuracy and precision and reduce cost of population abundance estimates. However, when variables influencing abundance are of interest, if individuals detected via different methods are influenced by the landscape differently, separate analysis of multiple detection methods
Authors
Tabitha A. Graves, J. Andrew Royle, Katherine C. Kendall, Paul Beier, Jeffrey B. Stetz, Amy C. Macleod
Linking landscape characteristics to local grizzly bear abundance using multiple detection methods in a hierarchical model
Few studies link habitat to grizzly bear Ursus arctos abundance and these have not accounted for the variation in detection or spatial autocorrelation. We collected and genotyped bear hair in and around Glacier National Park in northwestern Montana during the summer of 2000. We developed a hierarchical Markov chain Monte Carlo model that extends the existing occupancy and count models by accountin
Authors
T.A. Graves, Katherine C. Kendall, J. Andrew Royle, J.B. Stetz, A.C. Macleod
Non-USGS Publications**
Graves, T.A., S. Farley, M. Goldstein, and C.Servheen. 2007. Identification of functional corridors with movement characteristics of brown bears on the Kenai Peninsula, Alaska. Landscape Ecology.
Graves, T.A., S. Farley, and C.Servheen. 2006. Frequency and distribution of highway crossings by Kenai Peninsula brown bears. Wildlife Society Bulletin. 34: 800-808.
Graves, T.A. and J. Waller. 2006. Identification of causes of missed fixes in GPS collar on animals. Journal of Wildlife Management. 70: 844-851.
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.