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
Predicting changes in Bear Foods
Grizzly Bear Dispersal
Bighorn Sheep in and near Glacier National Park
Ecology of Elk on Department of Interior Lands in Southwest Wyoming
Geocaching Natural Features - Applying Game Mechanics to Citizen Science Data Collection
Occurrence data of the western bumble bee from 1998 to 2020 across the western United States Occurrence data of the western bumble bee from 1998 to 2020 across the western United States
Wyoming statewide time-stamped oil and gas activity, 1900-2020 Wyoming statewide time-stamped oil and gas activity, 1900-2020
Bumblebee Surveys in Montana, North Dakota, South Dakota, and Nevada, USA (ver. 3.0, March 2025) Bumblebee Surveys in Montana, North Dakota, South Dakota, and Nevada, USA (ver. 3.0, March 2025)
Neonicotinoid nitroguanidine group insecticide application rates estimated across the western conterminous United States, 2008 to 2014 Neonicotinoid nitroguanidine group insecticide application rates estimated across the western conterminous United States, 2008 to 2014
Western bumble bee predicted occupancy (1998, 2020) and future projections (2050s), western conterminous United States Western bumble bee predicted occupancy (1998, 2020) and future projections (2050s), western conterminous United States
Daily 30-m fractional snow covered area and summary stats for the National Elk Refuge, Wyoming from 2015 to 2020 Daily 30-m fractional snow covered area and summary stats for the National Elk Refuge, Wyoming from 2015 to 2020
Historical trend analysis of phenology dates across the Western US from 1982 to 2016 Historical trend analysis of phenology dates across the Western US from 1982 to 2016
Projected peak instantaneous rate of green-up date and spring scale across Wyoming from 2000 to 2099 Projected peak instantaneous rate of green-up date and spring scale across Wyoming from 2000 to 2099
Remotely sensed elk locations on the National Elk Refuge, Wyoming, 2017-2019 Remotely sensed elk locations on the National Elk Refuge, Wyoming, 2017-2019
WildAgg: an R package to estimate and visualize wildlife aggregation data WildAgg: an R package to estimate and visualize wildlife aggregation data
Western bumble bee predicted occupancy and detection probability rasters for the western continental United States from 1998 to 2018 Western bumble bee predicted occupancy and detection probability rasters for the western continental United States from 1998 to 2018
Ungulate Migrations of the Western United States, Volume 1 Ungulate Migrations of the Western United States, Volume 1
Population and spatial dynamics of desert bighorn sheep in Grand Canyon during an outbreak of respiratory pneumonia Population and spatial dynamics of desert bighorn sheep in Grand Canyon during an outbreak of respiratory pneumonia
Evaluating density-weighted connectivity of black bears (Ursus americanus) in Glacier National Park with spatial capture–recapture models Evaluating density-weighted connectivity of black bears (Ursus americanus) in Glacier National Park with spatial capture–recapture models
Quantifying effectiveness and best practices for bumblebee identification from photographs Quantifying effectiveness and best practices for bumblebee identification from photographs
Bighorn sheep associations: Understanding tradeoffs of sociality and implications for disease transmission Bighorn sheep associations: Understanding tradeoffs of sociality and implications for disease transmission
Ecological significance of Wild Huckleberries (Vaccinium membranaceum) Ecological significance of Wild Huckleberries (Vaccinium membranaceum)
Recent and future declines of a historically widespread pollinator linked to climate, land cover, and pesticides Recent and future declines of a historically widespread pollinator linked to climate, land cover, and pesticides
A statistical framework for modelling migration corridors A statistical framework for modelling migration corridors
Precision and bias of spatial capture–recapture estimates: A multi-site, multi-year Utah black bear case study Precision and bias of spatial capture–recapture estimates: A multi-site, multi-year Utah black bear case study
Eyes on the herd: Quantifying ungulate density from satellite, unmanned aerial systems, and GPScollar data Eyes on the herd: Quantifying ungulate density from satellite, unmanned aerial systems, and GPScollar data
Average kinship within bighorn sheep populations is associated with connectivity, augmentation, and bottlenecks Average kinship within bighorn sheep populations is associated with connectivity, augmentation, and bottlenecks
Genetic attributes and research interests Genetic attributes and research interests
Non-USGS Publications**
**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
Predicting changes in Bear Foods
Grizzly Bear Dispersal
Bighorn Sheep in and near Glacier National Park
Ecology of Elk on Department of Interior Lands in Southwest Wyoming
Geocaching Natural Features - Applying Game Mechanics to Citizen Science Data Collection
Occurrence data of the western bumble bee from 1998 to 2020 across the western United States Occurrence data of the western bumble bee from 1998 to 2020 across the western United States
Wyoming statewide time-stamped oil and gas activity, 1900-2020 Wyoming statewide time-stamped oil and gas activity, 1900-2020
Bumblebee Surveys in Montana, North Dakota, South Dakota, and Nevada, USA (ver. 3.0, March 2025) Bumblebee Surveys in Montana, North Dakota, South Dakota, and Nevada, USA (ver. 3.0, March 2025)
Neonicotinoid nitroguanidine group insecticide application rates estimated across the western conterminous United States, 2008 to 2014 Neonicotinoid nitroguanidine group insecticide application rates estimated across the western conterminous United States, 2008 to 2014
Western bumble bee predicted occupancy (1998, 2020) and future projections (2050s), western conterminous United States Western bumble bee predicted occupancy (1998, 2020) and future projections (2050s), western conterminous United States
Daily 30-m fractional snow covered area and summary stats for the National Elk Refuge, Wyoming from 2015 to 2020 Daily 30-m fractional snow covered area and summary stats for the National Elk Refuge, Wyoming from 2015 to 2020
Historical trend analysis of phenology dates across the Western US from 1982 to 2016 Historical trend analysis of phenology dates across the Western US from 1982 to 2016
Projected peak instantaneous rate of green-up date and spring scale across Wyoming from 2000 to 2099 Projected peak instantaneous rate of green-up date and spring scale across Wyoming from 2000 to 2099
Remotely sensed elk locations on the National Elk Refuge, Wyoming, 2017-2019 Remotely sensed elk locations on the National Elk Refuge, Wyoming, 2017-2019
WildAgg: an R package to estimate and visualize wildlife aggregation data WildAgg: an R package to estimate and visualize wildlife aggregation data
Western bumble bee predicted occupancy and detection probability rasters for the western continental United States from 1998 to 2018 Western bumble bee predicted occupancy and detection probability rasters for the western continental United States from 1998 to 2018
Ungulate Migrations of the Western United States, Volume 1 Ungulate Migrations of the Western United States, Volume 1
Population and spatial dynamics of desert bighorn sheep in Grand Canyon during an outbreak of respiratory pneumonia Population and spatial dynamics of desert bighorn sheep in Grand Canyon during an outbreak of respiratory pneumonia
Evaluating density-weighted connectivity of black bears (Ursus americanus) in Glacier National Park with spatial capture–recapture models Evaluating density-weighted connectivity of black bears (Ursus americanus) in Glacier National Park with spatial capture–recapture models
Quantifying effectiveness and best practices for bumblebee identification from photographs Quantifying effectiveness and best practices for bumblebee identification from photographs
Bighorn sheep associations: Understanding tradeoffs of sociality and implications for disease transmission Bighorn sheep associations: Understanding tradeoffs of sociality and implications for disease transmission
Ecological significance of Wild Huckleberries (Vaccinium membranaceum) Ecological significance of Wild Huckleberries (Vaccinium membranaceum)
Recent and future declines of a historically widespread pollinator linked to climate, land cover, and pesticides Recent and future declines of a historically widespread pollinator linked to climate, land cover, and pesticides
A statistical framework for modelling migration corridors A statistical framework for modelling migration corridors
Precision and bias of spatial capture–recapture estimates: A multi-site, multi-year Utah black bear case study Precision and bias of spatial capture–recapture estimates: A multi-site, multi-year Utah black bear case study
Eyes on the herd: Quantifying ungulate density from satellite, unmanned aerial systems, and GPScollar data Eyes on the herd: Quantifying ungulate density from satellite, unmanned aerial systems, and GPScollar data
Average kinship within bighorn sheep populations is associated with connectivity, augmentation, and bottlenecks Average kinship within bighorn sheep populations is associated with connectivity, augmentation, and bottlenecks
Genetic attributes and research interests Genetic attributes and research interests
Non-USGS Publications**
**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.