Mark Haroldson
Mark Haroldson is an emeritus USGS Wildlife Biologist for the Interagency Grizzly Bears Study Team and works out of the Northern Rocky Mountain Science Center, Bozeman, MT.
Research Interest
Mark has had a passion for bears since he began studying them as an undergraduate in 1976. He has worked in bear research and management in several western states ever since. Since 1984 he has worked in various capacities for the Interagency Grizzly Bear Study Team in the Greater Yellowstone Ecosystem. Current research is focused on mortality and population trend of grizzly bears in the Greater Yellowstone Ecosystem.
Education and Certifications
B.S. Wildlife Biology, 1979, University of Montana
Graduate level class work, 1982-88, University of Montana
Science and Products
Informing Management Options for Grizzly Bears in a Changing Greater Yellowstone Ecosystem
Project Overview The iconic grizzly bear of the Greater Yellowstone Ecosystem has exhibited a remarkable recovery in response to concerted conservation actions implemented since its listing as threatened under the Endangered Species Act in 1975. However, information regarding the potential effects and timing of climate change in conjunction with increasing human recreation and...
Interagency Grizzly Bear Study Team
The Interagency Grizzly Bear Study Team (IGBST) is an interdisciplinary group of scientists and biologists responsible for long-term monitoring and research efforts on grizzly bears in the Greater Yellowstone Ecosystem (GYE). The team was formed by the Department of the Interior (DOI) in 1973 as a direct result of controversy surrounding the closure of open pit garbage dumps within Yellowstone...
NOROCK Large Carnivore Research Program
NOROCK has substantial expertise in large carnivore research, primarily involving species listed as Threatened or Endangered. NOROCK’s Large Carnivore Research Program includes scientists from NOROCK’s Headquarters, West Glacier Field Station, and the Southern Appalachian Field Station. Studies are conducted in a wide variety of landscapes throughout the U.S., as well as international research...
Mortality, morphology, and water chemistry for 6PPD-quinone exposed coho embryos Mortality, morphology, and water chemistry for 6PPD-quinone exposed coho embryos
Understanding evolutionary processes that drive population dynamics is critical in ecology. Measuring the performance-density relationship in long-lived mammalian species demands long-term data, limiting the ability to observe such mechanisms. We tested density-dependent (intrinsic) and density-independent (extrinsic) drivers of body composition of grizzly bears (Ursus arctos) in the...
Body composition data of grizzly bears in the Greater Yellowstone Ecosystem 2000-2020 Body composition data of grizzly bears in the Greater Yellowstone Ecosystem 2000-2020
Understanding evolutionary processes that drive population dynamics is critical in ecology. Measuring the performance-density relationship in long-lived mammalian species demands long-term data, limiting the ability to observe such mechanisms. We tested density-dependent (intrinsic) and density-independent (extrinsic) drivers of body composition of grizzly bears (Ursus arctos) in the...
Documented known and probable grizzly bear mortalities in the Greater Yellowstone Ecosystem, 2015-2024 (ver. 4.0 May 2025) Documented known and probable grizzly bear mortalities in the Greater Yellowstone Ecosystem, 2015-2024 (ver. 4.0 May 2025)
The Interagency Grizzly Bear Study Team (IGBST) evaluates mortalities for population segments within the DMA by deriving estimates of total mortality for independent-age (2 years or older) females and independent-age males, including estimates of unknown/unreported mortalities based on Cherry et al. (2002). We then determine the total annual mortality rate for these segments as a percent...
Detection histories of grizzly bears in Grand Teton National Park, 2014-2015 Detection histories of grizzly bears in Grand Teton National Park, 2014-2015
This dataset contains detection histories of grizzly bears in areas of Grand Teton National Park that are open for elk harvest as part of the Elk Reduction Program. Sampling followed a robust design analysis with 6 primary sampling periods of 4 weekly secondary sampling periods each during 2014-2015. In both years, primary sampling periods were in July-August (no elk hunt), September...
Canine distemper virus antibody titer results for grizzly bears and wolves in the Greater Yellowstone Ecosystem 1984-2014 Canine distemper virus antibody titer results for grizzly bears and wolves in the Greater Yellowstone Ecosystem 1984-2014
We investigated the dynamics of canine distemper virus (CDV) in grizzly bears (Ursus arctos) and wolves (Canis lupus) of the Greater Yellowstone Ecosystem using serological data collected from 1984 to 2014. 565 sera samples were obtained from 425 unique grizzly bears (134 females and 291 males) from 1984 to 2014 and 319 sera samples were obtained from 285 unique wolves (130 females and...
Potential movement paths for male grizzly bear (Ursus arctos) dispersal between the Northern Continental Divide and Greater Yellowstone Ecosystems, 2000-2015 Potential movement paths for male grizzly bear (Ursus arctos) dispersal between the Northern Continental Divide and Greater Yellowstone Ecosystems, 2000-2015
For several decades, grizzly bear (Ursus arctos) populations in the Greater Yellowstone Ecosystem (GYE) and the Northern Continental Divide Ecosystem (NCDE) have increased in numbers and range extent. Whereas the NCDE population is contiguous with grizzly bear populations in the Canadian Rocky Mountains, genetic evidence suggests the GYE population remains isolated. Recent analyses...
Filter Total Items: 87
The influence of human presence and footprint on animal space use in US national parks The influence of human presence and footprint on animal space use in US national parks
Given the importance of protected areas for biodiversity, the growth of visitation to many areas has raised concerns about the effects of humans on wildlife. In 2020, the COVID-19 pandemic led to temporary closure of national parks in the United States, offering a pseudonatural experiment to tease apart the effects of permanent infrastructure and transient human presence on animals. We...
Authors
Kaitlyn M. Gaynor, Forest Hayes, Kezia R. Manlove, Nathan L. Galloway, John Benson, Michael J. Cherry, Clinton Epps, Robert Fletcher, John Orrock, Justine Smith, Christina M. Aiello, Jerrold Belant, Joel Berger, Mark Biel, Jill Bright, Joseph Bump, Michael Burchett, Carson Butler, Jennifer Carlson, Eric Cole, Neal Darby, Erin DeGutis, Sarah Dewey, Pete Figura, Tom Gable, Jeff Gagnon, Danielle Glass, Jennifer Green, Kerry Gunther, Mark Haroldson, Kent Hersey, Brandon Holton, Austin T. Homkes, Sarah Hoy, Debra Hughson, Kyle Joly, Ryan Leahy, Caitlin Lee-Roney, Rob Lester, Daniel MacNulty, Michael Magnuson, Daniel Martin, Rachel Mazur, Seth A. Moore, Elizabeth Orning, Katie Patrick, Rolf Peterson, Lynette Potvin, Paige Prentice, Seth Riley, Mark Romanski, Annette Roug, Jeff Sikich, Nova Simpson, William Sloan, Douglas Smith, Mathew Sorum, Scott Sprague, Daniel Stahler, John Stephenson, Thomas Stephenson, Janice Stroud-Settles, Frank van Manen, John Vucetich, Kate Wilmot, Steve Windels, Tiffany Wolf, Paul C. Cross
Female and male grizzly bears differ in their responses to low-intensity recreation in a protected area Female and male grizzly bears differ in their responses to low-intensity recreation in a protected area
Strategies animals use to navigate human-dominated landscapes frequently mimic anti-predator responses employed by prey species. Understanding how large carnivores respond to outdoor recreation is important for conservation, particularly in protected areas with preservation mandates. Visitation to Yellowstone National Park doubled from 1980 to 2015, increasing the need to examine...
Authors
Elise Loggers, Andrea Litt, Mark Haroldson, Kerry Gunther, Frank van Manen
The diel niche of brown bears: Constraints on adaptive capacity in human-modified landscapes The diel niche of brown bears: Constraints on adaptive capacity in human-modified landscapes
DDiel activity rhythms, representing the behavioral pattern of the sleep–wake cycle, may be adjusted by wildlife in response to changes in environmental conditions. An increase in nocturnality is typically recognized as an adaptive strategy to segregate from humans and mitigate heat stress. Numerous studies have investigated spatial patterns and habitat use of large carnivores in human...
Authors
A. Donatelli, D. Ćirović, Mark Haroldson, Đuro Huber, J. Kindberg, I. Kojola, J. Kusak, G. Mastrantonio, A. Ordiz, S. Reljić, L. Santini, Frank van Manen, P. Ciucci
Identifying presence or absence of grizzly and polar bear cubs from the movements of adult females with machine learning Identifying presence or absence of grizzly and polar bear cubs from the movements of adult females with machine learning
BackgroundInformation on reproductive success is crucial to understanding population dynamics but can be difficult to obtain, particularly for species that birth while denning. For grizzly (Ursus arctos) and polar bears (U. maritimus), den visits are impractical because of safety and logistical considerations. Reproduction is typically documented through direct observation, which can be...
Authors
Erik Andersen, Justin Clapp, Milan Vinks, Todd Atwood, Daniel D. Bjornlie, Cecily M. Costello, David Gustine, Mark Haroldson, Lori Roberts, Karyn Rode, Frank van Manen, Ryan Wilson
A unified approach to long-term population monitoring of grizzly bears in the Greater Yellowstone Ecosystem A unified approach to long-term population monitoring of grizzly bears in the Greater Yellowstone Ecosystem
Long-term wildlife research and monitoring programs strive to maintain consistent data collections and analytical methods. Incorporating new techniques is important but can render data sets incongruent and limit their potential to discern trends in demographic parameters. Integrated population models (IPMs) can address these limitations by combining data sources that may span different...
Authors
Matthew Gould, Justin Clapp, Mark Haroldson, Cecily M. Costello, J. Nowak, Hans Martin, Michael Ebinger, Daniel D. Bjornlie, Daniel Thompson, Justin Dellinger, Matthew Mumma, Paul Lukacs, Frank van Manen
Integrating ecological value and charismatic species habitats to prioritize habitats for conservation: A case study from Greater Yellowstone Integrating ecological value and charismatic species habitats to prioritize habitats for conservation: A case study from Greater Yellowstone
Expanding human pressure has reduced natural habitats globally and motivated strategies to conserve remaining natural habitats. Decisions about conservation on private lands, however, are typically made by local stakeholders who are motivated by the elements of nature they most highly value. Thus, national prioritization for conservation should be complemented by local analysis of...
Authors
A. Hansena, A. Easta, Z. Ashford, C. Crittendena, O. Jakabosky, D. Quinby, Shannon K. Brewer, Frank van Manen, Mark Haroldson, A. Middleton, N. Robinson, D. Theobald
Grizzly bear responses to restrictions of recreation in Yellowstone National Park Grizzly bear responses to restrictions of recreation in Yellowstone National Park
Avoiding humans will be more difficult and energetically costly for animals as outdoor recreation increases and people venture farther into wildland areas that provide high-quality habitat for wildlife. Restricting human access can be an attractive management tool to mitigate effects of human recreation activities on wildlife; however, the efficacy of such measures is rarely assessed. In...
Authors
Elise Loggers, Andrea Litt, Frank van Manen, Mark Haroldson, Kerry Gunther
Grizzly bear lean body mass, but not fat gain, is inversely correlated with bear density in a changing Greater Yellowstone Ecosystem Grizzly bear lean body mass, but not fat gain, is inversely correlated with bear density in a changing Greater Yellowstone Ecosystem
No abstract available.
Authors
Andrea Corradini, Mark Haroldson, Frank van Manen
A summary of grizzly bear distribution in Montana: Application of consistent methods in 2022 A summary of grizzly bear distribution in Montana: Application of consistent methods in 2022
No abstract available.
Authors
Cecily M. Costello, J. Dellinger, Jennifer Fortin-Noreus, Mark Haroldson, Wayne Kasworm, J. Tiesberg, Frank van Manen
Evidence for density-dependent effects on body composition of a large omnivore in a changing Greater Yellowstone Ecosystem Evidence for density-dependent effects on body composition of a large omnivore in a changing Greater Yellowstone Ecosystem
Understanding the density-dependent processes that drive population demography in a changing world is critical in ecology, yet measuring performance–density relationships in long-lived mammalian species demands long-term data, limiting scientists' ability to observe such mechanisms. We tested performance–density relationships for an opportunistic omnivore, grizzly bears (Ursus arctos...
Authors
Andrea Corradini, Mark Haroldson, Francesca Cagnacci, Cecily M. Costello, Daniel D. Bjornlie, Daniel Thompson, Jeremy M. Nicholson, Kerry Gunther, Katharine Wilmot, Frank van Manen
Grizzly bear movement models predict habitat use for nearby populations Grizzly bear movement models predict habitat use for nearby populations
Conservation planning and decision-making can be enhanced by ecological models that reliably transfer to times and places beyond those where models were developed. Transferrable models can be especially helpful for species of conservation concern, such as grizzly bears (Ursus arctos). Currently, only four grizzly bear populations remain in the contiguous United States. We evaluated...
Authors
Sarah Sells, Cecily M. Costello, Paul Lukacs, Frank van Manen, Mark Haroldson, Wayne Kasworm, Justin Tesiberg, Milan Vinks, Daniel Bjornlie
Enhancements to population monitoring of Yellowstone grizzly bears Enhancements to population monitoring of Yellowstone grizzly bears
In the Greater Yellowstone Ecosystem, counts of female grizzly bears (Ursus arctos) with cubs-of-the-year (females with cubs) from systematic aerial surveys and opportunistic ground sightings are combined with demographic data to derive annual population estimates. We addressed 2 limitations to the monitoring approach. As part of a rule set, a conservative distance of >30 km currently is...
Authors
Frank van Manen, Michael Ebinger, Cecily M. Costello, Daniel D. Bjornlie, Justin Clapp, Daniel Thompson, Mark Haroldson, Kevin Frey, Curtis Hendricks, Jeremy M. Nicholson, Kerry Gunther, Katharine Wilmot, Hilary Cooley, Jennifer Fortin-Noreus, Pat Hnilicka, Daniel Tyers
Science and Products
Informing Management Options for Grizzly Bears in a Changing Greater Yellowstone Ecosystem
Project Overview The iconic grizzly bear of the Greater Yellowstone Ecosystem has exhibited a remarkable recovery in response to concerted conservation actions implemented since its listing as threatened under the Endangered Species Act in 1975. However, information regarding the potential effects and timing of climate change in conjunction with increasing human recreation and...
Interagency Grizzly Bear Study Team
The Interagency Grizzly Bear Study Team (IGBST) is an interdisciplinary group of scientists and biologists responsible for long-term monitoring and research efforts on grizzly bears in the Greater Yellowstone Ecosystem (GYE). The team was formed by the Department of the Interior (DOI) in 1973 as a direct result of controversy surrounding the closure of open pit garbage dumps within Yellowstone...
NOROCK Large Carnivore Research Program
NOROCK has substantial expertise in large carnivore research, primarily involving species listed as Threatened or Endangered. NOROCK’s Large Carnivore Research Program includes scientists from NOROCK’s Headquarters, West Glacier Field Station, and the Southern Appalachian Field Station. Studies are conducted in a wide variety of landscapes throughout the U.S., as well as international research...
Mortality, morphology, and water chemistry for 6PPD-quinone exposed coho embryos Mortality, morphology, and water chemistry for 6PPD-quinone exposed coho embryos
Understanding evolutionary processes that drive population dynamics is critical in ecology. Measuring the performance-density relationship in long-lived mammalian species demands long-term data, limiting the ability to observe such mechanisms. We tested density-dependent (intrinsic) and density-independent (extrinsic) drivers of body composition of grizzly bears (Ursus arctos) in the...
Body composition data of grizzly bears in the Greater Yellowstone Ecosystem 2000-2020 Body composition data of grizzly bears in the Greater Yellowstone Ecosystem 2000-2020
Understanding evolutionary processes that drive population dynamics is critical in ecology. Measuring the performance-density relationship in long-lived mammalian species demands long-term data, limiting the ability to observe such mechanisms. We tested density-dependent (intrinsic) and density-independent (extrinsic) drivers of body composition of grizzly bears (Ursus arctos) in the...
Documented known and probable grizzly bear mortalities in the Greater Yellowstone Ecosystem, 2015-2024 (ver. 4.0 May 2025) Documented known and probable grizzly bear mortalities in the Greater Yellowstone Ecosystem, 2015-2024 (ver. 4.0 May 2025)
The Interagency Grizzly Bear Study Team (IGBST) evaluates mortalities for population segments within the DMA by deriving estimates of total mortality for independent-age (2 years or older) females and independent-age males, including estimates of unknown/unreported mortalities based on Cherry et al. (2002). We then determine the total annual mortality rate for these segments as a percent...
Detection histories of grizzly bears in Grand Teton National Park, 2014-2015 Detection histories of grizzly bears in Grand Teton National Park, 2014-2015
This dataset contains detection histories of grizzly bears in areas of Grand Teton National Park that are open for elk harvest as part of the Elk Reduction Program. Sampling followed a robust design analysis with 6 primary sampling periods of 4 weekly secondary sampling periods each during 2014-2015. In both years, primary sampling periods were in July-August (no elk hunt), September...
Canine distemper virus antibody titer results for grizzly bears and wolves in the Greater Yellowstone Ecosystem 1984-2014 Canine distemper virus antibody titer results for grizzly bears and wolves in the Greater Yellowstone Ecosystem 1984-2014
We investigated the dynamics of canine distemper virus (CDV) in grizzly bears (Ursus arctos) and wolves (Canis lupus) of the Greater Yellowstone Ecosystem using serological data collected from 1984 to 2014. 565 sera samples were obtained from 425 unique grizzly bears (134 females and 291 males) from 1984 to 2014 and 319 sera samples were obtained from 285 unique wolves (130 females and...
Potential movement paths for male grizzly bear (Ursus arctos) dispersal between the Northern Continental Divide and Greater Yellowstone Ecosystems, 2000-2015 Potential movement paths for male grizzly bear (Ursus arctos) dispersal between the Northern Continental Divide and Greater Yellowstone Ecosystems, 2000-2015
For several decades, grizzly bear (Ursus arctos) populations in the Greater Yellowstone Ecosystem (GYE) and the Northern Continental Divide Ecosystem (NCDE) have increased in numbers and range extent. Whereas the NCDE population is contiguous with grizzly bear populations in the Canadian Rocky Mountains, genetic evidence suggests the GYE population remains isolated. Recent analyses...
Filter Total Items: 87
The influence of human presence and footprint on animal space use in US national parks The influence of human presence and footprint on animal space use in US national parks
Given the importance of protected areas for biodiversity, the growth of visitation to many areas has raised concerns about the effects of humans on wildlife. In 2020, the COVID-19 pandemic led to temporary closure of national parks in the United States, offering a pseudonatural experiment to tease apart the effects of permanent infrastructure and transient human presence on animals. We...
Authors
Kaitlyn M. Gaynor, Forest Hayes, Kezia R. Manlove, Nathan L. Galloway, John Benson, Michael J. Cherry, Clinton Epps, Robert Fletcher, John Orrock, Justine Smith, Christina M. Aiello, Jerrold Belant, Joel Berger, Mark Biel, Jill Bright, Joseph Bump, Michael Burchett, Carson Butler, Jennifer Carlson, Eric Cole, Neal Darby, Erin DeGutis, Sarah Dewey, Pete Figura, Tom Gable, Jeff Gagnon, Danielle Glass, Jennifer Green, Kerry Gunther, Mark Haroldson, Kent Hersey, Brandon Holton, Austin T. Homkes, Sarah Hoy, Debra Hughson, Kyle Joly, Ryan Leahy, Caitlin Lee-Roney, Rob Lester, Daniel MacNulty, Michael Magnuson, Daniel Martin, Rachel Mazur, Seth A. Moore, Elizabeth Orning, Katie Patrick, Rolf Peterson, Lynette Potvin, Paige Prentice, Seth Riley, Mark Romanski, Annette Roug, Jeff Sikich, Nova Simpson, William Sloan, Douglas Smith, Mathew Sorum, Scott Sprague, Daniel Stahler, John Stephenson, Thomas Stephenson, Janice Stroud-Settles, Frank van Manen, John Vucetich, Kate Wilmot, Steve Windels, Tiffany Wolf, Paul C. Cross
Female and male grizzly bears differ in their responses to low-intensity recreation in a protected area Female and male grizzly bears differ in their responses to low-intensity recreation in a protected area
Strategies animals use to navigate human-dominated landscapes frequently mimic anti-predator responses employed by prey species. Understanding how large carnivores respond to outdoor recreation is important for conservation, particularly in protected areas with preservation mandates. Visitation to Yellowstone National Park doubled from 1980 to 2015, increasing the need to examine...
Authors
Elise Loggers, Andrea Litt, Mark Haroldson, Kerry Gunther, Frank van Manen
The diel niche of brown bears: Constraints on adaptive capacity in human-modified landscapes The diel niche of brown bears: Constraints on adaptive capacity in human-modified landscapes
DDiel activity rhythms, representing the behavioral pattern of the sleep–wake cycle, may be adjusted by wildlife in response to changes in environmental conditions. An increase in nocturnality is typically recognized as an adaptive strategy to segregate from humans and mitigate heat stress. Numerous studies have investigated spatial patterns and habitat use of large carnivores in human...
Authors
A. Donatelli, D. Ćirović, Mark Haroldson, Đuro Huber, J. Kindberg, I. Kojola, J. Kusak, G. Mastrantonio, A. Ordiz, S. Reljić, L. Santini, Frank van Manen, P. Ciucci
Identifying presence or absence of grizzly and polar bear cubs from the movements of adult females with machine learning Identifying presence or absence of grizzly and polar bear cubs from the movements of adult females with machine learning
BackgroundInformation on reproductive success is crucial to understanding population dynamics but can be difficult to obtain, particularly for species that birth while denning. For grizzly (Ursus arctos) and polar bears (U. maritimus), den visits are impractical because of safety and logistical considerations. Reproduction is typically documented through direct observation, which can be...
Authors
Erik Andersen, Justin Clapp, Milan Vinks, Todd Atwood, Daniel D. Bjornlie, Cecily M. Costello, David Gustine, Mark Haroldson, Lori Roberts, Karyn Rode, Frank van Manen, Ryan Wilson
A unified approach to long-term population monitoring of grizzly bears in the Greater Yellowstone Ecosystem A unified approach to long-term population monitoring of grizzly bears in the Greater Yellowstone Ecosystem
Long-term wildlife research and monitoring programs strive to maintain consistent data collections and analytical methods. Incorporating new techniques is important but can render data sets incongruent and limit their potential to discern trends in demographic parameters. Integrated population models (IPMs) can address these limitations by combining data sources that may span different...
Authors
Matthew Gould, Justin Clapp, Mark Haroldson, Cecily M. Costello, J. Nowak, Hans Martin, Michael Ebinger, Daniel D. Bjornlie, Daniel Thompson, Justin Dellinger, Matthew Mumma, Paul Lukacs, Frank van Manen
Integrating ecological value and charismatic species habitats to prioritize habitats for conservation: A case study from Greater Yellowstone Integrating ecological value and charismatic species habitats to prioritize habitats for conservation: A case study from Greater Yellowstone
Expanding human pressure has reduced natural habitats globally and motivated strategies to conserve remaining natural habitats. Decisions about conservation on private lands, however, are typically made by local stakeholders who are motivated by the elements of nature they most highly value. Thus, national prioritization for conservation should be complemented by local analysis of...
Authors
A. Hansena, A. Easta, Z. Ashford, C. Crittendena, O. Jakabosky, D. Quinby, Shannon K. Brewer, Frank van Manen, Mark Haroldson, A. Middleton, N. Robinson, D. Theobald
Grizzly bear responses to restrictions of recreation in Yellowstone National Park Grizzly bear responses to restrictions of recreation in Yellowstone National Park
Avoiding humans will be more difficult and energetically costly for animals as outdoor recreation increases and people venture farther into wildland areas that provide high-quality habitat for wildlife. Restricting human access can be an attractive management tool to mitigate effects of human recreation activities on wildlife; however, the efficacy of such measures is rarely assessed. In...
Authors
Elise Loggers, Andrea Litt, Frank van Manen, Mark Haroldson, Kerry Gunther
Grizzly bear lean body mass, but not fat gain, is inversely correlated with bear density in a changing Greater Yellowstone Ecosystem Grizzly bear lean body mass, but not fat gain, is inversely correlated with bear density in a changing Greater Yellowstone Ecosystem
No abstract available.
Authors
Andrea Corradini, Mark Haroldson, Frank van Manen
A summary of grizzly bear distribution in Montana: Application of consistent methods in 2022 A summary of grizzly bear distribution in Montana: Application of consistent methods in 2022
No abstract available.
Authors
Cecily M. Costello, J. Dellinger, Jennifer Fortin-Noreus, Mark Haroldson, Wayne Kasworm, J. Tiesberg, Frank van Manen
Evidence for density-dependent effects on body composition of a large omnivore in a changing Greater Yellowstone Ecosystem Evidence for density-dependent effects on body composition of a large omnivore in a changing Greater Yellowstone Ecosystem
Understanding the density-dependent processes that drive population demography in a changing world is critical in ecology, yet measuring performance–density relationships in long-lived mammalian species demands long-term data, limiting scientists' ability to observe such mechanisms. We tested performance–density relationships for an opportunistic omnivore, grizzly bears (Ursus arctos...
Authors
Andrea Corradini, Mark Haroldson, Francesca Cagnacci, Cecily M. Costello, Daniel D. Bjornlie, Daniel Thompson, Jeremy M. Nicholson, Kerry Gunther, Katharine Wilmot, Frank van Manen
Grizzly bear movement models predict habitat use for nearby populations Grizzly bear movement models predict habitat use for nearby populations
Conservation planning and decision-making can be enhanced by ecological models that reliably transfer to times and places beyond those where models were developed. Transferrable models can be especially helpful for species of conservation concern, such as grizzly bears (Ursus arctos). Currently, only four grizzly bear populations remain in the contiguous United States. We evaluated...
Authors
Sarah Sells, Cecily M. Costello, Paul Lukacs, Frank van Manen, Mark Haroldson, Wayne Kasworm, Justin Tesiberg, Milan Vinks, Daniel Bjornlie
Enhancements to population monitoring of Yellowstone grizzly bears Enhancements to population monitoring of Yellowstone grizzly bears
In the Greater Yellowstone Ecosystem, counts of female grizzly bears (Ursus arctos) with cubs-of-the-year (females with cubs) from systematic aerial surveys and opportunistic ground sightings are combined with demographic data to derive annual population estimates. We addressed 2 limitations to the monitoring approach. As part of a rule set, a conservative distance of >30 km currently is...
Authors
Frank van Manen, Michael Ebinger, Cecily M. Costello, Daniel D. Bjornlie, Justin Clapp, Daniel Thompson, Mark Haroldson, Kevin Frey, Curtis Hendricks, Jeremy M. Nicholson, Kerry Gunther, Katharine Wilmot, Hilary Cooley, Jennifer Fortin-Noreus, Pat Hnilicka, Daniel Tyers