Sequential estimates of occupied ranges for grizzly bears in the Greater Yellowstone Ecosystem during 1990–2022 (Dellinger et al. 2023). Range extents are based on methods described in Bjornlie et al. (2014).
Frank T van Manen, Ph.D.
Frank van Manen is an ecologist who blends his research interest in large carnivores with landscape ecology and is the team lead of the Interagency Grizzly Bear Study Team.
Research Interests
Frank's research focus is on 1) grizzly bear and black bear ecology and management, 2) demographic models to inform large carnivore management, 3) resource selection and energy landscapes, 4) wildlife genetics, and 5) international bear conservation.
Formerly, Frank spent 12 years with the USGS Leetown Science Center specializing in responses of mammals to landscape changes, management of large carnivores, and habitat models to support protection and restoration of plants and trees.
For available articles, click on the Publications tab.
Professional Experience
In 2012 Frank became Team Leader of the Interagency Grizzly Bear Study Team, a cooperative research team that addresses monitoring and research needs for the Greater Yellowstone grizzly bear population.
His research focus for the past 35 years has been on bear ecology and management. Prior to his current research on Yellowstone grizzly bears, he conducted numerous studies on American black bears in the southeastern U.S. He has also collaborated on field studies with bear researchers in Ecuador (Andean bear), Sri Lanka (sloth bear), Malaysia, (sun bear), and China (giant panda).
Frank served as Treasurer and then President of the International Association for Bear Research and Management from 2001 through 2013 and is an Associate Editor for the scientific journal Ursus. He has adjunct appointments with Montana State University and the University of Tennessee.
Education and Certifications
Ph.D. 1994. Ecology and Statistics. University of Tennessee
B.S. and M.S. 1989. Biology. Wageningen Agricultural University, Netherlands
Science and Products
The Effects of Climate Variability and Change on Human-Bear Interactions in North America
Interagency Grizzly Bear Study Team
NOROCK Large Carnivore Research Program
IGBST Grizzly Bear Food Synthesis Report
Mortality, morphology, and water chemistry for 6PPD-quinone exposed coho embryos
Body composition data of grizzly bears in the Greater Yellowstone Ecosystem 2000-2020
Documented known and probable grizzly bear mortalities in the Greater Yellowstone Ecosystem, 2015-2022 (ver. 2.0, April 2023)
Detection histories of grizzly bears in Grand Teton National Park, 2014-2015
Canine distemper virus antibody titer results for grizzly bears and wolves in the Greater Yellowstone Ecosystem 1984-2014
Predicted carnivore conservation hotspots in Peninsular Malaysia
Potential movement paths for male grizzly bear (Ursus arctos) dispersal between the Northern Continental Divide and Greater Yellowstone Ecosystems, 2000-2015
Sequential estimates of occupied ranges for grizzly bears in the Greater Yellowstone Ecosystem during 1990–2022 (Dellinger et al. 2023). Range extents are based on methods described in Bjornlie et al. (2014).
Sequential estimates of occupied ranges for grizzly bears in the Greater Yellowstone Ecosystem during 1990–2018. Range extents are based on methods described in Bjornlie et al. (2014).
Sequential estimates of occupied ranges for grizzly bears in the Greater Yellowstone Ecosystem during 1990–2018. Range extents are based on methods described in Bjornlie et al. (2014).
When looking for a place to set up a capture location, biologists look for existing bear sign such as scratches on trees and bear scat. Sometimes traps are set in areas that have no obvious bear sign to determine if indeed bears are present.
When looking for a place to set up a capture location, biologists look for existing bear sign such as scratches on trees and bear scat. Sometimes traps are set in areas that have no obvious bear sign to determine if indeed bears are present.
USGS biologists collecting biological information from a grizzly bear they have captured. Biologists collect hair samples for genetic analysis, weigh the bear, and gather numerous measurements of the body, such as the head, paws, claws, teeth, etc. Overall condition of the bear is assessed as well, including a body fat measurement.
USGS biologists collecting biological information from a grizzly bear they have captured. Biologists collect hair samples for genetic analysis, weigh the bear, and gather numerous measurements of the body, such as the head, paws, claws, teeth, etc. Overall condition of the bear is assessed as well, including a body fat measurement.
A systematic review of the effects of climate variability and change on black and brown bear ecology and interactions with humans
Grizzly bear responses to restrictions of recreation in Yellowstone National Park
Spatial variation in density of American black bears in northern Yellowstone National Park
Grizzly bear lean body mass, but not fat gain, is inversely correlated with bear density in a changing Greater Yellowstone Ecosystem
A summary of grizzly bear distribution in Montana: Application of consistent methods in 2022
A test of the green wave hypothesis in omnivorous brown bears across North America
Evidence for density-dependent effects on body composition of a large omnivore in a changing Greater Yellowstone Ecosystem
Secondary forest within a timber plantation concession in Borneo contributes to a diverse mammal assemblage
Grizzly bear movement models predict habitat use for nearby populations
Enhancements to population monitoring of Yellowstone grizzly bears
Genetic architecture and evolution of color variation in American black bears
Tooth wear and the apparent consumption of human foods among American black bears (Ursus americanus) in Great Smoky Mountains National Park, USA
Science and Products
- Science
The Effects of Climate Variability and Change on Human-Bear Interactions in North America
Negative human-bear interactions are a common problem and management priority for many wildlife agencies in North America. Bears are adaptable to anthropogenic activity and food sources which creates opportunities for conflict with humans, including property damage, livestock depredation, and in severe cases, human injury. Acute climate events and long-term directional climate change can exacerbatInteragency 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...IGBST Grizzly Bear Food Synthesis Report
How to Cite: Interagency Grizzly Bear Study Team. 2013. Response of Yellowstone grizzly bears to changes in food resources: a synthesis. Report to the Interagency Grizzly Bear Committee and Yellowstone Ecosystem Subcommittee. Interagency Grizzly Bear Study Team, U.S. Geological Survey, Northern Rocky Mountain Science Center, Bozeman, Montana, USA. - Data
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 Greater YelloBody 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 Greater YelloDocumented known and probable grizzly bear mortalities in the Greater Yellowstone Ecosystem, 2015-2022 (ver. 2.0, April 2023)
We evaluate mortalities for population segments within the DMA by deriving estimates of total mortality for independent-age (equal to or less than 2 years old) 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 of their respective population estimatDetection 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-October (no eCanine 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 155 males)Predicted carnivore conservation hotspots in Peninsular Malaysia
A raster surface identifying hotspots of conservation priority based on 375 location records (89 unique geographic locations) of 28 species of Carnivora in Peninsular Malaysia. Hotspot analysis was conducted by calculating the Getis-Ord Gi* (pronounced G-i-star) statistic, using IUCN Red List status rank for each species as a weighting variable. Raster cell values represent a kernel density of z-sPotential 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 indicate the ef - Multimedia
Animated image showing grizzly bear range expansion in GYE: 1990-2022Animated image showing grizzly bear range expansion in GYE: 1990-2022
Sequential estimates of occupied ranges for grizzly bears in the Greater Yellowstone Ecosystem during 1990–2022 (Dellinger et al. 2023). Range extents are based on methods described in Bjornlie et al. (2014).
Sequential estimates of occupied ranges for grizzly bears in the Greater Yellowstone Ecosystem during 1990–2022 (Dellinger et al. 2023). Range extents are based on methods described in Bjornlie et al. (2014).
Animated image showing grizzly bear range expansion in GYE: 1990-2018Animated image showing grizzly bear range expansion in GYE: 1990-2018Sequential estimates of occupied ranges for grizzly bears in the Greater Yellowstone Ecosystem during 1990–2018. Range extents are based on methods described in Bjornlie et al. (2014).
Sequential estimates of occupied ranges for grizzly bears in the Greater Yellowstone Ecosystem during 1990–2018. Range extents are based on methods described in Bjornlie et al. (2014).
Grizzly bear on a remote camera.When looking for a place to set up a capture location, biologists look for existing bear sign such as scratches on trees and bear scat. Sometimes traps are set in areas that have no obvious bear sign to determine if indeed bears are present.
When looking for a place to set up a capture location, biologists look for existing bear sign such as scratches on trees and bear scat. Sometimes traps are set in areas that have no obvious bear sign to determine if indeed bears are present.
Biologists Collecting Biological Samples from Grizzly BearBiologists Collecting Biological Samples from Grizzly BearUSGS biologists collecting biological information from a grizzly bear they have captured. Biologists collect hair samples for genetic analysis, weigh the bear, and gather numerous measurements of the body, such as the head, paws, claws, teeth, etc. Overall condition of the bear is assessed as well, including a body fat measurement.
USGS biologists collecting biological information from a grizzly bear they have captured. Biologists collect hair samples for genetic analysis, weigh the bear, and gather numerous measurements of the body, such as the head, paws, claws, teeth, etc. Overall condition of the bear is assessed as well, including a body fat measurement.
- Publications
Filter Total Items: 79
A systematic review of the effects of climate variability and change on black and brown bear ecology and interactions with humans
Climate change poses a pervasive threat to humans and wildlife by altering resource availability, changing co-occurrences, and directly or indirectly influencing human-wildlife interactions. For many wildlife agencies in North America, managing bears (Ursus spp.) and human-bear interactions is a priority, yet the direct and indirect effects of climate change are exacerbating management challenges.AuthorsKatherine Anne Kurth, Kate Malpeli, Joseph D. Clark, Heather E. Johnson, Frank T. van ManenGrizzly 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 1982, YelAuthorsElise Loggers, Andrea R. Litt, Frank T. van Manen, Mark A. Haroldson, Kerry A. GuntherSpatial variation in density of American black bears in northern Yellowstone National Park
The quality and availability of resources are known to influence spatial patterns of animal density. In Yellowstone National Park, relationships between the availability of resources and the distribution of grizzly bears (Ursus arctos) have been explored but have yet to be examined in American black bears (Ursus americanus). We conducted non-invasive genetic sampling during 2017–2018 (mid-May to mAuthorsNathaniel R. Bowersock, Andrea R. Litt, Michael A. Sawaya, Kerry A. Gunther, Frank T. van ManenGrizzly bear lean body mass, but not fat gain, is inversely correlated with bear density in a changing Greater Yellowstone Ecosystem
No abstract available.AuthorsAndrea Corradini, Mark A. Haroldson, Frank T. van ManenA summary of grizzly bear distribution in Montana: Application of consistent methods in 2022
No abstract available.AuthorsCecily M. Costello, J. Dellinger, Jennifer Fortin-Noreus, Mark A. Haroldson, Wayne F. Kasworm, J. E. Tiesberg, Frank T. van ManenA test of the green wave hypothesis in omnivorous brown bears across North America
Herbivorous animals tend to seek out plants at intermediate phenological states to improve energy intake while minimizing consumption of fibrous material. In some ecosystems, the timing of green-up is heterogeneous and propagates across space in a wave-like pattern, known as the green wave. Tracking the green wave allows individuals to prolong access to higher-quality forage. While there is a pletAuthorsNathaniel R. Bowersock, L. M. Ciarniello, William W. Deacy, D. C. Heard, Kyle Joly, Clayton T. Lamb, William B. Leacock, Bruce Mclellan, Garth Mowat, Mathew S Sorum, Frank T. van Manen, Jerod A. MerkleEvidence 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, Linnaeus, 17AuthorsAndrea Corradini, Mark A. Haroldson, Francesca Cagnacci, Cecily M. Costello, Daniel D. Bjornlie, Daniel Thompson, Jeremy M. Nicholson, Kerry A. Gunther, Katharine R. Wilmot, Frank T. van ManenSecondary forest within a timber plantation concession in Borneo contributes to a diverse mammal assemblage
Commercial tree plantations of fast-growing species have become increasingly important in Southeast Asia to meet global demand for wood and wood fiber products. There is a growing need to understand more about their value for wildlife and how they can be managed for biodiversity. We evaluated the effects of landscape attributes on mammal communities in a timber concession consisting of 83 % secondAuthorsWilvia Olivia William, Frank T. van Manen, Stuart P. Sharp, Shyamala RatnayekeGrizzly 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 transferabilityAuthorsSarah Nelson Sells, Cecily M. Costello, Paul Lukacs, Frank T. van Manen, Mark A. Haroldson, Wayne Kasworm, Justin Tesiberg, Milan Vinks, Daniel D. BjornlieEnhancements 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 used as aAuthorsFrank T. van Manen, Michael Ebinger, Cecily M. Costello, Daniel D. Bjornlie, Justin Clapp, Daniel Thompson, Mark A. Haroldson, Kevin L. Frey, Curtis Hendricks, Jeremy M. Nicholson, Kerry A. Gunther, Katharine R. Wilmot, Hilary Cooley, Jennifer Fortin-Noreus, Pat Hnilicka, Daniel B. TyersGenetic architecture and evolution of color variation in American black bears
Color variation is a frequent evolutionary substrate for camouflage in small mammals, but the underlying genetics and evolutionary forces that drive color variation in natural populations of large mammals are mostly unexplained. The American black bear, Ursus americanus (U. americanus), exhibits a range of colors including the cinnamon morph, which has a similar color to the brown bear, U. arctos,AuthorsE. Puckett, I. S. Davis, D. C. Harper, K. Wakamatsu, G. Battu, J. L. Belant, D. E. Beyer, C. Carpenter, A. P. Crupi, M. Davidson, C. S. DePerno, N. Forman, N. L. Fowler, D. L. Garshelis, N. Gould, K. Gunther, Mark A. Haroldson, S. Ito, David. M Kocka, C. Lackey, R. Leahy, C. Lee-Roney, T. Lewis, A. Lutto, K. McGowan, C. Olfenbuttel, M. Orlando, A. Platt, M. D. Pollard, M. Ramaker, Heather Reich, Jaime L. Sajecki, S. K. Sell, J. Strules, S. Thompson, Frank T. van Manen, Craig Whitman, R. Williamson, F. Winslow, C. B. Kaelin, M. S. Marks, G. S. BarshTooth wear and the apparent consumption of human foods among American black bears (Ursus americanus) in Great Smoky Mountains National Park, USA
Stable isotope analyses of hair have been used to estimate the consumption of human foods by American black bears (Ursus americanus). Consumption of human foods influences body mass and reproductive success of bears. However, the underlying factors that cause some bears to become conflict bears and resort to consuming human foods as a portion of their diet are not fully understood. We collected haAuthorsKent A. Hatch, Kimberly A. Kester, Amanda Loveless, Beverly L. Roeder, Frank T. van Manen - News