Black Bear use of urban environments - testing management strategies to reduce bear-human conflicts and assessing the role of human development on bear behavior and population dynamics
Led by Heather Johnson in collaboration with Chad Bishop, Jerry Apker, John Broderick, Stacy Lischke, Mat Alldredge, Patt Dorsey (all CPW), Stewart Breck (National Wildlife Research Center), Jon Beckmann (Wildlife Conservation Society), Ken Wilson (Colorado State University), and Melissa Reynolds-Hogland (Bear Trust International).
In Colorado conflicts among people and black bears are increasing in frequency and severity, and have become a high priority wildlife management issue. Whether increases in conflicts reflect recent changes in bear population trends or just bear behavioral shifts to anthropogenic food resources, is largely unknown, with key implications for bear management. This pressing issue initiated a 5-year study on black bears that 1) tests management strategies for reducing bear-human conflicts, including a large-scale treatment/control urban-food-removal experiment; 2) determines the consequences of bear use of urban environments on regional bear population dynamics; 3) develops population and habitat models to support the sustainable monitoring and management of bears in Colorado; and 4) examines human attitudes and perceptions related bear-human conflicts and management practices. To meet the objectives of this project we are collecting fine-scale data in the vicinity of Durango, and are also using bear data available from across the state. This will be one the most comprehensive studies to date on black bear use of urban environments, explicitly linking bear movement patterns and resource-acquisition to population trends, while rigorously testing an array of management techniques. This information will provide solutions for sustainably managing black bears outside urban environments, while reducing bear-human conflicts within urban environments; knowledge that is critical for wildlife managers in Colorado and elsewhere.
(updated 5/2012)
Genetic analysis of Bear DNA
Led by Jerry Apker, Statewide Carnivore Manager, Mat Alldredge, and Chuck Anderson.
Genetic samples are being obtained statewide from harvested bears to assess the genetic relatedness among bears across the state in an effort to evaluate whether major differences in bear management might be indicated by genetic information. As part of the mandatory harvest check program, genetic samples are obtained from teeth that are extracted from harvested bears to obtain estimates of animal age. To date based on 2-years of data, analysis of DNA characteristics suggest bears are comprised of one large meta-population across the western 2/3 of the state indicating considerable mixing of bear DNA across large geographic areas, presumably by male bears dispersing when young.
(updated 5/2012)
Estimating density of Black Bears using hair snags and Hunter Harvest
Led by Jerry Apker, Statewide Carnivore Manager, in coordination with Mat Alldredge, Chuck Anderson, Heather Johnson, and John Runge, Biometrician.
Genetic sampling of black bears occurs by using scent baited hair-snares deployed over 6-8 weeks in July/August within 6 different bear population areas. DNA obtained from hair snares is assayed and using the frequency of capture/recapture events allows the use of mark/recapture analysis to estimate the density of bears in different areas and habitat types. Subsequently, the different bear densities may be applied to habitat models to extrapolate bear population projections.
(updated 5/2012)
Monitoring Black Bear age and gender composition and reproductive history in mortality
Led by Jerry Apker, Statewide Carnivore Manager, in coordination with Mat Alldredge, Heather Johnson, and John Runge, Biometrician.
Reported black bear mortalities are verified through a mandatory check system during which biological samples are collected, including the 1st upper premolar. Laboratory analysis of this tooth allows determination of the age class at death, age of first reproduction (primipatry) and frequency of births in some females. Analysis of harvest composition, primipatry, and frequency of litters is used in monitoring population trends and as elements of population models.
(updated 5/2012)
Use of Chromosomal Telomeres to estimate age structure of Bear populations
Led by Mat Alldredge in collaboration with, Jerry Apker, Statewide Carnivore Manager, and Jon Pauli, University of Wisconsin.
Analysis of bear genetic samples are being conducted in collaboration with the University of Wisconsin to assess the potential use of telomere length, a specific portion of chromosomes, to estimate age structure of bear populations. The project is using genetic material from known age bears harvested by hunters and conflict bears. This research is being conducted as a Ph.D. project to develop standard curves for the relationship of age to telomere length using high quality genetic material. A suite of covariates will also be used to explain variation in telomere length associated with sex, reproductive status, habitat type, and other factors. Once these curves are developed, additional curves will be developed for genetic samples collected from hair samples. Potential application of this method will be to estimate age structure for bear hair samples collected in the bear hair snag surveys described above.
(updated 5/2012)
Use of Stable Isotopes to determine diet composition of Bears
Led by Mat Alldredge in collaboration with, Jerry Apker, Statewide Carnivore Manager, and Jon Pauli, University of Wisconsin.
Diet composition of bears is being determined over different time periods of an individual's life by examining stable isotope signatures from blood, tissue, bone and hair samples collected from harvested bears. One focus of this research is to determine the proportion of anthropogenic food sources consumed by bears across different areas of the state. We also will investigate the use of fawns and calves by bears in three areas across the state representing different ungulate densities by examining stable isotope signatures in bear hair. To do this we will to develop hair growth curves using captive bears so that bear hair can be segmented into specific growth periods.
(updated 5/2012)