Demography and Genetic Structure of a Recovering Grizzly Bear Population
Kendall KC, Stetz JB, Boulanger J, MacLeod AC, Paetkau D, White GC. 2009. Demography and Genetic Structure of a Recovering Grizzly Bear Population. The Journal of Wildlife Management. 73(1):3-17
We used data from a large noninvasive genetic sampling effort conducted in 2004 and 33 years of physical captures to assess abundance, distribution, and genetic health of this population. We combined data from our 3 sampling methods (hair trap, bear rub, and physical capture) to construct individual bear encounter histories for use in Huggins–Pledger closed mark–recapture models. Our population estimate, = 765 (95% CI = 715–831) was more than double the existing estimate derived from sightings of females with young. Based on our results, the estimated known, human-caused mortality rate in 2004 was 4.6% (95% CI = 4.2–4.9%), slightly above the 4% considered sustainable; however, the high proportion of female mortalities raises concern. We used location data from telemetry, confirmed sightings, and genetic sampling to estimate occupied habitat. We found that grizzly bears occupied 33,480 km2 in the Northern Continental Divide Ecosystem (NCDE) during 1994–2007, including 10,340 km2 beyond the Recovery Zone. We used factorial correspondence analysis to identify potential barriers to gene flow within this population. Our results suggested that genetic interchange recently increased in areas with low gene flow in the past; however, we also detected evidence of incipient fragmentation across the major transportation corridor in this ecosystem. Our results suggest that the NCDE population is faring better than previously thought, and they highlight the need for a more rigorous monitoring program.
- Type
- Journal Article
- Authors
- Kendall, Katherine; Stetz, Jeffrey; Boulanger, John; MacLeod, Amy; Paetkau, David; White, Gary
- Units
- GLAC
- Keywords
- Crown of the Continent Ecosystem, Genetic structure, Grizzly Bear, mammal studies, noninvasive sampling, Population Ecology, Population Monitoring, Ursus arctos