Demography of Black Bears in Hunted and Unhunted Areas of the Boreal Forest of Ontario

• Published in: The Journal of wildlife management 2008-05, Vol.72 (4), p.869-880
• Main Authors: Obbard, Martyn E, Howe, Eric J
• Format: Article
• Language: English
• Subjects: American black bear; animal reproduction; Baits; Bears; Birds; Black bears; boreal forest; Boreal forests; cause-specific mortality; Demography; density-dependence; Females; Food shortages; Food supply; game preserves; Grizzly bears; Harvest; Mammals; Management and Conservation; Mortality; Natural resources; Ontario; population density; Population growth; reproduction; sport hunting; Summer; Survival; Survival rates; Telemetry; temporal variation; Trapping; Ursus americanus; wildlife habitats; Wildlife management; Winter; Yearlings
• ISSN: 0022-541X; 1937-2817
• DOI: 10.2193/2006-158

We estimated relative density, survival, and reproduction of American black bears (Ursus americanus) from capture–recapture and telemetry data collected from 1989 to 1999 in the unhunted Chapleau Crown Game Preserve (CCGP) and nearby hunted areas in the boreal forest of Ontario, Canada. We tested for combinations of effects of age class, sex, year, years of food shortage, encumbrance status, and residency (on or off the Game Preserve) on vital rates. Results from live captures, remote captures, and bait-station hit rates indicated that density was highest inside CCGP. Total survival of adult females, subadults, and cubs were similar among residents and nonresidents of CCGP, but yearling survival was lower among CCGP residents. Adult females were approximately twice as likely to die and nearly 10 times as likely to be cannibalized (risk ratio [RR] = 9.62, 95% CI = 2.088–44.29) while encumbered with cubs of the year. Nonresidents of CCGP had greater risk of being harvested (RR = 4.00, 95% CI = 1.19–13.46) but similar risk of being cannibalized (RR = 0.875, 95% CI = 0.300–2.55) relative to CCGP residents, suggesting that harvest mortality was additive to other forms of mortality. Residents of CCGP had older ages at primiparity and lower litter-production rates than bears resident in hunted areas. Few litters were produced in years following food shortages, but litter size was unaffected. We recommend that managers allow for additive harvest mortality and reduced survival of bears encumbered with cubs of the year, and we caution that assuming density-compensatory increases in cub production could optimistically bias estimates of population growth.