The American black bear (Ursus americanus) has one of the broadest geographic distributions of any mammalian carnivore in North America. Populations occur from high to low elevations and from mesic to arid environments, and their demographic traits have been documented in a wide variety of environments. However, the demography of American black bears in semiarid environments, which comprise a significant portion of the geographic range, is poorly documented. Semiarid environments are characterized by highly variable environmental and climatic conditions across seasons and among years. To determine whether environmental variation is related to demographic traits of black bears, we used data from a long-term mark–recapture study of black bears in the semiarid environment of eastern Utah, USA, from 1991 to 2019. Traits associated with reproduction (i.e., cub production, cub survival, and yearling survival) were more variable compared with adult survival rates. Cub production was strongly associated with measures of drought in the previous year. Wetter years resulted in higher cub production the next spring. Demographic analysis suggests a stable population (λ H 0.96) dominated by adult life stages where the highest reproductive value is found in old adults. Vital rates and demographic patterns fall within the range of patterns found in other populations of black bears in western North America; however, yearling survival and estimates of fecundity were lower in this population in a semiarid environment. Black bear life histories and resulting demography in this semiarid environment appear to be a response to the uncertainty associated with resource availability. We suggest additional long-term studies in underrepresented environments for comparison with our results and conclusions.
- Volume 37
- Issue 5
- Pages 1-16
- Publication Date 6 April 2026
- DOI 10.2192/URSUS-D-24-00022
- File Size 1.21 MB
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