Compounding effects of human development and a natural food shortage on a black bear population along a human development-wildland interface

Compounding effects of human development and a natural food shortage on a black bear population along a human development-wildland interface

Human development and climate change are two stressors that threaten numerous wildlife populations, and their combined effects are likely to be most pronounced along the human development-wildland interface where changes in both natural and anthropogenic conditions interact to affect wildlife. To better understand the compounding influence of these stressors, we investigated the effects of a climate-induced natural food shortage on the dynamics of a black bear population in the vicinity of Durango, Colorado. We integrated 4 years of DNA-based capture-mark-recapture data with GPS-based telemetry data to evaluate the combined effects of human development and the food shortage on the abundance, population growth rate, and spatial distribution of female black bears. We documented a 57% decline in female bear abundance immediately following the natural food shortage coinciding with an increase in human-caused bear mortality (e.g., vehicle collisions, harvest and lethal removals) primarily in developed areas. We also detected a change in the spatial distribution of female bears with fewer bears occurring near human development in years immediately following the food shortage, likely as a consequence of high mortality near human infrastructure during the food shortage. Given expected future increases in human development and climate-induced food shortages, we expect that bear dynamics may be increasingly influenced by human-caused mortality, which will be difficult to detect with current management practices. To ensure long-term sustainability of bear populations, we recommend that wildlife agencies invest in monitoring programs that can accurately track bear populations, incorporate non-harvest human-caused mortality into management models, and work to reduce human-caused mortality, particularly in years with natural food shortages.

Laufenberg, J. S., H. E. Johnson, P. F. Doherty, and S. W. Breck. 2018. Compounding effects of human development and a natural food shortage on a black bear population along a human development–wildland interface. Biological Conservation 224:188–198. https://doi.org/10.1016/j.biocon.2018.05.004

Laufenberg, Jared S.

Johnson, Heather E.

Doherty, Jr, Paul F.

Breck, Stewart W.

Black bear

Human-bear conflict

Integrated population model

Spatial capture-recapture

28 pages

Article

application/pdf

English

Biological Conservation

05/08/2018

06/15/2018

02/21/2018

10/06/2017