Ecology and Vulnerability
Black Bear

Image
Black Bear (Ursus americanus)

Photo credit: Bill Byrne, MassWildlife

Scientific name
Ursus americanus

Profile: Black Bear

Background
The black bear is a widespread mammal species in North America and its presence in Massachusetts is unlikely to be greatly affected by climate change1,2.  The pre-colonial range of black...

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Background
The black bear is a widespread mammal species in North America and its presence in Massachusetts is unlikely to be greatly affected by climate change1,2.  The pre-colonial range of black bears covered forested areas of North America into Mexico and the species is highly adaptable in terms of diet and habitat use3.  This wide range and adaptive capacity should make black bears well-suited to persist in the face of climate change.

Climate Impacts
However, black bears do have a variable life-history that may be impacted by climate change.  In northern portions of the range, black bears hibernate for up to seven months, while in more southern regions, this period of hibernation is greatly reduced4.  Bears may enter dens to hibernate as early as October and as late as January3 and emergence timing (when they come back out) appears to be tied to weather5.  Hibernation is an adaptation to winter food shortages and severe weather3.  In Massachusetts, milder winters may reduce the length of time bears spend in hibernation.  Increased bear activity combined with the potential for low food availability during winter months may increase the potential for human-bear conflict, as bears are more likely to visit urbanized areas in search of food during shortages6,7.  Such conflict is tied to increases in bear mortality due to humans7.

References

1. Kerr, J., and L. Packer. 1998. The impact of climate change on mammal diversity in Canada. Environmental Monitoring and Assessment 49:263-270.

2. Groffman, P.M., L.E. Rustad, P.H. Templer, J.L. Campbell, L.M. Christenson, N.K. Lany, A.M. Socci, M.A. Vadeboncoeur, P.G. Schaberg, G.F. Wilson, C.T. Driscoll, T.J. Fahey, M.C. Fisk, C.L. Goodale, M.B. Green, S.P. Hamburg, C.E. Johnson, M.J. Mitchell, J.L. Morse, L.H. Pardo, and N.L. Rodenhouse. 2012. Long-term integrated studies show complex and surprising effects of climate change in the northern hardwood forest. BioScience 62:1056-1066.

3. Pelton, M.R. 2003. Black Bear (Ursus americanus). Pages 547-555 in G.A. Feldhamer, B.C. Thompson, and J.A. Chapman, editors. Wild Mammals of North America, 2nd edition. The Johns Hopkins University Press, Baltimore, MD.

4. Garshelis, D.L., D. Crider, and F. van Manen (IUCN SSC Bear Specialist Group). 2008. Ursus americanus. The IUCN Red List of Threatened Species. Version 2014.3. <www.iucnredlist.org>. (Accessed on 17 April 2015).

5. Rayl, N.D., T.K. Fuller, J.F. Organ, J.E. McDonald, R.D. Otto, and S.P. Mahoney. 2014. Den abandonment and transitional day bed use by black bears Ursus americanus in Newfoundland. Wildlife Biology 20:222-228.  

6. Obbard, M.E., E.J. Howe, L.L. Wall, B. Allison, R. Black, P. Davis, L. Dix-Gibson, M. Gatt, and M.N. Hall. 2014. Relationships among food availability, harvest, and human–bear conflict at landscape scales in Ontario, Canada. Ursus 25:98-110.

7. Baruch-Mordo, S., K.R. Wilson, D.L. Lewis, J. Broderick, J.S. Mao, and S.W. Breck. 2014. Stochasticity in natural forage production affects use of urban areas by black bears: Implications to management of human-bear conflicts. PloS ONE 9(1):e85122.

8. Baruch-Mordo, S., S.W. Breck, K.R. Wilson, and J. Broderick. 2011. The carrot or the stick? Evaluation of education and enforcement as management tools for human-wildlife conflicts. PloS ONE 6(1):e15681.

Climate Change Vulnerability Assessment: Black Bear (Michigan)

Ranking
Presumed Stable
Confidence
Very High
Climate scenario
SRES A1B (Mid-range emissions scenario)
Location
Michigan
Time period
2050