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Ecology and Vulnerability
American Beaver
Photo credit: Bill Byrne, MassWildlife
Scientific name
Castor canadensis
Profile: American Beaver ▾▸
Background
Before European colonization of North America, beavers were present from coast to coast, with the exception of a few locations such as Florida, parts of southern California, and Nevada1. ...
Background
Before European colonization of North America, beavers were present from coast to coast, with the exception of a few locations such as Florida, parts of southern California, and Nevada1. Beavers were present in the Rio Grande River as well as coastal streams along the Gulf of Mexico. They are currently found as far north as northern Quebec2.
Climate Impacts
Their broad distribution indicates that beavers are adapted to a variety of climatic, vegetative, and geological conditions and as such, are likely to be relatively adaptable to a changing climate. Researchers used beaver abundance data from more than 1 million km2 in Quebec to model beaver population response to climate change2. They predicted varying increases in beaver numbers in southern locations, suggesting that climate change could cause increases where other factors were also favorable. However, it is unknown whether these results are transferable to regions south of Quebec.
Beavers rely on suitable habitat, which generally includes lakes or ponds with standing water and streams with gentle gradients and at least intermittent flow1,3. Climate change scenarios for the northeastern U.S. generally predict that increased temperatures will lengthen the growing season and may change evapotranspiration rates (loss of water from plants and the soil through evaporation and transpiration). Climate change is also expected to result in an increased frequency of short term drought conditions, lower summer stream flows, and increased duration of low summer flows4.There is the potential that such changes could result in some reduction of suitable habitat for beavers.
References
1. Baker, R.J., and E.P. Hill. 2003. Beaver (Castor canadensis). Pages 288-310 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.
2. Jarema, S.I., J. Samson, B.J. McGill, and M. Murray. 2009. Variation in abundance across a species’ range predicts climate change responses in the range interior will exceed those at the edge: a case study with North American beaver. Global Change Biology 15:508-522.
3. Howard, R.J., and J.S. Larson. 1985. A stream habitat classification system for beaver. The Journal of Wildlife Management 49:19-25.
4. Huntington, T.G., A.D. Richardson, K.J. McGuire, and K. Hayhoe. 2009. Climate and hydrological changes in the northeastern United States: recent trends and implications for forested and aquatic ecosystems. Canadian Journal of Forest Research 39:199-212.
5. Hood, G.A., and S.E. Bayley. 2008. Beaver (Castor canadensis) mitigate the effects of climate on the area of open water in boreal wetlands in western Canada. Biological Conservation 141:556-567.
6. Gurnell, A.M. 1998. The hydrogeomorphological effects of beaver dam-building activity. Progress in Physical Geography 22:167-189.
7. Westbrook, C.J., D.J. Cooper, and B.W. Baker. 2006. Beaver dams and overbank floods influence groundwater–surface water interactions of a Rocky Mountain riparian area. Water Resources Research W06404.
8. Popescu, V.D., and J.P. Gibbs. 2009. Interactions between climate, beaver activity, and pond occupancy by the cold-adapted mink frog in New York State, USA. Biological Conservation 142:2059-2068.
9. Bird, B., M. O’Brien, and M. Petersen. 2011. Beaver and climate change adaptation in North America: A simple, cost-effective strategy. Wild Earth Guardians, Grand Canyon Trust, and The Lands Council.
10. Collen, P., and R.J. Gibson. 2001. The general ecology of beavers (Castor spp.), as related to their influence on stream ecosystems and riparian habitats, and the subsequent effects on fish – a review. Reviews in Fish Biology and Fisheries 10:439-461.
Climate Change Vulnerability Assessment: American Beaver (Maine)
Ranking
Presumed Stable
Confidence
Moderate
Climate scenario
Not specified
Location
Maine
Time period
Not specified
Climate Change Vulnerability Assessment: American Beaver (Vermont)
Ranking
Presumed Stable
Confidence
High
Climate scenario
None specified
Location
Vermont
Time period
2050-2100
Climate Change Vulnerability Assessment: American Beaver (Michigan)
Ranking
Presumed Stable
Confidence
Very High
Climate scenario
SRES A1B (Mid-range emissions scenario)
Location
Michigan
Time period
2050