Where beavers ( Castor canadensis ) build: testing the influence of habitat quality, predation risk, and anthropogenic disturbance on colony occurrence

• Published in: Canadian Journal of Zoology
• Main Authors: Mumma, M.A., Gillingham, M.P., Johnson, C.J., Parker, K.L.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 2018
• Subjects: Animal Science and Zoology; Ecology, Evolution, Behavior and Systematics; Canada; British Columbia; Canis lupus; gray wolf
• Online Access: http://dx.doi.org/10.1139/cjz-2017-0327; http://www.nrcresearchpress.com/doi/full-xml/10.1139/cjz-2017-0327; http://www.nrcresearchpress.com/doi/pdf/10.1139/cjz-2017-0327

Species distributions are shaped by numerous factors that vary in importance across spatiotemporal scale. Understanding drivers of the distribution of North American beavers (Castor canadensis Kuhl, 1820) is paramount given their profound influence on ecological communities. Our objectives were to evaluate the influence of habitat quality, risk of gray wolf (Canis lupus Linnaeus, 1758) predation, and anthropogenic disturbance on the occurrence of beaver colonies in northeast British Columbia (BC), Canada. We used mixed-effects multinomial logistic regression to model the occurrence of active and inactive colonies and t tests to compare landscape covariates associated with active versus inactive colonies. We determined that occurrence of beavers was driven by habitat quality. Occurrence increased in areas with higher vegetation-class richness and greater proportions of open water, nutrient-rich fen, and deciduous swamp. We also observed that active colonies were surrounded by greater amounts of deciduous swamps relative to inactive colonies. We found no evidence that predation risk or industrial activities decreased the occurrence of beavers in northeast BC, although numerical changes in abundance might occur without changes in distribution. This research illuminated drivers of beaver distribution while providing a means to predict the occurrence of a keystone species in the boreal ecosystem.