title: Beaver Colony Density Trends on the Chequamegon-Nicolet National Forest, 1987 - 2013.
abstract: The North American beaver (Castor canadensis) is a managed species in the United States. In northern Wisconsin, as part of the state-wide beaver management program, the Chequamegon-Nicolet National Forest removes beavers from targeted trout streams on U.S. Forest Service lands. However, the success of this management program has not been evaluated. Targeted removals comprise only 3% of the annual beaver harvest, a level of effort that may not affect the beaver population. We used colony location data along Forest streams from 1987-2013 (Nicolet, northeast Wisconsin) and 1997-2013 (Chequamegon, northwest Wisconsin) to assess trends in beaver colony density on targeted trout streams compared to non-targeted streams. On the Chequamegon, colony density on non-targeted trout and non-trout streams did not change over time, while colony density on targeted trout streams declined and then stabilized. On the Nicolet, beaver colony density decreased on both non-targeted streams and targeted trout streams. However, colony density on targeted trout streams declined faster. The impact of targeted trapping was similar across the two sides of the Forest (60% reduction relative to non-targeted trout streams). Exploratory analyses of weather influences found that very dry conditions and severe winters were associated with transient reductions in beaver colony density on non-targeted streams on both sides of the Forest. Our findings may help land management agencies weigh more finely calibrated beaver control measures against continued large-scale removal programs.
authors.affiliation: US Geological Survey, Wisconsin Cooperative Wildlife Research Unit, University of Wisconsin, Madison, Wisconsin, United States of America.
authors.forename: Christine A
authors.initials: CA
authors.lastname: Ribic
authors.affiliation: Institute for Applied Ecosystem Studies, Northern Research Station, US Forest Service, Rhinelander, Wisconsin, United States of America.
authors.forename: Deahn M
authors.initials: DM
authors.lastname: Donner
authors.affiliation: Wisconsin Cooperative Wildlife Research Unit, Department of Forest and Wildlife Ecology, University of Wisconsin, Madison, Wisconsin, United States of America.
authors.forename: Albert J
authors.initials: AJ
authors.lastname: Beck
authors.affiliation: Northern Research Station, US Forest Service, Madison, Wisconsin, United States of America.
authors.forename: David J
authors.identifier: http://orcid.org/0000-0003-2280-8302
authors.initials: DJ
authors.lastname: Rugg
authors.affiliation: Chequamegon-Nicolet National Forest, US Forest Service, Park Falls, Wisconsin, United States of America.
authors.forename: Sue
authors.initials: S
authors.lastname: Reinecke
authors.affiliation: Chequamegon-Nicolet National Forest, US Forest Service, Park Falls, Wisconsin, United States of America.
authors.forename: Dan
authors.initials: D
authors.lastname: Eklund
mesh_terms: D000818:Animals; D065928:Forests; D008962:Models, Theoretical; D011156:Population Density; D012377:Rodentia / Q000502:physiology*; D012621:Seasons; D014481:United States; D014887:Weather