Beaver monitoring data from the Chequamegon-Nicolet National Forest, Wisconsin

The primary raw data are aerial counts of beaver (Castor canadensis) colonies on streams across the Chequamegon-Nicolet National Forest (CNNF). These aerial counts were performed in the fall of each year from 1987 (Nicolet side of CNNF) or 1997 (Chequamegon side of CNNF). Based on the colony counts, we also provide derived beaver colony density values. The surveyed streams were classified into four categories: managed trout, non-managed trout, managed non-trout, and non-managed non-trout. Trout versus non-trout status was assigned by the CNNF using Wisconsin Department of Natural Resources information. Managed streams were those on which targeted removal of beavers was conducted in the spring of each year under a contract with USDA-Wildlife Services. Data also include proportion of stream-side aspen, temperature, snowfall, and soil moisture as measured by the Palmer Drought Severity Index.
The CNNF participates in a beaver management program that the State of Wisconsin implemented. One objective of the program was to protect economically important cold-water trout fisheries from adverse impacts of beaver dams on trout streams. Targeted management of beaver was important because regulated trapping of beaver also provides economic value to Wisconsin’s economy. The monitoring data were collected as part of the beaver management program, and were used to assess the effectiveness of the targeted management program in accomplishing the objective of reducing beaver populations on trout streams.

A second component of the CNNF’s beaver management program was reducing the amount of aspen (primarily Populus tremuloides) in the riparian areas adjoining targeted streams. The data on stream-side aspen were assembled to help assess the effectiveness of this strategy.

The other secondary data were assembled to help model annual beaver dynamics as part of understanding whether targeted trapping was successful.
These data were originally published in December 2016. On 03/06/2020 minor metadata updates were made, which included adding reference to an article that was published after the data became available.