Responses of red-backed voles (Myodes gapperi) to windrows of woody debris along forest-clearcut edges

摘要

Southern red-backed voles (Myodes gapperi) disappear from clearcuts within the first year or two after harvest, at least in studies in coniferous and mixed forests of western North America. Post-harvest woody debris arranged in large piles and windrows supports populations of M. gapperi on clearcuts and may extend their persistence there. Aims. To test the hypotheses (H) that for M. gapperi, (H_1) population parameters of abundance, reproduction, and survival would be higher in windrow-forest than isolated windrow sites, and higher or similar to those in interior old forest sites; (H_2) connectivity provided by windrow-forest structures will mitigate potential negative effects of clearcuts and abundance of M. gapperi will remain similar at the abrupt edge between forest and new clearcuts; and (H_3) connectivity provided by windrow-forest structures will allow increased movements between both habitats. Methods. Study areas were located in three forest ecological zones in southern British Columbia, Canada. Populations of M. gapperi were sampled from 2010 to 2012 in three types of habitats on new clearcuts: isolated windrows of woody debris, windrows attached to uncut old forest, and in uncut old forest. Key results. Higher mean values of abundance and number of juvenile recruits of M. gapperi in the isolated windrow and windrow-forest sites than forest sites was contrary to our prediction for H_1. In support of H_2, we could not detect any differences in the mean number of captures among forest, edge and windrow sections of the windrow-forest sites, nor in the mean range length among the three habitat types. For H_3, connectivity provided by windrow-forest structures may mitigate potential negative effects on abundance for M. gapperi at the abrupt edge between forest and new clearcuts. Conclusions and Implications. Voles did not commonly move between the forest and windrow habitats, but did move readily within forest and within windrows. Substantial movement by M. gapperi within windrows suggested that this microtine will move along windrows and potentially use these paths of connectivity to cross clearcuts. If the prey base is present, windrow connectivity may enhance these open areas for small mustelids and other carnivores and help maintain abundance and diversity of some forest mammals on clearcuts.