Small mammal responses to vegetation recovery on seismic lines in Alberta's boreal forest

Hydrocarbon exploration has created extensive networks of seismic lines across Alberta's boreal forest, many of which remain in early successional states for decades. We assessed how small mammals responded to vegetation recovery on these linear features by modelling detections of Sorex spp., southern red-backed voles (Myodes gapperi), deer mice (Peromyscus maniculatus), and red squirrels (Tamiasciurus hudsonicus). From May to August 2023, we deployed baited, ground-level camera traps at 282 seismic-line sites in northeastern Alberta, paired with adjacent forest-interior controls across deciduous, mixedwood, and lowland coniferous ecosites. Seismic-line recovery was visually classified as low, medium, or high. We analyzed independent detections with negative-binomial generalized linear mixed models that included camera active hours as an offset and pair ID as a random effect, and ranked candidate models using AICc. Across taxa, detections were generally lower on low-recovery lines than in forest interior. Forest-interior detections were 2.95 times higher than low-recovery lines for Sorex spp. and 3.39 times higher for southern red-backed voles, whereas medium and high recovery generally did not differ from forest interior for either taxon. Deer Mouse and Red Squirrel detections showed weaker responses, but both tended to be lower on low-recovery lines. Southern red-backed voles and red squirrels were also detected more often on narrow low-impact lines than on conventional lines, and Deer Mouse detections varied with forest cover. Our results suggest that open, herbaceous seismic lines provide poorer habitat than forest interior even for generalist taxa, whereas development of woody understory structure may restore small mammal use to levels comparable to interior forest. Restoration that accelerates shrub and near-ground structural recovery while minimizing line width is therefore likely to provide the greatest benefit.