Linear anthropogenic disturbances increase butterfly abundance, species richness, and cross-corridor movements

Understanding how invertebrates respond to disturbance is essential for anticipating the effects of anthropogenic developments. In western Canada’s boreal forests, linear corridor disturbances constructed for oil and gas exploration, called seismic lines, are pervasive. Previous research indicates that butterfly abundance and species richness increase along conventional seismic lines (6–12 m wide) in peatland boreal forest and that at least one butterfly species preferentially uses these seismic lines as travel corridors. Here, we investigated how a butterfly assemblage’s abundance, species richness, and movement responded to seismic lines in the dry, sandy Richardson area of Alberta, Canada’s boreal forest. We used Malaise traps at five sites to compare butterfly abundance, species richness, and movement direction on conventional seismic lines to 50 m into the adjacent interior forest. Butterfly abundance and richness were 7.8 times and 1.5 times higher, respectively, on conventional seismic lines than in the forest interior. Butterflies were also 6.5 times as abundant flying across seismic lines than flying along them. These results demonstrate that conventional seismic lines are locally increasing butterfly abundance and diversity in boreal forests, while also further affecting butterfly movement behaviour compared to undisturbed boreal forest habitat.