Temporal segregation among sympatric boreal predators

Abstract

Mechanisms that decrease niche overlap, whether dietary, spatial, or temporal, are important in facilitating the coexistence of sympatric competitors. Since predators commonly partition resources via temporal segregation, we investigated whether it plays a significant role in mediating the coexistence of four common boreal predators: black bear (Ursus americanus), Canada lynx (Lynx canadensis), wolverine (Gulo gulo luscus), and fisher (Pekania pennanti). We examined their daily activity patterns at camera traps (19 sampling sites) in the boreal forest of northwest Alberta (2380 km2). Fishers were distinctly diurnal, while black bears, Canada lynx, and wolverines were cathemeral, resulting in high overlaps among the species (∆ = 0.62 to ∆ = 0.86). Fishers showed the lowest overlap with other species, while other pairs of species were relatively higher. Our results suggest that temporal partitioning plays a smaller role in the coexistence of these predators than anticipated, while revealing some interesting trends and suggesting other factors that may play a role in their niche segregation.