Functional responses to anthropogenic linear features in a complex predator-multi-prey system

Context Anthropogenic linear features can have negative effects on wildlife by altering movements or increasing risk. Spatial responses to linear features vary depending on local conditions (functional responses), including linear feature availability. Several studies explored functional responses of wildlife to linear features, but few examined responses of multiple interacting species. Objectives We evaluated functional responses of Threatened boreal woodland caribou (Rangifer tarandus caribou), moose (Alces alces), and gray wolves (Canis lupus) to roads and seismic lines (linear features created during fossil fuel exploration) to assess the influence these responses might have on predator-prey interactions. Methods We estimated median distance to and the density of roads and seismic lines around used and available locations by landcover (peatlands and non-peatlands) and season for each individual. To quantify functional responses, we regressed use in response to availability in peatlands and non-peatlands across seasons and selected the most parsimonious models for each species. Results Boreal caribou generally avoided higher road density. Wolves selected areas closer to roads in peatlands and demonstrated selection or indifference to higher road density as availability increased. Female moose generally avoided areas with higher road density, except in early winter. Female caribou and moose demonstrated weaker responses to seismic line density. During calving, late summer, and early winter, wolves often selected for seismic line density, particularly in peatlands, when availability was high. Conclusions Our analyses suggest that boreal caribou, moose, and wolves respond to linear features in complex ways that alter individual space-use and likely influence predation risk.