Habitat partitioning between woodland caribou and moose in Ontario: the potential role of shared prédation risk

Abstract

This paper explores mechanisms of coexistence for woodland caribou (Rangifer tarandus caribou) and moose (Akes alces) preyed upon by gray wolves (Canis lupus) in northern Ontario. Autocorrelation analysis of winter track locations showed habitat partitioning by caribou and moose. Numbers of Delaunay link edges for moose-wolves did not differ significantly from what would be expected by random process, but those for caribou-wolves were significantly fewer. Thus, habitat partitioning provided implicit refuges that put greater distances between caribou and wolves, presumably decreasing predation on the caribou. Yet, direct competition cannot be ruled out; both apparent and direct competition may be involved in real-life situations. A synthesis including both explanations fits ecological theory, as well as current understanding about caribou ecology.