Unveiling trade-offs in resource selection of migratory caribou using a mechanistic movement model of availability

animals move in response to a variety of competing pressures such as the need to feed, avoid predators, breed, and rear offspring (Brown et al. 1999, Cresswell 2008). These competing demands give rise to trade-offs that individuals must mediate through their space use and movements (Lima 1998, Hebblewhite and Merrill 2009), resulting in distinctive patterns of habitat selection. Numerous studies have tried to unveil potential trade-offs for prey through the process of habitat selection (Creel et al. 2005, Fortin and Fortin 2009, Hebblewhite and Merrill 2009). Habitat selection is defined as the disproportionate use of a habitat relative to its availability (Johnson 1980, Manly et al. 2002), and elucidating habitat selection determinants remains a central and unifying concept bridging spatial and temporal scales (Morris 2003, Mayor et al. 2007). Indeed, studies often have compared habitat selection across multiple scales (Dussault et al. 2005, Hebblewhite and Merrill 2009, van Beest et al. 2010). Especially owing to prevalent and rapid environmental change, there is Ecography 38: 1049–1059, 2015 doi: 10.1111/ecog.01305 © 2015 The Authors. Ecography © 2015 Nordic Society Oikos Subject Editor: Jean-Michel Gaillard. Editor-in-Chief: Jens-Christian Svenning. Accepted 21 December 2014