Caveats
Our research focussed on a heavily developed landscape in the western Nearctic boreal forest of Alberta, Canada. Extrapolating to other landscapes in this region should not be done without future research to understand the range of inference. In their province-wide analysis, (Dawe, Bayne & Boutin 2014; Dawe & Boutin 2016) concluded that deer expansion is likely facilitated in large part by climate change as the metabolic costs of cold temperatures and especially deep snow are ameliorated by contemporary mild winters. Evidence at landscape scales suggests climate is a contributory mechanism but abundant nutritional forage is pivotal for deer populations (Fisher et al. 2020), and historically the northern boreal forest has been dominated by largely inedible conifer (Fisher & Wilkinson 2005; Pickell et al. 2015). We contend forage subsidies induced by landscape change play a large role not yet disentangled from climate change; indeed it is likely the two act synergistically.