Quantifying the relative influence of multiple mechanisms driving recent range expansion of non‐native species is essential for predicting future changes and for informing adaptation and management plans to protect native species. White‐tailed deer (Odocoileus virginianus) have been expanding their range into the North American boreal forest over the last half of the 20th century. This has already altered predator–prey dynamics in Alberta, Canada, where the distribution likely reaches the northern extent of its continuous range. Although current white‐tailed deer distribution is explained by both climate and human land use, the influence each factor had on the observed range expansion would depend on the spatial and temporal pattern of these changes. Our objective was to quantify the relative importance of land use and climate change as drivers of white‐tailed deer range expansion and to predict decadal changes in white‐tailed deer distribution in northern Alberta for the first half of the 21st century. An existing species distribution model was used to predict past decadal distributions of white‐tailed deer which were validated using independent data. The effects of climate and land use change were isolated by comparing predictions under theoretical “no‐change between decades” scenarios, for each factor, to predictions under observed climate and land use change. Climate changes led to more than 88%, by area, of the increases in probability of white‐tailed deer presence across all decades. The distribution is predicted to extend 100 km further north across the northeastern Alberta boreal forest as climate continues to change over the first half of the 21st century.

Understanding the factors that drive species distributions is emerging as an important tool in wildlife management, under unprecedented changes in species ranges. While invasion ecologists have long studied the impact of human land use on species’ distributions, and models developed more recently to explain changes in species range boundaries have been largely parameterized by climate variables, few authors have considered climate and land-use factors together to explain species distribution. The purpose of this study was to test two main competing hypotheses involving human land use and climate effects on white-tailed deer (Odocoileus virginianus (Zimmermann, 1780)) distribution, which has expanded into the boreal ecosystem in recent decades. Using a species distribution modeling approach with data from boreal Alberta, we found that climate, as measured by an index of winter severity, was the most important individual factor determining current white-tailed deer distribution in boreal Alberta. Human land use (as measured by total land-use footprint) acted to substantially increase white-tailed deer presence but only in areas with more severe winter conditions. We use our findings to recommend where limiting or reclaiming the industrial footprint may be most beneficial to limiting white-tailed deer distribution.

Habitat protection has been identified as an important strategy for the conservation of woodland caribou (Rangifer tarandus). However, because of the economic opportunity costs associated with protection it is unlikely that all caribou ranges can be protected in their entirety. We used an optimization approach to identify reserve designs for caribou in Alberta, Canada, across a range of potential protection targets. Our designs minimized costs as well as three demographic risk factors: current industrial footprint, presence of white-tailed deer (Odocoileus virginianus), and climate change. We found that, using optimization, 60% of current caribou range can be protected (including 17% in existing parks) while maintaining access to over 98% of the value of resources on public lands. The trade-off between minimizing cost and minimizing demographic risk factors was minimal because the spatial distributions of cost and risk were similar. The prospects for protection are much reduced if protection is directed towards the herds that are most at risk of near-term extirpation.

The maritime shrew, Sorex maritimensis, is a Canadian endemic species with a limited distribution in two provinces in eastern Canada. Phylogeographic analysis of mitochondrial DNA control region and cytochrome b sequences revealed two clades, one found in New Brunswick and the other primarily in Nova Scotia, Canada. We propose that these clades have come back into secondary contact following the Wisconsin glaciation via wetlands on the narrow Isthmus of Chigneto that connects these provinces. Despite evidence of an historic separation of maritime shrew subpopulations in Nova Scotia and New Brunswick, we conclude that shrews in these two regions should be considered a single evolutionary significant unit but separate, semi-isolated management units that should be recognized as such for conservation purposes. The susceptibility of this stenotopic species with limited dispersal capabilities raises concerns about its long-term persistence if climate-change induced habitat fragmentation increases. Maintenance of contiguous wetland habitats is needed to ensure connectivity and gene flow among populations of the maritime shrew.

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