Range Shifts of Large Mammals Under Warming: North American Case Studies
Context: Climate warming is reshaping North American mammal distributions by altering snow, vegetation, fire, pathogens, and sea ice. Large mammals are often treated as slow responders, yet several species now show measurable shifts in abundance, occupancy, or seasonal habitat use. Findings: Evidence is strongest where warming modifies physical habitat or biotic interactions: moose are expanding into shrub-rich Arctic tundra while declining near southern thermal limits; white-tailed deer are moving farther into boreal forests, increasing parasite and predator-mediated risks for caribou; polar bears are losing sea-ice habitat and shifting landward in parts of their range. Elk, mule deer, and bighorn sheep show more heterogeneous responses because forage, drought, snowpack, and human land use interact. Implications: Range shifts are not simple poleward movements. Conservation will require dynamic monitoring, cross-jurisdictional planning, disease surveillance, and protection of movement pathways across climate gradients.
Introduction
Climate warming is changing where North American wildlife can persist, reproduce, and move. For large mammals, range shifts are often slower and less visually obvious than those of insects, birds, or plants, but they are already detectable in changes in occupancy, abundance, seasonal habitat use, and the timing of movements [1]. Because large mammals structure vegetation, predator-prey dynamics, scavenger food webs, and human livelihoods, their redistribution has ecological and social consequences beyond the species themselves [2].
The dominant expectation is that species track suitable climate northward or upward in elevation. In practice, large-mammal responses are…
Unlock the full research paper
Full text, findings, discussion and every reference — plus every past & future paper — comes with your Grower subscription to Climate Plant Analyser.