Journal Article

Habitat loss on seasonal migratory range imperils an endangered ungulate

Hegel, Troy, Hebblewhite, Mark, Steenweg, Robin, Russell, Mike, Hervieux, Dave, Williams, Sara H.

2021

Overview

1. Endangered species policies and their associated recovery documents and management actions do not always sufficiently address the importance of migratory behaviour and seasonal ranges for imperilled populations. 2. Using a telemetry location dataset spanning 1981–2018, we tested for changes in prevalence of migratory tactics (resident, migrant) over time, switching between tactics, shifts in seasonal space use including migration corridors, and survival consequences of migrant and resident tactics for 237 adult female endangered woodland mountain caribou in one population in western Canada. 3. Over more than three decades, the proportion of individuals displaying annual migration to the low elevation forested winter range declined from nearly 100%–38%. Correspondingly, there was a strong switch away from being migrant to being year‐round residents at high elevation. 4. These behavioural changes corresponded to abandonment of low elevation winter ranges in association with increasing levels of anthropogenic land uses, including forestry and oil and gas developments. Furthermore, there were no identifiable migration corridors to target for migratory route protection. 5. These shifts translated to lower survival rates, particularly for caribou demonstrating resident tactics, consistent with recent declines of the caribou population. That migrants switched to residency in their largely undisturbed summer range, despite lower survival, indicates maladaptive habitat selection consistent with recent patterns of mountain caribou extirpations. 6. Globally, endangered species policies and their associated recovery plans and management actions often do not explicitly consider the challenge of protecting migratory species. Effective conservation of migratory species requires protecting critical habitats needed for the entire life history of the species, including all seasonal ranges and migratory habitat. Our work shows long‐term effects of indirect and direct habitat loss on low elevation seasonal range through roads, oil and gas development, and forestry caused declines in migratory behavior in a threatened central caribou population in Alberta and British Columbia over 30‐years. Caribou use of roads, such as illustrated here, comes with severe survival consequences through increased predation through the mechanism of apparent competition from large carnivores such as wolves.

• Publisher: John Wiley & Sons, Inc,Wiley
• Subject: Anthropogenic factors / Caribou / Corridors / Ecological trap / Ecosystems / Endangered species / Habitat loss / Habitat selection / Habitats / Life history / migration / Migratory species / Mountains / National parks / Policies / Population decline / Predation / Protected species / Rangier tarandus caribou / Recovery plans / Survival / Tactics / Telemetry / Wildlife conservation / Winter / woodland caribou / Woodlands