THE HISTORIC RESPONSE OF GREY WOLVES TO CLIMATE CHANGE: A CASE STUDY FROM NORTHERN ALBERTA

Grey wolves (Canis lupus) are one of the most widespread terrestrial carnivores, with a historic range that covers essentially the entire northern Hemisphere. As apex predators, wolf response to climate change may have a top-down influence on the structure of ecosystems. Furthermore, wolves act as ecological integrators, and the stable isotope composition of their tissues reflects changes to the isotopic composition of their prey. Ultimately, this reflects changes in both behavior and the ecosystems baseline isotope composition, the latter of which is linked to regional and global climate.

Wood Buffalo National Park, Alberta, Canada, takes its name from its large herds of wood buffalo (Bison bison athabascae), which support some of the highest wolf densities in North America. The park is dominated by a cool (mean annual temperature ~ 0°C) boreal climate. However, regional climate data indicate the park has warmed more quickly than global trends with a mean temperature increase of ~1.7°C by the 1980’s.

We collected stable isotope data (δ¹⁵N_collagen, δ¹³C_collagen, δ¹³C_enamel, δ¹⁸O_enamel) from wolves culled in Wood Buffalo National park during three time periods (1927, 1945, 1979), to investigate the effects of global climate change on wolf behavior and ecology.

Enamel carbon and oxygen isotope compositions are linked to diet and climate. Serial enamel samples from canines indicate only small changes in wolf δ¹³C and δ¹⁸O values from 1927 to 1979. Our enamel isotope compositions are paired with δ¹⁵N and δ¹³C values collected from the underlying dental collagen, allowing us to us to link changes in climate and ecology with estimates of individual and population niche width as well as specialist or generalist behavior.

Understanding how animals respond to climate change is one of the enduring goals in both modern and paleo-ecology. Moving forward, our study will provide a framework for investigating how wolves have responded to both modern and quaternary climate change.