Ecology and Evolution: Functional response of wolves to human development across boreal North America

This study provides one of the most extensive assessments of how predators like wolves select habitat in response to various degrees of footprint across boreal ecosystems encompassing over a million square kilometers of Canada.

Previous research on how wolves are affected by human development have been limited in scope and location and the results were mixed. Wolves adapted in a range of ways depending on contextual factors like road or cutblock density.

Research undertaken by a team of conservation scientists, including Paul Paquet of Raincoast Conservation Foundation, endeavoured to overcome these limits by including a large number of wolves and a wide range of boreal ecosystems. They compiled measurements from GPS datasets for 255 wolves ranging over a whopping 1,000,000 km2.

Their findings, published as an Open Access paper in Ecology and Evolution, find that the functional response to habitat change from human footprint is significant. Wolves choose to use cutblocks when road density is low, and will use roads when cutblock density is low. In the winter, wolves will opt to use roads, regardless of cutblock density. These results, taken together with other impacts of the human footprint on habitat, should be considered by conservation policy makers.

Figure 2

Map, Figure 2: Boreal forest of Canada and its seven ecoprovinces, where wolf location data was available.
Boreal forest of Canada and its seven ecoprovinces, where wolf location data was available

Authors

Tyler B. Muhly, Cheryl A. Johnson, Mark Hebblewhite, Eric W. Neilson, Daniel Fortin, John M. Fryxell, Andrew David, M. Latham, Maria C. Latham, Philip D. McLoughlin, Evelyn Merrill, Paul C. Paquet, Brent R. Patterson, Fiona Schmiegelow, Fiona Scurrah, Marco Musiani

Abstract

Aim

The influence of humans on large carnivores, including wolves, is a worldwide conservation concern. In addition, human‐caused changes in carnivore density and distribution might have impacts on prey and, indirectly, on vegetation. We therefore tested wolf responses to infrastructure related to natural resource development (i.e., human footprint).

Location

Our study provides one of the most extensive assessments of how predators like wolves select habitat in response to various degrees of footprint across boreal ecosystems encompassing over a million square kilometers of Canada.

Methods

We deployed GPS‐collars on 172 wolves, monitored movements and used a generalized functional response (GFR) model of resource selection. A functional response in habitat selection occurs when selection varies as a function of the availability of that habitat. GFRs can clarify how human‐induced habitat changes are influencing wildlife across large, diverse landscapes.

Results

Wolves displayed a functional response to footprint. Wolves were more likely to select forest harvest cutblocks in regions with higher cutblock density (i.e., a positive functional response to high‐quality habitats for ungulate prey) and to select for higher road density in regions where road density was high (i.e., a positive functional response to human‐created travel routes). Wolves were more likely to use cutblocks in habitats with low road densities, and more likely to use roads in habitats with low cutblock densities, except in winter when wolves were more likely to use roads regardless of cutblock density.

Main conclusions

These interactions suggest that wolves trade‐off among human‐impacted habitats, and adaptively switch from using roads to facilitate movement (while also risking encounters with humans), to using cutblocks that may have higher ungulate densities. We recommend that conservation managers consider the contextual and interacting effects of footprints when assessing impacts on carnivores. These effects likely have indirect impacts on ecosystems too, including on prey species.

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Coastal wolf with a salmon in its month.
Photo by Dene Rossouw.