Ecological factors influencing the spatial pattern of Canada lynx relative to its southern range edge in Alberta, Canada

Abstract

We examined the spatial pattern of Canada lynx ( Lynx canadensis Kerr, 1792) relative to its southern range edge at the boreal plains – prairie ecotone in Alberta, Canada. Relative to the original distribution of boreal forest in our study area, lynx range seems to have contracted up to 22%. In 100 km2 sampling areas, lynx occupancy rate increased 1.93 times every 100 km farther (north) from the range edge that we sampled. An information–theoretic approach was used to evaluate 31 models to see which environmental factors were the best predictors of this spatial pattern. Lynx were strongly correlated with track counts of their primary prey, the snowshoe hare ( Lepus americanus Erxleben, 1777), but this did not explain the observed increase in occupancy farther north. Rather, lynx occupancy was lower in areas with higher road densities and this effect was magnified in areas where coyote ( Canis latrans Say, 1823) activity was highest. The inclusion of these effects rendered the south–north pattern no longer significant. The rapid pace of road building and associated development in Alberta’s boreal forest seems to be reducing habitat quality for Canada lynx, particularly at the southern edge of its range. This may be leading to range contractions for lynx in Alberta, much like has happened elsewhere in North America.