Complex seasonal patterns of habitat use by a keystone mesopredator in
boreal forest landscapes fragmented by fire.
Abstract
Wildfire is the most important disturbance regime in North American
boreal forest communities, driving forest composition and structure
across this region. Recent climate models predict that increasing fire
intensity and frequency will result in a shift from a largely coniferous
forest to one with a greater dominance by deciduous species. We
investigated how an iconic predator of the boreal system, the Canada
lynx (Lynx canadensis), moves through a range of burn scars (2-78 years
old) and if these movements reflect habitat selection of their main
prey, the snowshoe hare (Lepus americanus). Using GPS collars at 4-h fix
rates, we fitted integrated step selection models to lynx movements
across an 80-year post-fire chronosequence to assess habitat selection
in both deciduous and coniferous forests. We predicted that lynx would
primarily select intermediately-aged spruce, but young deciduous stands,
mirroring the habitat selection of snowshoe hares. We found, however,
that lynx habitat selection peaked at intermediately aged stands in both
forest types. We hypothesize that this difference is driven by selection
for habitats that maximize capture probability as opposed to simply
representing the highest hare density. This idea is supported by
observed seasonal changes in peak selection in deciduous stands, with
selection for younger stands in winter, when leaf loss reduces cover.
There was no seasonal change in coniferous stands as they experience
little change in cover across seasons. Together these results show that
lynx can be resilient to short-term shifts toward intermediate-aged
stands. However, these benefits will likely diminish in the longer term
as the decrease in fire return interval may reduce the prevalence of
intermediate-age stands.