Kananaskis/Willmore Camera and Landcover Data

Anthropogenic landscape change is a leading driver of biodiversity loss.
Preceding dramatic changes such as wildlife population declines and range
shifts, more subtle responses may signal impending larger-scale change.
For example, disturbance-induced shifts to species’ activity patterns may
disrupt temporal niche partitioning along the 24-h time axis, compromising
community structure via altered competitive interactions. We investigated
the impacts of human landscape disturbance on species’ activity patterns
and temporal niche partitioning in the Canadian Rocky Mountain carnivore
guild using camera trap images collected across two regions encompassing a
wide gradient of human footprint. Applying kernel density estimation
techniques, we tested for carnivore species’ activity shifts 1) between a
low versus high disturbance landscape, and 2) in relation to site-scale
disturbance. To test our hypothesis that human disturbance impacts
species’ temporal niche partitioning, we modelled activity overlap between
co-occurring carnivore species in relation to natural and anthropogenic
landscape features, as well as carnivore community composition. Multiple
carnivore species altered activity patterns between the low versus high
disturbance landscapes and camera sites, but these shifts varied
considerably among species. While wolves appeared to increase nocturnal
activity in relation to disturbance, coyote activity consistently trended
towards cathemerality and marten increased diurnal activity. Detecting
effects of landscape disturbance on activity overlap between co-occurring
species was highly sensitive to site-level detection sample sizes, and our
results suggest altered temporal niche partitioning between marten and
wolverine in relation to forest cover. This study indicates that
mesocarnivores may respond differently and perhaps indirectly to
anthropogenic disturbance compared to apex predators. Apex predator shifts
to nocturnality may facilitate a ‘behavioural release’ in mesocarnivores.
This may be a likely component of mesocarnivore population release, with
important management implications for ecological communities on disturbed
landscapes.