Wolverines in winter: indirect habitat loss and functional responses to backcountry recreation

Abstract

Outdoor recreation is increasingly recognized to impact nature and wildlife, yet few studies have examined recreation within large natural landscapes that are critical habitat to some of our most rare and potentially disturbance‐sensitive species. Over six winters (2010–2015) and four study areas (>1.1 million ha) in Idaho, Wyoming, and Montana, we studied the responses of wolverines (Gulo gulo) to backcountry winter recreation. We fit Global Positioning System (GPS) collars to 24 individual wolverines and acquired >54,000 GPS locations over 39 animal‐years during winter (January–April). Simultaneously, we monitored winter recreation, collecting ~6000 GPS tracks (~200,000 km) from backcountry recreationists. We combined the GPS tracks with trail use counts and aerial recreation surveys to map the extent and relative intensity of motorized and non‐motorized recreation. We integrated our wolverine and backcountry recreation data to (1) assess patterns of wolverine habitat selection and (2) evaluate the effect of backcountry recreation on wolverine habitat relationships. We used resource selection functions to model habitat selection of male and female wolverines within their home ranges. We first modeled habitat selection for environmental covariates to understand male and female habitat use then incorporated winter recreation covariates. We assessed the potential for indirect habitat loss from winter recreation and tested for functional responses of wolverines to differing levels and types of recreation. Motorized recreation occurred at higher intensity across a larger footprint than non‐motorized recreation in most wolverine home ranges. Wolverines avoided areas of both motorized and non‐motorized winter recreation with off‐road recreation eliciting a stronger response than road‐based recreation. Female wolverines exhibited stronger avoidance of off‐road motorized recreation and experienced higher indirect habitat loss than male wolverines. Wolverines showed negative functional responses to the level of recreation exposure within the home range, with female wolverines showing the strongest functional response to motorized winter recreation. We suggest indirect habitat loss, particularly to females, could be of concern in areas with higher recreation levels. We speculate that the potential for backcountry winter recreation to affect wolverines may increase under climate change if reduced snow pack concentrates winter recreationists and wolverines in the remaining areas of persistent snow cover.

Winter recreation and Canada lynx: reducing conflict through niche partitioning

“…For example, moose preferentially selected habitats away from areas of high snowmobile-trail density (Colescott andGillingham 1998, Harris et al 2014) and intensive snowmobile activity displaced woodland caribou (R. tarandus caribou) from suitable habitat (Seip et al 2007). Female wolverines tend to avoid motorized winter recreation resulting in significant habitat loss (Heinemeyer et al 2019). Results from our study demonstrated that lynx were most responsive to environmental heterogeneity related to habitat characteristics as hypothesized ( Table 2, Fig.…”

“…), and wolverines ( Gulo gulo , Heinemeyer et al. ). We believe the patterns of spatial separation we documented between Canada lynx and winter recreationists, such as in areas of low tree canopy cover selected by snowmobilers, were mostly a function of resource‐use decisions rather than a landscape of fear that precluded access.…”

“…Female wolverines tend to avoid motorized winter recreation resulting in significant habitat loss (Heinemeyer et al. ). Results from our study demonstrated that lynx were most responsive to environmental heterogeneity related to habitat characteristics as hypothesized (Table , Fig.…”

“…, Heinemeyer et al. ). Yet, despite these challenges, carnivore conservation requires a clear understanding of how disturbance from outdoor recreation may alter resource selection, movements, or access to required habitats in ways that threaten population persistence.…”

“…Understanding how recreation impacts habitat choice and demography of carnivores is particularly pressing given their heightened conservation risk (Ripple et al 2014). However, carnivores are challenging to study given their low densities, large home ranges, secretive habits, and the variation of within-species responses to human disturbance dependent on landscape context (Knopff et al 2014, Heinemeyer et al 2019). Yet, despite these challenges, carnivore conservation requires a clear understanding of how disturbance from outdoor recreation may alter resource selection, movements, or access to required habitats in ways that threaten population persistence.…”