Wolverine (Gulo gulo luscus) movement, habitat selection, and foraging in a landscape with resource extraction

  • Author / Creator
    Scrafford, Matthew A
  • Industrial infrastructure and activities can fragment boreal landscapes and alter the ecology of wildlife species. Wolverines (Gulo gulo luscus) are a species considered especially sensitive to resource extraction because wolverines are wide-ranging, low-density, and have low-reproductive rates. Wolverines May be at Risk in Alberta and are a Species of Special Concern in Canada. Both assessments relate a lack of information on the effects of industrial disturbance on wolverine ecology. The aim of my thesis was to better understand the movement, habitat selection, and foraging ecology of wolverines in the northern boreal forest of Alberta (Rainbow Lake) where resource extraction has been occurring since the 1950s. My first objective was to determine whether active logging and industrial infrastructure attracted or displaced wolverines. I used resource selection functions (mixed-effect logistic regression) to evaluate competing hypotheses regarding their effects on wolverine habitat selection. I found wolverines were not displaced but instead were attracted to areas of active logging. I also found that wolverines were attracted to seismic lines, borrow pits, and the edges of intermediate-aged cutblocks. I suggested that the attraction of wolverines to these features might be a result of foraging and movement opportunities. I also suggest attraction to the features might increase their mortality. My second objective was to evaluate the behavioral strategy wolverines use to reduce predation risk from roads and vehicle traffic, including, avoiding, increasing speed, or avoiding and increasing speed near roads. I collected traffic data on industrial roads using motion-sensor cameras and modeled variables explaining traffic volume using a mixed-effects linear regression model. I modeled wolverine space use relative to roads using an integrated step-selection analysis. Models that included variables for avoidance and increased speed nears roads better explained wolverine space use than all other models. Wolverines avoided roads and increase speed near roads, while increasing speed more near roads with greater volumes of traffic. I suggest that displacement of wolverines near roads, and especially high-traffic roads, could reduce suitable habitats in industrial landscapes. My third objective was to compare the habitat selection and movement of wolverines within their home range versus during dispersal. I classified wolverine movements into home range and dispersal categories based on plots of net-squared displacement. I found that males increased their selection strength for linear features (roads, streams) during dispersal, reduced their movement rate, and increased their foraging rate. These results align with optimal-dispersal strategies. Females habitat selection during dispersal appeared more flexible. In addition, females during dispersal did not change their movement or foraging rates when compared with their movements in the home range. These data show that wolverines might be limited during dispersal by food and predation risk. My final objective was to evaluate the foraging ecology of wolverines. I visited GPS radiotelemetry clusters in the field and documented the occurrence of wolverine scavenging, beaver-kill, and resting sites. I then predicted large-feeding sites (ungulate carcass, beaver-kill site) across all radiotelemetry data in winter and summer seasons. I used time-to-event models to investigate factors influencing the time to detection of large-feeding sites, the time spent at large-feeding sites, and return time to large-feeding sites after leaving. I found that the time to detection of a large-feeding site was lowest in summer when beavers were more available. I also found that the residency time during a visit to a large-feeding site decreased and return time increased with an increase in the cumulative time spent at a feeding site. Moreover, wolverines spent more time at large-feeding sites if there were other wolverines detected or if the visit was in the winter. Wolverines decreased their time at large-feeding sites if the wolverine also was visiting multiple other feeding sites. These data highlight the strategies wolverines use to reduce competition and opportunity costs while foraging. Overall, my work provides evidence that industrial disturbance can both attract and displace wolverines and that simply measuring the human footprint is a poor proxy for the suitability of wolverine habitats.

  • Subjects / Keywords
  • Graduation date
    Fall 2017
  • Type of Item
  • Degree
    Doctor of Philosophy
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.