Johanna Griggs

Topic

The influence of industrial logging on wolf and deer spatial associations in a coastal temperate rainforest

Department of Geography

Date & location

• Friday, September 11, 2026

• 1:00 P.M.

• David Turpin Building

Reviewers

Supervisory Committee

• Dr. Chris Darimont, Department of Geography, University of Victoria (Supervisor)

• Dr. Cole Burton, Department of Forest Resource Management, UBC (Non-Unit Member) 

External Examiner

• Dr. Allyson Menzies, Department of Biological Sciences, University of Calgary 

Chair of Oral Examination

• Dr. Daniel Rondeau, Department of Economics, UVic 

Abstract

Industrial logging directly fragments habitat, but how might it influence species interactions, such as between predators and prey? In Haíɫzaqv (Heiltsuk) territory, logging has created a patchwork of harvested areas, roads, and old-growth forest. We used 2 years of detection data from wildlife cameras and multi-species occupancy modeling to assess how habitat characteristics and forest age influence the site use and co-occurrence of wolves and their primary prey, Sitka black-tailed deer. Single-species habitat associations were similar across seasons. Deer site use was positively associated with higher proportions of second growth (21-80 years) and old growth (>140 years) forest in both summer and winter. Wolves were more likely to use sites with a higher proportion of old growth forest year-round. Deer and wolf site use was not influenced by the presence of the other species. Despite well-documented logging effects on wolf-deer systems in more heavily logged areas, we found no evidence of comparable effects on either species-specific site use or co-occurrence in our study system where logging remains less extensive. This research not only informs Haíɫzaqv land management but also suggests that changes to predator-prey interactions might only manifest after thresholds of habitat disturbance are crossed.