Time to Event Modelling: Wolf Search Efficiency in Northern Ontario

• Main Author: Moffatt, Scott
• Other Authors: Fryxell, John, Patterson, Brent
• Format: Thesis
• Language: English
• Published: 2009
• Subjects: Canada; caribou
• Online Access: http://hdl.handle.net/10214/3682

With the potentially additive anthropogenic effects of deforestation, climate change, mining, oil and gas extraction there may be rapidly changing predator-prey dynamics in Canada‘s boreal forest. Of particular concern is whether wolf predation is responsible for the retraction in the historical range of woodland caribou in Northern Ontario. Using time to event modelling, I determined how environmental heterogeneity in heavily forested sites of northern Ontario Canada, and animal movement behaviour, affected wolf kill success. I used Cox proportional hazard models to test several alternative hypotheses, including the wolf functional response, wolf pack characteristics, wolf satiation, landscape and other environmental features. In the proportional hazards model, an increased relative killing efficiency corresponds with a decreased time between predation events. In a comparison of top models, the predator road use hypothesis (defined by distance from road and wolf search velocity) had the most evidence. Wolves used linear features such as roads to quickly navigate their territory while targeting moose habitat near forest access roads. As the most efficient search trajectories occurred near roads, moose and woodland caribou were likely to be at significantly greater risk of predation in sites with high road densities. NSERC, OGS, University of Guelph, Canadian Forest Service, MNR – Wildlife Research and Development Division, Forest Ecosystem Science Co-operative Inc., the Center for Northern Forest Ecosystem Research.