Mathieu’s PhD research examined how the movement ecology of grizzly bears has changed over time in relation to changing spatial-temporal patterns of landscape disturbance and resource availability. Specifically, he examined how individual grizzly bear movements and behaviour respond to lethal (e.g., legal hunting of grizzly bears from 2001 – 2005) and non-lethal (e.g., disturbance related to roads and resource extraction) risk associated with human activities. Using GPS collar data from 2001 – 2014 and hierarchical Bayesian models, he tested the effects of hunting on grizzly bear movement rates during the legal hunt period (2001 – 2005) and non-hunt period (2006 – 2014). He found that adult male bears decreased their daytime movement rates by 122% during the legal hunt season and became increasingly nocturnal. However, immediately following the end of the hunt season, males returned to biologically driven bi-modal movement patterns. The observed patterns provide support for the predation risk hypothesis in large carnivores, whereby individuals will briefly modify behaviour to reduce exposure to a source of acute risk. Further, inter-seasonal differences in movement rates suggest long-term and persistent behavioural modifications in large carnivores resulting from hunting may be overstated.
To understand how grizzly bears in the Yellowhead and Grande Cache BMA’s have responded to changing landscape conditions over time, he examined how habitat use and movement were influenced by disturbance, resource availability, topography, and climate at two relevant scales: the individual movement and the home range. He found the behavioural response of grizzly bears to landscape disturbance differs dependent on scale. For example, at the home range scale individuals limit risk by broadly avoiding habitat with high road densities. However, individuals strongly selected movements associated with roads and harvest blocks at finer scales, likely due to resource availability and limited resistance to movement through the landscape.
Finally, he examined how an individual’s body condition influenced movement and behaviour. He hypothesized that individuals in poorer body condition would be more likely to engage in risky behaviour, for example foraging in habitat with high densities of human disturbance, due to potential physiological gains associated with resource availability. Individual grizzly bear movements were classified using hidden Markov models, and the influence of body condition was tested while controlling for landscape disturbance densities and resource availability. Individuals in poorer body condition were found to have a higher probability of foraging in habitat with high densities of roads and harvest blocks when food was abundant. In comparison, individuals in good condition were found to move quickly through these same habitat, limiting risk and exposure to human-bear conflict. Considering an individuals physiological state provides important context for understanding behavioural decisions relevant to grizzly bear management and conservation.