Habitat and community ecology of Canada lynx across intensively managed forest landscapes

,In the subboreal forests of central British Columbia, large-scale and rapid timber harvest has resulted in fundamental changes to the age distribution of forests. Canada lynx (Lynx canadensis) is a habitat and prey specialist on snowshoe hare (Lepus americanus) that is likely sensitive to broad-scale habitat change. It is unclear how large-scale timber harvest may influence community dynamics, including the much studied lynx-hare predator-prey cycle. The density and associated population cycles of Canada lynx differ substantially between northern and southern populations with few studies of the population or habitat ecology of lynx inhabiting southern boreal forests. My research addressed gaps in our understanding of the population, community, and habitat ecology of Canada lynx in subboreal forests of British Columbia. Specifically, I investigated the ecological factors influencing the habitat use, community interactions, and survey methods of Canada lynx during two contrasting periods of cyclic lynx and hare abundance and across a landscape with widespread and rapid forest harvesting. In Chapter 2, I compared habitat selection at two different movement scales using GPS-collared lynx and American marten as well as camera data collected during two contrasting periods of prey abundance. I found that camera traps, in general, reflected the habitat use of GPS-collared lynx and marten. Mid-level and top-level vegetation cover were important predictors of habitat use for both marten and lynx, but with opposite directional influences. Lynx and marten demonstrated differential use of habitat defined by forest age and structure suggesting that each species would serve as a unique indicator of forest condition and change. My objective in Chapter 3 was to determine if a combination of camera traps, abundance estimates, and behavioural cues could be used to monitor cyclic population trends. I found that lynx behaviours and relative abundance were strongly correlated. Consistent with my predictions, years with higher lynx and hare abundance were characterized by increases in cheek-rubbing, scentmarking, and grouping behaviours. Population indices and estimates, in combination with behavioural observations for lynx, provided insights into the ecological drivers of population trends. In Chapter 4, I used camera traps to investigate the influence of sympatric carnivores (coyote, fisher, wolverine) and prey (snowshoe hare, red squirrel) on the habitat use and cooccurrence of Canada lynx. I found that lynx occurrences mirrored the cyclic change in hare abundance, while the number of sympatric mustelid species and the occurrences of each species increased during the low period. The co-occurrence of lynx with other sympatric carnivores increased at a time of prey scarcity suggesting predator populations in subboreal forests may be in a dynamic state of habitat overlap dependent on cyclic prey abundance. In total, my research provides new insights on the habitat, behavioural, and community ecology of lynx found in subboreal forests that are experiencing rapid change. The ecology of lynx in that system is a dynamic response to not only change in forest structure, but also the abundance of their primary prey, snowshoe hare. Also, my results provide guidance on the appropriate application and possible biases of a range of methods for monitoring the distribution and abundance of lynx.

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