Lynx cycles and barriers: Evaluating dispersal versus climate change in flatlining populations

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Persistent and regular population cycles produced by specialist predators and their prey are a rarity in nature, but appear to be a major force creating a periodic rhythm in boreal ecosystems. Canadian lynx (Lynx canadensis) and snowshoe hare (Lepus americanus) display such a pervasive 10-year cycle. The health of these dynamic systems are at risk as evidenced by the threatened status of the lynx in the US and low numbers in what remains of its southern range in Canada. For instance, lynx numbers in the Cascades Mountain Range of southern Canada and northern Washington have approximately halved in recent years. The persistence of lynx near the Canada-US border may depend on either quality of dispersal connections with the core Canadian population or stemming the progression of climate change before it permanently alters the species' dynamics.We propose to evaluate alternative hypotheses to explain the breakdown in the periodicity and amplitude of the lynx-hare cycle: the homogenizing effect of predator dispersal versus the reduction in environmental seasonality that is hypothesized to maintain the 10-year cycle. My research outcomes are to 1) evaluate if either climate change or barriers to dispersal is the main biological mechanism behind the breakdown of southern lynx cycles and 2) use a sample of radiocollared lynx to create a model of habitats that facilitate dispersal and produce habitat/dispersal maps identifying barriers to movement through key lynx habitats in the southern portions of the species' range.  Understanding dispersal trends is essential for managing habitat fragmentation and protecting habitat connections.   Alternatively, climate change might be rapidly dismantling population cycles in the boreal forest.  This study will benefit wildlife managers, forestry and other resource extraction industries, the trapping industry, and the collective knowledge of population ecology.