Predator persistence in fragmented forests: lynx and snowshoe hares

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One of the major threats to imperiled species is the loss of habitat.  In forests, this loss often leaves remnant stands of the original forest surrounded by other stands that differ in age or species composition.  For forest mammals, these complex mosaics of different stand types strongly affect population dynamics; for some species, populations decline as habitat fragmentation occurs.  Often, predators and prey in forests will respond to fragmentation at different spatial scales, with prey staying in particular forest stands and predators moving among stands.  As habitat loss occurs and the stands that prey can use become smaller or farther apart, predators may not be able to obtain enough prey to survive because the cost of traveling among the stands with prey becomes too high.  I am interested in how forest mammals respond to forest fragmentation, and my main research objective is to explain how predator-prey interactions are changed as a landscape becomes increasingly fragmented.  The population dynamics of prey in different stand types will largely determine whether their predators can persist in a fragmented landscape.  At one extreme, prey might use only a few, far apart stands; at the other extreme, they might occur in the majority of stands.  As a model system, I am focusing on snowshoe hares (Lepus americanus) and Canada lynx (Lynx canadensis) in western Montana.  I am characterizing density, survival, and reproduction of hares in different stand types.  I am then exploring which stand types lynx use for hunting, how far they travel between kills, and what proportion of their diet consists of hares in this region.  I am unifying these results in spatial models so that I can model the effects of  changing the amount of different types of habitat on these species.  This research program will advance our general understanding of how predators and prey respond to forest fragmentation, as well as predicting configurations of remaining forest stands that might help to retain species in the landscape.