Movement of individuals links the effects of local variation in habitat quality with growth and persistence of populations at the landscape scale. This movement may also transmit the population-level effects of interspecific interactions such as predation, potentially leading to a complex feedback between population growth and adaptive movement behavior of individuals. We ask how adaptive predator responses to prey abundance influence the predicted effects of habitat degradation. We develop a simple model of predator-prey population dynamics on a landscape composed of unaltered and degraded habitat with movement between habitat types. We compare the predicted population abundances when predators forage at random with the case in which predators move according to an evolutionary stable strategy.
Results/Conclusions
In the absence of an adaptive response by predators, we predict that decreasing prey movement between habitat types increases equilibrium prey abundance, potentially preventing system-wide prey population collapse. This occurs because low movement allows prey abundance to build up in unaltered habitat, which creates a source population that supports a sink in degraded habitat. However, if predators utilize habitat types adaptively, the prediction is reversed. In this case, decreasing prey movement leads to an evolutionary stable strategy in which predators drive prey extinct even if the landscape average habitat quality is sufficient to support prey and predator populations. Our results suggest that the predicted population response based solely on average habitat productivity will overestimate the amount of habitat degradation that can be tolerated by a population. We also predict that natural selection will favor decreasing prey dispersal, resulting in a feedback that pushes the population toward extinction.