Ecological and evolutionary dynamics of habitat selection.

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My research program aims to develop and test theories that can predict the future consequences of habitat and habitat change on natural populations and ecological communities. In order to do so, we must understand the ecological and evolutionary conditions that allow some species to invade existing communities while others fail. More generally, species represent evolutionary strategies whose ability to invade, or resist invasion from, communities with other species depends on how many individuals are involved (density), and the relative proportions (frequency) of each species (strategy). My team will use habitat selection in order to probe the invasion potential of such alternative strategies. Habitat selection is a suitable arena for assessing evolutionary strategies because the value of choosing one habitat over another 1, depreciates with density, and 2, depends on the choices made by other individuals. Our studies will capitalize on three different model systems. We will begin with short-term field experiments manipulating the quality of adjacent habitats used by differing densities and types of rodents. This system is designed to determine whether one type of behaviour (foraging) can be used to assess the value and stability of another (habitat selection). We will complement the field experiments with a second model system assessing evolutionary fitness in the laboratory. The lab experiments will use arthropods (springtails) whose short life cycles allow us to test for differences in population growth rates (fitness) between competing habitat-selection strategies. Our third model takes advantage of a continuing 32-yr field study on white-footed mice. We will use this remarkable time-series to assess whether changes in habitat and habitat selection cause changes in density, demography, and life history (fitness). Our three-pronged approach should enable us to not only test crucial theories on adaptive evolution, but to also garner insights that will allow us to predict how changes in habitat are likely to impinge on future biodiversity.