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Modeling behavioral decisions of voles in complex landscapes.
Russell, Robin *,1, Swihart, Robert1, 1 Purdue University, West Lafayette, IN
ABSTRACT- Present-day landscapes often consist of a patch work of land-cover types, including areas heavily modified by human use. Wildlife species differ in their ability to cross resource poor areas and willingness to venture into areas that increase their exposure to predators. Transitions from one land-cover type to another reflect a behavioral decision process which presumably relies on the animal's assessment of risk versus gain in the new land-cover type. We observed meadow voles, Microtus pennsylvanicus, in experimental landscapes to estimate their transition probabilities between habitat types.Voles were released within an enclosure containing habitat patches connected by corridors and tracked by radio-telemetry.Vegetation within the corridors was modified to represent four different levels of risk. Transition probabilities from a patch to a particular corridor type were determined using multi-strata modeling in program MARK. Transitions from patches to corridors composed of tall vegetation (0.8m) and half-height vegetation (0.4m) were significantly more common than transitions to corridors devoid of vegetation or containing mown vegetation (0.05m).However, bare- ground corridors were utilized more often than expected and preferred over mown corridors.We previously conducted computer simulations of animal movements in complex landscapes which indicated that the movement rule utilized in the model influenced the abundance and distribution of the population. Our field results combined with our simulations indicate that assumptions of optimal movements in landscape models may lead to inaccurate conclusions regarding the ability of wildlife populations to persist in complex landscapes.
Key words: multi-strata models, Microtus pennsylvanicus, behavior, movement