HABITAT HETEROGENEITY AND FORAGING EFFICIENCY - AN INDIVIDUAL-BASED MODEL

We present a rule-based, event-driven model of foraging behavior, and use it to demonstrate the influence of structure and variability of habitats in determining the foraging efficiency of an individual herbivore. The structural and distributional properties of resources were assigned based on vegetation measurements in subalpine habitats in Denali National Park and Preserve, Alaska. The forager was characterized in terms of the physical, physiological, and cognitive attributes of a moose (Alces alces). We modelled movement as a sequence of steps in response to perceived resources. Simulation of foraging behavior in the model was event-driven. Artificial habitats were simulated to evaluate the influence of biomass per plant and mean bite size of plants on the foraging efficiency of the simulated animal. The mean rate of dry matter intake, and the 24-h activity budgets simulated by the model were similar to those reported for moose by Risenhoover. Foraging efficiency varied with changes in the size and variability of plants and individual bites available in the habitat. We discuss the results of our simulations in terms of modelling at the individual level.