Educational Model: Lotka-Volterra Predator-Prey Model

This model is a component of the IUMC (Innovative Educational and Methodological Complex) "Ecology: Constructing the Biosphere," developed in 2008 by D. A. Shabanov, A. G. Kozlenko, and M. A. Kravchenko by order of the NTFP. The model is posted for educational use. It demonstrates dynamics of two interacting species: predator and prey. The theoretical material is in the section "Lotka-Volterra Model" of the manual "Ecology: Biology of Interactions." The dynamics are presented in a near-classical form: prey dN1/dt = r1×N1 - ε×N1^2 - p1×N1×N2, where ε=r1/K1; predator dN2/dt = r2×N2 - d×N2^2 + p2×N1×N2, where d=r2/K2. N1 is prey abundance, N2 predator abundance; r1 and r2 are intrinsic growth parameters; K1 and K2 are carrying capacities; p1 and p2 describe interaction effects. The model also includes a refuge (a habitat fraction where prey are inaccessible to predators). By changing parameters, users can examine abundance dynamics and responses to disturbances (sudden declines or surges). Instructions are located at the bottom of the model window; if they do not fit, scroll with the arrows on the right. Some tasks: (1) Analyze how each parameter affects predator and prey curves. (2) Evaluate effects of refugia and sudden predator/prey abundance surges.