APPLYING DIFFERENCE-EQUATIONS TO WOLF PREDATION

Parameters for generalized Lotka-Volterra equations, expressed as diff erence equations, have been estimated from actual data on wolves and t heir prey. The functional response is represented by a single constant , while the numerical response is expressed as a ratio-dependent limit ation on predator abundance. Parameters for the Lotka-Volterra equatio ns were estimated by multiple-regression fits to data on moose (Alces alces) and wolves (Canis lupus) on Isle Royale, and from other sources . Observed prey-predator ratios are highly variable, but much of the v ariability may arise from nonequilibrium conditions. A. multiple-prey model has been developed by assuming that utilization rates vary in pr oportion to relative current biomass. If analyses are to be useful, th e: dynamic, nonlinear nature of predator-prey systems requires that a system of equations be developed, along with extensive series of obser vations of actual abundances of predator and prey.