INBREEDING DEPRESSION EFFECTS ON EXTINCTION TIME IN A PREDATOR-PREY SYSTEM

Traditional methods of assessing population viability ignore both genetic-demographic interactions as well as community level dynamics. We address these deficiencies by presenting a model that investigates the effects of predation on a prey population experiencing inbreeding depression. Beginning with a simple Lotka-Volterra predator-prey system, we rewrite prey per capita mortality as a function of inbreeding. Inbreeding varies as a function of population size. Using computer simulation, we find that prey extinction times are inversely related to the level of inbreeding depression with and without predation. For all but very low levels of inbreeding depression, predation appreciably reduces persistence time. At moderate levels of inbreeding, predators go extinct before prey. When migration is introduced at low and moderate rates, persistence times only improve for those populations with low inbreeding depression measures. At a higher migration rate, persistence times are lengthened for low and moderately depressed prey populations. Increasing birth rates produce a visible, though noisy, trend towards increased times to extinction for low to moderate levels of inbreeding.