Rk. Swihart et al., Effects of habitat destruction and resource supplementation in a predator-prey metapopulation model, J THEOR BIO, 210(3), 2001, pp. 287-303
We developed a mean field, metapopulation model to study the consequences o
f habitat destruction on a predator-prey interaction. The model complements
and extends earlier work published by Bascompte and Sole (1998, J. theor.
Biol. 195, 383-393) in that it also permits use of alternative prey (i.e.,
resource supplementation) by predators. The current model is stable wheneve
r coexistence occurs, whereas the earlier model is not stable over the enti
re domain of coexistence. More importantly, the current model permits an as
sessment of the effect of a generalist predator on the trophic interaction.
Habitat destruction negatively affects the equilibrium fraction of patches
occupied by predators, but the effect is most pronounced for specialists.
The effect of habitat destruction on prey coexisting with predators is depe
ndent on the ratio of extinction risk due to predation and prey colonizatio
n rate. When this ratio is less than unity, equilibrial prey occupancy of p
atches declines as habitat destruction increases. When the ratio exceeds on
e, equilibrial prey occupancy increases even as habitat destruction increas
es; i.e., prey "escape" from predation is facilitated by habitat loss. Reso
urce supplementation reduces the threshold colonization rate of predators n
ecessary for their regional persistence, and the benefit derived from resou
rce supplementation increases in a nonlinear fashion as habitat destruction
increases. We also compared the analytical results to those from a stochas
tic, spatially explicit simulation model. The simulation model was a discre
te time analog of our analytical model, with one exception. Colonization wa
s restricted locally in the simulation, whereas colonization was a global p
rocess in the analytical model. After correcting for differences between no
minal and effective colonization rates, most of the main conclusions of the
two types of models were similar. Some important differences did emerge, h
owever, and we discuss these in relation to the need to develop fully spati
ally explicit analytical models. Finally, we comment on the implications of
our results for community structure and for the conservation of prey speci
es interacting with generalist predators. (C) 2001 Academic Press.