Landscape pattern and population conservation

Abstract

Theory relating population survival to landscape spatial pattern is reviewed. Important generalizations are: 1) as the amount of habitat decreases the probability of regional population survival decreases; 2) for the same total amount of habitat, increased habitat clumping (increasing patch size) increases the probability of population survival, and this positive effect of increasing patch size outweighs the negative effect of increasing inter-patch distance; 3) increasing inter-patch variance in patch size increases the possibility of regional survival; 4) when the landscape pattern is dynamic (patches are ephemeral or disturbance rate is high), landscape spatial pattern is relatively unimportant; and 5) when habitat is ephemeral, regional population survival increases with increasing patch lifespan. Empirical studies cannot be used to rigorously test the theoretical predictions because human activities usually alter several aspects of landscape pattern simultaneously. Important questions for future research are: 1) To what extent can careful planning of landscape pattern compensate for loss of habitat? 2) Under what circumstances (for what kinds of species in what kinds of landscapes) is spatially explicit modeling necessary for predicting the effects of habitat fragmentation on population survival? 3) How can we make predictions of effects on alteration of landscape pattern on species diversity? -Authors