Habitat Fragmentation and Biodiversity Collapse Under Recruitment Limitation

Ricard V. Solé and David Alonso

00-12-066

Models of habitat fragmentation have mainly explored the effects on a few species ecologies or on a hierarchical community of competitors. These models reveal that, under different conditions, ecosystem response can underly sharp changes when some given thresholds are reached. Here we explore both spatially implicit and a spatially explicit metapopulation models where the colonization-extinction dynamics takes place through recruitment limitation. Colonization and extinction are linked through a simple tradeoff. The spatial model is able to reproduce the species-rank and species-area laws obtained from recent studies on rain forest plots. It is shown that percolation thresholds play an important role in limiting diversity once the landscape is broken into many patches. The multiplicity of states implicit in the model leads to a strong path dependence in the system, making predictions about the extinction of particular species very difficult.