Species fragmentation or area loss?

摘要

Tilman et al., extending a metapopulation model to include multi-species competition and habitat destruction, arrive at the paradoxical conclusion that, in a patchy habitat, the species most at risk to deterministic extinction when habitat is lost is the dominant competitor. This result arises from the equilibrium between the dominant species' colonization of new sites occupied by inferior competitors and its mortality loss. The fraction of sites p occupied by the dominant competitor is described by the equilibrium relationship dp/dt = 0 = cp (1 -p - D) - mp, where c and m are coloniza- tion and mortality rates and D is the fraction of sites destroyed. The factor (1 -p -D) thus represents the proportion of sites available for colonization by the dominant competitor.