THE EFFECTS OF HABITAT FRAGMENTATION ON CHAPARRAL PLANTS AND VERTEBRATES

The effects of fragmentation in a scrub habitat in California on three taxa (plants, birds, and rodents) are concordant. Extinctions within the habitat remnants occur quickly and the sequence of species disappe arances of birds and rodents is predictable based on population densit y in undisturbed habitat. Distance effects on species diversity are we ak to non-existent, and habitat area effects are strong. Edge effects and cumulative habitat loss following isolation of the remnants are co rrelated with loss of species diversity. Recolonization in these taxa occurs rarely. Rodents appear to be extremely susceptible to extinctio n. Small, old patches retain a predictable subset of bird and rodent s pecies, reinforcing the principle that larger reserves are generally s uperior.