Biological invasions and deletions: community change in south Florida

This study used the endangered and exotic fauna of south Florida, USA, to test three non-exclusive hypotheses about community change. Over one third of the vertebrate fauna of south Florida is either endangered or exotic. We assumed that in the future, many of the currently endangered species will become extinct, while established exotics become more widespread and abundant. Using species' distributions, body mass data, and niche classifications, we compare the past (without exotics) and our predicted future (with exotics, without endangered species) vertebrate communities to determine if the future fauna would be on average smaller, more generalized feeders, or if there would be direct niche replacement. The results of the comparisons indicate that none of the hypotheses explained all of the expected changes in the vertebrate fauna of south Florida, and that the future vertebrate fauna of south Florida is likely to be very different from that of the recent past. These changes are symptomatic of the profound ecosystem-level changes occurring here. Hypotheses generated by systemic-level investigations are more likely to increase our understanding of invasions and extinctions. (C) 1998 Elsevier Science Ltd. All rights reserved.