THE LIKELY CAUSE OF EXTINCTION OF THE TREE SNAIL ORTHALICUS RESES RESES (SAY).

The Stock Island tree snail, Orthalicus reses reses, went extinct in its native range in the Florida Keys in 1992. Fortunately, O. r. reses has been introduced elsewhere and further reintroductions are currently planned. Before these reintroductions are implemented, it is important to try and determine which factors were most likely to have caused the decline and extinction. While habitat destruction was prob-ably the ultimate reason why there were so few tree snails, it is likely that an interaction of habitat frag-mentation and the invasion of an exotic predator caused the final decline that lead to the extinction in 1992. We examined the last 93 O. r. reses shells to infer cause of death. In addition, using surrogate Florida tree snails, Liguus fasciatus, we conducted experiments on two previously unstudied causes of mortality: predation by red imported fire ants, Solenopsis invicta, and mortality from falls caused by wind. [ABSTRACT FROM PUBLISHER]