Late quaternary land snails from the north coast of Jamaica: Local extinctions and climatic change

Abstract

Analysis of the land snail faunas and chronology ( 14C and amino acid epimer ratios) of six late Quaternary deposits from a site on the north coast of Jamaica provides a basis for reconstruction of local extinction events and their relation to paleoclimate. Paleotemperature estimates are derived from epimerization rates at an interior site and indicate an average Holocene-late last glacial temperature difference of c.4–5°C. Size variation in land snails indicates relatively dry conditions during the late last glacial and moist conditions in the late Holocene, followed by drier conditions beginning sometime during the last millennium. The rich faunas of the latter half of the last glacial are represented today at the same site by only a relatively few remnant species. Two major periods of extinction are identified. During latest last glacial to early Holocene time, a number of species became locally extinct, probably due to increased temperatures; many survive today in the cooler interior of the island. Extensive extinctions occurred again during the last millennium. These apparently resulted largely from habitat disturbance by man. A similar pattern of late Holocene extinctions has also been documented for vertebrates on other tropical islands and is also thought to result from human disturbance.