THE BIOGEOGRAPHY OF LAND SNAILS IN THE ISLANDS OF THE GULF OF GUINEA

Data on land snail diversity in the Gulf of Guinea islands is presente d and the biogeography of the Gulf of Guinea fauna is discussed with r eference to island snail faunas in the other areas of the world. Altho ugh the land snail faunas of the four islands clearly have west and ce ntral African affinities, speciation events following rare colonizatio ns have led to high rates of endemism at the species and generic level s. The influence of island size, altitude, isolation and other factors on the development of the land snail faunas is discussed. The effect of land use changes on the land snail fauna over the last 150 years is evaluated. Current threats include recent changes in agricultural pra ctice leading to the destruction of snail habitats in both forest and plantation areas. The potential threat posed by introduced species is also discussed. The Gulf of Guinea snail faunas appear to be in relati vely good health in comparison to many other island snail faunas. Howe ver, the uniqueness of the faunas makes it imperative that further eco logical and taxonomic research is undertaken both to understand the pr ocesses by which they developed and to evaluate the current status of many species in terms of distribution and threats.