Biogeography may be defined simply as the study of the geographical distribution of
organisms, but this simple defmition hides the great complexity of the subject. Biogeography
transcends classical subject areas and involves a range of scientific disciplines that includes
geogra phy, geology and biology. Not surprisingly, therefore, it means rather different things
to different people. Historically, the study of biogeogra phy has been concentrated into
compartments at separate points along a spatio-temporal gradient. At one end of the …