Africa occupies about one-fifth of the global land surface and contains about one-fifth of all known species of plants, mammals, and birds in the world, as well as onesixth of amphibians and reptiles (Siegfried, 1989). About one-fifth of southern African bird species migrate on a seasonal basis within Africa, and a further one-tenth migrate annually between Africa and the rest of the world (Hockey, 2000). One of the main intra-Africa migratory patterns involves waterfowl, which spend the austral summer in southern Africa and winter in central Africa.
Palearctic migrants spend the austral summer in locations such as the Langebaan Lagoon, near Cape Town, and the boreal summer in the wetlands of Siberia. If climatic conditions or very specific habitat conditions at either terminus of these migratory routes change beyond the tolerance of the species involved, significant losses of biodiversity could result. Although the species involved have some capacity to alter their destinations, in an increasingly intensively used world the probability of finding sufficient areas of suitable habitat in the new areas is small. The current system of protected habitats under the Ramsar Convention is based on the present distribution of climate, raising the possibility of vastly changed habitat type and quality under climate change.