A REVIEW OF THE BIOGEOGRAPHY OF THE PROTOZOAN GENUS NEBELA IN THE SOUTHERN TEMPERATE AND ANTARCTIC ZONES

Most examples used in biogeography textbooks are derived from studies of macroscopic organisms. As an example of microbial biogeography stud ies on the distribution of the protozoan genus Nebela in the southern temperature and Antarctic zones are presented. The results suggest a m ajor role for climate (characterised by mean January temperature) in c ontrolling species richness. The high number of endemic taxa along wit h the deviation of several sites from the general relationship between species richness and climate suggests that geographical barriers play an important role in Nebela biogeography. It is suggested that the ge nus has responded to past climate changes (eg glacial/interglacial cyc les) by migration. Possible effects of anthropogenic climate change ar e considered. It is suggested that their small size (hence potentially rapid wind-borne migration) and short generation time make protozoa a potentially sensitive measure of biological response to climate chang e.