Geography, climate, and biodiversity: the history and future of Mediterranean-type ecosystems
Oxford University Press
Faculty of Health, Engineering and Science
School of Natural Sciences/Centre for Ecosystem Management
The world’s mediterranean-climate regions all have mild, winter-rain climates that have developed over the past several million years, but beyond these similarities they have distinct geological and evolutionary histories that have shaped the floras of each region. This chapter considers the historical and regional influences that have shaped the floras of MT regions, focusing on South Africa, California and Western Australia. One of the most striking differences is their positions on the respective continents, and their tectonic history, and the absence of a high latitude, terrestrial region bordering South Africa and Australia. As a result, the Cape flora does not have a clearly identified temperate element, in striking contrast with California, and this may contribute to the high level of in-situ radiation in Cape lineages. While radiations have occurred in the sclerophyllous lineages in both areas, the moist-adapted, forest communities tend to be derived from cool-temperate lineages in California and from warm, afrotropical lineages in South Africa. In both cases, these components of the flora represent greater phylogenetic diversity. The absence of temperate land masses adjacent to South Africa and Western Australia result in greater reduction in the area of mediterranean-type climate in the face of 21st century global warming. Other aspects of geology, topography and human land-use impacting the prospects for biodiversity conservation are addressed.