The five mediterranean-climate regions of the world – California, central Chile, the Mediterranean Basin, the Cape Region of South Africa, and southwest Australia – share a remarkable similarity in the structure of evergreen, leathery-leaved shrublands that dominated their landscapes. Each region is considered a global hotspot for biodiversity, arguably the most species rich ecossytems outside of tropical rainforests. This pattern has long evoked interest in comparative ecological studies among these five geographically isolated regions with their unique climatic regime. The focus of scientific research has progressed through time from initial generalizations about ecosystem convergence in the five mediterranean-climate regions, to the complexity of multiple exceptions to patterns of convergence, and finally to a deeper understanding of geographic processes and ecological relationships that both link and separate individual regions.
Hal Mooney was a pioneer in establishing studies of convergent ecosystem evolution with his focus on comparative studies of California and central Chile, beginning with the International Biological Program (IBP) in the early 1970s. These efforts led to the establishment of the highly successful MEDECOS conferences in 1971 that continue today, bringing together researchers from the five mediterranean-climate regions and promoting collaborative work. More than any other ecosystem, the Mediterranean Biome has become a key system in understanding the role of plant life-history traits in structuring communities and the nature of past and present selective forces in the diversification of the floras of these species-rich biomes. Because of Hal’s long history of leadership, mediterranean-climate ecosystems continue to provide productive opportunities for comparative research on the controlling factors in community structure and biodiversity, and on macroecological patterns in convergent community evolution.