The Southwest Australian Floristic Region: Evolution and Conservation of a Global Hot Spot of Biodiversity

• Published in: Annual review of ecology, evolution, and systematics Vol. 35; pp. 623 - 650
• Main Authors: Hopper, Stephen D., Gioia, Paul
• Format: Journal Article
• Language: English
• Published: Annual Reviews 31.12.2004
• Subjects: Biodiversity conservation; Biological taxonomies; Evolution; Flora; Plants; Rain; Speciation; Species; Taxa; Wildlife conservation
• DOI: 10.1146/annurev.ecolsys.34.011802.132535
• ISSN: 1543-592X

Like South Africa's Greater Cape Floristic Region, the Southwest Australian Floristic Region (SWAFR) is species rich, with a Mediterranean climate and old, weathered, nutrient-deficient landscapes. This region has 7380 native vascular plants (species/subspecies): one third described since 1970, 49% endemic, and 2500 of conservation concern. Origins are complex. Molecular phylogenies suggest multiple dispersal events into, out of, and within the SWAFR throughout the Cretaceous and Cenozoic; in many phylogenetically unrelated clades; and from many directions. Either explosive speciation or steady cladogenesis occurred among some woody sclerophyll and herbaceous families from the mid-Tertiary in response to progressive aridity. Genomic coalescence was sometimes involved. Rainforest taxa went extinct by the Pleistocene. Old lineages nevertheless persist as one endemic order (Dasypogonales) and 6-11 endemic families. Such a rich flora on old landscapes that have been exposed to European land-use practices is highly threatened. Conservation programs must minimize soil removal and use local germplasm in restoration programs.