Granite outcrop plants- biogeography, evolution and conservation
North Hill from Mt Arid in the Southwest Australian Floristic Region. Photo: © S.D. Hopper
About 15% of the earth's continents consists of granite, which may outcrop in the form of inselbergs - ranges, ridges and isolated hills - that stand abruptly from surrounding terrain, like islands in a sea. Most commonly, granite outcrops appear as dome-shaped hills with bare rock exposed over much of their surfaces. The water catchment so formed, combined with a diversity of microhabitats, make granite outcrops havens for biodiversity world-wide.
Granite outcrops are of special interest:
• geologically, being among the world's oldest rocks
• hydrologically, providing a source of water in dry landscapes
• biologically, as refuges rich in endemic plants and animals
• culturally, being vital for aboriginal, colonial and contemporary peoples alike.
Despite their intrinsic interest, world-wide occurrence, and special values in places like Western Australia, granite outcrop plants are poorly studied. Potentially, research might highlight ideas of general importance concerning the geology, landforms, biodiversity and human use of granite outcrops. Special research opportunities arise from the insularity and geographically compact nature of most outcrops. They offer model systems for exploring evolutionary and ecological processes, and for achieving conservation outcomes through stewardship by informed local communities.
Outcrops often constitute a classic archipelago - real terrestrial islands surrounded by terrain and communities that are inhospitable to many species. As a consequence, there are opportunities to explore evolutionary, biogeographic and ecological questions relating to disjunct population systems. In addition, serious conservation problems such as weed invasion, grazing by feral herbivores, inappropriate fire regimes, dieback disease infection, excessive recreational use and mining are impacting granite outcrops.
This project aims to achieve a cross-disciplinary synthesis of current knowledge on granite outcrops, and to distill effective guidelines for conservation managers. Special focus is on Australian and South African outcrops, but global syntheses are being prepared in collaboration with researchers from around the world.
Project Team
Directorate
Stephen Hopper, Rhian Smith