KARST WETLANDS BIODIVERSITY ANI) CONTINUITY THROUGH MAJOR CLIMATIC CHANGE: AN EXAMPLE FROM ARID TROPICAL WESTERN AUSTRALIA W.F.Humphreys krrestrial InvertebrateZoology, Museum o.f l,{atural Science, WesternAustralian Museum, Francis Street,Perth, WA6000, Australia; E-mail:
[email protected]. gov. au Abstract Subterraneankarst wetlands,recently included as a wetland type under the Ramsarclassification, are introducedhere to the wetlandsbiodiversity literature.The generalcharacteristics of karst land- scapesexplain the connectionswith non-karsticwetlands, the often diffuse limits to karst wetlands and their vulnerability to exploitation and pollution. Less than l0oA of the Earth shows distinctive karst landforms but on a global basiskarst wetlandssupport the greaterpart of subterraneanbiodi- versity.This introduction is amplified by a detailed account of a single karst wetland Cape Range peninsula,Western Australia. Cape Range,the only orogenicTertiary limestone in Australia, occurs on a continent relatively devoid of karst. It lies in the arid tropics where surface water flows are mostly episodic and fre- quently saline. The Cape Range karst wetlands contain both freshwater and anchialine wetlands whose natural accessis through a few karst windows and caves.The anchialine system shows marked stratification of their physico-chemicaland biological profiles. The lack of surfacewaters and the particular geographical context means that much of the groundwater fauna represents ancient geographical or phyletic relicts. A general case is made supporting the persistenceof groundwaterfauna in karstic systemsthrough geologicaleras. Introduction The 6th Conferenceof ContractingParties to the RamsarConventionl (Brisbane 1996) voted to include subterraneankarst wetlandsas a wetland type under the Ramsarclassification system. This inclusionhas far reachingimplications, not only for karst regions,but also for a wide rangeof wetlands,and for groundwatercon- servationgenerally.