Gerald Kuchling, Department of Biodiversity, Conservation and Attractions

The longneck turtle Chelodina kuchlingi is the only vertebrate species known to be endemic to the lower Ord River floodplain, Kimberley, Western Australia. After the opening of the Ord River Diversion Dam in 1963, three specimens were collected at its south-western edge at Parry Creek in 1965. In 1972 the main Ord River Dam was opened, holding back Lake Argyle, Australia’s largest dam reservoir, reducing wet season and increasing dry season flows below the dams. This effectively transformed the former ‘dry tropics’ river with high seasonal flow variation and strong wet season pulses of floodplain inundation into a ‘wet tropics’ river with a permanent flow regime and minimal floodplain inundation. One more specimen of C. kuchlingi was collected at Parry Creek in 1974 together with the first C. walloyarrina, a sandstone plateau species. During a few surveys this century only C. walloyarrina and ‘C. rugosa?-like’ specimen were found in the lower Ord River area. The temporal pattern of turtles recorded since the 1960s suggests a recent expansion of the wide-spread sandstone plateau species C. walloyarrina into the floodplain, progressively replacing C. kuchlingi concomitant with the hydrological changes caused by the damming of the Ord River. Chelodina kuchlingi, the only vertebrate species endemic to this area, is pushed to the brink of extinction by the past and present failure to include freshwater turtles in pre-development fauna surveys and environmental impact assessments for the Ord River developments. A genetic study of all historic specimens of C. kuchlingi and of C. walloyarrina and ‘C. rugosa-like’ specimens is currently underway to assess the possibility of hybridization and introgression and to provide a basis for targeted surveys to find genetically pure C. kuchlingi to plan and implement conservation actions.