Restricted to a very specific habitat, dependant on delicate associations between the fauna and flora and the water hydrology, the Blue Mountains water skink has probably never been abundant. However, as a result of an increasing human population encroaching upon its habitat, it has become threatened, and today, has a very small population (1) (2). Relict populations are extremely isolated and fragmented and, therefore, highly vulnerable to habitat degradation, especially as the majority of Blue Mountains water skink populations are surrounded by urban development (2). Pollution from rubbish disposal, commercial run-off and septic discharge is a particular problem at several locations, and can lead to nitrification, promoting weed infestations. Earthworks for the establishment of sewage pipelines and poor erosion control mechanisms, has also resulted in sedimentation, causing swamps to dry up. Furthermore, the Blue Mountains water skink’s range is intersected by corridors of powerlines, and their servicing has been identified as an additional threat, through the slashing, burning and spraying of pesticides that is required to gain maintenance access (4).
Predation by feral and domestic cats poses further problems, as these introduced predators, which arrived in Australia in the 18thcentury, are now widespread, and threaten many rare species (7). Similarly, pigs have also been introduced into vast areas of Australia, and threaten Blue Mountain water skink habitat by digging up the soils, and altering the composition of the vegetation (8).