Small vertebrate colonisers of mine site rehabilitated waste dumps in the Goldfields of Western Australia
Faculty of Business and Law
School of Marketing, Tourism and Leisure
Mine site waste dumps pass through various stages as they progress towards the development of mature ecosystems. The ultimate ecosystem on a rehabilitated waste dump is largely determined by the soils and vegetation, and connections with the adjacent habitats that enable invertebrates and vertebrates to move into this area. For some mine sites, the primary objective is to create near-natural, self-sustaining functional ecosystems, others settle for lesser outcomes. To achieve a near-natural, self-sustaining, functional ecosystem is not easy and a lofty objective because of the difficulty in creating the weathered topography and soils of the region, and creating vegetation assemblages of natural ecosystems. Most often waste dumps are huge structures that rise above the existing soil profile, are filled with mining waste in the sequence that it is extracted from the mine, and have a top soil capping that is ripped to reduce erosion and maximise water penetration rather than running off. In the Western Australian Goldfields, mining waste can contain pyrite, which when exposed to water and oxygen increases soil acidity, can contain hypersaline water, may contain concentrations of toxic chemicals or may be hard rock, all of which provide challenges for mine site rehabilitation planners and extra difficulties in achieving near-natural, functional ecosystems as final outcomes for rehabilitated areas. Typically, once the geophysical structure for a waste dump is complete, it is seeded and left for nature to take its course. Microbial organisms are generally brought onto the site in the soils, and by wind and water; invertebrates colonise the waste dump from adjacent areas; and vertebrate communities are generally the last to move onto waste dumps because of their need for complex vegetation assemblages and invertebrate prey. It is for this reason that vertebrates provide a very useful bio-indicator of the success of waste dump rehabilitation programs in creating near natural, self-sustaining, functional ecosystems. We report here on the relative abundance of amphibians, reptiles and mammals on five waste dumps in the early successional stages (3-14 years) in the mined area around Ora Banda in Western Australia and compare these data with species richness and abundance in adjacent undisturbed areas.