Using reference sites to guide ecological engineering and restoration of an internationally significant uranium mine in the Northern Territory, Australia

Abstract

Ranger uranium mine, surrounded by Kakadu National Park in northern Australia, is about to undertake broad-scale restoration of the first of its two pits and cease all mining and processing activities. Over the mine’s forty-year life information from two detailed vegetation maps and five significant reference site surveys has been used to assist with closure. All relevant and available data were reviewed and, as a result, biophysical, remote sensing and vegetation survey data, across an area known as the Georgetown analogue, were subsequently analysed in greater detail. Vegetation communities were assessed using cluster analysis, spatial analysis and regional scale fire mapping. Regional floristic patterns were reflected in vegetation survey data, but the frequency of fires in the assessed Georgetown analogue site was significantly lower to the landscape adjacent to most of the mine site. Indeed, reference ecosystems that capture the variability of fire regimes in the area surrounding the mine should be utilised in the future to provide further engineering and restoration guidance for the new landform, determine appropriate understory species and inform pathways for restoration success. Of the 44 over-storey species assessed in this study there is limited information on the propagation techniques for eighteen species, whilst the establishment of more than 40% of the species on unnatural, mine-created substrates is unknown. Therefore, a more complete list of plant species, knowledge of their propagation and establishment requirements, and appropriate spatial patterns are still needed to ensure that the restoration of Ranger Uranium mine will be successful.