Restoration of Open-Cut Mining in Semi-Arid Systems: A Synthesis of Long-Term Monitoring Data and Implications for Management

Restoration is becoming an increasing global priority. Particularly in high impact developments like open cut mining, restoring ecosystems to pre-disturbance states is difficult but essential. Successful restoration of vegetation communities requires complex achievements of cover, density, community composition, species richness, and structural elements. This study synthesises 10years of monitoring surveys to measure restoration success in six mining operations in the semi-arid Pilbara of Western Australia, with the goal of quantifying current and past restoration performance. We assessed composition, structure, cover, density, and richness. We found that each metric resulted in slightly different performance measures within mining operations. For example, native perennial grasses in restored sites fell short of reference density and cover, while woody species density and cover were regularly within the reference range. Richness was often much higher in restored than in reference sites. Finally, to explore the potential drivers of performance, we analysed the influence of restoration characteristics on each of the vegetation metrics. We found that older restoration had increased cover and density of all vegetation types compared to more recent restoration, while other variables had impacts on restoration results that shifted between metrics and monitoring periods. Compositional similarity with reference sites was higher when restoration occurred on low impact mining activities, when first year rainfall was higher, and when seeding treatments were not applied. Overall, this assessment of long-term monitoring data highlighted where each performance measure was important to understanding overall restoration patterns in semi-arid systems and paves the way for improving future restoration practice. Copyright (c) 2017 John Wiley & Sons, Ltd.