Rapid ecological assessment report – Douglas, Cairncross and Wallace islets

Abstract

This report presents the findings of rapid ecological assessments conducted on Douglas Islet, Cairncross Islets, and Wallace Islet in the northern Great Barrier Reef, focusing on quantifying biodiversity values and identifying key ecological threats to Pisonia grandis forests. The assessment provides a snapshot of island condition and potential stressors affecting P. grandis, with particular attention to the presence and impacts of soft scale (Pulvinaria urbicola), alongside other pressures such as weeds and invertebrate activity. The study was designed as a rapid survey rather than a comprehensive inventory of island flora and fauna, and therefore provides targeted observational data to inform management priorities. The assessments also included limited sampling of root and soil material for future analysis of ectomycorrhizal associations and genetic research, with all samples retained for future processing and not analysed within this report. The findings are intended to support management of Pisonia-dominated ecosystems by improving understanding of current condition, emerging threats, and ecological pressures across northern Great Barrier Reef islands, where knowledge gaps remain regarding system trajectory and resilience. This work forms a key deliverable under the Restoration of Reef Islands Project, delivered through the Reef Joint Field Management Program (Great Barrier Reef Marine Park Authority and Queensland Parks and Wildlife Service) in partnership with Ipima Ikaya Aboriginal Corporation, and Aestra as the environmental delivery partner, and funded by the Australian Government’s Reef Trust. The project aims to support the rehabilitation, enhancement, and long-term resilience of island ecosystems within the Great Barrier Reef World Heritage Area.