Ecology and management of invasive plants in the sub-Antarctic and Antarctic regions: evidence and synthesis from Macquarie Island

Background The Antarctic is an extreme environment for plants. Several invasive plant species, however, have invaded the sub-Antarctic Southern Ocean islands and increasingly threaten the vulnerability of maritime and continental Antarctica, particularly with changes in climate. Aims We provide an overview of issues to consider with regard to the impact, ecology and management of non-native plants in the Antarctic, focusing on knowledge gained and recent research results from the sub-Antarctic with possible application to Antarctica. Methods We provide a brief review of literature and bring together experience and previously unpublished research with Poa annua and Stellaria media on Macquarie Island. Results While no one set of biological characteristics predicts plant invasiveness in the sub-Antarctic, all are adapted to survive extreme cold conditions and persistence is enabled through large and long-lived soil seed banks. Ecological drivers for invasion include accidental human introductions and continuing movement, along with animal and other disturbance to soil. Conclusion The invasive cold-tolerant plant species now prevalent on sub-Antarctic islands also pose a threat to Antarctica due to a warming climate and so efforts should continue to prevent further spread, while developing effective, low-impact control and eradication options to protect these high-value extreme ecosystems.