Management of invasive 'Poa annua' in the sub-Antarctic wilderness of Macquarie Island

Abstract

'Poa annua' L. is the most widespread weed in the sub-Antarctic, present on all major island groups and on the Antarctic Peninsula. Its ability to withstand heavy grazing has enabled it to spread significantly on islands with introduced herbivores. On Australia's World Heritage Macquarie Island it is common and widespread. With the recent eradication of rabbits and associated change to vegetation dyna-mics it is critical to understand the distribution and abundance of 'P. annua' in this rapidly changing environment. Our study aimed to investigate management techniques for 'P. annua' to assist in the development of non-native plant management in the sub-Antarctic and Antarctic. Experiments were designed to study the response of 'P. annua' and native species to physical disturbance and herbicide application. Our preliminary studies indicated that physical disturbance promotes the growth of 'P. annua' over native species, and glyphosate, rimsulfuron and trifloxysulfuron selectively control 'P. annua' under simulated sub-Antarctic temperatures while amitrole, clethodim, dithiopyr, ethofumesate, fluproponate-sodium, imazamox, simazine and methabenzthiazuron are less effective. These results provide promising avenues for further research that will contribute to the development of control programs in the sub-Antarctic and Antarctic region.