Ecological Restoration of Sub-Antarctic Macquarie Island

Abstract

Invasive vertebrate species have had devastating impacts on the flora, fauna and landforms of Macquarie Island over a period of 200 years. Following the successful eradication of weka by 1989 and feral cats by 2001, planning for the eradication of ship rats, house mice, and European rabbits began in 2004. Funding of AUD$24.7M was secured in 2007 for a multi-year project based on aerial baiting targeting rabbits and rodents followed by ground hunting targeting surviving rabbits. The first aerial baiting attempt in 2010 was abandoned due to unfavourable weather and shipping delays. The degree of non-target seabird species mortality from limited baiting in 2010 led to a renewed examination of non-target mitigation options. Rabbit Haemorrhagic Disease Virus (RHDV) was introduced in February 2011 to reduce the pre-baiting rabbit population and thus minimise non-target mortality amongst scavenging seabirds. Aerial baiting resumed in May 2011 using 4 AS350 helicopters and a team of 27 people, and was completed by July 2011. No rodents have been detected post-baiting, and the estimated rabbit population of 150,000 has been reduced to fewer than 30 at the conclusion of baiting. The rabbit hunting phase commenced in July 2011 using a team of 15 hunters and 12 dogs and is ongoing, with 3 rabbits accounted for. Hunting and monitoring is expected to take a total of 5 years post-baiting and will be based on annual progress reviews. A minimum of 2 years monitoring will be conducted. Rodent detection dogs will deploy in 2013 to assist in determining rodent eradication success. Six months after baiting, vegetation recovery was already evident, and increased burrownesting seabird activity has also been observed in the first breeding season post-baiting.