State of the Islands Report Case Study: Pest Eradication on Macquarie Island

1.0Island Arks Australiahttp://islandarks.com.auderekhttp://islandarks.com.au/author/derek/State of the Islands Report Case Study: Pest Eradication on Macquarie Island - Island Arks Australiarich600338<blockquote class="wp-embedded-content"><a href="http://islandarks.com.au/state-of-the-islands-report-case-study-pest-eradication-on-macquarie-island/">State of the Islands Report Case Study: Pest Eradication on Macquarie Island</a></blockquote> <script type='text/javascript'> <![CDATA[//><!]]> </script><iframe sandbox="allow-scripts" security="restricted" src="http://islandarks.com.au/state-of-the-islands-report-case-study-pest-eradication-on-macquarie-island/embed/" width="600" height="338" title="“State of the Islands Report Case Study: Pest Eradication on Macquarie Island” — Island Arks Australia" frameborder="0" marginwidth="0" marginheight="0" scrolling="no" class="wp-embedded-content"></iframe>http://islandarks.com.au/files/2014/01/SIRtasmaniafeatureimagewcasestudy.png640240Author Information Keith Springer Tasmania Parks and Wildlife Service, PO Box 126, Moonah, Tasmania 7009, Australia. Keith.Springer@parks.tas.gov.au Summary Invasive vertebrate species have been present on Macquarie Island for over 200 years, and have had devastating impacts on flora, fauna and landforms. Weka (Gallirallus australis) were successfully eradicated by 1989 and feral cats (Felis catus) by 2001. Planning for the eradication of ship rats (Rattus rattus), house mice (Mus musculus) and European rabbits (Oryctolagus cuniculus) began in 2004. Funding of AUD$24.7M was secured in 2007 for a multi-year project based on aerial baiting that targeted rabbits and rodents, followed by hunting of any surviving rabbits. Following three years of planning, the first aerial baiting attempt in 2010 was abandoned after two months due to unfavourable weather and shipping delays. The degree of non-target seabird species mortality from the limited baiting in 2010 lead 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 four 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 in excess of 150,000 has been reduced to less than an estimated 30 at the conclusion of baiting. Some rabbits were expected to survive baiting, and the hunting phase commenced in July 2011 using a team of 15 hunters and 12 dogs. By December 2011thirteen rabbits had been accounted for. Hunting efforts are ongoing, and together with a monitoring phase are planned to continue for five years. A minimum of two years monitoring for rabbits will be conducted. Continued effort each year will be based on annual progress reviews. Rodent detection dogs will deploy in 2013 to assist in determining rodent eradication success. After one summer since baiting, vegetation recovery is already evident and increased burrow-nesting seabird activity has also been observed in the first breeding season post- baiting. Introduction Macquarie Island (12,780 hectares) is a listed World Heritage site that lies in the Southern Ocean (54°37’53″S, 158°52’15″E) 1500 km from Hobart, Tasmania and 1000 km from Bluff, in southern New Zealand (Figure 1). It is part of the state of Tasmania. Discovered in July 1810 by sealers, early European activity centred on commercial exploitation of seals and later penguins, and continued until 1919 (Cumpston 1968). Sealing and oiling gangs deliberately or inadvertently introduced numerous mammal species. Five species (ship rats Rattus rattus, cats Felis catus, house mouse Mus musculus, European rabbits Oryctolagus cuniculus and weka Gallirallus australis scotti established feral populations and caused significant impacts on landscapes and native flora (Copson and Whinam 2001) and fauna (including extinction of two endemic land birds (Taylor 1979). Weka were eradicated by 1989 and cats by 2001. Increasing landscape and vegetation impacts from rabbit grazing (Jenkin 1975, Taylor 1955) combined with greater capacity to achieve larger scale eradications (e.g. Howald et al 2007) led to the consideration of undertaking such a project on Macquarie Island to eradicate the remaining three vertebrate pest species (PWS 2007). Public awareness and lobbying also increased with protection of world heritage values as a central theme. Following planning undertaken in 2004-5 and 2006-7, the Macquarie Island Pest Eradication Project was established in June 2007 following agreement between the Tasmanian and Australian governments to jointly fund A$24.6M toward the project, following a A$100,000 donation by Peregrine Adventures and WWF Australia. Planning With full funding for the duration of the project secured, implementation of the Macquarie Island Pest Eradication Plan proceeded. By that stage a justification and overview had already been prepared, as had a detailed operational plan, and these had formed the basis for securing funding. Planning continued with aspects of regulatory work, environmental impact assessment, staff recruitment, tenders for major services, contract management, field equipment procurement and training of dogs.. The approved plan was based on a two-phase project with aerial baiting using brodifacoum baits spread by helicopters, followed by ground hunting of surviving rabbits. Based on the experience gained from previous projects elsewhere, aerial baiting was expected to achieve rodent eradication and reduce the rabbit population by >99%. A three year timeframe was required to get dogs trained to the required standards (including a tender process, acquisition of pups, training and certification), to secure all regulatory approvals (38 approvals and permits were required), recruit staff and to procure all supplies, equipment and services required. The logistics operation needed to aerially bait an island of this size was considerable. Three hundred and five tonnes of Pestoff 20R bait containing brodifacoum at 20ppm was ordered (Animal Control Products, Wanganui, New Zealand). A tender process resulted in Helicopter Resources Pty Ltd (Tasmania, Australia) being contracted to supply two AS350BA and two AS350B2 helicopters, along with engineering support, helicopter spares, pilots and ground crew experienced at aerial baiting operations, bait spreading buckets, switching gear and Tracmap GPS systems (Mosgiel, New Zealand). A team of 19 staff were recruited (additional to the helicopter team) to provide bait loading, non-target mitigation, safety, and GIS technical support. Other support was received from the Australian Antarctic Division and Bureau of Meteorology staff at the Macquarie Island station where the aerial baiting team was accommodated. A ship was chartered with the capacity to deliver the large quantities of bait and helicopter fuel to Macquarie Island, along with the baiting team, helicopters and other equipment. Operational 2010 aerial baiting Due to circumstances beyond the project’s control, the selected ship was unavailable for the required departure date in April 2010. Consequently a delay of four weeks was experienced before the team could be delivered to the island. On arrival, a small amount of baiting was conducted (<1300 ha) before persistent strong winds and low cloud precluded helicopter operations for extended periods. Eventually, with winter ending and the imminent return of many seabird species to the island, the lack of progress forced a decision to cease operations and for the […]