The following extract is taken from a two page article published in The Australasian Wildlife Management Newsletter, November 2012 edition.
Macquarie Island on the road to recovery following eradication
Liz Wren, Tasmania Parks and Wildlife Service
With the removal of rabbits, rats and mice, the welcome mat was rolled out to burrowing sea birds which return to the island each spring to breed. Populations of some bird species are slowly increasing, with the island’s burrowing petrels in particular showing a strong response to the removal of the three pest species. Blue petrels, previously restricted to breeding on offshore rock stacks due to rat predation, have begun to breed again on the main island. Likewise, grey petrels have shown increased breeding success and have fledged greater numbers of chicks, both positive indicators even in these early days. In the first breeding season since baiting finished, Antarctic terns are now breeding on the island’s cobblestone beaches in far greater numbers than previously, when they were restricted to less accessible rock stacks.
Dense spider webs, shimmering with moisture particles, have been observed in recovering vegetation, a sight not seen on Macquarie Island for many years and a strong indicator of the rapid recovery of spider populations in the absence of mice predation. Botanists too are excited by the rapid re-greening of the island now that Macquarie’s unique vegetation is no longer under the crushing pressure of grazing by more than 100,000 rabbits. Although it is exciting to see endemic megaherbs such as the silver leaf daisy (Pleurophyllum hookeri) and Macquarie Island cabbage (Stilbocarpa polaris) obviously flourishing, botanists warn that the entire island ecosystem had suffered serious damage as a result of the decades of intense grazing pressure and it may be as long as 20 years before a new ecological equilibrium is reached.