Rabbits, landslips and vegetation change on the coastal slopes of Subantarctic Macquarie Island, 1980-2007

Abstract

Subantarctic tall tussock grassland and megaherb vegetation has been massively aVected by feral herbivores on islands where both occur. The eVects of rabbits in this vegetation on Macquarie Island were monitored using 66 permanent quadrats and numerous photo-points on the steep coastal slopes of the island from 1980 to 2007. Vegetation change after landslips was also monitored. At the start of this period rabbit numbers plummeted due to the introduction of myxoma virus, but then increased from the late 1990s. Over the years of reduced rabbit numbers, some recovery of tall tussock grassland took place. With the resurgence in rabbit numbers, successional patterns converged towards a uniform pattern of degraded vegetation with more bare ground. The patterns of vegetation change indicate that recovery of the vegetation, after eradication of rabbits, rats and mice, is likely to be rapid where degradation is recent and where seed sources are in close proximity. The exotic plant species currently on the island are unlikely to present a problem.