Recovery of native plant communities after eradication of rabbits from the subantarctic Kerguelen Islands, and influence of climate change

The introduction of rabbits in 1874 into the Kerguelen archipelago had a significant impact on plant communities: the most sensitive species Pringlea antiscorbutica and Azorella selago disappeared and Acaena magellanica became dominant in most of the coastal areas. To study the recovery of native plant communities, rabbits were eradicated by poisoning on two islands. This produced a significant increase in species richness on both islands with a decline in the cover of some native species (primarily A. magellanica) and an increase in the abundance of alien species (especially Taraxacum officinale). Other native species showed signs of increased abundance but overall responses were slow. These trends are obviously due to the removal of grazing, but recent changes in climatic conditions (warming and drought) may also be responsible for the decline or slow recovery of native species, and for the success of introduced species. Owing to the effects of present climate changes on plant communities, eradication of alien herbivores may not be always appropriate for the conservation of native biota in the subantarctic islands, and regulation of populations should be explored. (C) 2003 Elsevier Ltd. All rights reserved.