Vegetation change on subantarctic Macquarie Island

Macquarie Island has undergone rapid vegetation change following the successful eradication of feral rabbits, rats, and mice in 2011. This large-scale project revealed that the absence of grazing pressure allows plant species distribution and vegetation structure to be primarily influenced by abiotic factors like climate. Research using repeat photographs over 34 years and satellite imagery demonstrated geographic variation in vegetation trends post-eradication. Spatial analysis showed that south-westerly winds were more damaging to plants than prevailing westerlies, while steep air temperature lapse rates limited diurnal and seasonal variation. Tussock grass and megaherbs, which declined by 2009, rebounded by 2014 without grazing pressure. However, high-elevation feldmark vegetation showed no consistent trends linked to rabbit impacts or climate change. Species distribution models indicated that generalist plant species have a smaller 'core range' where they dominate. The study highlights the ongoing ecosystem recovery and the interplay between climate change and the absence of grazing in shaping Macquarie Island's lowland vegetation.

Fitzgerald, N. B. (2020). Vegetation change on subantarctic Macquarie Island. University of Tasmania. https://doi.org/10.25959/100.00034913