Mr Nick Fitzgerald1, Distinguished Professor Jamie Kirkpatrick, Dr Jenny Scott1, Associate Professor Arko Lucieer1
1University Of Tasmania, Hobart, Australia
Eradication of invasive European rabbits from subantarctic Macquarie Island was achieved in 2011. The impacts of introduced rabbits on the vegetation of Macquarie Island are well-documented but few studies have investigated the ecosystem recovery process following the eradication or compared vegetation change between types of terrestrial ecosystems. We hypothesised that changes in vegetation would vary in their magnitude and direction in different ecosystems. Repeat landscape photography covering a 34 year period was used to examine differences in vegetation characteristics at three times with different rabbit populations: moderate, high and none. Plant species cover data from long-term monitoring sites were also used to obtain spatial data. Spectral vegetation indices derived from satellite imagery provided a wider geographic picture of change covering the transition from high rabbit numbers to no rabbits. In high elevation feldmark vegetation, where rabbit impacts were minor, there was little to no change over 34 years. Tussock grass and megaherb vegetation severely impacted by rabbits shifted to short grassland and herbfield communities, a process that was partially reversed between 2009 and 2014. The spectral data proved to be of limited use in detecting vegetation change compared to the rephotography and plot data.
Nick Fitzgerald is a PhD candidate with interests in plant ecology, vegetation dynamics and spatial analysis who is presently studying the vegetation of subantarctic Macquarie Island