 It is likely that further changes will occur, and possibly at an accelerated rate.Changes in population numbers of seal and seabird species are also expected to affect the vegetation by changing nutrient availability and disturbance through trampling.One plant species on Heard Island, "Poa annua", a cosmopolitan grass native to Europe, was possibly introduced by humans, though is more likely to have arrived naturally, probably by skuas from the Kerguelen Islands where it is widespread.