Relationships among Native and Alien Plants on Pacific Islands with and without Significant Human Disturbance and Feral Ungulates

The native plants of remote tropical islands have been frequently characterized as poor competitors against seemingly more aggressive alien species. Does this "weak competitor" characterization relate to some real adaptive consequences of island isolation and endemism, or does the generally concurrent presence of introduced ungulates and other forms of recurrent human disturbance also act to encourage alien plant dominance? A comparison of tropical islands with and without introduced ungulates suggests that some insular plant species competitively resist alien displacement in the absence of ungulates.