Discussion
Our study set out to examine if invasion by a plant which drastically alters the environment would create a sink habitat through changes in biotic interactions, attracting endemic taxa from native forest into habitat containing conditions that may diminish fitness (Pulliam 1988). Our first goal was to determine whether endemic natural predators maintain their natural interactions with prey, despite the marked modification in habitat; this would suggest that ginger-invaded sites can serve as a habitat refuge for native arthropods and support natural biotic interactions. Alternatively, the diet of the spiders in invaded sites could differ significantly from spiders in native forest and consist of less native prey taxa, which may indicate suboptimal habitat. Our second goal was to assess how interactions with parasites may change, in which there may be a higher prevalence of non-native parasites in ginger-invaded sites, imparting a fitness cost on native prey or on spiders themselves. Using both prey and parasitism, our results support the idea that ginger-invaded sites may serve as a sink for Pagiopalus spiders.