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.