Eradication of rats is now becoming a widespread tool to restore ecosystems, and many impacted consumer groups show strong numerical responses to rat eradication. However, the effect of rats – and rat eradication - on other consumers is highly variable across systems and likely to extend beyond direct numerical effects, to changes in behavior, diet, and other ecological parameters. In this study we 1) explore the extent to which environmental context (island size and productivity) may drive variation in consumer and foodweb responses to eradication and 2) examine the extent to which consumers exhibit changes in trophic ecology following eradication, and how this may vary across the range of environmental contexts.
We see strong responses of consumer groups, in abundance, ecology and composition following rat eradication. These changes cause overall changes in food chain length and trophic structure of the communities. Notably we also find evidence that environmental context drives systematic variation in the effect size of these responses to eradication, notably including stronger effect sizes in larger ecosystems.