Stable isotope analysis as an early monitoring tool for community-scale effects of rat eradication

Restoration Ecology
By: , and 



Invasive rats have colonized most of the islands of the world, resulting in strong negative impacts on native biodiversity and on ecosystem functions. As prolific omnivores, invasive rats can cause local extirpation of a wide range of native species, with cascading consequences that can reshape communities and ecosystems. Eradication of rats on islands is now becoming a widespread approach to restore ecosystems, and many native island species show strong numerical responses to rat eradication. However, the effect of rat eradication on other consumers can extend beyond direct numerical effects, to changes in behavior, dietary composition, and other ecological parameters. These behavioral and trophic effects may have strong cascading impacts on the ecology of restored ecosystems, but they have rarely been examined. In this study, we explore how rat eradication has affected the trophic ecology of native land crab communities. Using stable isotope analysis of rats and crabs, we demonstrate that the diet or trophic position of most crabs changed subsequent to rat eradication. Combined with the numerical recovery of two carnivorous land crab species (Geograpsus spp.), this led to a dramatic widening of the crab trophic niche following rat eradication. Given the established importance of land crabs in structuring island communities, particularly plants, this suggests an unappreciated mechanism by which rat eradication may alter island ecology. This study also demonstrates the potential for stable isotope analysis as a complementary monitoring tool to traditional techniques, with the potential to provide more nuanced assessments of the community- and ecosystem-wide effects of restoration.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Stable isotope analysis as an early monitoring tool for community-scale effects of rat eradication
Series title Restoration Ecology
DOI 10.1111/rec.12511
Volume 25
Issue 6
Year Published 2017
Language English
Publisher Society for Ecological Restoration
Publisher location Malden, MA
Contributing office(s) Western Ecological Research Center
Description 11 p.
First page 1015
Last page 1025
Country United States
Other Geospatial Palmyra Atoll National Wildlife Refuge
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