This project will investigate the combined effects of top predators and ecosystem size on the coexistence of species in food webs. Using numerous forest fragments of varying size that have been naturally created by lava flows in Hawai'i, the researchers will test the hypothesis that, as top predators, non-native rats alter food webs consisting of native birds, insects and spiders, with greater effects in smaller forest fragments. The study will involve experimental removal of rats, experimental exclusion of birds, stable isotope analysis of arthropods, and remote sensing analysis of forest size, complexity and productivity, all across a 100-fold gradient of forest fragment size.
Many forests around the world have been fragmented by development and pastoral land use, and also invaded by rats and other non-native predators. This project will improve the scientific basis for making management decisions, especially with regard to how non-native species removal can be used to restore native forests and how the effect may depend on forest size. This project will also enable the researchers to train a number of undergraduate and graduate students and postdoctoral fellows through their participation in research. Students will be recruited through internship programs at Stanford University and the University of Hawai'i, Hilo, which has a successful record of training under-represented students in environmental sciences.
