Assessing a potential invasion mechanism and control method for Eleutherodactylus coqui in Hawaii

The Puerto Rican frog, Eleutherodactylus coqui, was introduced into Hawaii around 1988, where it reaches high densities, and may control its invertebrate prey. The mechanisms E. coqui uses to invade forests and the effects it has on litter invertebrate communities are unknown, and effective control measures for E. coqui are needed. I conducted an enclosure experiment to determine the relative importance of bottom-up and top-down effects on litter invertebrate abundance and composition in a Hawaiian lowland forest. I found that litter quality had a greater influence on litter invertebrate composition and abundance than E. coqui; and that these effects did not cascade to influence E. coqui diet, growth, or survivorship. I also determined the effectiveness of 16% and 11% aerial applications of citric acid for controlling E. coqui, by estimating abundance and survival of frogs before and after treatment. I found that both concentrations of citric acid reduced frog populations.