Date of Award:

5-2011

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Ecology

Committee Chair(s)

Karen H. Beard

Committee

Karen H. Beard

Committee

David N. Koons

Committee

Ethan P. White

Abstract

The Puerto Rican coqui frog, Eleutherodactylus coqui, was introduced to Hawaii in the late 1980s via the commercial horticulture trade. Previous research has shown that coquis can change invertebrate communities, but these studies were conducted at small scales using controlled, manipulative experiments. The objective of this research was to determine whether coqui invasions change invertebrate communities at the landscape scale across the island of Hawaii. At each invasion front, we measured environmental variability on either side of the front and removed sites that were too variable across the front to ensure that the impacts we measured were the result of the invasion. After doing this, there remained 15 sites for which we compared invertebrate communities in 30 m x 30 m plots situated on either side of coqui invasion fronts. In each plot, we collected invertebrate samples from three invertebrate communities, the leaf litter, foliage, and flying invertebrate communities. Multivariate analyses show that coqui frogs change leaf litter communities, by reducing microbivore and herbivore abundances. Coqui also change flying community composition, but have no measurable effect on foliage communities. Across sites, we found that coquis reduced the number of leaf litter invertebrates by 27%, and specifically abundant Acari by 36%. We also found that coquis increased the abundance of flying Diptera by 19% across sites. We suggest that the leaf litter community is altered through direct coqui predation and that Diptera increase because of increased frog carcasses and excrement in invaded plots. Results support previous studies conducted in more controlled settings, but add to our understanding of the invasion by demonstrating that coqui effects on invertebrate communities are measurable at the landscape scale.

Checksum

17531d54827e7f8d0858c975b682315a

Comments

This work made publicly available electronically on June 10, 2011.

Download

Share

COinS

Copyright for this work is retained by the student. If you have any questions regarding the inclusion of this work in the Digital Commons, please email us at .