Graduation Year

2008

Document Type

Thesis

Degree

M.S.

Degree Granting Department

Biology

Major Professor

Gordon Fox, Ph.D.

Keywords

H. cinerea, H. femoralis, H. squirella, Invasive, PVC

Abstract

The Cuban treefrog, Osteopilus septentrionalis, is an invasive species in Florida that may be negatively impacting adult and larval native treefrog species through competition via direct predation. The purpose of this study was to determine the abundance and distribution of O. septentrionalis in urban, semi-urban and natural habitats. The distribution and abundance of native treefrogs within the study area, Hyla cinerea, Hyla femoralis and Hyla squirella, were also estimated and compared to that of O. septentrionalis. Treefrogs were captured using PVC pipes with two internal diameters, 1.9 cm and 4.45 cm, hung on three tree types, Pinus, Quercus and Sabal. Distance to water, time of year and monthly rainfall were also considered as a potential influence of treefrog captures. O. septentrionalis was found in sites with both urban and natural habitats in frequencies far greater than those of native treefrogs.

Results indicate that O. septentrionalis are captured more frequently in sites with urban habitat; however recapture rates and estimates of population size indicate that the population sizes of O. septentrionalis may actually be larger at sites with natural habitat. O. septentrionalis are found significantly more frequently in Quercus. H. femoralis and H. squirella were found significantly more frequently in PVC pipes with an internal diameter of 4.45 cm. A weak, although significant, positive correlation was found between distance to water and treefrog abundances for O. septentrionalis and H. squirella. Native treefrogs were found less frequently in PVC pipes that also contained O. septentrionalis; this result is perhaps the most interesting because it may indicate that native treefrogs will avoid habitat or refuges where O. septentrionalis are present. If O. septentrionalis is a real threat to species of treefrogs in Florida, these results should be of concern.

Findings suggest that PVC pipes may give biased estimates of treefrog densities. Available refuge, temperature and precipitation all appear to have an effect on how attractive PVC pipes are to treefrogs.

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