Biology Commons^™

Biodiversity And Evolution In The Guiana Shield, South America, Andrew Michael Snyder

Electronic Theses and Dissertations

The neotropics are characterized as the most species rich region in the world. Unfortunately, the region's unparalleled biodiversity has not protected it from ongoing threats such as agriculture, mining, logging, oil extraction, and climate change. I studied the biodiversity and evolution of the herpetofauna of South America in order to investigate the influence of historical geological and climatological events in shaping extant neotropical diversity, particularly the Guiana shield. For my research, I set out to explore the processes involved in shaping the remarkable extant diversity using anuran amphibians as models. With my dissertation, I provide a comprehensive review of the …

Stress, Sexual Signaling, And Alternative Mating Tactics In Male Green Treefrogs, Hyla Cinerea, Sarah Crocker-Buta

Electronic Theses and Dissertations

This thesis examines how the endocrine stress response mediates the expression of courtship signals and alternative mating tactics in male green treefrogs, Hyla cinerea. Males of this species produce acoustic signals that stimulate production of the stress hormone corticosterone (CORT) in vocal competitors, suggesting a role of CORT in intrasexual competition. I predicted that modulation of CORT level during intraspecific contests plays a pivotal role in regulating the expression of male courtship signals and behavior. Consistent with this prediction, CORT administration to calling males, simulating CORT production during male vocal contests, decreased attractiveness by compromising energetic investment in vocalization, increasing …

Limnological And Landscape Factors Affecting Use Of Manufactured Ponds By The Invasive Cuban Treefrog (Osteopilus Septentrionalis), Terina Nusinov

Electronic Theses and Dissertations

Exotic amphibians are often detrimental to native biotas. In Florida, the exotic Cuban Treefrog (Osteopilus septentrionalis) eats native frogs and may outcompete them for resources. Cuban Treefrogs thrive in disturbed areas and around buildings, and often breed in manufactured wetlands such as retention ponds and borrow pits. This study identified limnological, landscape, and biotic characteristics that discouraged pond use by Cuban Treefrogs and promoted use by native amphibian species. I sampled natural and manufactured ponds in Orange County, Florida, for one year, using standard methods to estimate the species richness and relative abundance of amphibians and their potential fish and …

Survey And Comparison Of Amphibian Assemblages In Two Physiographic Regions Of Northeast Tennessee., Marquette Elaine Crockett

Electronic Theses and Dissertations

Declines in amphibian populations have prompted study of their ecology and distribution. The purpose of this study was to survey two sites located within different physiographic and one herpetofaunal region of Northeast Tennessee, comparing species composition and activity. The first, Henderson Wetland, is in the Appalachian Ridge and Valley physiographic region. The second, John's Bog, is in the Blue Ridge. Survey methods included random walks, aural surveys, and point source collections during a 16-month period (February 1999 to May 2000).

Nine caudate (Plethodontidae) and one anuran species (Ranidae) were found in John's Bog. Seven caudate (Ambystomatidae, Plethodontidae, Salamandridae) and five …

Distribution Of The Herpetofauna Of Kentucky., Symoine Kamin Laufe

Electronic Theses and Dissertations

Although the herpetofauna of Kentucky is extensive and varied. it has received much less attention than that of most other states. Many herpetologists have reported on various phases of the state's amphibians and reptiles, but for the most part these reports are discrete, either pertaining to a collection, or a generic or specific study. Hence, there is no single adequate work which aptly describes the herpetology of Kentucky as a whole. When one realizes the keystone position of Kentucky in relation to northern and southern forms, the need of a zoogeographical summary of the state becomes even more apparent. Therefore, …