Date of Award

5-2018

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Biological Sciences

Committee Member

Dr. Robert Baldwin, Committee Chair

Committee Member

Dr. Jamie Duberstein

Committee Member

Dr. William Conner

Committee Member

Dr. Hardin Waddle

Committee Member

Dr. William Bridges

Abstract

Tidal swamps provide habitats for a variety of reptiles and amphibians (herpetofauna), but their community compositions in most tidal swamps are currently unknown. These swamps currently face a number of threats, such as saltwater intrusion, yet the impacts to herpetofaunal communities have not been assessed. Saltwater intrusions into the upper reaches of coastal rivers contribute to their salinity gradients, which can influence associated plant and animal communities. Our study assessed the reptile and amphibian diversity along a salinity gradient in the upper estuary of the Savannah River to further predictive capabilities regarding herpetofauna. Goals included: species inventorying; determining communities; examining microhabitat associations; and modeling reptile and amphibian occupancy to predict the impacts of salinity. We conducted surveys in tidal swamps of the Savannah National Wildlife Refuge from March to June during 2016 and 2017 using a variety of methods. Our surveys detected 20 species: 8 amphibians and 12 reptiles. Community analyses failed to detect any patterns due to data sparsity. Species richness/diversity generally declined along the salinity gradient, but the drivers of the observed patterns were unclear and may be related to landscape-level mosaics of tidal wetland habits. Microhabitat associations were detected for two amphibian species via the occupancy analyses. Occupancy and regression analyses indicated that a number of species’ occurrences were significantly influenced by soil salinity. Amphibian detections were uniquely related to water depth, pH values, and weather conditions. These results expand our understanding of amphibian and reptile species within an understudied, and threatened, wetland type.

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