Semester

Summer

Date of Graduation

2014

Document Type

Dissertation

Degree Type

PhD

College

Davis College of Agriculture, Natural Resources and Design

Department

Forest Resource Management

Committee Chair

James T. Anderson

Committee Co-Chair

Kevin Dodge

Committee Member

Thomas K. Pauley

Committee Member

Philip J. Turk

Committee Member

Petra B. Wood

Abstract

Evaluating the adequacy of created wetlands to replace the functions of lost natural wetlands is important because wetland mitigation is a major tool used to offset wetland losses. However, measurements such as vegetative cover and presence of wildlife may not provide sufficient evidence that created wetlands are functioning properly and thus examining the ecology of wetland biota such as that of amphibians may be a more useful surrogate for function. The objectives of this study were to assess the reproductive success, temporal calling patterns, and diet composition of amphibians inhabiting created wetlands relative to natural wetlands in order to facilitate determination of the adequacy of created wetlands as functional replacements of natural wetlands.;To evaluate reproductive success, I compared the abundance of amphibian metamorphs and survival and growth of larval amphibians in created wetlands relative to natural wetlands. Amphibian metamorphs were trapped in created and natural wetlands during the spring and summer of 2009 and 2010, and 165 green frog (Lithobates clamitans) larvae were raised during the spring of 2010 in laboratory aquaria containing water from created or natural wetlands. Abundance of spring peeper (Pseudacris crucifer ) metamorphs decreased significantly from 2009 to 2010 and abundance of green frog metamorphs increased with habitat complexity, but both were unaffected by wetland type. Detection probability of metamorphs of both species was very low, increased with water temperature, and declined with month of observation. Survival, growth curves, and mass were similar between green frog larvae raised in created and natural wetland aquaria. My results suggest that the function of providing adequate breeding habitat for generalist amphibians such as green frogs and spring peepers is being fulfilled by the created wetlands that were examined.;I compared the occupancy and detection of calling anurans in created wetlands relative to natural wetlands to assess temporal calling patterns. Five-minute, ten-minute, and broadcast call surveys were performed at 24 wetlands throughout the Central Appalachians once every month from March through August of 2009 and 2010. Occupancy modeling was used to estimate the occupancy and detection of individual species, incorporating relevant environmental variables. The occupancy of anurans did not differ between created and natural wetlands. Detection of anurans was largely unaffected by call survey type, but several environmental covariates had a significant effect on the detectability of calling anurans. I conclude that the function of providing adequate breeding habitat for adult anurans is being fulfilled by the created wetlands that were examined.;To assess the diet composition of amphibians, I measured the diet composition of adult red-spotted newts (Notophthalmus viridescens viridescens ) and compared the selection of prey by newts between created and natural wetlands. Newts were trapped during the spring and summer of 2009 and 2010, and the stomach contents of 149 newts were obtained with gastric lavage. Invertebrate prey availability was obtained within a 5 m radius of each captured newt. Selection of prey by newts was nonrandom, but was only minimally affected by wetland type. Both dietary breadth and prey selection were affected primarily by time of year, likely driven by temporal variation in invertebrate abundance. My results suggest that the function of providing an adequate prey base for a generalist wetland predator such as the red-spotted newt is being fulfilled for the created wetlands that were examined.

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