Date of Award

2016

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Biology

Abstract

With current declines of vertebrate taxa meeting or exceeding those of historic mass extinction events, there is a growing need to investigate the main drivers of declines. Amphibians are perhaps at greatest risk of global climate change and land-use changes than most other vertebrate classes and also have significant roles in ecosystem processes – combined, this creates a cause for concern. I designed a study that would investigate the effects of current and predicted climate change and land-use changes on amphibians using species distribution models and a field study to identify the potential consequences of amphibian species declines by investigating the role of larval pond-breeding salamanders in wetlands in the Midwestern U.S. My objectives were to: (1) quantify changes in suitable habitat space and species richness for amphibians from current to future predictions, (2) compare predictions based exclusively on climate with predictions based on both climate and land-use, (3) identify what factors influence density of biota in ephemeral wetlands in the Midwest and (4) determine if larval pond-breeding salamanders have a measurable role in shaping wetland biotic communities. Model results indicate climate, not land-use, is a primary factor driving predicted changes in suitable habitat for amphibians in the Midwest and the changing climate is predicted to result in an overall decline of amphibian species richness based on future predictions. Wetland investigations showed local level factors influence aquatic invertebrate density while landscape level factors influence larval pond-breeding salamanders. I did not find any significant effects of larval pond-breeding salamander densities on the density of aquatic invertebrates. However, larval salamanders showed a predation bias for certain taxa as well as for taxa within the predator functional group. Future research should center on the role larval ambystomatid salamanders have on whole-ecosystem processes within wetlands and further interpolate the relationships between current and predicted global climate change on the potential decline of ecosystem processes.

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.

Available for download on Sunday, April 07, 2019

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