Date of Award

8-2010

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Wildlife and Fisheries Biology

Advisor

Baldwin, Robert F

Committee Member

Tonkyn , David W

Committee Member

Brown , Bryan L

Abstract

Amphibian declines have been observed globally for several decades and populations continue to decline in many areas today. Through an extensive literature review of amphibian `impact studies,' I evaluated the use of multiple species, multiple spatial and temporal scales in an effort to ascertain a more complete, community-wide perspective on the causes of amphibian declines as well as management and conservation implications aimed at reversing these declines. Additionally, I performed multivariate analysis of an amphibian community dataset from southern Maine, USA using a multi-species and scalar approach to identify potentially important environmental variables associated with high levels of amphibian reproductive effort. By taking a community perspective on amphibian conservation, I suggest that scientists can better assess how multiple species respond to environmental changes and how these changes affect communities at multiple levels of organization. The metacommunity framework can serve as an important starting point for assessing amphibian community dynamics across a landscape because many amphibian life histories have phases that are dependent on multiple spatial scales. Multivariate statistical techniques are useful for the analysis of community data because most ecological datasets are complex, highly-dimensional and are more often robust to the relaxed assumptions of multivariate analyses than to those of more predictive univariate methods. Multivariate techniques can aid in the initial description of the structure of community data as well as in the development of a priori hypotheses. By studying amphibians in their natural community context (i.e., considering their interaction with other abiotic factors) and by recognizing the potential for multiple communities to interact across a landscape, researchers can better understand how and at what spatial and temporal scales amphibians are being impacted by environmental disturbance. My research suggests that amphibian conservation will be greatly served by community approaches because it is likely that communities as functional entities rather than individual species are better, more reliable indicators of environmental disturbance and biological stress. The utilization of a community theoretical approach coupled with multivariate analytical techniques will serve to further our knowledge of the processes contributing to amphibian declines as well as to inform us of the most optimal ways to both address and potentially reverse these declines.

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