Doctoral Dissertations

Date of Award

8-2010

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Ecology and Evolutionary Biology

Major Professor

Arthur C. Echternacht

Committee Members

Benjamin M. Fitzpatrick, Sally Horn, James Fordyce

Abstract

We are now in the midst of a mass extinction crisis. The top threats to biodiversity include habitat destruction, pollution, over-harvesting, and invasive species. The field of conservation genetics seeks to understand these threats and devise management to preserve taxa with the ability to cope with environmental change. Preserving genetic variation and the processes in which variation is created and maintained is vital to long-term conservation goals. Limited conservation resources are cause for the prioritization of taxa and areas. Nine basic methods of prioritization have been developed. Though there are differences in these methods, and thus in the resulting target areas, many, including biodiversity hotspots, list Mesoamerica, in which the highest diversity of iguanids confined to a single genus, Ctenosaura, occur. Though ctenosaurs are the most diverse genus of iguanas, have the most Redlisted species, lack protection and are in danger of extinction, they have been overlooked. The Ctenosaura palearis complex, occurs in central Mesoamerica and is made up of four endangered species. In order aid in the conservation of this biodiversity, a multi-scale molecular evaluation of this complex was preformed. I first used a species tree approach to elucidate the relationships between the focal species, showing that these species have gone through recent and rapid speciation, resulting in four closely related endemics. Thus, the nominal groupings should be upheld and given individual protection. Second, I evaluated the degree to which gene flow from the widely distributed congener threatens the genetic distinctiveness of the endemic C. bakeri. Low levels of introgression indicated no current threat. Hybridization could increase if habitat destruction or changes in relative abundance increase the probability of interbreeding. Continued monitoring of this situation is justified. Third, I used a variety of population genetic techniques to elucidate the genetic structure within and among populations of C. melanosterna. These results indicate that the populations in the Valle de Aguán and Cayos Cochinos are not interchangeable thus protection of both areas is necessary, and extreme caution should be used when implementing breeding and translocation programs. Local conservation efforts may be evaluated and developed using this information.

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