University of Missouri - Saint Louis

The Graduate School

Announcement

An oral examination in defense of the dissertation for the degree

Doctor of Philosophy in Biology

Adriana Rodríguez-Ferraro
M.S. in Biology, December, 2004, University of Missouri-St. Louis.
B.S. in Biology, October, 1994, Universidad Simón Bolívar, Caracas, Venezuela.

Community ecology and phylogeography of bird assemblages in arid zones of northern Venezuela:
Implications for the conservation of restricted-range birds

Abstract

This study intended to characterize bird assemblages inhabiting six arid zones in northern Venezuela at both ecological and genetic levels, and to generate information relevant for conservation planning in these regions. Aridlands of northern Venezuela are relevant from an ornithological perspective because of the occurrence of habitat specialist birds, which depend exclusively on desert scrubs for their survival and whose long-term survival is threatened by ongoing changes in vegetation structure and composition. The study involved assessments of patterns of avian species richness, abundance, community composition and genetic diversity, as well as specific bird-habitat associations. Species richness was not a good indicator of an area’s conservation value because the protection of the area with highest number of species does not guarantee the effective conservation of all the habitat specialist birds. Conservation initiatives for arid zone birds should not only consider species richness and representativeness, but also other factors such as abundance patterns and complementarity between eastern and western areas. Even though habitat specialist birds did not respond strongly to vegetation variables, this study suggests that some structural attributes are important for the survival of this particular group of species. Molecular techniques used to investigate patterns of genetic diversity in three codistributed specialist birds (Yellow-shouldered Parrot, Buffy Hummingbird, and Vermilion Cardinal) indicated geographic structure in the three species, but the extent of geographic structure vary among them. Conservation efforts should focus not only in the preservation of genetic diversity in each species but also in the maintenance of the diverse set of processes that generated such patterns.

Defense of Dissertation Committee