Term of Award

Fall 2008

Degree Name

Master of Science in Biology (M.S.)

Document Type and Release Option

Thesis (open access)

Department

Department of Biology

Committee Chair

Bruce A. Schulte

Committee Member 1

Risa A. Cohen

Committee Member 2

Lance D. McBrayer

Abstract

The distribution of mammals in a savanna environment is influenced by abiotic and biotic factors. The African savanna experiences distinct wet and dry seasons. Species become spatially restricted around water resources during the dry season, resulting in increased intraspecies and interspecies resource-based aggregation. A dominate species, such as the African elephant (Loxodonta africana), may influence this aggregation. I examined the influence of wet and dry seasons and ambient temperature on the use of a waterhole by elephants as well as the co-occurrence of elephants and other mammals at the waterhole. Biodiversity scans (October 2004-June 2007) and were performed at a permanent waterhole on the Ndarakwai Ranch in northern Tanzania. More elephant and mammal species used the waterhole during the dry season and during higher ambient temperatures. Elephant-mammal co-occurrence was rare, suggesting the workings of interference competition by elephants. Intraspecific aggregation at waterholes can facilitate reproductive communication in elephants, often via chemical signals. This study also determined behaviorally via biological assays (June 2006-June 2007) whether four known insect pheromones identified in the ovulatory urine of African elephants serve as sex-specific pheromones. When tested singly, none of the four compounds evoked significant behavioral responses compared to control samples. Although this experiment was unable to confirm behaviorally an African elephant chemical signal, it provided insight into the next phase of study.

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