Dissertation/Thesis Abstract

Is There Evidence of Competitive Exclusion in Eastern African Later Miocene Mammalian Communities?
by Burns, Nicholas, M.S., The George Washington University, 2020, 46; 28087345
Abstract (Summary)

Research on hominin macroevolutionary trends has focused on increasing aridification in eastern Africa resulting in the spread of grasslands as drivers for large scale change. However, this ignores the smaller changes that result from community interactions including competition, mutualism, parasitism, and predation. These biotic interactions contribute to a species’ relative fitness and to microevolutionary changes. The goal of this thesis is to determine if there is evidence for competition among large mammalian species during the later Miocene in eastern Africa based on species co-occurrence patterns. This thesis uses statistical analysis to examine those co-occurrence patterns and determine if taxa appear together more, or less, frequently than would be the case if their temporal and spatial distribution had been random. By specifically focusing on the segregated or the least frequently co-occurring species pairs, this thesis provides information on the paleoecology of species, as well as informing researchers about species interactions with a focus on competition for resources, and eventual competitive exclusion. The results from the study indicate that while more species were aggregated than segregated, there is still evidence for interspecies avoidance or a lack of cohabitation between different species. In both mixed and closed environments, proboscideans were frequently found in segregated pairs, with co-occurrence values that are statistically significant. The small sample size for open environments may explain why it does not follow the same pattern. While there was no dietary overlap evident within the closed or mixed results to indicate competition over resources, the results imply there were species interactions that influenced species behavior and occurrence. The modification of habitats by megafauna, as well as variation within mixed and closed environments, likely contributed more than strict competition over resources towards the co-occurrence patterns observed in this thesis.

Indexing (document details)
Advisor: Barr, W. A.
School: The George Washington University
Department: Human Paleobiology
School Location: United States -- District of Columbia
Source: MAI 82/3(E), Masters Abstracts International
Subjects: Ecology, Archaeology
Keywords: Anthropology, Community dynamics, Paleoecology
Publication Number: 28087345
ISBN: 9798664790214
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