Master's Theses

Date of Award

Spring 2012

Degree Name

Master of Science (MS)




Dr. Rob Channell


Conservationists have suggested extinction is non-random; some species are more prone to extinction than others. Multiple traits (e.g., large bodied, long-lived, slow-reproducing, migratory, habitat and/or dietary specialists) have been cited as contributing to the endangerment of species. Due to global anthropogenic demand for wild species (e.g., sport, trade, fashion, medicine, religion, food), I propose charisma as an additional trait of endangerment. This predicts charismatic species are more often targets of direct exploitation than less charismatic species, and that global demand will continue to increase with world population and development. These species represent our most iconic and animated organisms. I quantified charisma through color, ornamentation, and vocalizations in 1609 Old and New World species of passerine and psittaciform birds; this represents approximately 1/6 of all extant avian species worldwide. Color and ornamentation correlate significantly with both exploitation and endangerment, while melodious song, occurring only in passerines, correlates significantly with endangerment only. Mimicry did not appear to have an effect on either exploitation or endangerment. Additionally, an increase in number of variables (e.g., color, ornamentation, mimicry, song), number of colors, and proportion of color increased exploitation and endangerment overall. These charismatic traits, which also represent the exaggerated traits resulting from sexual selection, have been hypothesized as potential contributors to speciation. I propose overexploitation is removing charismatic species from the Earth’s biota as well as negatively influencing speciation rates, thereby accelerating homogenization of global biodiversity. This study might be valuable in identification of species that are potential targets of exploitation, and suggests a need for conservation of charismatic species in the future.


Copyright 2012 Andrée M. Brisson


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