Ecology of Invasion: Potential for Parasite Spillover in Abert’s Squirrels (Sciurus Aberti) and Endangered Mt. Graham Red Squirrels (Tamiasciurus Fremonti Grahamensis)
AdvisorKoprowski, John L.
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PublisherThe University of Arizona.
RightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction, presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
AbstractInvasive species are among the leading global threats to native wildlife and are a factor in the decline of 42% of threatened and endangered species. Invasive species can influence ecosystem health through parasite loads that they introduce during establishment in new areas. In the 1940s, Abert’s squirrels (Sciurus aberti) were introduced to the Pinaleño Mountains in southeastern Arizona where they now co-occur with endemic endangered Mount Graham red squirrels (Tamiasciurus fremonti grahamensis). Parasite loads between invaders and imperiled endemic species are poorly understood, including S. aberti and T. f. grahamensis; where we identified and quantified parasites in this important system. We hypothesized that spillover of parasites occurred between S. aberti and T. f. grahamensis. We also hypothesized that presence/absence of parasites might be affected by host-linked factors and extrinsic factors. Genetic analyses through PCR amplification revealed two species of helminths from single nematode DNA: Citellinema sp. and Trypanoxyuris (Rodentoxyuris) sp. Our results suggest the potential for spillover of Trypanoxyuris (Rodentoxyuris) sp. between S. aberti and T. f. grahamensis. The following ectoparasites were encountered in Abert’s squirrels: Opisodasys robustus, Anomiopsyllus sp., and Neohaematoinnus sciurinus. The following ectoparasites were encountered in Mt. Graham red squirrels: Orchopeas caeden and a species of mite from the Glycyphagidae family. Body mass influenced presence/absence of endoparasites and males are more likely to have presence of ectoparasites than females in Abert’s squirrels. Enhanced insight into possible parasite transmission routes and the role that parasites play in biological invasion can offer a better understanding of all factors that place species at risk of extinction. Our data highlight the importance of developing future management and conservation strategies for similarly threatened or endangered species.
Degree ProgramGraduate College