Genetic diversity of non-native fishes exceeds natives in the Pecos River, NM

Authors: Tracy A. Diver, Megan J. Osborne, Thomas F. Turner

Year: 2010 (xlii)

Abstract

Within New Mexico, the Pecos River supports a diverse community of fishes compared to other arid-land streams in the southwestern US. Relatively high alpha diversity results from an intact native fish fauna coupled with non-native species. We assessed nucleotide diversity for three native and two introduced fishes at the protein-encoding mtDNA ND4 gene. Contrary to expectation, diversity (as measured by Á¨) was higher for recently introduced species Notropis girardi and Hybognathus placitus compared to native Macrhybopsis aestivalis, Notropis jemezanus, and Notropis simus pecosensis. We tested whether increased levels of genetic diversity in non-natives resulted from multiple introductions from genetically divergent sources. In this study, samples from the introduced Pecos River population of N. girardi were compared to samples collected throughout the native range in New Mexico and Oklahoma. Nucleotide sequence data indicated that the Canadian River is the likely source population of the introduced population and that introduced individuals harbor nearly all genetic variation present at the source population. Increased genetic diversity may allow non-natives to persist and thrive despite presumed local adaptation and competitive advantage of natives.