Patterns of genetic diversity in a community of cyprinid fish in the Pecos river, New Mexico

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

Year: 2008 (xl)

Abstract

Genetic diversity has long been recognized as an important parameter to measure in conservation biology. The level of genetic variation displayed by a species is determined by the interaction of several factors including mutation rate, effective population size, selection and evolutionary history. Contemporary population dynamics and life-history can affect patterns of diversity as well. In this study we collected molecular data from seven members of the Pecos river (New Mexico) cyprinid community including native and recently introduced taxa, to explore the effects of these factors on diversity. We examined predictions including (i) that recent immigrants should show evidence of having undergone founding events with only a fraction of genetic variants of the source population and, (ii) native species should have higher levels of diversity as they have had longer to accumulate mutations. Results obtained were contrary to expectations with lower diversity in native species including Pecos bluntnose shiner (Notropis simus pecosensis), Rio Grande shiner (Notropis jemezanus) and speckled chub (Macrhybopsis aestavalis) compared to recent immigrants including Plains minnow (Hybognathus amarus) and the Arkansas river shiner (Notropis girardi). The sand shiner (Notropis stramineus) shows patterns of diversity that align it with the recent immigrants even though it is considered native to the Pecos river. Deeper divergences among haplotypes for recent immigrant imply introductions from multiple source populations. Our results also suggest that the Pecos river supports two genetically distinct forms of red shiner (Cyprinella lutrensis).