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Presented at the NABS Annual meeting, Pittsburgh, Pennsylvania, 2002
in Conservation Ecology
GENETIC VARIABILITY OF THE GAMMARUS-PECOS SPECIES COMPLEX (CRUSTACEA: AMPHIPODA) IN CHIHUAHUAN DESERT SPRINGS.
V. Gervasio1, D.J. Berg2, B.K. Lang3, N. Allan4, M.E. Gordon5, G. Warrick6, and S.I. Guttman1. 1Department of Zoology, Miami University, Oxford, OH 45056, 2Department of Zoology, Miami University, Hamilton, OH 45011, 3Conservation Services Division, New Mexico Department of Game and Fish, P.O. Box 25112, Santa Fe, NM 87504, 4United States Fish and Wildlife Service, Ecological Services Office, 10711 Burnet Road 200, Austin, TX 78758, 5New Mexico Museum of Natural History and Science, 1801 Mountain Road, Albuquerque, NM 87101-1375, 6Bitter Lake National Wildlife Refuge, 4065 Bitter Lakes Road, Roswell, NM 88201-007
Development of effective conservation measures for endangered taxa requires an adequate knowledge of the genetic structure and taxonomic status of such taxa. We present the first study on the genetic variability of the Gammarus-pecos species complex endemic to the spring system of the Chihuahuan Desert region. We used allozyme electrophoresis to quantify within- and among-population genetic variability of the nine known populations of the Gammarus-pecos species complex. Preliminary analysis indicates significant within-population variation (mean heterozygosity from 0.00 to 0.07). Only 35% of population-by-polymorphic-locus combinations had genotype frequencies that met Hardy-Weinberg expectation, while the rest showed heterozygotes deficits. Several populations exhibited heterozygosity deficits along with high percentages of polymorphic loci. Such circumstances may indicate the presence of cryptic species. Cluster analysis of genetic distances showed two major groups of populations within the G.-pecos complex. Relatively large genetic distances between populations suggest long periods of isolation. Given the alarming rate at which Chihuahuan desert spring systems are being altered, understanding of the genetic structure and taxonomic status of this species complex and other endemic taxa must be a priority of the agencies charged with protecting this unique faunal assemblage.
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