Genetic signatures of translocations and habitat fragmentation for two evolutionarily significant units of a protected fish species
Genetic population structure was evaluated for the White Sands pupfish (Cyprinodon tularosa), a protected fish species comprised of two Evolutionarily Significant Units (ESUs); the Malpais Spring ESU and the Salt Creek ESU. The Malpais Spring ESU is restricted to Malpais Spring, whereas the Salt Creek ESU includes the native Salt Creek population and two Salt Creek-derived populations at Mound Spring and Lost River; all three of these habitats are physically fragmented. We sampled the upper and lower reaches of the four populations, examining 13 DNA microsatellite loci from 40 individuals per population. As expected, significant genetic structure was observed between the two ESUs; Malpais Spring and Salt Creek. Substantial genetic drift was observed for the introduced Lost River population, with modest genetic drift for the introduced Mound Spring population. Taken together with ecological data, neither of the introduced populations successfully replicates the Salt Creek population. We also report significant reductions in genetic diversity for the upper reaches of both Salt Creek and Lost River, indicating that recent habitat changes have altered the genetic structure of these two populations. We consider these findings along with previously reported ecological data to develop guidelines for managing C. tularosa.
KeywordsESU Translocations Barriers Genetic drift White Sands pupfish Cyprinodon tularosa Contemporary evolution Genetic rescue
Special thanks are due to David Layfield for his assistance with collecting these data. The authors would also like to thank Jeanne Dye and Hildegard Reiser (CES/CEV, Holloman AFB) and Robert Myers (Environmental Stewardship, Environmental Division in the Directorate of Public Works, WSMR), for arrangement of range visitation. Janice Terfehr and Makenzie Stockwell assisted with collecting fish. This research was funded by DOD Legacy Resource Program Grant no. DACA87-00-H-0014 administered by H. Reiser and J. Dye, (CES/CEV, Holloman AFB) and North Dakota EPA-STAR EPSCoR Grant to CAS. Pupfish were collected on White Sands Missile Range under New Mexico State collecting permit 2887 and fish were handled and sacrificed following a North Dakota State University Animal Care and Use Committee approved protocol (#A0117). The authors do not have any conflicts of interest concerning the information presented in this manuscript. This manuscript benefitted from comments provided by R. Myers, S. Carman, K. Purcell, Y. Chen and two anonymous reviewers. This paper was approved for public release by White Sands Missile Range; distribution unlimited. OPSEC review completed on 31 March 2009.
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