Evolutionary and Conservation Genetics of Desert Fishes
Desert springs are sentinels of the health of our planet. Increasing demand on groundwater is leading to a gradual dessication of inland western North America with dramatic effects on biodiversity dependent on springs. Fish are perhaps the best known, and most readily identified, organisms that depend on groundwater for habitat. Our research uses molecular data to infer the demography and evolution of fishes confined to spring systems of the Mojave Desert. Most of our research centers on the pupfish (genus Cyprinodon) of the Ash Meadows system adjacent to Death Valley.
Recent discoveries
Inferring the Demographic and Recent History of the Warm Springs Pupfish
The Warm Springs pupfish (Cyprinodon nevadensis pectoralis) is restricted to five low flow springs (≈0.15 cubic feet per second). Most of the springs have been modified in some way by humans with effects on the populations. Furthermore, several springs have been invaded by crayfish (a predator on pupfish) and the mosquito (a predator and competitor). All springs are isolated most of the time, although exceptional precipitation can result in the anastomization of the spring outflow channels downstream from the springs.
Using a combination of microsatellite genotypes and mtDNA for samples collected in 1998 and 2007, we showed that most populations are genetically isolated, although there is evidence of episodic gene flow. Most springs harbor very small populations. Increasing demands on the groundwater coupled with climate model predications of increased dessication portend a future of declining population size and perhaps extirpation of populations. Our genetic work is providing rare insight into the long term history of the populations and will help guide restoration and management efforts aimed at reducing the probability of extinction. For more information, see Martin. 2009. Genetic management plan for the Warm Springs pupfish. Report for the USFWS.
Publications
Martin, A. P. 2005. Genetic analysis of Cyprinodon diabolis: Hybridization with C. nevadensis in the Point of Rocks refuge. Report to the Nevada Division of Wildlife, 10 p.
Martin, A. P. and J. L. Wilcox. 2004. Evolutionary history of Ash Meadows pupfish (genus Cyprinodon) populations inferred using microsatellite markers. Conservation Genetics 5: 769-782.
Burg, T. M., J. Wilcox, and A. P. Martin. 2001. Polymorphic microsatellite loci from pupfish (genus Cyprinodon). Conservation Genetics 3: 197-204.
Wilcox, J. L. 2001. Ph.D. Dissertation, University of Colorado, Boulder, CO.
Wilcox, J. & A. P. Martin. 2001. Report on the studies of the Devil's Hole pupfish. National Parks Service Technical Report, 55 p.
Wilcox, J., C. Serway, J. Stein & A. P. Martin. 2001. Systematics and conservation genetics of the tui chub (Siphateles bicolor) in Nevada. Nevada Division of Wildlife, Annual Report.
Martin, A. P. and J. Wilcox. 1999. Conservation genetics of Ash Meadows pupfish. Report to the United States Fish and Wildlife Service, 33 p.
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