Journal of Heredity Advance Access originally published online on March 2, 2008
Journal of Heredity 2008 99(3):265-274; doi:10.1093/jhered/esn009
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Deciphering Ecological Barriers to North American River Otter (Lontra canadensis) Gene Flow in the Louisiana Landscape
From the Department of Forestry and Natural Resources, Purdue University, 715 West State Street, W. Lafayette, IN 47907 (Latch, Fike, and Rhodes); the College of Forestry and Agriculture, Stephen F. Austin State University, Nacogdoches, TX 75962 (Scognamillo); and the School of Renewable Natural Resources, Louisiana State University Agricultural Center, Baton Rouge, LA 70803 (Chamberlain)
Address correspondence to Emily K. Latch, Center for Conservation and Evolutionary Genetics, Smithsonian's National Zoological Park, 3001 Connecticut Avenue, NW, Washington, DC 20008, or e-mail: latche{at}si.edu.
For North American river otters (Lontra canadensis) in Louisiana, statewide distribution, availability of aquatic habitats, and the absence of physical barriers to dispersal might suggest that they exist as a large, panmictic population. However, the wide variety of habitat types in this region, and the dynamic nature of these habitats over time, could potentially structure river otter populations in accordance with cryptic landscape features. Recently developed landscape genetic models offer a spatially explicit approach that could be useful in identifying potential barriers to the movement of river otters through the dynamic aquatic landscape of Louisiana. We used georeferenced multilocus microsatellite genotypes in spatially implicit (STRUCTURE) and spatially explicit (GENELAND) models to characterize patterns of landscape genetic structure. All models identified 3 subpopulations of river otters in Louisiana, corresponding to Inland, Atchafalaya River, and Mississippi River regions. Variation in breeding seasonality, brought about by variation in prey abundance between inland and coastal populations, may have contributed to genetic differentiation among populations. It is also possible that the genetic discontinuities we observed indicate a correlation between otter distribution and access to freshwater. Regardless of the mechanism, it is likely that any genetic differentiation among subpopulations is exacerbated by relatively poor dispersal.
Corresponding Editor: Warren Johnson
Received June 4, 2007
Accepted January 11, 2008