Evaluating the contribution of multiple dispersal pathways to the genetic population structure of northern dusky salamanders (Desmognathus fuscus)
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Type of Workapplication/pdf
ix, 84 pages
DepartmentTowson University. Department of Biological Sciences
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Headwater species are organisms that are primarily constrained to the upstream terminus of river networks with limited capacities for both in-stream and overland dispersal. Movement along alternative dispersal pathways is suggested to contribute to gene flow and the overall stability of headwater populations. Six microsatellite markers were used to assess gene flow along in-network and out-of-network pathways in a species of headwater salamander, Desmognathus fuscus, over multiple spatial scales. Overall, genetic divergence was significant among all populations (Fst = 0.027 to 0.405) and at all hierarchical spatial scales. Genetic clustering analyses suggested limited gene flow within and among watersheds, indicating that both dispersal pathways are involved in maintaining gene flow among headwater populations. Increased genetic distance was associated with out-of-network distance and the degree of urbanization in upland habitat. These results suggest that significant dispersal occurred along terrestrial pathways, but dispersal resistance appears to be greatest along these pathways.