PARENT SESSION

Genetics/Evolution 2 -- Session Chair: Jay Storz-- Nelson Hall East, Goodwin Forum

PHYLOGEOGRAPHY AND GENETIC DIVERSITY OF THE FISHER (MARTES PENNANTI) IN A PENINSULAR AND PERIPHERAL METAPOPULATION. Steven W. Buskirk¹, Samantha M. Wisely², Gregory A. Russell¹, Keith B. Aubry³ and William J. Zielinski⁴. ¹ Department of Zoology and Physiology, University of Wyoming, Laramie, WY, USA; ² Genetics Program, Smithsonian Institution, 3001 Connecticut Ave. NW, Washington, DC, USA; ³ Pacific Northwest Research Station, U. S. Forest Service, 3625 93rd Ave. SW, Olympia, WA, USA; ⁴ Pacific Southwest Research Station, U. S. Forest Service, 1700 Bayview Drive, Arcata, CA, USA.

ABSTRACT- Evolutionary processes can be strongly affected by landscape features. In vagile carnivores that disperse widely, however, genetic structure has been found to be minimal. Using microsatellite DNA primers developed for other mustelids, we found that populations of a vagile forest carnivore, the fisher (Martes pennanti), exhibit high genetic structure (F_ST = 0.45, SE = 0.07) and limited gene flow (Nm < 1) within a >1600-km-long distributional peninsula, that genetic diversity decreases from the base to the tip of the peninsula and that the fisher exhibits a non-equilibrium isolation-by-distance pattern of differentiation. Genetic structure was greater at the periphery than at the core of their distribution and data fit a one dimensional model of stepping stone range expansion. Multiple lines of paleontological and genetic evidence suggest that the fisher recently (< 5000 bp) expanded into the mountain forests of the Pacific coast. The reduced dimensionality of the distribution of the fisher in the West appears to have contributed to the high levels of structure and decreasing levels of diversity from north to south. These effects were likely exacerbated by human-caused changes to the environment. The low genetic diversity and high genetic structure of populations in the Sierra Nevada suggest that this population is vulnerable to extinction.

KEY WORDS: genetics, phylogeography, fisher, Martes pennanti