Genetic Structure of a Recolonizing Population of Fishers (Martes pennanti)

We present the results of 769 fisher genotypes (Martes pennanti) studied across 35 landscapes in and around Ontario, Canada. Fishers were extirpated from much of southern Ontario prior to the 1950s. The recent recolonization of southern Ontario has been highly successful. We hypothesised that this recent expansion and recolonization originated from Algonquin Provincial Park, an area that has historically served as a refuge for fishers. To test this hypothesis, a sampling landscape lattice was created to encompass Algonquin and the surrounding study area. DNA samples were collected mostly from the 2001-2002 fur harvest to examine the spatial dynamics of fishers at a single point in time. Twenty to thirty fishers from each of the 35 landscapes in the lattice were genotyped at 16 microsatellite loci. Using a Bayesian assignment approach, with no a priori geographic information, we identified five discrete inferred genetic populations, and used genetic population assignment as a means to cluster landscapes together. The degree of genetic differentiation between these landscape clusters varied (FST = 0.019 to 0.14). This was likely a result of the difference in historical expansion and recent differentiation among breeding groups. Each of the five genetic clusters contained high levels of genetic diversity (HE = 0.590-0.682 ) and had no trace of recent bottlenecks. A regression analysis of geographic distance and FST values identified a positive relationship when excluding landscapes from the Adirondack cluster (F(1,463) = 84.27; R = 0.154; p<0.001), and a positive relationship between landscapes in the Adirondack cluster and all other landscapes (F(1,122)Adirondack = 14.93; R = 0.109; p < 0.001). More