Rapid Homogenization of Multiple Sources: Genetic Structure of a Recolonizing Population of Fishers

Abstract: Fishers (Martes pennanti) were extirpated from much of southern Ontario, Canada, prior to the 1950s. We hypothesised that the recent recolonization of this area originated from an expansion of the population in Algonquin Provincial Park, which historically served as a refuge for fishers. To test this hypothesis, we created a sampling lattice to encompass Algonquin and the surrounding area, and we collected contemporaneous DNA samples. We sampled fishers from each of 35 sites and genotyped them at 16 microsatellite loci. Using a Bayesian assignment approach, with no a priori geographic information, we inferred 5 discrete genetic populations and used genetic population assignment as a means to cluster sites together. We concluded that the Algonquin Park fisher population has not been a substantial source for recolonization and expansion, which has instead occurred from a number of remnant populations within Ontario, Quebec, and most recently from the Adirondacks in New York, USA. The genetic structure among sampling sites across the entire area revealed a pattern of isolation-by-distance (IBD). However, an examination of the distribution of genetic structure (F_ST/1^- F_ST) at different distances showed higher rates of gene flow than predicted under a strict IBD model at small distances (40 km) within clusters and at larger distances up to 100 km among clusters. This pattern of genetic structure suggests increased migration and gene flow among expanding reproductive fronts.     

Effects of Recreation and Hunting on Flushing Distance of Capercaillie

Abstract: The capercaillie (Tetrao urogallus) in Central Europe is an endangered species of grouse that is thought to be highly susceptible to human disturbance, possibly causing local populations to decline. We investigated the behavioral response of capercaillie in the Black Forest, Germany, and the French Pyrenees to an off-trail hiker by measuring flushing distances. Flushing distance varied with capercaillie sex, visibility of the hiker, intensity of winter tourism, and hunting pressure. Independent of the study area, males flushed at consistently longer distances than females, and lower visual blocking between bird and hiker resulted in longer flushing distances. Capercaillie flew at longer distances from an approaching hiker in areas with high intensity of winter tourism or hunting pressure than in undisturbed areas. We recommend the establishment of regulations requiring hikers to stay on trails and to close trails where intertrail distances fall below 100 m (90% of all flushing events appeared within 50 m). Furthermore, planting or preserving evergreen conifer trees in dense rows along critical parts of disturbance sources, reducing the degree of visibility between capercaillie and recreationists would increase habitat for capercaillie in forests with predictable recreation activities.