Landscape and population genetics reveal long distance sharp-tailed grouse (Tympanuchus phasianellus) movements and a recent bottleneck in Minnesota

Abstract

Sharp-tailed grouse (Tympanuchus phasianellus) are an area-sensitive species that relies on open landscapes of grass and brush. These areas have become highly fragmented in the Great Lakes Region by succession to forest, agriculture, and other human land uses. We used microsatellites in a landscape-genetic approach to identify landscape features that influence movement and connectivity for sharp-tailed grouse in Minnesota, where they have a regional stronghold. Feathers from leks and hunter wing submissions resulted in 367 individuals from the northwest (NW) and 84 from the east-central (EC) management regions. Both the NW and EC regions were genetically diverse and distinct, with high connectivity between them, although it is unclear whether this connection is contemporary or historical. Our analysis indicated that sharp-tailed grouse were structured across regions by land cover or by the amount of agriculture, grasslands, shrublands, and wet meadows on the larger landscape. Numerous long distance dispersal events were detected. Population clustering analysis indicated greatest support for two genetic clusters in the NW and three clusters in the EC region; however, mapping sample locations of individuals by assigned cluster revealed panmixia of clusters in the EC region. High genetic diversity, a low inbreeding coefficient, and significant excess in heterozygosity are consistent with a recent demographic compression or bottleneck in the EC region, and also consistent with surveys indicating a recent decline there. Sustained low population size or further declines would be expected to reduce genetic diversity. We recommend increasing grassland and shrubland quantity and quality to increase population size in the EC region soon.