Influence of landscape composition on sharp-tailed grouse lek location and attendance in Wisconsin pine barrens

Abstract

:Populations of sharp-tailed grouse (Tympanuchus phasianellus) in the upper Midwest are in danger of extirpation due to habitat loss caused by succession, tree planting, and control of wildfire. Sharp-tailed grouse in Wisconsin have persisted primarily on reserves maintained in early succession using prescribed burning and mechanical disturbance. However, during the late 1990s the highest and densest populations of sharp-tailed grouse in Wisconsin were found in a complex of clearcuts in southeastern Douglas County. We compared landcover composition and fragmentation at multiple scales within 2.4 km of 36 sharp-tailed grouse leks and 213 unused locations in a 1,350-km2 study area in the pine barrens of northwestern Wisconsin. Leks were located on managed reserves (n = 11) and habitats recently created by timber harvest (n = 23) and wildfire (n = 2). Leks were clustered in the landscape, with distance to nearest neighbour lek shorter for leks than unused points. Leks were characterized by higher proportions of grass and shrub cover classes, lower proportions of forest, fewer forest patches, and greater distances to forest edge relative to unused points. Proportions of grass and shrub cover classes, distance to nearest lek, and distance to forest edge were strong predictors of lek presence in a logistic regression model. Differences between leks and unused points varied with scale of sampling. Response of sharp-tailed grouse to indices of fragmentation varied among scales and metrics. Number of sharp-tailed grouse attending leks was positively associated with recently created habitat and proportion of grass cover in the landscape.