Landscape requirements of prairie sharp-tailed grouse Tympanuchus phasianellus campestris in Minnesota, USA

Abstract

The prairie sharp-tailed grouse Tympanuchus phasianellus campestris occurs throughout the north central region of North America. It is of management concern because it has decreased in the southeast portion of its range over the past three decades, including marked declines in Minnesota and the Great Lakes region, USA. Although there is general knowledge about the habitat requirements for this species, no quantitative lek site or landscape information has been documented. We quantified landscape composition around active and inactive sharp-tailed grouse lek sites and random points in brush landscapes in northeast Minnesota at multiple scales (200-3,000 m radii circles). Our objective was to compare landscape composition among these sites. We also developed a model to predict the probability of grouse lek site occurrence in the study area. Landscape composition around active and inactive lek sites differed from each other primarily at the 500 m and 1,000 m radii scales. Inactive sites had higher proportions of upland forest and brush cover types and active sites had a higher percentage of native grass than inactive sites. No differences were found in landscape composition between site types at the 200 m radius scale and only one landscape variable (number of cover types) was different at the 3,000 m radius scale. We found non-random distributions of this grouse species at four different scales. Random brush land sites differed from both active and inactive sites having higher percentages of forest and brush cover. In contrast, lek sites had more bare ground, emergent aquatic vegetation, bog brush and roads than the random points. A regression model for the grouse at the 3,000 m scale was used to predict the probability of grouse occurrence in the landscape. The model resulted in a spatial map with about 8% of the area having a probability of grouse occurrence of >80%. This information can be used to locate new lek sites and to guide management activities for this species.