Summer habitat selection by black grouse in the Belluno province (Eastern Italian Alps)

We report the preliminary results of a study aimed to evaluate the summer habitat selection by black grouse in the Belluno province (North Eastern Italian Alps). Thirteen sample areas (369 ha of average size, s.d.=129) for a total of 4797 ha were chosen to cover the different climatic and environmental conditions of the province. Each area was mapped from field surveys and with a GIS software for land cover types (stands of Fagus sylvatica, Picea abies, mixed Fagus s. and Picea a., Pinus sylvestris, Larix decidua, mixed Larix d. and Picea a., Pinus mugo, Alnus viridis; mixed shrubs (Juniperus spp., Salix spp. and others); shrubs of Rhododendron spp. and Juniperus communis; grassland; areas of grassland-forest transition; mixed grassland and rocks; rock), elevation (with classes of 200 m), slope (with classes of 15 degrees) and aspect (with classes of 45 degrees). Counts with pointing dogs were conducted during 1997, 1998 and 1999, and each observation was located on the map of its sample area. A circular area (buffer) of 100 m radius was digitized around each observation and habitat use was estimated from the buffers composition (vegetation type, elevation, slope, aspect), weighted for the proportion of individuals in each observation as respect to the total number of individuals. Elevation classes selected were in the range of 1500-1900 m, but there were exceptions due to artificial habitats at lower elevations; flat and steep areas, as well as ®warm¯ aspect classes, were tendentially avoided, and moderate slopes and "cold" aspect classes were preferred. Selection for, or against, the different classes of elevation, slope and aspect was less marked than selection for land cover types. Forest types with dense cover were avoided, as well as areas were ground vegetation is scarce; there was a clear preference for Larix decidua, Juniperus communis and Alnus viridis. These results are in general agreement with the available information on the species, but they show that it is possible to obtain a significant ranking of preferences, for the categories and classes used, as a basis for producing habitat suitability models.