The importance of landscape characteristics on hazel grouse Bonasa bonasia density was studied in two areas in Finland combining data from grouse counts and forest inventories. Hazel grouse data for 1985-95 originated from the Finnish wildlife monitoring program in which grouse were counted in August along permanent 12-km routes (wildlife triangles). Data for landscape characteristics were from satellite-based National Forest Inventory which provides information on land-use and stand structure for every 25 ? 25 m element. Areas within 2.5 km from the centre points of triangles were classified into three classes according to their importance for hazel grouse: 1) unsuitable area (e.g. water areas and fields), 2) poor habitat (e.g. young stages of forest succession), and 3) prime habitat (i.e. medium-aged and old stands). The mean hazel grouse density in August was 8.8 and 5.6 birds/km? in the southern and northern study area, respectively, roughly corresponding to the area of prime habitat in the study areas. The proportion of unsuitable habitat in the landscape had no significant effect on grouse density. Although unsuitable, the open areas decrease the area available for hazel grouse, this loss is compensated by the fact that stands along lake shores and fields are highly productive and among the ones most preferred by hazel grouse. The proportion of poor habitat in the landscape was significantly negatively correlated with hazel grouse density, whereas prime habitat was positively correlated with hazel grouse density. Correlations were generally stronger for the northern study area than for the southern area.
Key words: Bonasa bonasia, density, Finland, hazel grouse, landscape characteristics, land use, stand structure
Paavo Kumpu & Pekka Helle, Meltaus Game Research Station, Finnish Game and Fisheries Research Institute, FIN-97340 Meltaus, Finland
Ari Nikula, Finnish Forest Research Institute, Rovaniemi Research Station, FIN-96301 Rovaniemi, Finland