Capercaillie (<em>Tetrao urogallus</em> L.) habitats in managed Finnish forests – the current status, threats and possibilities

Abstract

The aim of this study was to provide applicable knowledge for taking capercaillie into consideration in forest management and thus progress ecologically sustainable forestry. Capercaillie is a respected game species, but it also has indicator and umbrella species characteristics. Therefore capercaillie is closely linked to many other species. The study focused on the question: which structural characteristics of forest are important for the capercaillie? To gain a thorough view of capercaillie habitat needs, various capercaillie habitats were studied at several spatial scales in Finland in 1990s and 2000s. Species data were mostly from the wildlife monitoring counts. Forest planning data from Metsahallitus and data from the national forest inventories formed the landscape data. At large spatial scale (2500 km study units) the capercaillie population density was positively associated with the proportion of young thinning stands throughout the country. The association between capercaillie and young thinning stands was also positive at smaller scales in summer habitats, winter habitats and lek surroundings in northern Finland, where also the stand density was found to be positively associated with capercaillie in the summer habitats. The positive relationship between capercaillie and mature forests was found at the beginning of 1990s, but later this association was weak. The managed boreal forests become suitable for the capercaillie within 30 – 40 years, and so the large areas clear-cut in 1950s and 1960s in Finland became suitable for the capercaillie mostly in the 1990s. But the habitat quality may also decrease in the later successional stages of forest. The shortterm effects of thinnings on the capercaillie microhabitat quality can vary depending on the stand characteristics and season, and between adult birds and broods, but in the long term low cover on the ground may be the factor, which reduces the habitat quality in older managed forests especially in the low-productive areas and sites. Overall forest cover at the landscape scale, canopy cover and cover on the ground are important forest characteristics for the capercaillie. Longer rotations, understorey management and selective cuts are suitable methods to increase the capercaillie habitat availability and quality in the managed Finnish forests. Capercaillie habitat management calls also for spatial planning and preserving the availability of pine specifically in southern Finland. Also the costs and benefits of cutting residue management and possibilities to reduce the ditch restoration intensity in peatland forest management deserve a careful evaluation in the future. Furthermore, the connections between the abovementioned forest characteristics and other species deserve also to be studied.