Grouse species as a conservation tool - effects of habitat dynamics on distribution and abundance of the black grouse (Tetrao tetrix) Sara Cristofoli1,2, 2002 Supervisor: Per Angelstam 3,4 1 Department of Biology, Facultés Universitaires Notre-Dame de la Paix, 5000 Namur, Belgium 2 Institutionen för Evolutionsbiology, 750 07 Uppsala, Sweden 3 Swedish University of Agricultural Sciences, Department of Conservation Biology, Grimsö Wildlife Research Station, 730 91Riddarhyttan, Sweden 4 Centre for landscape biology, Department of Natural Sciences, University of Örebro, 701 82 Örebro, Sweden Summary Biodiversity management should ideally consider all the components of biodiversity, i.e. species, habitats, genes and ecosystem functions, at multiple scales ranging from a single tree, to the forest management unit and up to landscapes in regions. At each scale, a number of different actors are involved. Being easy to communicate, the species component of biodiversity is, therefore, of particular interest. This has lead to the concept of umbrella species, which should be the most area-demanding specialised species for each type of environment. Boreal forests are characterised by their dynamic: they are dominated of a patchy distribution of different successional stages within the forest. Swedish boreal forests therefore provide a good opportunity to study if and how animal assemblages respond to this patchiness: they can therefore be used as benchmarks for setting conservation targets for region where habitat rehabilitation is needed to maintain biodiversity. This thesis has three parts. First I review the habitat and other factors that affect black grouse (Tetrao tetrix) at the level of individuals, populations and metapopulations. Then I present the results from a field study about the temporal dynamics of vegetation structure and food plants after clear-cutting in boreal forest. Finally, I report a study on the effects of 23 years of landscape dynamics on the distribution and abundance of the black grouse. The results of the second field study are discussed in the context of black grouse conservation in Europe.