title: Distribution and size of capercaillie leks in relation to old forest fragmentation.
abstract: Distribution and size of 38 capercaillie Tetrao urogallus leks were related to amount and configuration of old forest patches in two south-east Norwegian coniferous forests. The smallest occupied patch was 48 ha containing a solitary displaying cock. All patches larger than 1 km2contained leks. Number of cocks per lek increased with increasing patch size. Number of leks per patch increased in a step-wise manner with one lek added for each 2.5-3 km2increase in patch size. In large patches there was one lek per 3-5 km2old forest, and density of lekking cocks was 2-2.5 per km2. In small patches density of cocks varied considerably. Density of cocks was not related to patch isolation or patch shape. However, among leks surrounded by 50-60% old forest within a 1 km radius, number of cocks increased with increasing old forest fine-graininess. We argue that when old forests cover more than 50%, a fine-grained mosaic may support higher densities of lekking cocks than a coarse-grained mosaic. Conversely, when old forests cover less than 50%, a fine-grained mosaic is unfavourable, because each old forest patch becomes too small and isolated. Finally, we present a predictive model of how old forest fragmentation influences density of leks, number of cocks per lek, and total density of cocks.
authors.affiliation: Institute of Nature Conservation, Agriculatural University of Norway, Ås-NLH, P.O.Box 39, N-1432, Norway.
authors.forename: J
authors.initials: J
authors.lastname: Rolstad
authors.affiliation: Institute of Nature Conservation, Agriculatural University of Norway, Ås-NLH, P.O.Box 39, N-1432, Norway.
authors.forename: P
authors.initials: P
authors.lastname: Wegge
keywords: Boreal forest; Habitat fragmentation; Tetrao