Habitat thresholds and effects of forest landscape change on the distribution and abundance of black grouse and capercaillie

摘要: T. urogallus in boreal forest. I also examine the effects of forest age distribution on abundance two species at local and regional scales. Using systematic surveys displaying males landscape data, minimum habitat patch size requirements for presence black grouse capercaillie was found to be 0.2 0.8 km 2 single males, 0.9 2.2 lekking respectively. In large patches suitable density 5 –2 grouse, 2.5 capercaillie. The scale thresholds with a probability 0.9, were 15% solitarily 22% leks, For threshold ca 34%. A 97% incidence exceeding required size, asymptotic prevalence functions, suggest that available saturated populations equilibrium their habitat. On (16 plots), 84% 74% explained by amount preferred patches. Both short-term (decades) landscapes, nation-wide longterm (60 yr) scales Sweden, changes relative paralleled landscapes’ distribution. results indicate show close environmental tracking terms amount, regeneration time after stand-replacing disturbance represents resource axis subdivided forest-living Fennoscandia. Differences compared situation periphery these are discussed, as well role focal conservation.