Long-term dynamics of three types of black grouse habitat in the centr and at the edge of the distribution range in Sweden 1850-2000
2000
Angelstam, P. | Runfors, O. | Mikusinski, G. | Seiler, C. (Swedish Univ. of Agricultural Sciences, Riddarhyttan (Sweden). Forest Faculty. Dept. of Conservation Biology, Grimsoe Wildlife Reseach Station)
Being a habitat specialist with a large area requirement and a complex social system the black grouse is a good candidate for an umbrella species in conservation planning. Gradual land use changes are usually the major forces behind trends in the distribution and abundance of such species. Throughout its range, the black grouse is found in open to semi-open vegetation types that range from natural moors and bogs, and young seral stages in the forest succession to cultural landscapes. Using historical land use cover statistics for the trends in these three vegetation types and black grouse densities in them we modelled the long-term population trends in one landscape at the edge and one in the centre of the range in Sweden over a period of 150 years. The dynamics of these three types of black grouse habitats was very different. At the edge of the distribution a wide range of factors apparently caused the long-term negative trend, while in the centre of the distribution range the amount of the different habitat types fluctuated, but without any overall long-term trend. Using the long-term trend in hunting-bag records to validate the main outcome of the model did not contradict the results.
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