Authors: Väisänen, Rauno & Heliövaara, Kari & Kotiranta, Heikki & Niemelä, Tuomo
Journal: Karstenia, Volume 32 (1992), Issue 1, pages 17-28.
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Key words: biogeography, gradient analysis, polypores, rarity
Abstract: The analysis was based on the Finnish records in 100 x 100 km quadrats of species of the polypore genera Phellinus, Coltricia, Inonotopsis, Inonotus, Onnia, Phaeolus, Fistulina, Polyporus, Ganoderma and ischnoderma. Their distributions were preliminarily classified and related to environmental variables, using multivariate methods (two-way indicator species analysis, detrended correspondence analysis, canonical correspondence analysis). From the distribution patterns of the polypore species, it was possible to distinguish blocks of quadrats showing some resemblance to recognized vegetational zones. The continentality and number of tree species had the highest canonical coefficient values on the first axis of the canonical correspondence analysis, but the model was improved by the distribution of Picea abies and the proportion of grass-herb forest types. The quadrats with the most deviant rarity and typicalness indices were concentrated in the Åland archipelago, the surroundings of Helsinki and Turku, and in the area of the virgin forest of Pisavaara and the Paijfume lake district in southern Central Finland. These deviations reflect both exceptional species assemblages and uneven collecting activity.