Arealformen in der nivalen Spinnenfauna der Ostalpen (Arachnida, Aranei)

A survey of nival spiders in the East Alps yielded 49 species (19 Erigoninae, 15 Linyphiinae, 5 Gnaphosidae, 3 Lycosidae, 1-2 Philodromidae, Salticidae, Thomisidae and Agelenidae resp.) from 58 mountains, collecting sites from 2900-3500 m elevation. Concerning distribution in altitude, there are only 6 species occurring mainly in the nival zone, though there is a good number of eurynival species present also in the alpine zone, some of them even in lowlands. 5 erratic species are represented by wind-blown specimens only. Aerography:classic distribution types recognized already by BRAUN (1913) and by HANDSCHIN (1919) in nival organisms can be corroborated by spiders too:arctic-alpine distribution (9 spp.), endemisms within the Alps (19 spp.) or in the European mountain system (7 spp.). There are no close relatives known from the mountains of Asia, but in North American for two species (Chalcoscirtus alpicola (L. KOCH), Xysticus bonneti Denis). 6 species occurring over a wide range of altitude possibly might refer to the protocratic type of distribution described by BRINCK (1966). For most of the species distribution areas are rather continuous except for Lepthyphantes baebleri Lessert and for X. bonneti. Nevertheless, for 10 species there are area limits within the region studied. Along the Central Alps there are two breaks in species number, both at the western and at the eastern end of the Otztal/Stubai Alps, suggesting a severe impact of glacial events in the Central Alps of Austria and recolonization phenomena from the West. In peripheral isolation in Carinthia (Ankogel) as in the Dolomites there is evidence for local speciation also in nival spiders (Lepthyphantes sp. cf. armatus Kulczynski, L. brunneri Thaler, L. merretti Millidge).