Distribution and ecology of copepods in mountainous regions of the EasternAlps

Copepod species richness, patterns of distribution and composition of assem blages were evaluated in high-altitude sites in the Eastern Alps. Diverse h abitats were sampled in 160 lentic water bodies from different geologic are as, ranging from acid bog ponds to alkaline karst waters and from small tem porary puddles to deep lakes. The altitudinal range comprised all mountaino us regions from the montane (1290 m a.s.l.) to the alpine (2886 m a.s.l.) z one. Forty-four species were recorded, with the harpacticoids being the ric hest group. Although most species occupied a wide altitudinal range, some s tenotopic mountain forms were restricted to alpine habitats. The most wides pread taxa were Acanthocyclops vernalis, Eucyclops serrulatus, Bryocamptus rhaeticus, Arctodiaptomus alpinus and Cyclops abyssorum tatricus. All speci es found were listed along with notes on their distribution, ecology and pa tterns of coexistence. There was both a marked change in species compositio n and a decline in species richness from hardwater habitats in the Limeston e Alps to softwater sites in the Central Alps. Copepod taxocoenoses were mo st diverse in montane limestone lakes and impoverished with increasing alti tude. Copepods and sampling sites were ordinated using canonical correspond ence analysis (CCA), and copepod assemblages were defined in relation to ph ysical and chemical parameters, habitat type and presence/absence of plankt ivorous fish. Planktonic species were largely absent from lakes with introd uced fish. Although calanoid associations were common, coexisting diaptomid s were rare, suggesting a strong interspecific competition between these pr edominantly filter feeders. Most copepods found are common eurytopic or col d stenothermal, but some exhibit peculiar disjunct patterns of geographical distribution, and others are apparently restricted to the Alps. Some speci es are discussed in more detail from a zoogeographical point of view. A com plete checklist of copepods recorded to date from high-altitude sites in th e Eastern Alps is provided.