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The long-term succession of high-altitude cladoceran assemblages: a 9000-year record from Sägistalsee (Swiss Alps)

Research paper by Wolfgang Hofmann

Indexed on: 01 Oct '03Published on: 01 Oct '03Published in: Journal of paleolimnology



Abstract

Cladoceran remains were analysed in a 1344 cm long sediment core from Sägistalsee (Swiss Alps, 1935 m asl) which covered the last 9000 years. Planktonic Cladocera were almost exclusively represented by Daphnia species, which occurred throughout the core. The chydorid fauna consisted of four species: Alona quadrangularis, Alona affinis, Acroperus harpae and Chydorus sphaericus of which the former was by far the most frequent species. The chydorid succession was characterised by disappearance and re-appearance of Acroperus harpae and Chydorus sphaericus at about 8400 and 3340 cal. BP, respectively. As a result, there was a long period of about 5000 years in which only two chydorid species were present with strong predominance (88.9%) of Alona quadrangularis. There was also a long-term trend of an increase of Alona affinis at the expense of Alona quadrangularis throughout the core.