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RESEARCH PRODUCT

Water mites of small boreal forest lakes (Central Finland)

subject

description

The water mite fauna of 10 small forest lakes in close proximity to each other was studied in 1979–1985. In total approximately 62 species of water mites belonging to 22 genera were detected in the lakes. The most diverse genera were Piona (14 species), Arrenurus (11), Unionicola (4) and Limnesia (4). Widely spread and abundant species were Piona variabilis and Limnesia maculata. Locally abundant were Unionicola crassipes, U. minor, Piona carnea and P. paucipora. Zoogeographically interesting though accidental species were Arrenurus werestschagini, Limnesia polonica, Momonia karelica, Piona gyrophora and Unionicola parvipora. Considerable spatial and seasonal differences were observed in the occurrence of water mites. In acid and in “clear water” lakes as well as in some vegetated habitats the mite fauna was poor throughout the summer. In some slightly acid polyhumic lakes with deeply sloping shores the densities of water mites were high in June-July but decreased rapidly in August.