engleski

Freeliving Aquatic Nematodes at Five Stations along the Drava River

During six months of investigation (from November 1997 to April 1998), 42 freeliving aquatic nematode species were recorded at five eulittoral stations along the Drava. Two main factors influenced the nematodes' abundance and species composition, i.e., water level fluctuation that changed the granulometric properties of littoral sediments. During the investigated period, the Drava water level fluctuated from +112 cm to -123 cm. Six different sediment types were recorded at the investigated stations: silty sand pebble, silty pebble sand, sand, silty sand, sandy silt and silt. The lowest number of nematodes species, with no Monhysterida, was recorded in the silty sediment also discriminated by the multidimensional scaling statistical method. Only one species, Mononchus aquaticus, was recorded in all six seduiment types. Cluster analysis discriminated nematofauna at the loweast water level. Regarding the total nematode abundance, suction feeders dominated in the silt sediment and during the highest water level with thir 86% and 66%, respectively

Drava; sediment granulomety; freeliving nematodes; water level fluctuation

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