engleski

Macroinvertebrate community on an artificial substrate in the Sava river: long-term changes in the community structure and water quality

Macroinvertebrates on floating artificial substrates were studied in the Sava river during two investigation periods with an interval of nine years. T he level of water pollution differed in the two periods. During each investigation, macroinvertebrates were collected in two seasons with low water regimes (winter, summer), but under different temperature conditions. The macroinvertebrate community structure was analysed six and five weeks following colonisation in winter and summer respectively. Benthic macroinvertebrates colonised the artificial substrate mainly by drift. Chironomidae and Oligochaeta were the dominant groups in both investigation periods, but marked differences were found regarding the number of species, species diversity and their t rophic status. Chemical and bacteriological data of the river water which characterised the organic load were markedly higher in the first investigation period . in both investigation periods, saprobity was evaluated based on the composition of the taxocenoses. Saprobic indices were lower in the more recent investigation period , but they still corresponded to quality class ll. Chironomids showed great sensitivity to modrrate organic load than oligochaetes.

macroinvertebrates; artificial substrate; water quality; the Sava river; Croatia.

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