Chironomidae (Diptera, Nematocera) fauna in three small streams of Skania, Sweden.

Two unpolluted streams and one chemically and thermally polluted stream in Skania, Sweden, were investigated in summer 1995 for their temporary chironomid fauna and the occurrence of buccal deformities. The unpolluted streams 'Ovedsan' and 'Skäralidbäcken' each contained, respectively, 13 and 16 taxa, with a dominance of Microtendipes pedellus group and Micropsectra spp., respectively. Most taxa were found in the pebbles and the submerged vegetation. Deformities were insignificant. The degraded stream Ybbarpsan in Perstorp contained 5 taxa, dominated by Procladius choreus. This species had 14% deformed larvae, interpreted as an effect of the chemical pollution. Shannon H and equitability J reflected the differences in chironomid community structure between the two unpolluted and the polluted sites. The Belgian Biotic Index scored maximally '10' in Skäralid, however only '6' in Oved and '5' in Perstorp. The combination of rapid assessment of macrobenthos and description of communities of Chironomidae, with mention of deformed larvae, adds a bonus of information about the temporary state of a stream.