Composition and abundance of oligochaetes in large Scandinavian lakes in a morpho-edaphic index framework—in the 1970s and 50+ years later

Bottom-living oligochaetes and chironomid larvae, thanks to their supposedly integrative power, could provide more robust measures of the water quality lakes than separate chemical data. The oligochaete fauna large southern Scandinavia has been studied in detail over many years—often 100 years or (Milbrink, 2020). Characteristic species associations ecological preferences each are thus relatively well-known. In Milbrink (2020) it was shown that precision be greatly improved if relationship between data instead demonstrated within a morpho-edaphic index framework (Ryder et al. 1974). percentage composition total abundance per sample number selected basins Sweden Norway were tested against this 1970s 1978). trophic change which had taken place oligotrophic Lake Vättern—first with eutrophication later oligotrophication—was illustrated graphically discussed work 2020).
 A very similar also seen Vänern (the basin Värmlandssjön), as well eutrophic Lakes Mälaren Hjälmaren. All these lakes, once eutrophied 1950s 1960s, today undergoing oligotrophication. We simply have melioration advanced sewage treatment since 1960s. With our new knowledge, is informative studying changes after change. time when efforts save environment often fail, development real success story.