EMPIRICAL RELATIONSHIPS BETWEEN OLIGOCHAETE COMMUNITIES AND PHOSPHORUS IN LAKES BEFORE AND AFTER THE ABATEMENT OF EUTROPHICATION

In oligochaete communities of lakes, mean relative abundance (OS) of oligotrophic species (mostly Stylodrilus heringianus and Peloscolex velutinus) was negatively correlated with total phosphorus (TP) concentrations in the water. This empirical relationship, previously computed from nine lakes in which eutrophication was increasing, was extended in the present study to Lakes Geneva and Neuchatel (Switzerland) in which eutrophication was decreasing. Even in this situation, OS can be predicted from TP.