Bodenfaunistische Untersuchungen in Aare und Rhein

The results of the investigations of the river benthos, presented in part I 2], have been further analyzed with regard to statistics, saprobity and diversity. The contagious distribution of the organisms is linked with a great variance, which necessitates a big number of samples and causes problems in interpreting the counts. Different biological and diversity indices have been tested for validity; whereas the saprobic evaluation yielded α-β-mesosaprobic conditions for the river Aare and β-α-mesosaprobic conditions for the river Rhine, the diversity seems not suitable for river classification in our case. Problems concerning biological evaluation of water quality in big rivers are discussed.