A reappraisal of saprobic values and indicator weights based on Slovenian river quality data

The saprobic values and indicator weights used in the Slovenian saprobic sy stem are reappraised using data from the 1990 to 95 river quality surveys o f Slovenia. The conceptual basis of the reappraisal is described and then f ormulated mathematically. The analysis is based on 1106 biological samples and covers 300 taxa. The results are expressed in terms of revised saprobic values and indicator weights that mirror the ones previously assigned by e cological experts. The most significant differences between original and re vised values are highlighted and discussed. It is concluded that: (a) the r evised values and weights are more representative of their 'true' values th an are the original values and weights, but that it would be premature to c onsider them definitive; (b) the analytical method provides a sound data-ba sed approach to the revision of saprobic values and indicator weights; and (c) the method could help to improve and harmonise the various saprobic sys tems currently in use across Europe. (C) 2001 Elsevier Science Ltd. All rig hts reserved.