Is Austropotamobius pallipes a good bioindicator?

The use of indicators is among the most important and popular instruments of environmental control and nature conservation. Within the EU project Craynet, integrated research projects and general discussions have been presented with the aim of monitoring European native crayfish as indicators of biodiversity. Underlying many presentations on crayfish was the implicit assumption that Austropotamobius species were bioindicators for good water quality. With this as background, the Round-table discussion at the meeting in Kilkenny opened with two general questions, (1) what is a bioindicator and how well do crayfish, and especially Austropotamobius pallipes, match this concept? and (2) are other concepts such as surrogate species (sensu CARO and O'DOHERTY, 1999) more appropriate? The suitability of A. pallipes to be classed as a bioindicator was questioned by discussing its general tolerance to pollution, and the roles played by eutrophication and organic enrichment, water chemistry, chemical pollutants, and habitat. The value of A. pallipes as a bioindicator still remains debated; we are aware of many studies and statements of varying objectivity from fairly good to poor examples defining this species as a good to weak bioindicator. It seems that A. pallipes has potential as a bioindicator, however, perhaps only when we are able to narrow and define its tolerance levels. One conclusion of this interesting discussion is that a much better keyword, instead of bioindicator, would be flagship species, not least because of their cultural heritage value.