Can Austropotamobius italicus meridionalis to be used as a monitoring instrument in Central Italy? Preliminary observations

Attributing the term bioindicator to a species complex such as Austropotamobiuspallipes is complicated, considering that the meaning given to a bioindicator can varyaccording to the geographic position, and that A. pallipes species complex has beendivided into 2 species and 5 subspecies, the possibility of using A. i. meridionalis as abioindicator in watercourses of Central Italy was evaluated. To this end, we analysedthe structure and abundance of a number of crayfish populations and then comparedthem to the water quality of the corresponding watercourses, using E.B.I. (ExtendedBiotic Index). This index provides information on water quality through an analysis of themacrobenthos community. The watercourses are assigned to various classes (from I to V,increasing the degrees of alteration). This study was carried out in several watercoursesnear Rome. The abundance of crayfish was found to be greatest in those tracts that areassessed as class I, where the populations seem well structured with individuals of varioussizes and the sex ratio is approximately 1:1. In contrast, in class II we found a reducedpresence of specimens, mostly in bad conditions. No crayfish specimens were observedin watercourses designated as class III. In light of these preliminary results, it does notseem possible to consider A. i. meridionalis as a bioindicator, given that one of the typicalcharacteristics of a biological indicator (wide distribution) is not met. Though these resultsillustrate the possibility of using A. i. meridionalis populations as an excellent monitoringinstrument in Central Italy.