Allozyme diversity of european freshwater crayfish of the genius Austropotamobius

摘要

Data are reported on genetic variation at 30 enzyme loci in Austropotamobius crayfish from France, England, Italy, Spain, and the Balkans. Three population groups weredetected, corresponding to A. torrentium , A. pallipes and A. italicus (sensu KARAMAN, 1962). Reproductive isolation between these three taxa was demonstrated in the field.Populations from England, France, and north-western Italy belong to A. pallipes sensustricto , those from the rest of Italy, Spain, western Slovenia and north-western Croatiabelong to A. italicus , whereas A. torrentium was found in the Balkans up to the Italianborder. An average DW e / of 0.30 was found between A. pallipes and A. italicus , while theaverage genetic distance between these two species and A. torrentium was DNei = 0.77.Populations of A. italicus from Spain and north-central Apennines were found to be geneticallyclosely related (DNei = 0.05), not supporting a subspecific rank for these populations(A /. lusitanicus). Marked interpopulation genetic diversity was observed both within A. italicus (average FST - 0.80, DNe! up to 0.18), and within A. torrentium (average FST= 0.73, DNel upto 0.14), comparable to that previously reported for A. pallipes . Such genetic heterogeneityappears mainly related to range fragmentations and subsequent recolonizations frommultiple réfugia during the last glacial events. Overall low values of genetic variability werefound in the samples tested (e.g. He from 0 to 0.05), with the highest values in larger sizedpopulations from less disturbed areas (e.g. in A. italicus from Spain and Slovenia). The geneticerosion observed in Austropotamobius populations stresses the need to restore their geneticvariability, e.g. by controlled restocking, for successful programs of recovery and managementof these endangered crayfish.