Conservation genetics of the endemic Azorean slug Plutonia atlantica (Mollusca, Pulmonata)

摘要

Fifty-six specimens of the rare and endangered, endemic Azorean carnivorous slug, Plutonia atlantica, were surveyed for variation at 13 putative allozyme loci in eight populations from three islands. Genotypic proportions showed no significant deviations from Hardy-Weinberg equilibrium expectations and average observed and expected heterozygosity values were H_o =0.109 and H_e=0.118. At nearly all loci there were significant allele frequency differences between populations. Hierarchical F-statistics, genetic distances (identities), allelic distributions, and an independent analysis of isoelectric focused esterase profiles, suggested that genetic variation in P. atlantica is geographically structured, i.e. within the island of Sao Miguel (Tronqueira region vs the remainder of the island), between islands and between island groups (Faial/Pico vs. Sao Miguel). Genetic distances between populations from any of these geographic units were typical for interspecific comparisons. Therefore, it was concluded that conservation efforts in P. atlantica should recognize at least four management units (Faial, Pico, Tronqueira in Sao Miguel and the remainder of Sao Miguel), in order to effectively preserve the currently known genetic diversity in this species. How far these management units represent evolutionarily significant units or even different taxa remains to be investigated.