Resumen de Genetic Diversity Within and among Disjunct Populations of the Mediterranean Island Endemic Delphinium pictum and D. requienii (Ranunculaceae)
Maria Renée Orellana, Cèsar Blanché i Vergés, Joan Simon Pallisé, María Bosch
Allozyme diversity was assessed in 13 populations of Delphinium pictum and D. requienii, two short-lived and closely related insular Mediterranean endemics. While D. pictum has scattered distribution in Corsica, Sardinia and Majorca, D. requienii is found in a few small populations restricted to the Hyères Archipelago. Eleven enzyme systems were assayed, and 15 loci were resolved. Both species harboured moderate levels of genetic diversity, comparable to the values expected for endemic plants. All genetic parameters suggested higher diversity in D. pictum (A?=?1.93, P?=?40, H e?=?0.106) than in D. requienii (A?=?1.30, P?=?26.7, H e?=?0.096); F IS values revealed higher inbreeding in D. requienii. Although the two species did not harbour species-specific alelles in the surveyed loci, the UPGMA dendrogram based on Nei�s genetic similarity index supported divergence between them. These results, together with significant morphological similarity and evidence of successful hybridization between the species, support the hypothesis of a recent speciation event. The moderate levels of both genetic variability and population divergence observed for D. pictum are likely attributable to its ability to establish seed banks. Given that the allozyme variation detected for D. pictum was significantly partitioned among islands, we suggest the implementation of conservation programs throughout its distribution range, and not only in Corsica as it occurs nowadays. Management strategies are also desirable for D. requienii to maintain population size and control inbreeding.
