Historical and biological determinants of genetic diversity in the highly endemic triploid sea lavender Limonium dufourii (Plumbaginaceae)

14 páginas, 5 figuras, 2 tablas.

Microsatellite markers were used to evaluate the genetic diversity and population genetic structure in the critically endangered Limonium dufourii(Plumbaginaceae), a highly endemic triploid species from the coasts of eastern Spain. Sixty-five alleles from 13 microsatellite regions were amplified in a sample of 122 individuals collected from the six extant populations. Microsatellite patterns were consistent with the triploid nature of L. dufourii. Alleles were unambiguously assigned to two different parental subgenomes in this hybrid species and the greater contribution of the diploid parental subgenome was confirmed. Eleven, 25 and 26 multilocus genotypes were recorded from the haploid, diploid and from the combined information of both subgenomes, respectively. Genetic diversity was mostly distributed among populations (72.06% of the total genetic variation). Genotypes from Marjal del Moro populations grouped into two highly structured clusters (88.41% of the total variance). The observed patterns of distribution of genetic diversity are interpreted to result from multiple hybridization events and isolation between populations. Threats to this species are mainly anthropogenic (urbanization and tourism pressure), although stochastic risks cannot be ignored. Therefore, in order to preserve extant genetic variation of L. dufourii, in situ strategies such as the preservation of its habitat are a high priority. Several recommendations in order to assist ex situ measures to guarantee the success of conservation strategies and maintain the relationships between individuals and populations are proposed.

We are indebted to S. Rodríguez, J.A. Rosselló and the staff of the Consellería de Medio Ambiente for field assistance; C. Palacios for fruitful comments during the development of this study, S. Kresovich and S.M. Mitchell for technical assistance, and Andrew McCabe for help in revising our use of the English language. We thank the Generalitat Valenciana (GV) for providing permission for collecting samples. This study has been supported by project PB98-1436 from DGES-MEC. MPE was supported by a PhD grant from the GV and JGSM by an Itinerario Integrado de Inserción Profesional (I3P) postdoctoral fellowship from the Spanish Consejo Superior de Investigaciones Científicas (CSIC).

Peer reviewed