Phylogeography and conservation perspectives of an endangered macaronesian endemic: Picconia azorica (Tutin) Knobl. (Oleaceae)

The Azores provide an excellent field test for research activities aimed at developing conservation strategies for endangered tree species. In this work, the urgency to promote Picconia azorica conservation programs addressed (a) insights into the biotaxonomy of the species (including anevaluation of its origin and relationships with the only congeneric species of P. azorica: P. excelsa from the Canary and Madeira islands) and (b) the evaluation of P. azorica genetic diversity. Plastid DNA sequence analysis and molecular markers (RFLP and SSR) were used for this purpose. Phylogenetic data suggest the monophyly of Picconia and support a late Miocene divergence of the two species. Three polymorphic cpSSR loci allowed the identification of five different haplotypes in P. azorica. Uniqueness and relictuality of lineages are presented and discussed. Picconia azorica intra-specific diversity patterns revealed low genetic diversity and a weak genetic structure, which could result from long-lasting ecological stability and efficient interisland seed movement that have been severely affected in recent times. The species survival is at risk, and we suggest management practices focusing on ex situ and in situ conservation units based on eco-genetic data. Additional measures contributing to mild erosion of the genepool and to remove barriers to seed dispersal are indicated.