Understanding intra and inter-archipelago population genetic patterns within a recently evolved insular endemic lineage

The recently evolved genus Tolpis Adans. has its major center of diversity located in Macaronesia. Although recent advances have been made to understand the relationships of Tolpis species within Macaronesia, little is still known about the genetic patterns and genetic diversity of the Azorean and Madeiran Tolpis populations. To achieve this, a set of 8 microsatellite loci (SSR) was applied to 478 individuals of Tolpis azorica and T. succulenta. Genetic structure analysis, in addition to a spatial analysis, confirmed the existence of geographically circumscribed genetic patterns allied to a barrier effect by the sea in the Azorean T. azorica and T. succulenta. A detailed analysis of T. azorica revealed three different genetic groups, each group being particular to a different Azorean sub-archipelago, while the analysis conducted with T. succulenta confirmed the occurrence of a differential grouping between individuals from Azores and Madeira populations. The impact of catastrophic volcanic events and intense humanization of the habitats is discussed, in view of the present genetic diversity and structure of the species. In general, T. azorica populations showed high F (is) values and some populations of T. succulenta both in Azores and in Madeira also showed signs of putative inbreeding. Conservation actions such as the eradication of invasive plant and animal species are advised but translocations of plants or diaspores between islands or between populations of a same island should not be attempted.