Abstract

The oceanic islands, despite their small size, have been recognized as large natural reservoirs of biodiversity since host numerous unique species. These islands offer opportunities for evolutionary studies, which help to understand how species and populations diverge. Anagenesis is a speciation process that has allowed the generation of new species on oceanic islands, characterized by the arrival of a migrant on an island, which colonizes this new habitat without diversification event, establishing a population by microevolutionary processes, diverging into a new genetically different species, with levels of genetic variability equal to or slightly different than its ancestor. Anagenetic process directly affects biodiversity and it also has significant effects on population genetic variability and conservation genetics. The Juan Fernández Archipelago, a world biosphere reserve, has a high percentage of endemic species originating anagenetically, such as D. hirsuta, endemic of Robinson Crusoe Island and derived from the continental ancestor D. glechomoides. Due to the drastic reduction of habitat that Archipelago has experienced, D. hirsuta is in critical danger state, despite this, there are no antecedents to elucidate the genetic conservation status of island populations. For this reason, this study evaluated the microevolutionary processes that accompany anagenesis speciation mode, analyzing the results from a conservation point of view in Robinson Crusoe Island. Genetic diversity data obtained by AFLP and SNP markers were evaluated in 18 populations with 382 individuals and 14 populations with 367 individuals respectively. AFLP shows slightly lower levels of genetic diversity in D. hirsuta (I= 0.266 / He= 0.206) compared to D. glechomoides (I= 0.333 / He= 0.308). Within the island, data set from AFLP and SNP indicate a largest genetic reservoir in populations of Piedra Agujereada (He= 0.247, I= 0.390, NBLC= 44, Fis= 0.1572), and Rebaje La Piña (He = 0.123, I = 193, NBLC <= 50% = 15, Fis= 0.1182). FONDECYT Project No. 1160794 and CONAF Juan Fernández Archipelago National Park.