Genetic diversity and conservation of the Madeira Island (Portugal) endemic Geranium maderense Yeo (Geraniaceae)

Geranium maderense is a perennial, monocarpic herb, up to 200 cm tall, producing very showy inflorescences, very rare in the wild, although cultivated throughout the world as an ornamental plant. G. maderense is protected under the EC habitats directive (Annex *B-II, IV) and Bern Convention (Annex I) only found, so far, in two cliff-associated sites, and classified as a Critically Endangered species (IUCN). Using unmanned aerial vehicle (UAV; drone) technology, two new populations were detected, and a new distribution map is presented. Inter-simple sequence repeat markers were used to detect genetic diversity in natural populations and garden grown plants. Genetic diversity estimates revealed retention of genetic variation and weak genetic structure in G. maderense populations. Cluster and principal component analyses formed coherent groups, indicating that genetic diversity in the studied wild populations of G. maderense is heterogeneously distributed. Our results provide crucial information for the preservation of natural populations of G. maderense, and allow for the revaluation, following IUCN criteria as Endangered (EN).