Populations, conservation status and distribution modelling of the rare and narrow endemic Rhododendron frey-wysslingii (Ericaceae)

Northern Gayo Plateau, Sumatra, is home to at least five Sumatran endemic Ericaceae where large threats come from the expansion of agricultural-related activities and infrastructure development. Rhododendron frey-wysslingii (Ericaceae) which is a northern Gayo Plateau endemic was just recently rediscovered but many parts of its geographical ranges are under severe disturbance. In the present study, we reported results of population and conservation study of the species known only from four populations in the northern Gayo Plateau. The population of this species shows a J-shape pattern showing a good regeneration capacity in the wild. However, no population is known to occur in nationally protected areas. And, due to the narrow geographic ranges and threats from habitat loss from expansions of coffee and other agricultural area as well as the presence of roads and their associated activities, the species is proposed here as Endangered (EN) according to the IUCN Red List. Living plant for ex-situ conservation purposes was collected and maintained. Besides that, a species distribution modeling was performed and showed that there are several potential habitats of the species outside the currently known ranges where no plant has been recorded, including Mount Hulumasen, Mount Peuet Sagoe, Mount Leuser, and Mount Bendahara, from an elevation above 1000 m asl. The findings add to the importance of the northern Gayo Plateau as home to narrow endemic species. Future efforts are needed for the species that include further survey in potential but unexplored habitats and implementation of in-situ conservation involving relevant stakeholders.