Narrow gene pool can threaten the survival of R. R. Fernald & Dey: a highly, endemic dioecious rattan species in the Western Ghats of India.

Rattans, the spiny climbing palms of Arecaceae (Palmae) family exhibit high endemism to the biodiversity hot spots in India. Of the five rattan genera, is the only genus found in peninsular India with 15 of 21 species, endemic to the Western Ghats. The extensive utilization of rattans owing to their strength, durability and huge demand has resulted in depletion of their natural resources. Of the 15 endemic species, is the most affected species on account of endemism, low population size and restricted distribution with fragmented populations. The present study revealed high amount of genetic diversity in the surviving scattered populations of the species using microsatellite markers. High gene flow ( = 1.498) observed across the populations resulted in low genetic differentiation (14%). A clear genetic admixture could be seen in Kerala as well as one of the Karnataka's populations while the remaining two populations were genetically distinct. UPGMA, PCoA and STRUCTURE analyses showed significantly different genetic composition in Kerala population compared to other populations. Kerala and Karnataka populations of were also unique in their genetic structure and allelic composition. Therefore, effective management and conservation strategies have to be implemented to preserve the rarealleles with adaptive potential to protect this economically valuable species from endangerment. Over exploitation, low seed set and poor regeneration, as well as habitat fragmentation can further threaten the survival of this endemic, narrowly distributed dioecious rattan species in the Western Ghats region.