Genetic diversity, phylogeny and conservation of the Javan rhinoceros (Rhinoceros sondaicus)

With a total population of less than 60 individuals limited to two locations, the Javan rhinoceros is perhaps the most endangered large mammal on earth. Although species specific information is crucial to its conservation, its precarious status, habitat inaccessibility, and behavioral adaptations pose major obstacles to its study. Here we report on the first genetic analysis of the two extant populations, in Ujung Kulon, Indonesia, and Cat Tien, Vietnam, and discuss their conservation. As its critically endangered status precluded invasive sampling, we extracted DNA from dung, amplifying and sequencing segments of the mtDNA 12S rRNA gene and the non-coding D-loop. Divergence between Javan rhinos from Ujung Kulon and Cat Tien was similar to that between recognized subspecies of African rhinos, and exceeded that between Sumatran rhinos. The Ujung Kulon and Cat Tien populations represent separate Evolutionary Significant Units, advocating independent management. However, given the precariousness of the Cat Tien population, demographic considerations may override genetic issues in the short term. Genetic diversity of Javan rhinos was low and population expansion in the immediate future will be critical for its survival.