Mitochondrial DNA Variability and Conservation Genetics of the Sumatran Rhinoceros

Among mammalian species cited as endangered by the World Conservation Union (IUCN), the United States Department of the Interior (USDI), and the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), the Sumatran rhinoceros ( Dicerorhinus sumatrensis ) is one of the most threatened. Surviving populations are dwindling rapidly due to heavy poaching and habitat conversion (Fig. 1). On Sumatra alone the rhinoceros population has declined by more than half from 420–875 to 235–320 individuals over the past decade (Captive Breeding Specialist Group Species Survival Commission of the IUCN 1993). The number of Sumatran rhinoceros surviving today is between 413 and 563, and captive breeding programs established to contribute to the survival of this species have been unsuccessful (Foose & van Strien 1995). Managed breeding sanctuaries in natural habitats are being proposed as an alternative to captive breeding and as a refuge for rescued animals (Foose & van Strien 1995). These units are intended to concentrate large numbers of animals in protected areas. However, given all the conservation efforts being carried out on behalf of the Sumatran rhinoceros (Khan 1989; Captive Breeding Specialist Group 1994) and the recent discussions surrounding these efforts (Rabinowitz 1995 a , 1995 b ; Andau 1995; Hutchins 1995; Foose et al. 1995; Sumardja 1995), genetic information on this species is strikingly sparse. We know little about the extent of genetic variability in remnant populations or the extent of genetic divergence among them. The little we do know is based on the slowly evolving mtDNA ribosomal genes, and thus is not adequate for conservation management of conspecific populations (Amato 1994; Morales & Melnick 1994). The purpose of our study was to survey the pattern and extent of genetic heterogeneity among the remaining populations of Sumatran rhinoceros by analyzing the rapidly evolving mitochondrial control region. Our results constitute the most extensive contribution so far to our understanding of the genetic structure of the Sumatran rhino. These data, together with additional data from nuclear genes, will provide a genetic foundation that combined with other non-genetic data will further enhance the prospects of recovery of this highly endangered mammal.