Abundance and nutrient content of some food plants in Sumatran rhino habitat in the forest of Kutai Barat, East Kalimantan, Indonesia

The recent discovery of Sumatran rhinoceros proved that the species still exists in Kalimantan. Current attempts to conserve individual rhinos ex situ at a sanctuary in Kutai Barat requires accurate information on the vegetation composition and abundance of food plants in the rhinos’ natural habitat. We determined the diversity of rhino food plants in an area where the species was known to occur. We recorded all species of seedlings, saplings, poles and trees at two survey sites, and determined which of these species had been eaten by rhinos. We identified 177 species of plants from 106 genera in our survey area, typical of the lowland dipterocarp forest ecosystem in this region. We identified 36 of these species as food plants of Sumatran rhino, of which the most abundant were Koilodepas brevipes, Gonystylus affinis, Diospyros sp., Pternandra rostrata, Calophyllum sp., and Macaranga gigantea. Furthermore, we conducted an analysis of nutrient contents of 22 of these species that showed signs of rhino bites. We found that all samples had fulfilled the nutrient requirements of the Sumatran rhino (based on standards for horse) except the requirement for phosphorus. The list of food species identified in this study could be used as a reference for habitat enrichment in rhino habitats, particularly at the sanctuary of Kutai Barat, and provides vital information for species recovery programmes.