Population size, Red List status and conservation of the Natuna leaf monkey Presbytis natunae endemic to the island of Bunguran, Indonesia

We present the first population estimate for the Natuna leaf monkey Presbytis natunae, endemic to the island of Bunguran, Indonesia, based on a 2-month survey. Bunguran has a land area of only 1,605 km(2) and was until 1980 largely covered in primary forest. At present primary forest exists only in small patches within a matrix of logged forest, which covers nearly 70% of the island. Natuna leaf monkeys are confined to forest and have a preference for primary lowland forest patches. Groups average 3.5+/-SD 2.0 individuals and occur in a density of 2.3+/-SD 1.1 groups per km(2). Extrapolation of the density estimates to the entire island indicates that