Habitat Characteristic of Pongo pygmaeus morio in Prevab Area, Kutai National Park, Borneo, Indonesia

Abstract

The population of Bornean Orangutan now isolated in many habitat fragments. Prevab area in the Kutai National Park (Prevab KNP) is one of the few important natural habitats of Pongo pygmaeus morio remaining in East Kalimantan. Botanical assessments such as floristic composition, forest structure, and food sources availability studies are essential in view of their value in understanding the extent of the forest as an orangutan habitat and ecosystems. In this study, we investigate tree species composition, structure of forest stand, and distribution of orangutan food trees in the Prevab KNP. This study was carried out in the Prevab area (Orangutan Research Station in the Kutai National Park), East Kutai, East Kalimantan from October 2013 to September 2014. The structure data collection used the botanical plot of 0.6 ha and 1 ha for tree species composition. We were determined the number, total height, diameter of breast high, height of clear bole, the height of maximum crown width, and the crown width of all tree species.

Food trees were determined based on the direct observation, the information of community and staff of national parks, observed the after-eating signs of the orangutan, and the works of literature study.

Important Value Index is the pattern of calculation used to decide the dominant vegetation ecologically in the study area. The structure of forest stand was described in the form of architecture profile (horizontal and vertical). The food trees describe in the form of distribution map. Tree species (dbh ?5 cm) found in the botanical plot represented at least 148 species, 85 genera, and 43 families. The study plots are dominated by Cananga odorata. The trees density with ?5 cm dbh was 864 trees/ha, the average dbh of