Study of Natural Food Sources of Proboscis Monkey (Nasalis larvatus) in the Buffer Zone of New Capital City of Indonesia

Abstract

The riparian forest area along the Tunan river in Waru District, Penajam Paser Utara, is one of the proboscis monkey habitats in East Kalimantan. This area is included in the buffer zone closest to the new nation's capital city. As a result of the ongoing land use conversion, this area is divided into fragments, which have an effect on reducing the habitat. However, the presence of numerous groups of proboscis monkeys indicates that these habitat fragments can still meet their basic needs. The purpose of this study was to identify plant species used by proboscis monkey as natural food sources. Purposive sampling and observation method were used during this research. The result shows that there were 18 plant species as natural food sources, namely Avicennia marina, Elaeis guineensis, Excoecaria agalocha, Ficus benjamina, Sonneratia caseolaris, Vitex pinnata, Xylocarpus granatum, Achantus ilicifolius, Derris trifoliata, Ficus urata, Manihot esculenta, Melastoma malabathricum, Senna alata, Acrosticum aureum, Causonis trifolia, Flagellaria indica, Oxyceros longiflorus, and Loranthus sp. The hugest proportion of plant parts consumed were leaves (66.67%), while flowers and fruits were consumed in a smaller percentage.

Keywords: food sources, Nasalis larvatus, proboscis monkey, riparian