Struktur dan Komposisi Jenis Vegetasi pada Habitat Ungko (Hylobates agilis F.Cuvier 1821) dan Siamang (Symphalangus syndactylus Gloger 1841) di Stasiun Penelitian Hutan Batang Toru Bagian Barat, Sumatera Utara

Abstract

Gibbon (Hylobates agiliis) and siamang (Symphalangus syndactylus) are the two kinds of Hylobatidae species that inhabit a Sumatera’s forest. One of the Sumatera’s forest region, which was sympatrycally inhabited by the two kinds of Hylobatide, is Western Batang Toru Forest, North Sumatera Province. Gibbon and siamang are arboreal primates that lived exclusively at the forest canopies, and they are highly depended on their habitat’s vegetation condition. This research objectives were (1) to describe the structure, composition and diversity of the trees speciesat the gibbon and siamang habitat and (2) to identify a use of the vegetation by the gibbon and siamang in their habitat. There were three types of the forest in Western Batang Toru Forest namely transitory hill-montane forest formation (FHHM), peat forest formation (FHG) and upper Dipterocarpaceae forest formation (FHDA). All of the forest types in the gibbon and siamang’s habitat had high Shannon-Wiener’s diversity index (H’>3). Structure of that three forest types had an average density at 907 trees/ha with 80,89 m2 basal area value. Tree species with the highest frequency in the three habitat types were Anacardiaceae Campnosperma auriculatum (FHHM), Sapotaceae Madhuca laurifolia (FHG) and Ulmaceae Girroniera subequalis (FHDA). Hylobatidae habitat at Western Batang Toru Forest had a complete forest stratification level which were strata A, B, C and D. The highest space available on the gibbon and siamang habitat was strata C or 11-20 meter height above ground. Gibbon and siamang used mostly strata B and C at their habitat. It was related to the vegetation support for Hylobatidae movement and protection in their habitat, as well as food resources’s availability on those strata. Protection effort has to do to protect Western Batang Toru Forest ecosystem, because those forest region still get a threats and pressures from gold mining and logging area recently.