SEBARAN DAN KEPADATAN POPULASI SIAMANG (Symphalangus syndactylus Raffles, 1821) DI CAGAR ALAM DOLOK SIPIROK DAN SEKITARNYA, SUMATERA UTARA

Abstract

Siamang (Symphalangus syndactylus Raffles, 1821) is a primate of Sumatra that currently threatened by high rate of habitat degradation. Most of the population distribution in the wild remains in the conservation and protection areas. Information of distribution and density of siamang at natural habitat is important in ex-situ conservation effort. This research was aimed to determine their distribution and estimating the density population at Dolok Sipirok Natural Reserve and surrounding area. Line transect method was adopted to estimate siamang population while group composition was predicted based on age phases. Results from this study revealed that siamang was recorded in and surround Dolok Sipirok Nature Reserve. They were mostly distributed in an altitude of 900-1,200 asl. About 81.8% group or individual were found in primary dry land forest and 9.1% were recorded in secondary dry land and along the river nearby the cultivation area. The estimated population density was 9.91± 3.4 individual/km 2 , and CV value of 0.22. Size of the groups was 3.43 individual/group with group density of 3.71 group/km 2. Age distribution indicates that infant and juvenile-1 were the lowest among other age classes. This research showed that siamang population at CADS and surrounding area potentially to decline in the future. Habitat restoration is urgently needed for in-situ conservation of this species.