ORANGUTAN (Pongo pygmaeus ssp. wurmbii ) RANGE PATTERN IN PUNGGUALAS, SEBANGAU NATIONAL PARK, CENTRAL KALIMANTAN, INDONESIA

Abstract

Punggualas is a logged-over forest in Sebangau National Park (SNP), serving as a primary stronghold for orangutan (Pongo pygmaeus ssp. wurmbii) population. Therefore, this study aimed to evaluate orangutan range patterns and distribution within Punggualas forest. The ranging data were collected inside the area of interest (AOI) from February 2015 to December 2019 (P1) and March 2020 to May 2022 (P2). The minimum convex polygon (MCP) area and Kernel Utilization Distribution (KernelUD) of orangutan were estimated using the adehabitatHR package in RStudio 4.2.3, with the Kernel Density (KD) tool in ArcGIS 10.5 used for visualization. The results showed that the largest range size, measuring 259.6 Ha, was observed in the mother-infant pairs throughout the investigation, surpassing the flanged male home range (HR) size of 250 Ha per year reported at the Natural Peat Laboratory, CIMTROP-UPR. The range pattern also varied significantly between the two study periods. During P1, the distribution area was positioned in the northern part of the AOI, shifting to the southeastern during. This indicated that P. p. wurmbii range pattern in Punggualas moved to the southeastern part of the grid trails, as shown by MCP and KernelUD. The probability of orangutans using random points across the study area, specifically for food, was adequate from the total basal area (m2ha-1) and tree species composition. The compression effect became evident as a potential determining factor contributing to rapid changes in range patterns during the study periods.