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Sumatran orangutans which are found in the Province of NangroeAceh Darussalam and North Sumatra Province are fragmented into fourpopulations. One of the population occurs in Angkola, a forested area locatedin the southern part of Lake Toba. This population is considered to be smalland narrowly distributed. Our survey shows that individual orang utan appearin and in the vicinity of the Dolok Sibualbuali Nature Reserve. This indicatesthat orangutans can adapt to fragmented habitats, such as are found nearDolok Sibualbuali Nature Reserve, South of Tapanuli, North Sumatra.The preliminary study was conducted April 2002 - January 2003. Thisstudy recorded the distribution and the daily activities of orangutans in DolokSibualbuali Nature Reserve. Repeated crisscrossing surveys and focalanimal observation were used to document orangutan distribution and dailyactivity.Human activities are the main factor for the loss of orangutan habitat.Illegal logging, forest conversion for timber concessions and plantations, roadconstruction and settlement constitute the main factors for forest loss. Thisforces orangutans out of their native habitat and makes them vulnerable toextinction.Based on direct sightings, orangutan are found at Aek Nabara andSitolu. Moreover, the presence of orangutans is indicated by nests at theSihulambu and Bulu Mario sites. The orangutan population is not evenlydistributed but seems to be present at locations with food resources.Seven individuals were chosen as focal animals. They consisted of 3adult females, 3 sub-adult males and 1 juvenile. Total observation time was757 hours and 40 minutes. Feeding, moving, resting, nesting and socialactivities were the main activities that were recorded. Orangutans spent theirdaily activity budgets: feeding (42.29%), moving (16.47 %), resting (37.41%),nesting (1.89%) and social contact (1 .93%). Orangutans spent much of theirtime (42.29%) feeding, particularly when food resources were abundant. Dueto their large body size, food consumption was high.There are 115 types of orangutan food consisting of fruits (36.6%),flowers (3.89%), leaves (28.33%), bark (17.7%) and pith/stem (11.67%), andother food types (insects, honey, etc.) (1 .67%). Fruit is the main source oforangutans food.We concluded that the distribution and daily activity of orangutans atDolok Sibualbuali Nature Reserve was very much influenced by theavailability of food, particularly fruit. When favored fruit is abundantlyavailable, orangutans will constantly consume that fruit and visit fruit trees of the same species in other locations. Orangutans will also search out otherfood in community farms near the Nature Reserve when forest fruit availabilityis less, leading to conflict with local people. |
T11674-Reniastoetie Djojoasmoro.pdf :: Unduh