| dc.description.abstract | The distribution of Tapanuli orangutans is currently only recorded in the Batang
Toru landscape, at an altitude of 300 metres above sea level (masl) to the
mountainous region at around 1,300 masl. Based on surveys conducted in 2000-
2001 and 2021-2024, Tapanuli orangutans were found in Pesisir Lumut and
Kampung Sawah, Pesisir Barat, Tapanuli Tengah Regency. This study used thermal
drones to monitor and identify the presence of Tapanuli orangutans and other
animals. The use of thermal drones successfully identified three male individuals
and a pair of Tapanuli orangutan parents and their offspring. The optimal flying
height for drones is below 120 AGL (above ground level), with the best flying time
being in the morning between 06:00 and 08:00 WIB (Western Indonesian Time).
Land cover change analysis was conducted on an area of 155,000 ha using Landsat
imagery from 1989, 2007, and 2025 to detect the connectivity of the Batang Toru
and Lumut landscapes. The analysis results show that in the first 18-year period
(1989–2007), there was a change in forest cover area from 113,472.18 hectares to
only 89,122.41 hectares in 2007 (-24,349.77 hectares/21.46%). This decline in
forest area has resulted in the formation of forest pockets that are increasingly
distant from one another. In 1989, the distance between forest pockets was
approximately 1,314 m, then 4,237 m in 2007, and 6,092 m in 2025. Predictions
regarding land cover changes over the next 15 years (by 2040) indicate insignificant
changes in area, amounting to 537.57 ha. Modelling the carrying capacity of
population pockets using Maxent shows that the Pesisir Lumut and Kampung
Sawah forests are no longer able to provide habitat for Tapanuli orangutans, as only
2,230 hectares of the 24,558 hectares of observation area remain (9%). | en_US |
