Canopy bridges for Sumatran Orangutans in West Toba, Northern Sumatra

The emergency

A major road upgrade in West Toba will divide the Sikulaping Protected Forest and Siranggas Wildlife Reserve in North Sumatra. This will prevent arboreal mammals from accessing previously connected patches of natural forest, including Sumatran Orangutan. The area contains at least 40 Sumatran Orangutans; ensuring these patches of forest remain connected will be important for this population’s long-term survival. Other globally threatened primates that will be negatively impacted by the road development include the Endangered Black-crested Sumatran Langur, Agile Gibbon, and Siamang. Government permission to construct artificial canopy bridges has been secured, but the upcoming elections in Indonesia, and the potential for newly elected officials, would restart this process. There is an urgent need to establish artificial canopy bridges as soon as possible.

The project

Sumatran Orangutan Society will work in partnership with a local Indonesian NGO, TaHuKah, to construct five artificial canopy bridges along the road. Artificial canopy bridges are a proven intervention for assisting the movement of arboreal mammals, particularly primates, across previously connected patches of forest. The use of the bridges will be monitored using camera-traps over a 6-month period; the results will be used to improve understanding of how arboreal mammals utilise canopy bridges. A forum will be established to help disseminate the lessons learnt, to encourage future adoption of canopy bridges in infrastructure projects within orangutan landscapes to maintain connectivity.

Photo credit: Mandai Wildlife Group