Deforestation is responsible for approximately 17% of global greenhouse gas emissions, and is therefore a major contributor to climate change, but also to the loss of biodiversity and ecosystem services and a direct threat to Asia’s great ape – the orangutan.
Between 2005-2010, Indonesia had accelerating forest loss compared to 2000-2005 and is within the highest five countries for percentage of primary forest loss globally. This acceleration in forest loss not only negatively impacts forests and biodiversity, but also local and global ecosystem services such as water supply, human health and food security in addition to climate change mitigation. Much of the deforestation is caused by both illegal and short-term economic gains, often ndermining long-term development goals.
As its name implies, the Sumatran orangutan – “person (orang) of the forest (hutan)” in Malay – occurs only in forests on the island of Sumatra (Rijksen and Meijaard 1999). More specifically, the wild population today survives solely in the north-western regions of the island, in the provinces of Aceh and North Sumatra. These provinces stretch from the Indian Ocean in the west to the Strait of Malacca, which separates Sumatra from mainland Malaysia further to the east. They are also bisected by the Bukit Barisan mountain range that runs down the full length of Sumatra.
These mountains reach altitudes of over 3,000 meters above sea level (m asl), with the highest peaks being Gunung Kerinci in West Sumatra (3,800 m asl) and Gunung Leuser (3,404 m asl) in Aceh (Map 2) and exert a major influence on rainfall patterns. Western regions receive much more rain than those in the east, as prevailing winds from the Indonesian ocean are forced upwards, cooling rapidly and condensing water vapour, which then falls as precipitation.