The Orangutan Under Threat

Page - April 27, 2005
Orangutans, named for the Malay word meaning "person of the forest," are amazing animals. Rarely leaving the treetops, they are the largest animals to live in trees. Having once thrived throughout Southeast Asia, they are now critically endangered with a dwindling population estimated between 15,000 – 25,000, 30-50 percent less than were estimated ten years ago. With their forest home disappearing at an alarming rate – 80% in just 20 years – orangutans can only be found in limited areas in the tropical lowland rainforests of Borneo (shared by Indonesia, Malaysia and Brunei) and Sumatra. They could face complete extinction in as little as 20 years.

Orangutan sanctuary Wanariset Samboja

Each forest areas has its own distinct species of orangutan. Pongo pymaeus abelii lives in the Sumatran rainforest and Pongo pymaeus pymaeus resides in Borneo. Scientists speculate that the main reason these two species still survive in Sumatra and Borneo is because until recently, the presence of humans, especially in the extensive swamp forests, was very low.

Orangutans are not stationary animals. Each day they roam through large areas of forest collecting different kinds of fruits, insects and bark that they eat and use to build nests in trees. Orangutans are one of the only great apes to use tools. In 1994, scientists observed orangutans using sticks to avoid touching the sharp needle-covered skins of the puwin fruit in order to eat the protein-rich seeds.

Presently, orangutans are threatened because their forest home is being destroyed by logging, forest conversion to oil palm plantations and other crops, forest fires, the international pet trade and bushmeat. In Sumatra, scientists estimate that they are disappearing at a rate of 1000 individuals each year and in Borneo the estimation is even higher. In an effort to protect the orangutan, it has been listed on Appendix I of the Convention on Trade in Endangered Species of Wild Fauna and Flora (CITES), which bans international trade, yet the hunting of young orangutans for the pet trade still continues.

The orangutan plays a very important role in the lowland rainforests of Sumatra and Borneo and is considered a keystone species. Keystone species are species whose very existence in an ecosystem greatly effects the health of other species and the ecosystem at large. When a keystone species' numbers decline or they completely disappear, the survival and abundance of many other species in the ecosystem are negatively impacted. A comparison of different rainforest areas in Sumatra and Borneo where orangutans live shows that the biodiversity of plant and animal species is also the highest. As fruit eaters and travelers, orangutans play a large part in dispersing seeds and keeping diversity of rainforest woody plants. Their protection is vital to the overall health of the lowland forest ecosystem in which they thrive. In contrast, the vitality of the orangutan population will only flourish if their forest home is kept undisturbed and intact.

Orangutans are severely impacted by logging. When logging occurs in an orangutan's habitat they flee the area, causing social upheaval, fatal accidents and starvation. To escape the logging, orangutans escape to areas of undisturbed forest, even if this means crowding, which usually results in a lower birth rate. Once the logging has ceased, orangutans may return, but with a lower population than in the primary unlogged forest.

Most of the timber species logged for international markets do not produce the fruit that orangutans rely upon. However, they play an important role in the production of the orangutan's food. Large dipterocarps - the dominant tree species in Indonesian lowland rainforests - are the primary hosts to climbing and strangling figs and the removal of these valuable timber species destroys the source of the orangutan's main food. Over 50% of the tree stands studied in one orangutan habitat were found to be timber trees.

Despite Indonesia's efforts to protect the endangered orangutan with the establishment of national parks such as Tanjung Putting in Borneo and Gunung Leuser National Park in Sumatra, illegal logging is rampant in these parks. One of the main drivers of the illegal logging is the international markets for timber such as ramin. Placing ramin and ramin products on Appendix II of the Convention on the International Trade in Endangered Species will help protect this tree species and reduce the threats posed to the orangutan's rainforest home.