Ecology
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Young orangutan in the national park
Mount Leuser Forest
Gunung Leuser National Park is one of the two remaining habitats for Sumatran orangutans (Pongo abelii). In 1971, Herman Rijksen established the Ketambe Research Station, a specially designated research area for the orangutan. Other mammals found in the park are the Sumatran elephant, Sumatran tiger, Sumatran rhinoceros, siamang, Sumatran serow, sambar deer and leopard cat.
After researchers put 28 camera traps in July 2011, 6 months later the researchers found one male and six females, and predicted the population is not more than 27 Sumatran rhinos, of which the total population is predicted to be around 200 in Sumatra and Malaysia, half the population of 15 years ago.
Water supply[edit]
The first signs of reduced water replenishment have already been seen in and around the Leuser Ecosystem. Groundwater reservoirs are rapidly being exhausted, and several rivers fall completely dry during part of the year. This has severe consequences for the local community. Both households and industries need to anticipate water shortages and higher costs for water.
Fishery[edit]
Coastal fisheries and aquaculture in and around Leuser are very important. They provide a large portion of the animal protein in local people's diets and generate ample foreign exchange. Their annual value currently exceeds US $171 million. If the Leuser Ecosystem is degraded, the decline in fresh water may have a detrimental impact on the functioning of the fishery sector.
Flood and drought prevention[edit]
Flooding generally becomes more frequent and more destructive as a result of converting forests to other uses. Annual storm flows from a secondary forest are about threefold higher than from a similarly sized primary forest catchment area.
In Aceh, local farmers have reported an increasing frequency of drought and damaging floods due to degradation of the watercatchment area. In May 1998, over 5,000 hectares of intensive rice growing areas were taken out of active production. This was the result of the failure of 29 irrigation schemes due to a water shortage. Floods in December 2000 cost the lives of at least 190 people and left 660,000 people homeless. This cost the Aceh province almost US $90 million in losses. Logging companies are reportedly slowly recognising their role in increased flooding.
Agriculture and plantations[edit]
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Agriculture is a major source of income for the local communities around Leuser. Large rubber and oil palm plantations in northern Sumatra play a major role in the national economy.
Almost all remaining lowland forest area has been given out officially for oil palm plantations. Yield decline has been recorded, however, in several Leuser regencies. This decline can be ascribed mainly to a deterioration of nutrients in the soil, along with soil erosion, drought and floods, and an increase in weeds.
Hydroelectricity[edit]
Several regencies, such as Aceh Tenggara, have hydroelectric plants that use water from Leuser. The plants operated in Aceh Tenggara are designed as small-scale economic activities. It appears that the operational conditions for the hydroelectric plants have worsened in recent years. Increased erosion of the waterways has forced the operators to remove excessive sediments from their turbines. This has led to frequent interruption of the power supply, higher operational costs, and damage to the blades of the turbines. One plant closed down due to lack of water supply. Most of these disturbances are considered abnormal and may, therefore, be attributed to deforestation.
Tourism[edit]
Elephant jungle patrol near Tangkahan
Low-impact ecotourism can be one of the most important sustainable, nonconsumptive uses of Leuser, thereby giving local communities powerful incentives for conservation. Given the opportunities to view wildlife such as orangutans, some experts view ecotourism as a major potential source of revenue for communities living around Leuser.
Path to the summit of Mount Kemiri
Jungle view
Tourist village
Mount Leuser sunrise
Tangkahan trekking
A 7- to 8-hour drive from Medan, Tangkahan is visited by 4,000 foreign tourists and 40,000 domestic/local tourists a year. Modest inns are available, but generation set electricity is limited. Many Tangkahan people nowadays work for tourism and avoid illegal logging, with education sometimes past the elementary school, but with training, they can serve the tourists well. All tourists should enter Tangkahan Visitor Center first, and choose the various packages, with up to 4 day and 3 night packages, the prices are fixed even for the porters. Trekking can be done by foot or using elephants.
Biodiversity[edit]
Multiple macaques and an Asian water monitor in the park
Gunung Leuser National Park is known to be an area of high biodiversity. There are an estimated 10,000 different plant species, almost 600 bird species, 200 mammal species and close to 100 species of amphibians and reptiles.
Carbon sequestration[edit]
Anthropogenic increases in the concentrations of greenhouse gases (such as CO2) in the atmosphere lead to climate change. Carbon sequestration by rainforest ecosystems, therefore, has an economic value, since the carbon fixed in the ecosystem reduces or slows increases in atmospheric concentrations. Furthermore, the park's peat swamp forests sequester carbon at much higher densities than most typical rainforest ecosystems, as the thick organic soil layers store vastly more carbon than the forest biomass itself.
Nontimber forest products[edit]
Nontimber forest products can provide local communities with cash as long as exploitation does not surpass a threshold level.