Lake Sentarum National Park (LSNP) is a park protecting one of the world’s most biodiverse lake-systems situated deep in the Heart of Borneo, in Indonesia’s province of West Kalimantan.
Located in the Kapuas Hulu Regency, the Park lies in the upper Kapuas River tectonic basin some 700 kilometers upstream from the delta. The basin is a vast floodplain, consisting of about 20 seasonal lakes, freshwater swamp forests and peat swamp forests which local people call Lebak lebung (floodplain). Home to a wide variety of wildlife, the national park is the best place to observe activities of the true inhabitants of the Borneo Jungle such as the orangutans, proboscis monkeys, long tailed macaques, and many others in the beautiful setting of a unique lake system.
The area was first gazetted as a Wildlife Reserve in 1982 when it extended over 80,000 hectares, with just under one-third consisting of open water. In 1994 it was enlarged to 132,000 hectares to include extensive tracts of peat swamp forest, and several hill ranges with dry lowland and heath forest (a type of tropical moist forest found in areas with acidic, sandy soils that are extremely nutrient-poor). In April 1994, Lake Sentarum was declared Indonesia’s second Ramsar Wetland of International Importance, thus drawing international attention to this unique area. On 4 February 1999, its status was upgraded to that of national park, however a National Park Authority was only established in 2006.
The lakes in Lake Sentarum park are remarkable for their fish diversity. 240-266 fish species have been identified, including 12-26 new to science. As the lakes measure only 25,000 hectares, this diversity is remarkable when compared to Europe, where a total of only 195 primary freshwater fish are known. In fact, Lake Sentarum harbors one of the world’s most diverse fish fauna of any floodplain lake system. Of the 71 tropical and temperate lakes listed for their biodiversity by World Conservation Monitoring Center (WCMC) in 1992, Lake Sentarum (which is not listed) is surpassed only by Lake Tanganyika and Lake Malawi. LSNP is also the home for two highly popular aquarium fish: the rare and valuable red variety of the endangered Asian Arowana (Scleropaged legendrei) and the Clown Loach Botia or Tiger Botia (Chromobotia macracanthus). The latter is known only to live at Danau Sentarum and several locations in Jambi, Sumatra.
The national park is known to have the largest remaining populations of orangutans (Pongo pygmaeus) and is also considered to have the largest inland population of proboscis monkey (Nasalis larvatus) on the entire Borneo Island. The two families of apes are among 23 endemic fauna that make up 147 mammal species found in the Lake Sentarum Park. There are also 237 bird species recorded including the Storm Stork and Great Argus, and 26 reptile species including the False Gavial and Estuarine Crocodile. The mammals diversity in the national park contribute 29% to the 515 variety of mammals found in Indonesia which is regarded as the largest in the world.
The area of LSNP is also rich in flora diversity. Research revealed that there are a total of 675 species of flora in 97 families found in the national park. From that number, 33 are endemic to Lake Sentarum and 10 are newly discovered species. Most of the vegetation found in Lake Sentarum are unique and have different appearances than those outside of Lake Sentarum. One of the examples is the Dichilante borneesis, which is rare and endemic to the national park and regarded as the missing link between the families of Rubiaceae. Other fascinating feature of the national park is the existence of a type of vegetation endemic to the Amazon Jungle, the Crateva relegiosa, which came to be known to the locas who call these the Pungguk Tree.
Lake Sentarum is dominated by a marked fluctuation in water levels of the lakes and streams. During the highest tide, the lake’s depth can go from 6 to 8 meters. The waters in LSNP are reddish-brown due to the high level of tannin from the decomposing leaves and branches of various trees. The unique water condition and the annual cycle of rising and falling water levels dominate the ecosystem and exert a strong influence on the lives of its people, plants and animals.
Danau Sentarum National Park Office: Jl. C.Oevang Oeray No. 43 Sintang.
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