Sungai Lesan Protected Forest: A Vital Ecosystem for Biodiversity Conservation and Community Livelihoods
5 min read
Sungai Lesan Protected Forest (HLSL) is located within the administrative area of Kelay Subdistrict, Berau Regency, East Kalimantan Province. HLSL is one of the representative lowland tropical forests in Berau Regency, where land cover remains in good condition. This contributes to relatively good hydrological conditions in HLSL, as indicated by consistent water discharge throughout the year, low sedimentation, and a microclimate within normal limits. Although soil fertility in HLSL is relatively low, native vegetation continues to grow well because the nutrient cycle remains intact. HLSL consists predominantly of primary and secondary forests and is rich in various native tree species of Kalimantan. Some tree species that grow in HLSL and also serve as nesting sites for orangutans include Ulin, Meranti, Kayu Arang, Banitan, Bintangur, Jambu-jambu, Kenari, Kacang, Mandarahan, Rengas, Tulang, Rambutan Hutan, Durian Hutan, Empilung, Asam Kandis, Bayur, Pasang, and Putat. In addition, several tree species serve as food sources for orangutans, including Agathis, Bangkirai, Bayur, Durian, Jambu, Jelutung, Kenari, Keranji, Keruing, Manggis Hutan, Medang, Nyato, Rambutan, Petai, Tengkawang, and Ulin.
HLSL is also an important habitat for orangutans (Pongo pygmaeus), with an estimated population of approximately 150 individuals (TNC, 2006) to approximately 176 individuals (OWT, 2015). In addition, HLSL provides habitat for various other important wildlife species, such as the Müller’s gibbon (Hylobates muelleri), Storm’s stork (Ciconia stormi), proboscis monkey (Nasalis larvatus), long-tailed macaque (Macaca fascicularis), black hornbill (Anthracoceros malayanus), water monitor (Varanus salvator), and rhinoceros hornbill (Aceros cassidix).
Approximately 87% of the HLSL area consists of steep to very steep slopes at elevations of 40–430 meters above sea level. It serves an important hydrological and orological function for the surrounding area because it forms the catchment area (DTA) for the Leja, Ngaloi, Long Mahngan, and Ngumjuk rivers, whose waters flow into the Lesan River, then into the Kelay River, and eventually discharge into Tanjung Redeb, Berau Regency. Hydrologically, Sungai Lesan Protected Forest (HLSL) is bordered by two rivers: the Kelay River to the north and the Lesan River to the east. The Kelay River is one of the two main rivers in Berau Regency, with a width of approximately 120 meters and stable water discharge throughout the year. The Lesan River, which is approximately 30 meters wide, is one of the rivers contributing to the Kelay River. Therefore, damage to HLSL would increase sedimentation in the Kelay River, potentially leading to flooding in the city of Tanjung Redeb.
Access to HLSL is possible through four main routes: (1) Lesan Dayak (land and river routes), (2) Sidobangen (land route), (3) Merapun (land route), and (4) Muara Lesan (river route). HLSL can be reached by land transportation followed by river transportation. The land journey from Tanjung Redeb, the capital of Berau Regency, to the Kelay Subdistrict office covers approximately 110 km and takes around two hours. The journey then continues by land to Lesan Dayak Village, taking approximately 30 minutes. From Lesan Dayak, the research station in HLSL can be reached by river in approximately 30 minutes.
As one of the protected forest areas in Berau Regency, HLSL has many important values, including:
HLSL has become a conservation icon for Berau Regency and has attracted international attention.
Human–orangutan conflict is a sensitive issue that serves as an indicator of our concern for nature protection. This issue has been used by certain groups as an important reason to boycott Indonesian palm oil products.
In fact, HLSL is one of the relatively intact forests remaining in the region. Its existence is important not only for ecological balance, which supports the long-term sustainability of oil palm plantations, but also for its social and cultural value to local communities.
HLSL is an important orangutan habitat and has relatively high biodiversity, comprising native flora and fauna of Kalimantan, making it an important source of genetic resources.
HLSL is located near the border between Berau Regency and East Kutai Regency, which is also known for its forest area, the Wehea Forest Complex, an orangutan habitat. Historically and in terms of ecological landscape, HLSL and the Wehea Forest Complex form a single ecosystem, which is currently separated by the Trans-Kalimantan road (the Samarinda–Berau route) and the administrative boundary between the two regencies.
HLSL has the potential to become an ecotourism destination connected to marine tourism in Derawan and other marine and terrestrial tourism destinations in Berau Regency. A survey on the potential development of ecotourism in HLSL has been conducted, including efforts to establish a connection with Operation Wallacea Ltd. (Opwall), an international ecotourism operator. This is demonstrated by HLSL’s inclusion in the list of scientific ecotourism destinations on the Opwall website.
HLSL, located in the Kelay River Basin, has a relatively high erosion risk and serves as a catchment area and flood-control area for downstream regions, including Tanjung Redeb, the economic center and administrative capital of Berau Regency. Therefore, damage to HLSL would increase sedimentation and the risk of flooding downstream, including in Tanjung Redeb.
HLSL is highly suitable as a research site for studying the biodiversity of flora and fauna.
Developing HLSL as a tourism and research destination would have a positive impact on the local economy by encouraging the growth of transportation services and tour guides, homestay businesses, handicraft and merchandise businesses, food services such as eateries, and other related businesses.
Human–orangutan conflict is a sensitive issue that serves as an indicator of concern for nature protection. This issue has been used by certain groups as an important reason to boycott Indonesian palm oil products.
In fact, HLSL is one of the relatively intact forests remaining in the region. Its existence is important not only for ecological balance, which supports the long-term sustainability of oil palm plantations, but also for its social and cultural value to local communities. HLSL has been a source of livelihood for surrounding communities, particularly through the use of non-timber forest products, such as honey, agarwood, rattan, damar resin, klepiai (a type of resin), nius leaves (palm leaves), fish, hunted wildlife, and other resources.
HLSL has a substantial carbon stock, reaching approximately 2,296,558, equivalent to 8,420,714 tons of CO₂ equivalent (OWT, 2019). Therefore, maintaining the sustainability of the HLSL ecosystem will contribute to emission reduction efforts, particularly in Berau Regency.
As a forested area, HLSL supports high insect diversity, which is highly beneficial as a pollination agent for various plants in and around the forest, including oil palm plantation crops. Therefore, clearing HLSL would reduce the number of insect pollinators and could lead to crop cultivation failures in plantation areas.
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