Tropical Rainforest Heritage of Sumatra
Country
Indonesia
Inscribed in
2004
Criteria
(vii)
(ix)
(x)
The conservation outlook for this site has been assessed as "critical" in the latest assessment cycle. Explore the Conservation Outlook Assessment for the site below. You have the option to access the summary, or the detailed assessment.
The 2.5 million hectare Tropical Rainforest Heritage of Sumatra site comprises three national parks: Gunung Leuser National Park, Kerinci Seblat National Park and Bukit Barisan Selatan National Park. The site holds the greatest potential for long-term conservation of the distinctive and diverse biota of Sumatra, including many endangered species. The protected area is home to an estimated 10,000 plant species, including 17 endemic genera; more than 200 mammal species; and some 580 bird species of which 465 are resident and 21 are endemic. Of the mammal species, 22 are Asian, not found elsewhere in the archipelago and 15 are confined to the Indonesian region, including the endemic Sumatran orang-utan. The site also provides biogeographic evidence of the evolution of the island. © UNESCO
Summary
2025 Conservation Outlook
Finalised on
11 Oct 2025
Critical
Current state and trend of VALUES
High Concern
Overall THREATS
Overall PROTECTION and MANAGEMENT
Full assessment
Description of values
Exceptional scenic landscapes at all scales
Criterion
(vii)
The three national parks that comprise the Tropical Rainforest Heritage of Sumatra (TRHS): Gunung Leuser (GLNP), Kerinci Seblat (KSNP) and Bukit Barisan Selatan (BBSNP), are all located on the prominent main spine of the Bukit Barisan Mountains, known as the ‘Andes of Sumatra’. The mountains of the site, many of which descend into the sea, present prominent backdrops to the mostly settled and developed lowlands of Sumatra. The combination of the spectacularly beautiful Lake Gunung Tujuh (the highest lake in Southeast Asia), the magnificence of the giant Mount Kerinci volcano, numerous small volcanic, coastal and glacial lakes in natural forested settings, fumaroles belching smoke from forested mountains, montane peat swamps, and numerous waterfalls and cave systems in lush rainforest settings, emphasise the outstanding beauty of the TRHS (adapted from IUCN, 2004 & World Heritage Committee, 2013).
Outstanding examples of forest on the island of Sumatra for the conservation of the biodiversity of both lowland and mountain forest ecological processes.
Criterion
(ix)
Indonesia’s extraordinary biological richness is the reason why it is one of only seven megabiodiverse countries in the world. As one of Indonesia’s largest islands, Sumatra possesses globally exceptional forest biodiversity yet its tropical rainforests have been reduced to isolated remnants over the past 50 years. It is in this context that the site, which protects some of the most important remnant forest on Sumatra, is of outstanding universal value. Both GLNP and BBSNP extend from the highest mountains on Sumatra to sea level. All three components of TRHS exhibit wide altitudinal zonation of vegetation, from lowland rainforest to montane forest, extending to sub-alpine low forest, scrub and shrub thickets and covering an astounding diversity of ecosystems. The Leuser Ecosystem, including the GLNP, is by far the largest and most significant forest remnant remaining in Sumatra. All three components of the TRHS would have been important climatic refugia for species over evolutionary time and have now become critically important refugia for future evolutionary processes (adapted from IUCN, 2004 & World Heritage Committee, 2013).
Important and significant natural habitats for in-situ conservation of biological diversity of plant and animal species
Criterion
(x)
All three components of the site are areas of very diverse habitat and exceptional biodiversity. Collectively, the three parks include more than 50% of the total plant diversity of Sumatra. There are an estimated 10,000 species of plants, including 17 endemic genera. Animal diversity in TRHS is also impressive, with 201 mammal species and some 580 species of birds, of which 465 are resident and 21 are endemics. At least 92 locally endemic species have been identified in GLNP. The site contains relict lowland forests which are very important for conservation of the plant and animal biodiversity of the rapidly disappearing lowland forests of Southeast Asia. Similarly, the montane forests, although less threatened, are very important for conservation of the distinctive montane vegetation of the TRHS (adapted from IUCN, 2004 & World Heritage Committee, 2013).
A critical habitat refuge for several globally significant and endangered species
Criterion
(x)
The site holds the greatest potential for long-term conservation of the distinctive and diverse biota of Sumatra, including many endangered species. Of the mammal species, 22 are Asian, not found elsewhere in the archipelago and 15 are confined to the Indonesian region, including the endemic Sumatran orangutan. Key mammal species also include the Sumatran tiger, rhino, elephant and Malayan sun-bear. The site also contains populations of both the world’s largest flower (Rafflesia arnoldii) and the world’s tallest flower (Amorphophallus titanum) (adapted from IUCN, 2004 & World Heritage Committee, 2013).
Watershed values
The Rimba Karya Indah ‘finger’, which is surrounded on three sides by the property and has been repeatedly recommended for urgent inclusion in KSNP, for the first time by the World Bank in 2002, due to biodiversity and watershed protection values (IUCN, 2012), has been declared a Watershed Protection Forest (IUCN Consultation, 2014).
Assessment information
The State Party of Indonesia with the support of its conservation partners has made continued positive efforts to address the key threats to the WH property. This includes retaining the moratorium on new forest concessions, implementing forest restoration activities and ecosystem recovery plans including through engaging communities. EIAs and EMPs for road upgrades within the property were undertaken following the interventions by the WH Committee, and the activities either paused or leading to Indonesia expressing its commitment to fully implement all relevant mitigation measures. Compliance with the Committee requests concerning activities outside of the property boundaries however is much weaker, for example there remains concerns for the potential impacts of the Trans-Sumatran Highway that would run through the Leuser Ecosystem (KEL), an area important for the integrity of GLNP component of the property. The rate and extent of forest loss due to logging and agricultural encroachment appears to be declining, but this requires continuous vigilance particularly around the periphery and lowland areas of the property, combined with ongoing restoration efforts. Comprehensive data for key mammal species continue to be lacking though the anti-poaching efforts appear to be leading to a stabilisation of the Sumatran tiger populations, whilst the Sumatran elephant and rhino population appear to still be declining.
Invasive / Other Problematic Species, Genes & Pathogens, Invasive Non-Native/ Alien Species, Problematic Native Species
(Invasive native and non-native plants)
Invasive/problematic species
Lantana camara
Merremia peltata
Inside site
, Localised(<5%)
Merremia peltata (locally known as mantangan) is an invasive native plant is estimated to cover 22,000 ha (22%) of Bukit Barisan Selatan National Park (BBSNP) component of the WH property (State Party of Indonesia, 2020), literally suffocating the forests. A 2018-2022 Ecosystem Restoration Plan is being implemented by the Park Authorities in collaboration with local communities to control the spread of this invasive plant, and in 2023, the State Party of Indonesia reported that more than 80,000 ha of degraded areas within the park were rehabilitated in the past 10 years (State Party, 2023). The species was also previously reported in areas adjoining Kerinci Seblat National Park (KSNP), which raises concern for potential spread into the property (IUCN Consultation, 2017) but there appears to be no systematic data collection for the property to determine the current picture of the species coverage across the property. Lantana camara has also been reported in BBSNP though the extent of spread unclear (IUCN, 2018).
Roads, Trails & Railroads
(Roads)
Inside site
, Scattered(5-15%)
Outside site
The impact of existing and proposed roads was already identified as a threat at the time of inscription (IUCN, 2004) and has been examined by the Committee annually ever since. Roads through the property and adjacent to it provide access for poaching, illegal logging and encroachment, so constitute a major threat. In 2017 the State Party completed an SEA for road network in the Bukit Barisan Mountain Range, which concluded that road development within the property would likely have a direct negative impact on the OUV, causing "unacceptable habitat loss and biodiversity conflict" (UNESCO, 2017). The 2023 SEA undertaken for the property identified road networks (as well as energy, telecommunication and railway networks) to be posing a threat in all three components of the property across all the inscription criteria, and recommended that no new permits should be issued within the core conservation and forest zones of the property, as well as in primary and secondary dryland forest and swamp forest in the property, its buffer zone or areas in the wider setting of the property (Ministry of Environment and Forestry, 2023).
Concerning specific projects, the Karo-Langkat road upgrade through GLNP was noted by the 2018 IUCN mission, and following concerns raised by the WH Committee, the State Party completed an EIA and EMP, and committed to the full implementation of the mitigation measures (State Party of Indonesia, 2022, 2024, 2025). The road is within the Sumatran organgutan habitat range so one of the concerns relate to their habitat fragmentation. The expansion of Bukit Tapan-Sungai Penuh road widening was also noted in the 2018 IUCN mission report to have started without an EIA, and following the WH Committee's concerns, an EIA was developed (State Party of Indonesia, 2024), though leaving gaps in terms of the scientific underpinning of the mitigation measures on their adequacy to fully mitigate the impacts on the OUV.
The proposed Trans-Sumatran Highway would be located outside of the property, at approximately 6-8 km away from the boundary of GLNP. Whilst not crossing the property itself, the highway is within the wider Leuser Ecosystem Area (KEL) which is vital for the protection of the integrity of GLNP. The WH Committee has raised concerns on a number of occasions and has requested Indonesia to assess the potential impacts on the OUV, but it appears no progress has been made by Indonesia to examine potential connections to the protection of the property, and has not been included as part of the SEA (State Party of Indonesia, 2025; Ministry of Environment and Forestry, 2023).
Concerning specific projects, the Karo-Langkat road upgrade through GLNP was noted by the 2018 IUCN mission, and following concerns raised by the WH Committee, the State Party completed an EIA and EMP, and committed to the full implementation of the mitigation measures (State Party of Indonesia, 2022, 2024, 2025). The road is within the Sumatran organgutan habitat range so one of the concerns relate to their habitat fragmentation. The expansion of Bukit Tapan-Sungai Penuh road widening was also noted in the 2018 IUCN mission report to have started without an EIA, and following the WH Committee's concerns, an EIA was developed (State Party of Indonesia, 2024), though leaving gaps in terms of the scientific underpinning of the mitigation measures on their adequacy to fully mitigate the impacts on the OUV.
The proposed Trans-Sumatran Highway would be located outside of the property, at approximately 6-8 km away from the boundary of GLNP. Whilst not crossing the property itself, the highway is within the wider Leuser Ecosystem Area (KEL) which is vital for the protection of the integrity of GLNP. The WH Committee has raised concerns on a number of occasions and has requested Indonesia to assess the potential impacts on the OUV, but it appears no progress has been made by Indonesia to examine potential connections to the protection of the property, and has not been included as part of the SEA (State Party of Indonesia, 2025; Ministry of Environment and Forestry, 2023).
Biological Resource Use, Logging, Harvesting & Controlling Trees
(Poaching)
Other targeted species names
Panthera tigris sumatrae; Elephas maximus sumatrensis; Pongo abeii; Dicerorhinus sumatrensis
Inside site
, Widespread(15-50%)
Outside site
There are conflicting information on the extent of poaching but overall, it appears that poaching is more prevalent around the boundaries of the property in more accessible areas (State Party of Indonesia, 2020). The State Party has made significant efforts to implement SMART patrols across the property over the last decade, increasing 20-fold between 2013 and 2017 in GLNP and BBSNP (IUCN, 2018), and continued efforts to date. The number of poachers successfully apprehended also increased during this period, although the numbers still remained substantially lower than the number of poaching incidents detected. Poaching of Sumatran tiger in KSNP rose dramatically between 2012 and 2015 following a 400% rise in blackmarket prices for tiger body parts in that same period. Prices went down again since 2015, and the poaching threat to tigers has been falling since 2016. Low encounter rates, limited spatial coverage of surveys and therefore the resultant large margins of error for the Sumatran tiger mean that no trend can be obtained but it appears their population is stable (IUCN, 2024). Population numbers and range occupancy for rhino and elephant on the other hand continue to decline (IUCN, 2024), and much effort is still needed to ensure patrol coverage across the whole property. A new monitoring guideline developed for the property in 2024 aims to standardise data collection and reporting (State Party of Indonesia, 2025), and should help in obtaining clearer datasets and trends for these emblematic species for the property.
Logging, Harvesting & Controlling Trees
(Logging and land conversion (plantation and agriculture))
Inside site
, Scattered(5-15%)
Outside site
Forest loss due to encroachment and land conversion remains one of the pressing concerns for the protection of the property. Indonesia has continued to make considerable efforts to address the threat including through forest restoration activities, strengthening community engagement in the forest restoration, retaining the moratorium on new forest concessions, and continuing monitoring and patrolling (State Party of Indonesia, 2024). An ecosystem recovery plan (2019-2023) for each of the national park components of the property were developed and implemented, leading to an estimated area of 12,000 ha of degraded forest being restored over the decade to 2023. Indonesia reports forest loss to have relatively stabilised between the period 2011 to 2022 (State Party of Indonesia, 2024) but no data have been shared to demonstrate this. On the other hand, according to the 2023 SEA for the property, there was considerable increase in land cover change for mixed dry land agriculture between 2003 and 2022 (Ministry of Environment and Forestry, 2023). The 2024 IUCN mission noted that rate of forest cover loss appears to be declining, but that it continues to be observed around the fringes of the property.
The landscape context of the property is critical to its survival, yet faces pressures to the wider ecosystem that must be considered to protect its integrity. The Leuser Ecosystem, of which GLNP is a part, has been repeatedly noted as providing critical habitat for globally significant species, however, developments such as the Trans-Sumatran Highway does not appear to be registering as a threat that requires assessment of impact on the OUV. Several mining and hydropower proposals in the Leuser Ecosystem however have been successfully turned down, alleviating potential threats from such developments. Geothermal energy development continues to be a potential threat with some developments near the property previously noted, but no recent information available.
Mining & Quarrying
(Mining/ Quarrying)
Outside site
Mining is not permitted inside national parks and there are no mining concessions or exploration permits with the property, with closure and rehabilitation undertaken for small-scale illegal sites. Outside of the property in the Leuser Ecosystem however, there are reports of mining projects, but which have not yet been carried out (State Party of Indonesia, 2025). The 2023 SEA makes clear that no new permits will be issued within the national parks or in areas with land cover of primary or secondary dryland forest or swamp forest, whether its within the property, its buffer zone or in the wider setting of the property (Ministry of Environment and Forestry, 2023). The SEA also makes recommendation with regards to proposals in buffer zones and the wider setting in that impact mitigation should be conducted for proposals in these areas, especially in relation to tailings storage and water flow considerations.
Renewable Energy
(Proposed geothermal development)
Inside site
, Localised(<5%)
Outside site
Indonesia has ambitious plans for energy development and aims to increase the proportion of new and renewable energy sources from its present 7.7% of total output to 31% by 2050. It considers geothermal energy to be an environmental service (according to a 2016 Ministerial Decree). There had been a proposal to develop a controversial geothermal project at Kappi Plateau inside GLNP but a firm commitment was made at the national and provincial governmental levels to not develop this site.
Indonesia, including through the 2023 SEA refers to geothermal potential as one of the ecosystem services of BBSNP (Ministry of Environment and Forestry, 2023). The 2024 IUCN mission noted the government's national drive to expand geothermal power generation with potential implications for the property, though any developments within the property are reported to have been "so far successfully resisted" (IUCN, 2024). Mining projects in the wider Leuser Ecosystem have been proposed, which has not yet moved to implementation (State Party of Indonesia, 2025).
In the past there have been a number of occasions that geothermal development proposed adjacent to BBSNP was discussed by the WH Committee, including calling for an EIA that addresses potential impacts on the OUV of the property to be submitted for review (World Heritage Committee, 2015, 2016), but the State Party of Indonesia did not adequately respond to this request on the grounds that the development is not located within the property. An online report indicated that the proposal adjacent to BBSNP was proceeding, with maps showing the project’s proximity to the property and tiger habitat (PTT Greencap, 2017) but no recent information is available. Other proposals outside but in close vicinity of the property have also ben reported such as in an area immediately adjoining KSNP in Solok Selatan, West Sumatra Province. Exploration for geothermal is also reported to have been conducted in the Merangin and Kerinci areas of KSNP, and a geothermal contractor is said to have requested permission to conduct test drilling in a site bordering KSNP.
Indonesia, including through the 2023 SEA refers to geothermal potential as one of the ecosystem services of BBSNP (Ministry of Environment and Forestry, 2023). The 2024 IUCN mission noted the government's national drive to expand geothermal power generation with potential implications for the property, though any developments within the property are reported to have been "so far successfully resisted" (IUCN, 2024). Mining projects in the wider Leuser Ecosystem have been proposed, which has not yet moved to implementation (State Party of Indonesia, 2025).
In the past there have been a number of occasions that geothermal development proposed adjacent to BBSNP was discussed by the WH Committee, including calling for an EIA that addresses potential impacts on the OUV of the property to be submitted for review (World Heritage Committee, 2015, 2016), but the State Party of Indonesia did not adequately respond to this request on the grounds that the development is not located within the property. An online report indicated that the proposal adjacent to BBSNP was proceeding, with maps showing the project’s proximity to the property and tiger habitat (PTT Greencap, 2017) but no recent information is available. Other proposals outside but in close vicinity of the property have also ben reported such as in an area immediately adjoining KSNP in Solok Selatan, West Sumatra Province. Exploration for geothermal is also reported to have been conducted in the Merangin and Kerinci areas of KSNP, and a geothermal contractor is said to have requested permission to conduct test drilling in a site bordering KSNP.
Involvement of stakeholders and rightsholders, including indigenous peoples and local communities, in decision-making processes
Collaboration between managers and NGOs on patrols and community liaison are frequent but there appear to be no structured, transparent means for stakeholders to have input into the broader management of the property. The three PAs have rights-based systems in place, such as FPIC processes, that are part of their respective Environmental and Social Management Plans
Legal framework
The three components of the property are designated as national parks by the Government of Indonesia and receive the appropriate level of legal protection.
Governance arrangements
The property continues to face threats of infrastructure developments within and around the property, pointing to governance issues. However, recent examples of permissions not being granted for hydropower dams and mining in the Leuser Ecosystem, outside of the property, due to rejections from NGOs and decisions being taken by Court ruling indicates that there is a mechanism to consider inputs from stakeholders and there are multiple levels of decision-making. The continuation of the moratorium on new forest concessions, and cancellation of new road developments in line with the Committee decisions have been effective.
Integration into local, regional and national planning systems (including sea/landscape connectivity)
The boundaries of the property are not well known by local communities and landowners which contributes to the encroachment challenges.
Boundaries
Confused boundaries occur throughout the site, both on paper and on the ground. Furthermore, some official boundary changes have occurred since the inscription of the property on the WH List in 2004. The 2018 mission observed that these new boundaries imply a 4% reduction in the area of GLNP and a 12% reduction at BBSNP compared with the areas inscribed on the WH List. Additional confusion arises from the 2004 nomination dossier itself which includes different version of boundary maps. The Committee had long requested the State Party to incorporate key habitats of important species (World Heritage Committee, 2009), and had also requested the State Party to consider expanding GLNP to include the Leuser Ecosystem (World Heritage Committee, 2018), but the State Party announced that a decision had been taken not to expand the boundaries into the Leuser Ecosystem (State Party of Indonesia, 2019). In order to reflect other areas of important conservation values and to remove severely degraded areas, the State Party submitted a Significant Boundary Modification request in January 2025, which will be examined by the Committee in due course.
Overlapping international designations
The World Heritage property comprises Gunung Leuser National Park, which is the core area of the Gunung Leuser Biosphere Reserve (1981). The Kerinci Seblat National Park appears to overlaps with the UNESCO Global Geopark Merangin Jambi (2023). No information has been found on the level of coordination between management authorities of these different designations.
Implementation of World Heritage Committee decisions and recommendations
The State Party has mostly responded to the Committee's decisions albeit with slow progress. Inscription of the property on the List of World Heritage in Danger mobilised greater attention but the DSOCR indicators are yet to be met. The State Party is reactive to Committee Decisions, and has undertaken EIAs for road projects, and now completed the SEA, which is very positive. Achieving effective outcomes however remains a challenge however (e.g. species recovery and halting forest loss). The Committee Decisions which the State Party has not responded adequately to however, concern those developments that are located outside of the property, but which may negatively impact on the OUV e.g. Trans-Sumatran Highway and geothermal development.
Climate action
The property faces drought and wildfires to some extent but impact appears to be limited for the time being. The management plan does not include specific provisions to protect the OUV from any future impacts from climate change, and therefore is a gap that will need to be filled.
Management plan and overall management system
The three components have separate management plans, and there are finally indication that the State Party will develop an Integrated Management Plan for the entire property (State Party of Indonesia, 2025). The management plans and systems for each national park have not in themselves contributed to the exclusion of inappropriate developments. Whilst new roads have not been developed within the property and any large infrastructure projects such as dams or geothermal power have not been permitted within the property, these decisions were not due to the management plans. Therefore they appear ineffective in integrating into the local systems. Nonetheless, the management plans have likely guided the recently seen increase in monitoring and patrol efforts that have seen a decline in illegal activities.
Law enforcement
Patrol efforts have been significantly increased in recent times, but these are continuing to result in only a few arrests and prosecutions. In KSNP in 2019 for example, 1260 illegal activities were detected but only 4 individuals were sentenced (4 ongoing) for illegal logging and poaching/trade. The 2017 State Party report says “prosecution to encroachers have not been done properly, the data from 2013 to 2016 showed that only 17 people were brought to legal process”. The report documents only 24 arrests from 2,377 illegal incidents, an alarming failure to enforce critical protective laws. The responsibility for law enforcement lies with the Directorate General of Law Enforcement, which has its Sumatra office in Medan, and which has no representative staff within the management offices of the property (IUCN Consultation, 2017). The State Party’s central government should be driving a concerted effort to overcome this critical inadequacy in the management of the TRHS.
Sustainable finance
According to the 2023 Periodic Report, which is the State Party's self-assessment, the available budget is reportedly adequate for effective management of the property, and the existing sources of funding are secure over both the medium- and long-term. However, the State Party also notes that there are major deficiencies in capacity/resources to enforce legislations and regulations in the property.
Staff capacity, training and development
Patrol efforts has continued to increase, and the engagement with local communities contributes towards the monitoring and law enforcement efforts. Further efforts are needed nonetheless to lower the levels of forest loss and poaching. The State Party reports through its 2023 Periodic Report that human resources are inadequate for management needs, scoring particularly low in relation to responding to risk preparedness, and no capacity development opportunities available.
Education and interpretation programmes
Forest restoration activities have been undertaken through strengthening engagement with communities, some of whom would have previously been involved in encroachment (State Party of Indonesia, 2024). The State Party has also reported progress to increase public awareness through education and information dissemination including exposure to NTFP management through print and electronic media and school visits (State Party of Indonesia, 2020). However, the State Party also reports that the OUV of the property is not adequately presented and interpreted (State Party of Indonesia, 2023).
Tourism and visitation management
Zonation schemes within the property are defined, such that tourism in the core zone is supposed to be highly regulated. However, visitor use of the property is not being actively managed despite an identified need and there is no strategy to manage visitors, tourism activities and its derived impacts on the property (State Party of Indonesia, 2023). The 2018 IUCN mission reported that waste management for the route around Lake Tujuh needed significant efforts. There is also no contact between the tourism industry and the management authorities of the property, and the park entry fees do not contribute to the management of the property (State Party of Indonesia, 2023).
Sustainable use
Poaching and illegal logging continues to be reported in the property, although the rates appear to be decreasing. Both directly impact negatively on the OUV of the property and therefore measures to control and reduce the current unsustainable use of resources needs to be implemented in the long-term. Geothermal energy development in the areas around the property also poses a threat on the property itself.
Monitoring
The 4 flagship mammalian species (Sumatran elephant, rhino, tiger and orangutan) are being monitored regularly, including in partnership with conservation organisations, to assess their conservation status. Forest habitat monitoring is regularly conducted using satellite imagery to a high standard. Standardised methods are being applied for each species across the three components of the property, and including through enhanced patrols, the State Party is continuing to enhance the monitoring of the property.
Research
Targeted research programme for an adaptive management approach does not exist specifically, however a Coordination Team for the management of the Tropical Rainforest Heritage of Sumatra provides direct support from the central government and there could therefore be potential under this framing.
Effectiveness of management system and governance in addressing threats outside the site
The WH status does not appear to influence activities located outside of the property, and Committee decisions that request the State Party to consider impacts on the OUV for those proposals are frequently not considered.
Effectiveness of management system and governance in addressing threats inside the site
Several infrastructure developments that were proposed inside the property have not been permitted due to WH status and therefore the governance appears to be effective. However, illegal activities such as poaching and illegal logging within the property has been a major challenge for the State Party to bring under control in spite of the significant efforts made.
This serial property faces many challenges, but some improvements can be seen. Management has been undertaken on a park-by-park basis to date, and there are indications the State Party is at long last developing an Integrated Management Plan for the whole property. Boundaries of the property have been unclear and lack on-the-ground demarcation, but this should in part be clarified through the Significant Boundary Modification, though the demarcation on the ground will continue to be confusing due to the differences to the domestic national park boundaries. Patrolling and monitoring efforts have been enhanced but human and financial resources continue to be inadequate for the management needs and to enforce the legislations. Marked efforts are needed to enhance the tourism and visitation management as this is severely lacking at present. A major gap remains in terms of management system and governance in addressing threats outside of the property as the State Party at present is unable to respond to Committee requests that asks for World Heritage consideration for development proposals that are located outside the property boundaries but have the potential to negatively impact on the OUV.
Good practice examples
The development and implementation of Environmental and Social Management Plans, and associated instruments, in the three PAs is a good practice example for other PAs in Indonesia to follow. The use of SMART patrol systems and well-trained ranger teams, including in human rights, are noteworthy models for the PAs in the region.
Exceptional scenic landscapes at all scales
High Concern
Trend
Deteriorating
Large-scale and widespread encroachment coupled with an opening up of forest areas through illegal logging threaten the integrity of the aesthetic beauty of this property which acts as a backdrop to the lowlands of Sumatra. The undertaking of the State Party not to approve new roads within the property is positive but should be enshrined in a legal instrument. Invasive species continues to impact the property.
Outstanding examples of forest on the island of Sumatra for the conservation of the biodiversity of both lowland and mountain forest ecological processes.
High Concern
Trend
Deteriorating
Most of the threats identified above affect lowland forest. This includes threats from illegal logging, encroachment, proposed geothermal developments and proposed dams. Mountain ecosystems are less affected as it is more difficult to access, and the land is naturally less suited for agricultural purposes, although a growing national and international demand for Arabica coffee appears to have potential to impact on upper hill and montane forests. Poor management capacity coupled with ineffective integration with local development planning is limiting the capacity of park authorities to manage these threats.
Important and significant natural habitats for in-situ conservation of biological diversity of plant and animal species
High Concern
Trend
Deteriorating
Forest loss remains a key concern, with considerable change from primary and secondary dryland forest cover to agriculture (Ministry of Environment and Forestry, 2023). However forest loss has declined significantly in the last few years. It is positive that new road developments have not been permitted and the moratorium on new forest concessions remain in place, and that the State Party commits to not permitting any mining within the property. Proposals for road upgrades do appear however, as do hydropower and mining projects outside of the property (which were recently rejected) - these cases should be communicated strongly to the relevant provincial authorities and developers. The Trans-Sumatran Highway in the Leuser Ecosystem, even if outside of the property, raises concerns in the absence of the State Party's willingness to consider potential impacts on the OUV and could exacerbate the fragmentation of the forest and the habitat of critically endangered species.
A critical habitat refuge for several globally significant and endangered species
High Concern
Trend
Deteriorating
While the population of the Sumatran tiger appears to have stabilised, the population of Sumatran rhino and elephant continue to decline. The number of arrests and sentencing remains low, raising concern about whether law enforcement is able to keep pace with environmental crime, whilst also noting that in the cases of organised crimes comprising only a small number of individuals but responsible for large number of activities such data may be misleading. Poaching is facilitated by access so encroachment around the periphery of the property exacerbates this situation. Positive actions have been taken such as increase in patrols; plans to develop and Integrated Management Plan for the property, and if effectively implemented the 2023 SEA recommendations will go a long way. A concerted effort on law enforcement remains essential, including by posting officers of the Directorate General of Law Enforcement at the national park management offices, and by providing the national parks with a budget for law enforcement.
Assessment of the current state and trend of World Heritage values
Deteriorating
Although the property continues to face threats and requires improvements to its protection and management, the values of the property are still present. That said, many of the flagship species remain vulnerable in terms of their long-term viability and external development pressures are adversely impacting their prospects. Encroachment, roads, wildlife poaching and illegal logging continue to pose major threats to the property, though rate of forest lost has significantly reduced. The inscription of the TRHS on the List of World Heritage in Danger seems to have created a momentum to address the range of issues in a longer-term and more comprehensive manner, such as a massive increase in patrols. Unfortunately, such measures have not been accompanied by an improvement in law enforcement; a concerted effort is required on this front to prevent permanent loss of OUV and integrity. Similarly, the continued loss of forest must be halted and reversed in order to meet the requirements of the DSOCR - there remains large areas of significantly degraded areas. The broader landscape of the property continues to suffer from environmental pressure which have the potential to impact on the OUV. It is difficult to assess the overall status of the flagship species as comprehensive data is not available, though this may change with the new 2024 monitoring guideline. The outstanding qualities of the TRHS, though damaged, nevertheless remain. It is still an exceptionally beautiful landscape of mountains, rainforest and rivers, with extraordinary wild animals. Nevertheless, a concerted effort from the State Party and the international community remains essential to protect the property’s OUV.
Assessment of the current state and trend of other important biodiversity values
Data Deficient
Data Deficient
There is insufficient data on the status and trend of the other species.
Additional information
Water provision (importance for water quantity and quality)
The Leuser Ecosystem provides many environmental services to the surrounding region – valued at 400 million dollars per year. For instance, the water from the Leuser Ecosystem supports some 4 million people. An assessment of ecosystem services (water) from KSNP forests to the municipality of Sungaipenuh, Kerinci in 2011 valued water services for domestic consumption and rice field irrigation at 1.049 million Euros per year (IUCN Consultation, 2014).
The main threat to the provision of water stems from the illegal conversion of rainforests to industrial plantations, mostly for palm oil, but also for rubber.
Soil stabilisation
The steep slopes in the property experience heavy rainfall throughout the year, and are prone to landslides. Healthy forest cover is critical to stabilising these slopes.
As forests are illegally cut, there is a significant risk for landslides in the exposed areas.
Outdoor recreation and tourism,
Natural beauty and scenery
The property’s exceptional scenery, including the highest lake in Southeast Asia (Lake Gunung Tujuh), as well as its magnificent biodiversity, are of great interest to domestic and international tourists alike.
Wilderness and iconic features
The wilderness and natural beauty of the property are attributes that are rare and diminishing in Southeast Asia and the world generally.
The values of TRHS for Sumatra’s scenic amenity, rich assemblages of wildlife and cultural assets should be translated wherever possible into tangible benefits for all stakeholders, particularly local communities. The site’s significant ecotourism potential should be harnessed through a tourism/visitor management plan that allows the fees to be reinvested into the management of the property. The site also provides significant ecosystem services, most notably the provision of valuable water supplies to the surrounding region and the prevention of landslides and flood through retention of forest cover.
| № | Organization | Brief description of Active Projects | Website |
|---|---|---|---|
| 1 | Flora & Fauna International (SE Asia) | Programmes for conservation of Sumatran tigers, orangutans and elephants; global trees campaign; marine conservation; human–wildlife conflict; law-enforcement partnerships; community action in Kerinci. |
http://www.fauna-flora.org/explore/indonesia/
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| 2 | WCS | WCS has continued to work across the different landscapes of Sumatra, including Gunung Leuser National Park and Bukit Barisan Selatan National Park. |
https://indonesia.wcs.org/
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References
| № | References |
|---|---|
| 1 |
HAkA, YEL, Orangutan Information Centre, Sumatran Orangutan Society. (2017a). NGO Consortium Critique of “State of Conservation Status of the World Heritage in Indonesia World Heritage Property: Tropical Rainforest Heritage of Sumatra (N 1167) January 2017”. [Online] Available at: http://www.haka.or.id/?page_id=2451 (Accessed on 2 September 2017).
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| 2 |
HAkA, YEL, Orangutan Information Centre, Sumatran Orangutan Society. (2017b). Sumatran UNESCO World Heritage Site Facing New Wave of Destruction. [Online] Available at: https://www.orangutan.org.au/static/media/uploads/pdf/[pres… (Accessed on 13 September 2017).
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| 3 |
IUCN Consultation. (2013). IUCN World Heritage Confidential Consultation: Tropical Rainforest Heritage of Sumatra, Indonesia.
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| 4 |
IUCN Consultation. (2014). IUCN World Heritage Confidential Consultation: Tropical Rainforest Heritage of Sumatra, Indonesia.
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| 5 |
IUCN Consultation. (2017). IUCN World Heritage Confidential Consultation: Tropical Rainforest Heritage of Sumatra, Indonesia.
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| 6 |
IUCN and UNESCO. (2006). Reactive Monitoring Mission Report Tropical Rainforest Heritage of Sumatra (Indonesia). [Online] Gland, Switzerland and Paris, France: IUCN and UNESCO. Available at: https://whc.unesco.org/en/list/1167/documents/ (Accessed on 16 July 2019).
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| 7 |
IUCN. (2004). World Heritage Nomination – IUCN Technical Evaluation. Tropical Rainforest Heritage of Sumatra, Indonesia, ID No. 1167. [Online] Gland, Switzerland: IUCN. Available at: http://whc.unesco.org/en/list/1167/documents/ (Accessed on 31 August 2017).
http://whc.unesco.org/en/list/1167/documents/ Accessed 4 September 2017 |
| 8 |
IUCN. (2012). Report on the State of Conservation of Tropical Rainforest Heritage of Sumatra, Indonesia. State of Conservation Information System of the World Heritage Centre. [online] St Petersburg: World Heritage Committee. Available at: https://whc.unesco.org/en/documents/116994 (Accessed on 16 July 2019).
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| 9 |
IUCN. (2013). Report on the mission to Jakarta, Indonesia from 24 to 30 October, 2013 regarding the Tropical Rainforest Heritage of Sumatra. [Online] Gland, Switzerland: IUCN. Available at: http://whc.unesco.org/en/list/1167/documents/ (Accessed on 1 September 2017).
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| 10 |
Ministry of Environment and Forestry, Republic of Indonesia (2023) Strategic Environmental Assessment Report, Tropical Rainforest Heritage of Sumatera. Annexed to the 2025 Report of the State Party to the World Heritage Committee on the state of conservation of the Tropical Rainforest Heritage of Sumatra (Indonesia). [Online] Available at: http://whc.unesco.org/en/list/1167/documents/ (Accessed on 21 February 2025).
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| 11 |
Mongabay (2019) Indonesian court cancels dam project in last stronghold of tigers, rhinos. https://news.mongabay.com/2019/09/indonesian-court-cancels-…. (Accessed on 1 May 2020).
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| 12 |
Orangutan Centre. (2017). Tropical Rainforest Heritage of Sumatra – World Heritage Still in Danger. [Online] Available at: http://orangutancentre.org/wp-content/uploads/TRHS_WH_Still… . (Accessed on 13 September 2017).
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| 13 |
PT Greencap NAA Indonesia. (2017). Draft Biodiversity Action Plan (BAP) and Critical Habitat Assessment (CHA). INO: Rantau Dedap Geothermal Power Project (Phase 2). March 2017. [Online] Available at: https://www.adb.org/sites/default/files/project-documents/5… (Accessed on 5 September 2017).
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| 14 |
Setyawati, T., Nando, S., Marthy, W., Andayani, N. and Linkie, M., Planning to remove UNESCO World Heritage Sites in Sumatra from being ‘In Danger’. Animal Conservation, in press.
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| 15 |
Sloan, S., Alamgir, M., Campbell, M. J., Setyawati, T., & Laurance, W. F. (2019). Development corridors and remnant-forest conservation in Sumatra, Indonesia. Tropical Conservation Science, 12, 1-9. doi:10.1177/1940082919889509.
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| 16 |
State Party of Indonesia (2023) Periodic Reporting Cycle 3, Section II. [Online] Available at: http://whc.unesco.org/en/list/1167/documents/ (Accessed on 21 February 2025).
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| 17 |
State Party of Indonesia. (2003). Nomination of the Tropical Rainforest Heritage of Sumatra as a World Heritage Site. [online] Jakarta: The Government of the Republic of Indonesia. [Online] Available at: http://whc.unesco.org/uploads/nominations/1167.pdf (Accessed on 11 September 2017).
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| 18 |
State Party of Indonesia. (2013). Report of the State Party to the World Heritage Committee on the state of conservation of the Tropical Rainforest Heritage of Sumatra (Indonesia). Phnom Penh: The Government of the Republic of Indonesia.
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| 19 |
State Party of Indonesia. (2015). Report of the State Party to the World Heritage Committee on the state of conservation of the Tropical Rainforest Heritage of Sumatra (Indonesia). Bonn, Germany: The Government of the Republic of Indonesia. [Online] Available at:
http://whc.unesco.org/en/list/1167/documents/ (Accessed on 4 September 2017). |
| 20 |
State Party of Indonesia. (2016). Report of the State Party to the World Heritage Committee on the state of conservation of the Tropical Rainforest Heritage of Sumatra (Indonesia). Istanbul, Turkey: The Government of the Republic of Indonesia. [Online] Available at:
http://whc.unesco.org/en/list/1167/documents/ (Accessed on 4 September 2017). |
| 21 |
State Party of Indonesia. (2017). Report of the State Party to the World Heritage Committee on the state of conservation of the Tropical Rainforest Heritage of Sumatra (Indonesia). Krakow, Poland: The Government of the Republic of Indonesia. [Online] Available at:
http://whc.unesco.org/en/list/1167/documents/ (Accessed on 1 September 2017). |
| 22 |
State Party of Indonesia. (2018). Report of the State Party to the World Heritage Committee on the state of conservation of the Tropical Rainforest Heritage of Sumatra (Indonesia). Manama, Bahrain: The Government of the Republic of Indonesia. [Online] Available at: http://whc.unesco.org/en/list/1167/documents/ (Accessed on 1 May 2020).
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| 23 |
State Party of Indonesia. (2019). Report of the State Party to the World Heritage Committee on the state of conservation of the Tropical Rainforest Heritage of Sumatra (Indonesia). Baku, Azerbaijan: The Government of the Republic of Indonesia. [Online] Available at: http://whc.unesco.org/en/list/1167/documents/ (Accessed on 1 May 2020).
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| 24 |
State Party of Indonesia. (2020). Report of the State Party to the World Heritage Committee on the state of conservation of the Tropical Rainforest Heritage of Sumatra (Indonesia). [Online] Available at: http://whc.unesco.org/en/list/1167/documents/ (Accessed on 1 May 2020).
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| 25 |
State Party of Indonesia. (2022). Report of the State Party to the World Heritage Committee on the state of conservation of the Tropical Rainforest Heritage of Sumatra (Indonesia). [Online] Available at: http://whc.unesco.org/en/list/1167/documents/ (Accessed on 21 February 2025).
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| 26 |
State Party of Indonesia. (2023). Report of the State Party to the World Heritage Committee on the state of conservation of the Tropical Rainforest Heritage of Sumatra (Indonesia). [Online] Available at: http://whc.unesco.org/en/list/1167/documents/ (Accessed on 21 February 2025).
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| 27 |
State Party of Indonesia. (2024). Report of the State Party to the World Heritage Committee on the state of conservation of the Tropical Rainforest Heritage of Sumatra (Indonesia). [Online] Available at: http://whc.unesco.org/en/list/1167/documents/ (Accessed on 21 February 2025).
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| 28 |
State Party of Indonesia. (2025). Report of the State Party to the World Heritage Committee on the state of conservation of the Tropical Rainforest Heritage of Sumatra (Indonesia). [Online] Available at: http://whc.unesco.org/en/list/1167/documents/ (Accessed on 21 February 2025).
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| 29 |
Sumatran Orangutan Conservation Programme. (2017). Ketambe. [Online] Available at: http://sumatranorangutan.org/research/ketambe (Accessed on 8 September 2017).
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| 30 |
Teropong. (2016). Konsortium Indonesia-Cina Akan Bangun PLTA di Aceh Selatan. [Online] Available at: http://www.teropongsenayan.com/40765-%C2%AD%E2%80%90konsors… (Accessed on 6 September 2017).
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| 31 |
UNESCO MAB. (2015). Gunung Leuser UNESCO Biosphere Reserve. [Online] Available at: http://www.unesco.org/new/en/natural-sciences/environment/e… (Accessed on 16 July 2019)
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| 32 |
UNESCO. (2005). 7B. State of conservation reports of properties inscribed on the World Heritage List. [Online] Available at: http://whc.unesco.org/archive/2005/whc05-29com-07BReve.pdf (Accessed on 11 September 2017).
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| 33 |
UNESCO. (2013). WHC-13/37.COM/7A.Add. State of conservation of the properties inscribed on the List of World Heritage in Danger. [Online] Available at: http://whc.unesco.org/archive/2013/whc13-37com-7A-Add-en.pdf (Accessed on 4 September 2017).
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| 34 |
UNESCO. (2017a). WHC-17/41.COM/7A.Add. State of conservation of the properties inscribed on the List of World Heritage in Danger. [Online] Available at: http://whc.unesco.org/archive/2017/whc17-41com-7AAdd-en.pdf (Accessed on 5 September 2017).
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| 35 |
UNESCO. (2017b). 41st World Heritage Committee 4 July 2017. [Online] Available at: https://www.youtube.com/watch?v=0wX6Hbg0LHE&index=5&list=PL… (Accessed on 17 July 2019).
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| 36 |
UNESCO. (2017c). Tropical Rainforest Heritage of Sumatra / Maps. [Online] Available at: http://whc.unesco.org/en/list/1167/multiple=1&unique_number… (Accessed on 6 September 2017).
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| 37 |
WWF. (2017). Sumatran Islands Lowland and Montane Forests. [Online] Available at: http://wwf.panda.org/about_our_earth/ecoregions/sumatran_lo… (Accessed on 5 September 2017).
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| 38 |
Wich, S., Riswan, Jenson, J., Refisch, J. and Nellemann, C. (eds.) (2011). Orangutans and the Economics of Sustainable Forest Management in Sumatra. UNEP/GRASP/ PanEco/YEL/ICRAF/GRID-Arendal. [Online] Available at: https://wedocs.unep.org/bitstream/handle/20.500.11822/8027/… (Accessed on 5 September 2017).
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| 39 |
World Heritage Committee. (2004). 28 COM 14B.5 Tropical Rainforest Heritage of Sumatra Statement of Outstanding Universal Value (Indonesia). [online] Suzhou, China: The Government of the Republic of Indonesia, pp.11-12. Available at: https://whc.unesco.org/uploads/nominations/1167.pdf (Accessed on 16 July 2019).
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| 40 |
World Heritage Committee. (2005). Decision 29 COM 7B.9. Tropical Rainforest Heritage Sumatra (Indonesia). [Online] Available at: http://whc.unesco.org/en/decisions/364 (Accessed on 11 September 2017).
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| 41 |
World Heritage Committee. (2007). Decision 31 COM 7B.16. Tropical Rainforest Heritage Sumatra (Indonesia). [Online] Available at: http://whc.unesco.org/en/decisions/1397 (Accessed on 11 September 2017).
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| 42 |
World Heritage Committee. (2009). Decision 33 COM 7B.15. Tropical Rainforest Heritage Sumatra (Indonesia). [Online] Available at: http://whc.unesco.org/en/decisions/1807 (Accessed on 11 September 2017).
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| 43 |
World Heritage Committee. (2010). Decision: 34 COM 7B.14. Tropical Rainforest Heritage Sumatra (Indonesia). [Online] Available at: http://whc.unesco.org/en/decisions/4122 (Accessed on 11 September 2017).
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| 44 |
World Heritage Committee. (2011). Decision: 35 COM 7B.16. Tropical Rainforest Heritage Sumatra (Indonesia). [Online] Available at: http://whc.unesco.org/en/decisions/4424 (Accessed on 11 September 2017).
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| 45 |
World Heritage Committee. (2013a). Decision 37 COM 7A.14. Tropical Rainforest Heritage Sumatra (Indonesia). [Online] Phnom Penh, Cambodia. Available at: http://whc.unesco.org/en/decisions/4993 (Accessed on 2 September 2017).
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| 46 |
World Heritage Committee. (2013b). Statement of Outstanding Universal Value. [Online] Available at: http://whc.unesco.org/archive/2013/whc13-37com-8E-en.pdf (Accessed: 1 September 2017).
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| 47 |
World Heritage Committee. (2014). Decision 38 COM 7A.28. Tropical Rainforest Heritage Sumatra (Indonesia). [Online] Doha, Qatar. Available at: http://whc.unesco.org/en/decisions/5970 (Accessed on 4 September 2017).
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| 48 |
World Heritage Committee. (2015). Decision 39 COM 7A.15. Tropical Rainforest Heritage Sumatra (Indonesia). [Online] Available at: http://whc.unesco.org/en/decisions/6234 (Accessed on 5 September 2017).
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| 49 |
World Heritage Committee. (2016). Decision 40 COM 7A.48. Tropical Rainforest Heritage Sumatra (Indonesia). [Online] Available at: http://whc.unesco.org/en/decisions/6663 (Accessed on 5 September 2017).
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| 50 |
World Heritage Committee. (2017). Decision 41 COM 7A.18. Tropical Rainforest Heritage Sumatra (Indonesia). [Online] Available at: http://whc.unesco.org/en/decisions/6964 (Accessed on 3-8 September 2017).
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| 51 |
World Heritage Committee. (2018). Decision 42 COM 7A.40. Tropical Rainforest Heritage Sumatra (Indonesia). [Online] Available at: http://whc.unesco.org/en/decisions/7213 (Accessed on 1 May 2020).
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| 52 |
World Heritage Committee. (2019). Decision 43 COM 7A.1. Tropical Rainforest Heritage Sumatra (Indonesia). [Online] Available at: http://whc.unesco.org/en/decisions/7422 (Accessed on 1 May 2020).
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| 53 |
World Heritage Committee. (2021). Decision 44 COM 7A.52. Tropical Rainforest Heritage Sumatra (Indonesia). [Online] Available at: http://whc.unesco.org/en/decisions/7714 (Accessed on 21 February 2025).
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| 54 |
World Heritage Committee. (2023). Decision 45 COM 7A.15. Tropical Rainforest Heritage Sumatra (Indonesia). [Online] Available at: http://whc.unesco.org/en/decisions/8128 (Accessed on 21 February 2025).
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| 55 |
World Heritage Committee. (2024). Decision 46 COM 7A.56. Tropical Rainforest Heritage Sumatra (Indonesia). [Online] Available at: http://whc.unesco.org/en/decisions/8525 (Accessed on 21 February 2025).
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