The Dong Phayayan Khao-Yai Forest Complex (14°00’ to 14°33’S, 101°05’ to 103°14’E) is a World Heritage Site consisting of five protected forests in southern east Thailand forms a continuous topographic, climatic and vegetation gradient along some 200 kilometers (km) of hilly escarpment. It contains all the major rainforest habitat types of eastern Thailand and some of the region’s largest remaining populations of many tropical forest species which are under pressure elsewhere.
In south central eastern Thailand 160 km northeast of Bangkok and 15 km north of the town of Prachin Buri. Extends to the Cambodian border. Located between 14° 00’ to 14° 33’S and 101° 05’ to 103°14’E.
Date and History of Establishment
- 1962: Khao Yai National Park established under the National Parks Act B.E.2504 of 1961;
- 1981: Thap Lan National Park established under Act B.E.2504;
- 1982: Pang Sida National Park established under Act B.E.2504;
- 1984: Khao Yai National Park Declared an ASEAN Heritage Park;
- 1996: Ta Phraya National Park established under Act B.E.2504;
- 1996: Dong Yai Wildlife Sanctuary established under the Wild Animals Reservation Protection Act B.E.2503 of 1960 (amended 1992).
- 2005: Inscribed on World Heritage list under Natural Criterion iv.
Total area: 615,500 hectacres (ha):
- Khao Yai National Park (& ASEAN Heritage Park): 216,800 ha
- Thap Lan National Park: 223,600 ha
- Pang Sida National Park: 84,400 ha
- Dong Yai Wildlife Sanctuary: 31,300 ha
State. Administered by the Office of National Parks, Wildlife and Plant Conservation (ONP) and the Office of Wildlife Conservation (OWC) within the Division of Plant Conservation and Protection, under the Division of Laws.
100m to 1,351meters (m) (Khao Rom summit, Khao Yai).
The complex comprises four almost contiguous protected areas running east-west 230 km to the Cambodian border. They are located along and below the Korat Plateau, the southern edge of which is formed by the almost unbroken Phanom Dongrek escarpment. Khao Yai at the west end of the complex is the only mountainous section, with an elevational range between 100 and 1,351 m. It is rugged land with a steep south-facing scarp, at places 500 m high, which dips back gently to the north, and slopes gradually down over the south-east half of the site. Some 7,500 ha lies above 1,000 m. The north side is drained by several tributaries into the Mun River, a tributary of the Mekong River. The southern side is drained via numerous scenic waterfalls and gorges by four main fast-flowing streams into the Prachinburi River. Thap Lan National Park to its east has an elevational range of 100 to 992 m with much of its area lying between 300 and 500 m draining mainly north to the Mun river. Pang Sida National Park lies to its south across a watershed ridge, sloping south. It lies between 70 and 849 m with part of the broad Phanom Dongrak escarpment at its western end. The Ta Phraya National Park (120-562 m) extends out to the east in two physiographic units: north-draining uplands largely between 280 and 300 m, which fall in a 200 m scarp to the lowland valley of the Lam Sathorn river to the east. Nestled between the last three areas and connecting them all is the low hilly Dong Yai Sanctuary (230-685 m) which has a small outlier to its east next to Ta Phraya National Park.
The formation of the escarpment is attributed to long past crustal uptilting. The rugged western half of Khao-Yai Park lies on Permo-Triassic igneous volcanic rocks. To the south and east this is replaced by Jurassic calcareous and micaceous siltstones and sandstones. In the northwest part of Khao Yai there are small areas of limestone karst with steep cliffs, gorges, columns and caves. All of Thap Lan as far as upland Ta Phraya is the rim of the quartz-rich sandstone Korat Plateau edged by the Phanom Dongrek range and escarpment. This is broadest in the west, covering large areas of the three western parks but narrows and steepens in the east. Lowlands south of and below the Phanom Dongrak scarp are composed of quaternary colluvial deposits of rocks, sandy gravels and clays.
The annual rainfall over the complex falls from 2,270 millimeters (mm) in Khao-Yai Park in the west to under 1,000 mm in the east, mainly during the southwest monsoon between May and October. Higher elevations and south-facing slopes receive more rain. The north slopes are on the edge of Thailand’s drier north-east. The area has an average annual temperature of 23 degrees Celsius (°C). There is a long dry season between November to April when the moist evergreen forests retain their humidity but which favors the growth of dry open forest towards the east and on northern slopes.
The complex is in the biogeographical Thailandian Monsoon Forest on the border of the Indochinese Rainforest region and a Conservation International Hotspot. It is also World Wildlife Fund (WWF) Global 200 Ecoregion 35 (Tropical & Subtropical Moist Broadleaf Forest) and Ecoregion 54 (Indochina Dry Forests). No other protected area within this region has so well defined an east-west climatic and vegetation gradient. This could prove an informative datum during the current period of climatic change. It contains the seven major rainforest habitat types of eastern Thailand and at least 2,500 plant species are recorded, 16 being endemic. Within the area three main types of vegetation are dominant: evergreen forests (73,8% of all five reserves), mixed dipterocarp/deciduous forest (5.3%) and deforested scrub, grassland and secondary growth (18%). The first two categories, with karst and riverine ecosystems, comprise the most significant habitats. The evergreen forests are of three types: dry (28.7%), tropical rainforest above 600 m (25.8%) and hill and lower montane rainforests (19.3%). They provide a wide range of ecosystems and habitats. The dipterocarp/deciduous mixed forests provide a similarly wide range but in drier fire-prone areas with sandy soils. The drier areas include dry dipterocarp forest and grassland as well as mixed forests. The small area of karst in the north-west has distinctive microhabitats. Riverine ecosystems wind through the other forests with distinct features and limited habitats such as cascades, waterfalls and deep pools.
84% of Khao-Yai Park is covered in evergreen or semi-evergreen forest, much of it tall good quality primary forest though there are some logged lowland areas. The Park contains over 2,000 plant species including the valuable incense and medicinal aloewood or Aquilaria crassna (krisana). Moist and dry evergreen forests also occur in the other protected areas: 59% of Thap Lan, 86.5% of Pang Sida, 72.45% of Ta Phraya and 70.6% of Dong-Yai. A high proportion (32%) of Thap Lan has been degraded, mostly dry dipterocarp forest cleared for agriculture and tree plantations. It also has some 700 hectares of the fan-leaved corypha or talipot palm Corypha umbraculifera, on the leaves of which Buddhist sermons were originally inscribed. Notable trees include Adina cordifolia, Afzelia xylocarpa, Anogeisus cuminate, Lagerstroemia calyculata, Pterocarpus macrocarpus and Pterocymbium javanicum. Pang Sida has wide south-facing hill-slope habitats. There are also extensive areas of bamboo forest. In Ta Phraya 25% and in Dong-Yai almost 20% of the land is grassland or scrub.
The complex contains more than 800 species of fauna and protects some of the largest remaining populations in the region of many tropical forest species which are coming under pressure elsewhere, Its size should ensure their continued protection. A total of 112 mammal species is known from the four Parks: in Khao Yai Park - 72 species, Thap Lan - 76, Pang Sida - 85 and Ta Phraya - 21. Complete data are not yet known for Dong-Yai Sanctuary but it is known to contain important large mammals. 22 species are globally threatened. In the evergreen forests these include the Asian elephant Elephas maximus (EN: ±300 individuals), tiger Panthera tigris (EN); pigtailed macaque Macaca nemestrina (VU), stump-tailed macaque Macaca arctoides (VU), pileated gibbon Hylobates pileatus (VU), Asiatic black bear Ursus thibetanus (VU), Malayan sun bear Helarctos malayanus, Asiatic wild dog Cuon alpinus (EN) and large spotted civet Viverra megaspila. In the dipterocarp / deciduous forest, globally threatened species include tiger and banteng Bos javanicus (EN: 10 animals); stump-tailed macaque, Malayan porcupine Hystrix brachyura (VU), Asiatic wild dog, clouded leopard Neofelis nebulosa (VU), marbled cat Pardofelis marmorata (VU), serow Naemorhedus sumatrensis and gaur Bos frontalis (VU: 150 animals). The karst shelters microhabitats which favor endemic species of reptiles and bats. 200 species of reptiles and amphibians are known to exist in the Park, 63 reptile species are recorded in Khao-Yai alone. Riverine species differ distinctly from those of the surrounding forests. The smooth-coated otter Lutrogale perspicillata (VU) is found there and the endangered relict Siamese crocodile Crocodylus siamensis (CR), rediscovered in Pang Sida Park in 1992.
Other notable species found in the four Parks are: long-tailed macaque Macaca fascicularis, silvered langur Presbytis cristata, white-handed gibbon Hylobates lar, slow loris Nycticebus coucang, Malayan pangolin Manis javanica, black giant squirrel Ratufa bicolor, hairy-footed flying sqirrel Belomys pearsoni, Whitehead’s rat Maxomys whiteheadi, brushtailed porcupine Atherurus macrourus, palm civet Paradoxurus hermaphroditus, binturong Arctitus binturong, Bengal leopard cat Prionailurus bengalensis, jungle cat Felis chaus, leopard Panthera pardus and wild pig Sus scofa. There are also unconfirmed reports of wild buffalo Bubalis bubalis (EN) in that Park. If the kouprey or Cambodian wild ox Bos sauvalis (EN), were to be rediscovered on the Cambodian border in the Dongrak mountains which are a continuation of the Phanom Dongrak range, the Parks would provide suitable habitat for its reintroduction.
A total of 392 species of birds has been recorded in the Parks: in Khao Yai Park, 358 species, Thap Lan 284, Pang Sida 238 and Ta Phraya 200 species. Nearly two-thirds of the total are breeding species. Some 12.5% are vagrant or passage migrants including the spot-billed pelican Pelicanus phillipensis (VU) and the greater adjutant Leptoptilos dubius (EN). Pale-capped pigeon Columba punicea (VU) in the evergreen forest, green peafowl Pavo muticus (VU) and silver oriole Oriolus mellianus (VU) in the dipterocarp/deciduous forest and masked finfoot Heliopais personata (VU) from the riverside are resident. 53 species are considered nationally threatened or near threatened, including four species of hornbill, Siamese fireback pheasant Lophura diardi, the rare silver pheasant Lophura nycthemera and the mountain imperial pigeon Ducula badia.
No record is given of the traditional cultures associated with these areas.
Local Human Population
There is little record of the people living within the Parks, except for Khao Yai and Thap Lan. Khao Yai has villages within the Park itself and heavy settlement pressure from 104 villages along its borders. In 1991 some 195 families held disputed tenure certificates to land in Kaeng Khoi district in western Khao Yai, and the national Tourism Authority, the Highway Department, the Royal Thai Airforce, the Police and the national Electricity Generating Authority all hold land within the Park. In Thap Lan Park settlements and agricultural land cover some 48,000 ha (21.5% of the Park). People living there legally are allowed to stay; those living illegally are moved to alternative holdings.
Visitors and Visitor Facilities
In 2002 visitation to all four Parks totaled 784,370 visitors, 74% (580,400) going to Khao Yai which has good well-maintained visitor facilities. It has symbolic importance, being the oldest National Park. It is also only two hours drive from the Bangkok metropolitan area and it is possible to see a wide range of animals as well as the rivers and waterfalls. In each of the three biggest Parks there are visitor information centers, with food service, park guides and interpretive programs; there are also trails, shelters and viewing towers, low cost accommodation, bungalows and campgrounds. Small scale trekking and river rafting are beginning to become popular. Ta Phraya by contrast had only 280 visitors in 2003, perhaps due to insecurity on the border. No visiting or recreation is allowed in the Dong Yai Sanctuary.
Scientific Research and Facilities
The nomination bibliography lists eight past studies specific to the area, mostly of Khao Yai. During 2002-2003 the DNP with the Wildlife Conservation Society conducted faunal surveys of the sites in preparation for their nomination. Studies are ongoing into natural hybridizing between pileated and white-handed gibbons in the KhaoYai Park.
No other protected area within the biogeographical region has so long and well marked a continuous topographic, climatic and vegetation gradient. It contains all the major rainforest habitat types of eastern Thailand and some of the region’s largest remaining populations of many tropical forest species which are coming under pressure elsewhere.
The National Parks were established under the act for “public education and enjoyment” as much as for conservation. They come under two authorities, the Office of National Parks, Wildlife and Plant Conservation (ONP) and the Office of Wildlife Conservation and each park is separately administered, a division which has inherent difficulties. The ONP cooperates with the police, national and international non-governmental organizations (NGOs), and sometimes the army, in its three basic functions of preservation of biodiversity and ecosystems, research and education, and promoting recreation with tourism. Local issues have been tackled such as the poverty which leads to illegal activities, the employment of locals as park guards and the need for educational programs. In addition to preserving a wide range of animals, the forest provides an essential water catchment to the dry north-east, protecting the hills from erosion and the streams from sedimentation. A Strategic Management Plan for the complex was drafted in 1997 and operational management plans have been drawn up for Khao Yai and Thap Lan, with plans for the others to be completed in 2004. An updated Management Plan is being drawn up for the whole complex, allowing for the post of a Forest Complex manager. Regular monitoring is proposed of hunting, the extraction of timber and non-timber forest products, all forms of encroachment, river degradation, plant-collecting of aroids and orchids, and research.
Khao Yai Park was established in 1962 and was originally divided into six zones: Intensive Use, Outdoor Recreation (12% of the area), Special Use (for services), Forest Regeneration, limited Strict Nature Reserves, and Primitive Areas (78% of the Park). In this Park an Environment Protection Society project reduced poaching and gained local support for the Park. The subsequent Khao Yai Conservation Project started by the WCS and WildAid worked with DNP between 1999 and 2002 aimed to integrate protection, community outreach and wildlife monitoring in a regional model. It had over 100 staff and in 300 long-range patrols successfully reduced poaching (mainly for fragrant aloewood oil, mostly by Cambodian intruders). At the same time it reached into local communities with small farms to provide alternative incomes to poaching, with awareness training in camps for 1,500 children, and festivals; and it set up a regular schedule of monitoring wildlife and poaching. Tourist pressure is increasing, especially in Khao Yai Park, but is not yet too heavy, though the areas around riverside attractions are vulnerable, especially the waterfalls in Khao Yai. A tourism strategy for the whole complex has been suggested.
During the civil unrest in Cambodia during the 1980s and 1990s, the east half of the area suffered from incursions, which are now reduced. Settlers and insurgents cleared land for farming which has now become grassland and secondary woodland, and they hunted the larger mammals. There are still problems of encroachment, by farms buildings and highways, habitat degradation and disturbance, illegal sport hunting and poaching, illegal logging and the harvesting of forest products like aloewood for its fragrant oil. In the east there is encroachment for agriculture, in the west for the development of resorts and estates. In the past this has led the Parks’ administrations to emphasize law enforcement. Management is made more difficult by the complicated Park boundaries, especially in north and northwest Thap Lan where significant incursion and clearing for farmland has occurred, and in most of Ta Phraya which also has a high ratio of boundary to area, making protection of the remaining linear stretch of forest along the Thai-Cambodian border difficult. There is no clear buffer zone delineation and other land uses border directly onto protected areas. except where the northern boundary of Thap Lan borders the Sakaraet Biosphere Reserve. The Government, is committed to boundary adjustment by 2007. This will result in the degazetting of 437.73 square kilometers (km2) of inhabited degraded land in Thap Lan and the addition of 176.27 km2 of primary forest from the National Forest Reserve.
Fragmentation of the area by roads is another ongoing threat. Highway 304 to Korat separates Khao Yai from Thap Lan Parks along a strip of agricultural land. A highway runs north within a 100m-wide clearing from Prachinburi through western Khao Yai, and a highway crosses the west end of Ta Phraya and between the two sections of Dong Yai. Although speed humps have been introduced in Khao Yai in an attempt to enforce speed limits, road deaths occur on all three roads since they cross wildlife corridors which should remain continuous if the complex is to realize its potential as a reserve. To overcome this fragmentation, the construction of underpasses and green overpasses has been considered. In 2004 the Thai Government approved a budgetary allocation to undertake a feasibility study for construction of wildlife corridors.
Comparison with Similar Sites
Thailand has 82 terrestrial national parks and 55 wildlife sanctuaries. Of these, 17 protected area complexes have been identified as important for large mammal conservation. The Dong Phayayan Khao-Yai Forest Complex (DPKY), with Khao-Yai linked to the other four reserves, is the last substantial remnant habitat in eastern Thailand large enough to sustain viable populations of large fauna - provided there are effective wildlife corridors connecting them. It is the second largest forest complex in Thailand and the fourth largest in the region with continuous forest covering almost 3,500 km2. 79% is forested and contains all seven of the major rainforest types of eastern Thailand. Its flora is less varied than that of the western sanctuaries, but it contains a rich mosaic of habitats with conditions ranging between 1,000 and 3,000 mm of rainfall, 120 to 1,350 m in elevation, lowland to highland rainforest, dry evergreen hill forest to grassland and varied topography and soils. These habitats preserve some of the region’s largest mammal populations and an intact carnivore community. It is these which make it globally significant. On other counts it is notable only on the regional scale.
The DPKY forest complex compares favorably in faunal diversity with both existing World Heritage properties and other protected areas in the region. Its range of mammal species includes populations of globally endangered tiger and elephant. Actual numbers of tiger are currently unknown but all protected areas report sightings or tracks, though it is unclear if tigers remain in Khao Yai National Park. The elephant population in the complex is estimated to be about 300 animals. There are two similar large World Heritage sites within virtually the same biogeographical province: Thung Yai - Huai Kha Khaeng Wildlife Sanctuaries in the huge Western Forest Complex and Phong Nga-Ke Bang National Park in Vietnam. The Wildlife Sanctuaries (622,200 ha) form the core of the Western Forest Complex of 17 protected areas covering 18,730 km2 in mountain country. 91% is covered by largely but not wholly undisturbed forests with an exceptional mixture of species and the most diverse fauna of any protected area in Thailand. But the Sanctuaries are only slightly larger in area and number of species than the DPKY complex and they have almost no lowland forest. The Thai Kaeng Krachan Forest Complex (437,300 ha - not a World Heritage site) is comparable in area and number of birds but has far fewer mammals.
Properties in other countries in the region, including Laos, Cambodia and Myanmar have greater apparent habitat integrity but also greater problems with poaching and the wildlife trade, and there are major questions about their management. Phong Nga-Ke Bang National Park (85,800 ha) is much smaller but is the largest protected forest in Vietnam, 92% being primary forest. In numbers of species it compares well with the other sites, except for birds, but it has already been divided by a major road. In Myanmar, a recent survey report by the Wildlife Conservation Society (Lynam, 2003) on the status of tigers there concluded that "the tiger in Myanmar has suffered a range collapse and is in an advanced state of decline towards extinction". The survey compared the status of tigers in Thailand, noting that conservation in that country was more successful as a result of protected area establishment and management, even though "both countries had similar richness and abundance of [other] large mammals".
There is a total of 148 staff: 26 professionals with 122 permanent and 756 seasonal employees, totaling 904. Half of these are employed in Khao Yai. Each park has a separate headquarters. In addition Khao Yai has 21 substations, Thap Lan 14, Pang Sida, 11 and Ta Phraya and Dong Yai, 4 each. A range of training courses is supported by WCS, WWF, WFT and WildAid.
In 2003 the government supported the five units of the complex with 59,985,400 baht (US$1,500,000), a sum similar to that of recent years, with Khao Yai taking the major share.
IUCN Management Category
- Khao Yai National Park: II (National Park)
- Thap Lan National Park: II (National Park)
- Pang Sida National Park: II (National Park)
- Ta Phraya National Park: II (National Park)
- Dong Yai Wildlife Sanctuary: IV (Wildlife Sanctuary)
- Khao Yai National Park ASEAN Heritage Park (1984)
- IUCN. (2004). World Heritage Nomination IUCN Technical Evaluation, Dong Phayayan Khao-Yai Forest Complex (Thailand). IUCN, Gland, Switzerland.
- Department of National Parks, Wildlife and Plant Conservation (2004). Submission for Nomination of the Dong Phayayan Khao-Yai Forest Complex to be Included in the World Heritage List. Bangkok, Royal Thai Government. (Contains a bibliography of 60 references.)
- IUCN (1991). World Heritage Nomination IUCN Summary: Khao Yai National Park (Thailand). Gland, Switzerland.
- Lynam, A. (2003). A National Tiger Action Plan for the Union of Myanmar.
- MacKinnon, J. (1997). Protected Area Systems Review of the Indo-Malayan Realm. The Asian Bureau for Conservation/ W.C.M.C/World Bank Publication, Canterbury, U.K. ISBN: 2880326095
- Thailand National Park, Wildlife and Plant Conservation Department
- ASEAN Regional Centre for Biodiversity Information
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