Thung Yai Naresuan Wildlife Sanctuary

Souce: UNEP World Conservation Monitoring Centre

IUCN MANAGEMENT CATEGORY
IV (Habitat/Species Management Area)
Natural World Heritage Site - Criteria ii, iii, iv

BIOGEOGRAPHICAL PROVINCE 4.05.01 (Indochinese Rainforest)

GEOGRAPHICAL LOCATION Situated in Kanchanaburi and Tak provinces alongside the western international border with Burma and located at the southern end of the Dawna Range. 14 degree 55 libda -15 degree 45 libda North, 98 degree 28 libda - 99 degree 05 libda East

DATE AND HISTORY OF ESTABLISHMENT 24 April 1974. Inscribed with Huai Kha Kaeng Wildlife Sanctuary on the World Heritage List in 1991.

AREA 320,000ha. It is the largest conservation area in Thailand. With the inclusion of recent extensions and combined with the adjacent Huai Kha Khaeng Wildlife Sanctuary (257,464ha), it is the largest conservation area in Mainland South-east Asia, covering a total 622,200ha. In addition, Thung Yai adjoins Umphang Wildlife Sanctuary to the north (251,600ha), which has been demarcated but not yet gazetted, and Bung Kroeng Kawia Non-Hunting Area (51,200ha) and Khao Laem proposed National Park (122,300ha) to the south. Both Thung Yai Naresuan and Huai Kha Khaeng wildlife sanctuaries constitute a major component of the protected areas cluster in western Thailand, comprising Sri Nakarin National Park (153,200ha), Chaloem Rattankosin National Park (5,900ha), Erawan National Park (55,000ha), Sai Yok National Park (50,000ha) and Salak Phra Wildlife Sanctuary (85,855ha). Is proposed to increase the size of the sanctuary by 47,700 with the incorporation of the Nam Choan Forest Reserve (ONEB, 1990). Recent additions have increased the total area protected to 1,208,300ha.

LAND TENURE Government

ALTITUDE Ranges from 250m to the peak of Khao Thai Par at 1,811m in the south-west quarter of the sanctuary. There are several peaks over 1,500m and many over 1,100m distributed throughout the sanctuary.

PHYSICAL FEATURES The topography is generally mountainous with a network of many permanent rivers and streams dividing the area into valleys and lowland plains. The sanctuary's distinguishing feature is a large central grassland plain, from which it takes the name of Thung Yai (meaning 'big field'). Within the catchment area are four importantrivers: the Mae Khlong, which flows into the Kwai Yai (of "Bridge over the River Kwai" notoriety) and feeds into the Sri Nakarind Dam; Kwae Noi, which feeds into Khao Laem Reservoir; and Mae Kasart and Mae Suriat which, respectively, flow into Mekathat and Huang Tharaw rivers in Myanma. Red-brown earths and red-yellow podzols are the predominant soils, the former derived from limestone and found in the level uplands and Mae Chan Valley, whilst the latter is found in the Huai Kha Khaeng Valley. A physical feature that is important for wildlife is the presence of mineral licks. These occur throughout the sanctuary as either wet or dry, and most appear to be located on, or around, granite intrusions in areas with red-yellow podzolic soil and may be associated with the massive faults or lineaments in the intensely folded geomorphology of this area. Small lakes, ponds and swampy areas occur, some being seasonal whilst others are perennial; these are important wildlife habitats. Limestone sink holes are found; most are only about 20m in diameter and 10-12m in diameter, but some are more than 2km long, 250m wide and drop as much as 30m depth (ONEB, 1990).

CLIMATE Conditions range from tropical to semi-tropical. The climate is monsoonal, with a dry season from November to April/May, and a hot wet season from May to October. Mean annual rainfall in the west is 2000-2400mm, declining to 1600-2000mm in the east. There is a strong orographic effect, and more than 80% of the rain is brought by the south-west monsoon. Mean minimum and maximum temperatures range from 15 Deg Celcious to 35 Deg Celcious during the hot season; 20 Deg Celcious to 33 Deg Celcious during the wet season and 10 Deg Celcious to 29 Deg Celcious during the cooler season. Minimum and maximum night and day temperatures fall in the range 7 Deg Celcious to 40 Deg Celcious.

VEGETATION The principal vegetation types, and their estimated cover is as follows: hill evergreen forest (54,900ha); dry evergreen forest (112,900); mixed deciduous forest (164,100ha); dry dipterocarp forest (3,600ha); savanna forest (9,900ha); grassland (3,900ha); and areas of swidden agriculture (15,400ha) (Anon., 1991). The highest ground is generally covered with hill evergreen forest, also known as tropical lower montane rain forest, but slopes above 600m generally support dry evergreen forest (seasonal evergreen forest). This latter formation is tall, dense, stratified and always dominated by Dipterocarps, and may appear to be evergreen in wet areas such as the central uplands of the sanctuary. In some areas, particularly broad valleys, there is often a mosaic of vegetation types.
At lower altitudes mixed deciduous and bamboo forests predominate, with dry deciduous dipterocarp forest occurring in areas with poor or shallow soil. Mixed deciduous forest is the most predominant formation, probably dominated by Lagerstroemia calyculata associations, although pure stands of Xylia xylocarpa are found. Dry dipterocarp forest, also referred to as dry deciduous dipterocarp, is unique to mainland South-east Asia. It is dominated by five xerophilous dipterocarps and is confined to the poorest and most porous soils where fire occurs. Savanna forest and grassland, both very similar formations, occur at every elevation, although the 'thung yai' covers 14,000ha. Some 17 trees occur in the savanna forests, of which L. macrocarpa, Stereospermum nueranthum, Terminalia chebula and Dalbergia cultrata are amongst the most common. Trees within grassland are smaller, of generally the same genera, but not exceeding 5m, and stunted either by fire or other edaphic constraints.
In particularly moist areas along rivers and streams, evergreen gallery forest is present. This is noticeably lusher than other formations, and harbours many more creepers, climbers and epiphytes, with emergents as high as 40m. The gallery forest sustains a higher than usuallevel of biological diversity in comparison to the more widespread but drier habitats, especially during dry season fires. The most important wetlands are those along the upper Khwae Yai and is tributaries, the Mae Klong and Mae Chan, both deep, fast flowing rivers with steep banks, muddy bottoms and frequent rapids and rocky ravines.
Secondary forest on areas of former swidden agriculture are found in the Mae Chan Valley and central uplands towards the east. Swidden agriculture has been practised in areas of the most fertile soils which indicates that some of the richest forest has been destroyed but also that there is a good chance of regeneration. Characteristic species are those that grow in the surrounding forest, including L. macrocarpa, Vitex peduncularis, Bauhinia acuminata and Albizia odoratissima.

FAUNA The fauna of both Thung Yai and Huai Kha Khaeng includes an unusual mix of species with primarily Sundaic, Indo-Chinese, Indo-Burmese and Sino-Himalayan affinities, many of whose ranges do not overlap. Most species are either characteristic of the Oriental/Indo-Malayan region or more specifically associated with the Indo-Chinese province of that region, but with a strong Sundaic element included. A small proportion is Palaearctic.
Thung Yai has not been comprehensively surveyed, but it is known to support a significant proportion of Thailand's fauna (Nakasathien et al., 1987). It is big enough to support several of the larger and increasingly rare mammal species, such as tiger Panthera tigris (E), leopard P. pardus, clouded leopard Neofelis nebulosa (V), Elephas maximus (E), tapir Tapirus indicus (E), Sumatran rhinoceros Didermocerus sumatraensis (E), gaur Bos gaurus (V), mainland serow Capricornis sumatraensis (I) and hog deer Cervus porcinus. A herd of 50 gaur was seen in 1985, making it the largest herd recorded in Thailand (P.D. Round, pers. comm.). Neither banteng B. javanicus (V), nor wild water buffalo Bubalus arnee (E) has yet been reported from Thung Yai, although both occur in neighbouring Huai Kha Khaeng Wildlife Sanctuary. The Javan rhinoceros Rhinoceros sondaicus (E) is said to have existed in the area and a track was photographed in 1988 (J.Thorsell. pers. comm., 1991).
Notable bird species include white-winged wood duck Cairina scutulata, Kalij pheasant Lophura leucomelana, Burmese peafowl Polyplectron bicalaratum and green peafowl Pavo muticus (V) (Round, 1988).
A detailed summary discussion of the fauna of the combined Thung Yai-Huai Kha Khaeng sanctuaries is given in ONEB (1990) and species lists have been compiled. This includes some 120 mammals, 400 birds, 96 reptiles, 43 amphibians and 113 freshwater fish as confirmed occurrences, with a number of species suspected as being present but not confirmed. Thirty-four internationally threatened species are also found within the confines of the two sanctuaries (ONEB, 1990).

CULTURAL HERITAGE It is certain that Thung Yai contains several sites of great archaeological interest, possibly dating back to the Pleistocene era when early hominids are thought to have migrated east and southwards through the area. Stone artifacts have been found which reinforce this supposition, but the area has yet to be properly investigated (B.J. Stewart-Cox, pers. comm.).

LOCAL HUMAN POPULATION Some 3,800 tribal people live within the sanctuary. There are still four Hmong villages, mainly in the north-east and east although 900 peoplewere moved out of the sanctuary in 1988. Some Karen have been established in the area for at least 50 years, whereas the Hmong are said to have moved in from further north 20-30 years ago. Both groups cultivate crops around their villages, but the impact of their activities on the forest has not been assessed (B.J. Stewart-Cox, pers. comm.). Since 1987, 2-3 Hmong villages have been moved each year to Phop Phra district in Tak province, about 80km north of the Thung Yai-Huai Kha Khaeng sanctuary complex. By 1991 all villages will have been closed. Sixteen Karen villages (1,826 people) are still resident, but there are plans to resettle them. Similarly, it is envisaged that Thai villages established in the proposed buffer zone around the Thung Yai-Huai Kha Khaeng sanctuary complex will also be resettled (ONEB, 1990).

VISITORS AND VISITOR FACILITIES The sanctuary is not open to the general public, but permission may be given to researchers, naturalists and education groups for specific purposes. Some 400-500 visitors come each dry season. Permits can be obtained from the Wildlife Conservation Division in Bangkok, or from the Chief of the Sanctuary. Thung Yai is accessible by road (mostly unsurfaced) from Bangkok via Kanchanaburi. The journey takes 10-12 hours. A four-wheel drive road passes through the sanctuary from the headquarters to a mining concession on the international border.

DATE July 1987, reviewed December 1987, March 1991

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