Stretching over more than 600,000 ha along the Myanmar border, the sanctuaries, which are relatively intact, contain examples of almost all the forest types of continental South-East Asia. They are home to a very diverse array of animals, including 77% of the large mammals (especially elephants and tigers), 50% of the large birds and 33% of the land vertebrates to be found in this region.
A camera trap captures a tigress moving her cubs in Huai Kha Khaeng
© Wildlife Conservation Society
The site comprises two contiguous wildlife sanctuaries: Thung Yai and Huai Kha Khaeng, alongside the western international border with Myanmar, 300 km north-west of Bangkok.
The terrain in Huai Kha Khaeng is generally hilly with many permanent and seasonal streams. The highest peak lies in the extreme north of the sanctuary. Valleys are interspersed with small lowland plains. In Thung Yai the topography is more dissected with a network of many permanent rivers and streams dividing the area onto valleys and lowland plains. A distinguishing feature is a large central grassland plain, from which the Sanctuary takes the name of Thung Yai ('big field'). Within the catchment area are four important rivers, one of which flows through Burma to the Andaman Sea.
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 whereas others are perennial; these are important wildlife habitats; limestone sinkholes are found.
Five types of forest can be distinguished: the highest slopes are covered with hill evergreen forest, whereas slopes above 600 m generally support dry semi-evergreen forest. The rest of the sanctuary supports mixed deciduous and bamboo forest, and dry dipterocarp forest in areas with poor or shallow soil. Along some rivers and streams, evergreen gallery forest occurs.
Thung Yai also has two specific features not common in other areas which add to its uniqueness. One is the existence of a large grassland plain and surrounding savannah forest made up of cycads and Phoenix palm, a feature not known elsewhere in the region. The second feature is the existence of Thailand's most extensive riparian forests.
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. Species lists have been compiled that include 120 mammals, 400 birds, 96 reptiles, 43 amphibians and 113 freshwater fish. 34 internationally threatened species are also found within the confines of the two sanctuaries. It also is home to 22 species of woodpecker, more than any other park in the world. The reason for such exceptional diversity is partly due to its status as one of only two evergreen forest refuges during the driest periods of the Pleistocene glaciations. Few areas in Asia are large enough to support viable populations of large herbivores (300 elephants) and predators (e.g. tigers).
Being contiguous with the forest of Myanmar there are longer term prospects for a transfrontier reserve between the two countries. This would greatly add to its integrity as there is cross-border migration of some species and Thai logging concessions in Myanmar could be reduced.
Some 3,800 tribal people live within Thung Yai, whereas there is no resident population within Huai Kha Khaeng. Source: UNESCO/CLT/WHC