Monitoring and evaluation of identified corridors suggest that some corridors are already working; management of allowable activities in these corridors will be important over the long term.

In recent years, Thailand has markedly expanded its protected areas system. The kingdom now has 128 terrestrial national parks, 26 marine national parks, 60 wildlife sanctuaries, and 63 non-hunting areas managed by the Department of National Parks, Wildlife and Plant Conservation (DNP). These protected areas cover about 23% of Thailand’s territory, a figure justified by the numerous benefits conservation delivers to the Thai people. Where protected areas are adjacent or close together, they can be managed as ecological networks for conservation, but many of them are smaller areas fragmented by highways, railroads and other infrastructure.

Thailand’s protected areas are generally effective at curtailing deforestation within their boundaries (a significant exception being the continued poaching of particularly valuable timber such as rosewood). But continued deforestation and conversion of forests into plantations in areas surrounding many of Thailand’s protected areas is making them islands of nature in a sea of agriculture, too small to support all the species that occupied the landscape before it became fragmented.

To promote landscape connectivity, DNP has adopted the concept of ecological networks, which are referred to as ‘forest complexes’. National parks and wildlife sanctuaries are ecologically linked to form a larger area that will be able to support viable populations of wide-ranging species of plants and animals, as well as contribute to regional social and economic development through provision of ecosystem services. These areas can be connected by ecological corridors that include non-hunting areas, buffer zones, lands managed by government agencies other than DNP and private lands. This approach requires senior protected area staff to consider managing their sites as parts of larger landscapes.

The Eastern Forest Complex includes eight protected areas (Figure 1). Khao Chamao-Khao Wong National Park (84 km2) is slightly separated from Khao Ang Rue Nai Wildlife Sanctuary (1078 km2), but an ecological corridor has been shown to be feasible; its establishment depends on the owners of the connecting land being convinced to work with the protected areas. Khao Sipha Chan National Park (118 km2) is adjacent to Khao Ang Rue Nai and forms part of a naturally connected ecosystem. Similarly, the relatively small Khao Khitchakut National Park (58 km2) is connected to Khao Soi Dao Wildlife Sanctuary (744 km2), so they also form a natural unit. Klong Krua Wai Wildlife Sanctuary is connected to Namtok Khlong Kaew National Park, making them part of a long and rather narrow natural unit. They share a boundary with Cambodia, and DNP is working on transboundary protected area conservation with Cambodia’s Samlout Protected Area (this is being promoted by the Asian Development Bank).

All the protected areas of the Western Forest Complex are ecologically connected and form Thailand’s largest contiguous forest ecosystem complex, covering 14,866 km2 (Figure 2). Three national parks (part of Khao Laem National Park, Thong Pha Phum National Park, and Sai Yok National Park) are separated from the other sites in the western complex by a highway and various commercial developments along the highway, posing an ecological barrier that will need mitigations with crossing structures, such as broad overpasses covered with vegetation to enable free movement of large mammals.

Khao Ang Rue Nai Wildlife Sanctuary, Thailand © Adobe Stock

There is conclusive evidence that tigers, which are well protected in Huay Kha Khaeng Wildlife Sanctuary in the Western Forest Complex, are expanding their population, with “new” tigers dispersing northward to Mae Wong and Klong Lan national parks, where they have become well established. Many other species, including the reintroduced Eld’s deer, may also repopulate these national parks from Huay Kha Khaeng, indicating its importance as a source of wildlife for other areas due to the existence of ecological corridors. Local communities have been involved in demarcating boundaries in Mae Wong National Park and have benefitted from multiple-use zones, which can serve as ecological corridors. Communities surrounding Huay Kha Khaeng Wildlife Sanctuary have established community development zones that have been formally recognised as contributing to the objectives of the protected area. More work is clearly needed to develop and implement connectivity conservation in the protected area complexes, but the Eastern and Western forest complexes have shown the practical utility of the approach.