The IBA comprises Nam Nao National Park in the Phetchabun Range of north-eastern Thailand. The site is contiguous with Phu Khieo Wildlife Sanctuary (IBA TH018) to the south, Phu Pa Daeng Wildlife Sanctuary to the west and Tad Mok National Park to the south-west. The topography of the site is characterised by rolling sandstone hills, and there is a limited area at higher elevations. Several large, perennial streams, featuring scenic waterfalls, rise within the site, which forms part of the catchment of the Nam Phorm reservoir. The vegetation at the site mainly comprises mixed deciduous forest (covering c.42,700 ha) and dry evergreen forest (covering c.40,500 ha), with smaller areas of deciduous dipterocarp forest and bamboo. In addition, the site supports an unusual formation of deciduous forest dominated by large pines, which covers c.1,053 ha.
Together with the adjacent Phu Khieo Wildlife Sanctuary (IBA TH018), Nam Nao National Park is perhaps the most important site in Thailand for the conservation of the globally endangered White-winged Duck Cairina scutulata. The key area for the species is a small patch of lowland forest along the Huai Pham Leang stream, which is contiguous with Phu Khieo Wildlife Sanctuary. In addition to its importance for White-winged Duck, the site supports three globally near-threatened species: Siamese Fireback Lophura diardi, Great Hornbill Buceros bicornis and Brown Hornbill Anorrhinus tickelli. The site qualifies under criterion A3 because it supports 10 species restricted to the Indo-Malayan Tropical Dry Zone (Biome 11).
Non-bird biodiversity: Mammals Asian Elephant Elephas maximus (EN) Tiger Panthera tigris (EN) Gaur Bos frontalis (VU) Southern Serow Capricornis sumatra(EN)sis (VU) Asian Gold(EN) Cat Catopuma temminckii (VU) Dhole Cuon alpinus (VU) East Asian Porcupine Hystrix brachyura (VU) Northern Pig-tailed Macaque Macaca leonina (VU) Clouded Leopard Neofelis nebulosa (VU) Marbled Cat Pardofelis marmorata (VU) Asian Black Bear Ursus thibetanus (VU) Reptiles Big-headed Turtle Platysternon megacephalum (EN) Plants Dipterocarpus turbinatus (CR) Dalbergia oliveri (EN) Dipterocarpus costatus (EN)
BirdLife International (2020) Important Bird Areas factsheet: Nam Nao. Downloaded from http://www.birdlife.org on 21/10/2020.