Thailand covers a total land area of 13,115 square kilometers. It lies in a hot and humid climatic zone, and hence supports a variety of tropical ecosystems. Its forests harbor a large portion of the country’s biodiversity. Forest types range from rainforest, evergreen, deciduous and mangrove, to shrub forests and savannah forests. The freshwater ecosystem, which includes rivers, reservoirs, swamps and ponds, is where the endemic species of Thailand are found. For coastal ecosystems, the country’s more than 2,000-kilometer coastline surrounding islands numbering over 200 are comprised by coral reefs, sandy beaches, muddy beaches and seagrass beds. Marine ecosystems are located on both sides of the peninsula. Agriculture ecosystems make up about one-fifth of the country, and while entirely man-made, these bear certain components of biodiversity nonetheless.

Thailand has approximately 15,000 species of plants, which accounts for eight per cent of the estimated total number of plant species found globally. The country is at the center of the India-Burma, Indochina and Malaysian regions. It is estimated that there are 12,000 species of vascular plants, which include 658 fern species, 25 uncovered seeds, 10,000 flowering plants and 1,140 orchids.

Vertebrate animals consists of at least 302 species of mammals, where 42 per cent originate from the southern part of the region, 34 per cent from the Indochinese and Indian sub-regions, and the remaining 24 per cent coming from all over the Asian continent. Six of these mammal species are endemic. There are at least 982 bird species, 350 reptile species and 137 semi-water animal species. Thai waters support about 2,820 marine fish species, accounting for 10 per cent of the total fish species worldwide. There is also a total of 720 freshwater fish species. Invertebrate animals consist of around 83,000 species, mostly insects, where only 14,000 of which have been identified.