Bhutan has been identified as one of the 10 bio-diversity hot spots in the world and as one of the 221 global endemic bird areas. Almost three fourths of land area is covered by forests of temperate and sub-tropical species that are a natural habitat for a diversity of flora and fauna. Its various eco-systems harbour some of the most exotic species of the eastern Himalayas. An estimated 770 species of birds and over 50 species of rhododendron, along with an astonishing variety of medicinal plants (over 300 species) and orchids are endemic to this region. There are about 3,281 plant species per 10,000 square kilometers.