Owing to high levels of genetic and species diversity and endemism, Sri Lanka is designated as one of 34 globally significant biodiversity hotspots identified by Conservation International (CI). Birdlife International (BI) has identified the country as one of the worldÂs 356 endemic bird areas. Sri LankaÂs lowland rainforests, montane rainforests and south-western rivers and streams are listed in WWFÂs Global 200 eco-regions. This extremely high species diversity including a high level of endemism can be attributed to three factors. First, the wide variety of climatic, topographic and soil conditions that has resulted in high habitat variability (Sri Lanka comprise of 14 Great Soil Groups, 23 Agro-ecological regions, 15 floristic regions and four major ecosystems that can be further divided into 29 sub-systems). Second, abundance of water that includes 103 river basins and large number of man made tanks. Third, long period of isolation from the closest land mass and presence of large number of natural barriers isolating species promoting evolution of new species as evidenced by the presence of high level of endemicity in most taxonomic groups. For instance, 28% of the 3,771 species of flowering plants, 22% of the 96 species of mammals, 15% of the 227 bird species, 88% of the 255 species of land snails, 55% of the 102 species of freshwater fishes, 86% of the 119 species of amphibians, 65% of the 216 species of reptiles and 98% of the 51 species of fresh water crabs found in the country are endemic. Endemism among vertebrates is about 43%, with the highest endemism quotient being recorded among the herpetefauna and freshwater fishes. More than 75% of the endemic species of flora and fauna are restricted to the tropical wet forests located in the southwestern region of Sri Lanka.