The Sri Lanka lowland rain forests represents Sri Lanka's Tropical rainforests below in elevation in the southwestern part of the island. The year-around warm, wet climate together with thousands years of isolation from mainland India have resulted in the evolution of numerous plants and animal species that can only be found in rain forests in Sri Lanka. The thick forest canopy is made up of over 150 species of trees, some of the emergent layer reaching as high as . The lowland rain forests accounts for 2.14 percent of Sri Lanka's land area. This ecoregion is the home of the jungle shrew, a small endemic mammal of Sri Lanka. Sri Lanka has the highest density of amphibian species worldwide. Many of these, including 250 species of tree frogs, live in these rain forests. Forest cover The lowland rain forests cover in total and accounts for 2.14 percent of Sri Lanka's land area. Wet monsoon forests receive of annual rainfall and are situated belove of altitude. Kanneliya, Viharakele, Nakiyadeniya, and Sinharaja, which is a World Heritage Site, are the forests that represent this ecoregion. Bambarabotuwa, Morapitiya Runakanda, Gilimale and Eratne are some of the other forest reserves. Even rainfall throughout the year, and invariable temperature resulted in rich biodiversity. These forests also act as an important catchment area for rivers. Geological history Sri Lanka is a continental island, separated from the Asian continent only by shallow Palk Strait. Sri Lanka was once a part of Gondwanaland, until the Cretaceous Period. Then as a part of the Indian Plate, it detached and drifted northward. The Indian Plate collided with the Asian mainland about 55 million years later. Therefore, there are many ancient Gondwana taxonomic groups present in Sri Lanka. Sri Lanka first became separated from the mainland Indian subcontinent during the late Miocene Epoch. Due to climatic changes, an intermittent drier region emerged between the moist forests in southwest Sri Lanka and the Western Ghats in India, the closest other moist forests. Although the island has been connected with the mainland repeatedly by land bridges since the initial separation, Sri Lanka's moist forests and its wet forest-adapted biota have been identified as being ecologically isolated. Features The ecoregion partially encircles the Central Massif, which reach above and detached Knuckles Mountain Range. These mountains are represented by their own ecoregion, Sri Lanka montane rain forests. The type of the soil of the ecoregion