Geology and Ecology of Nicobar Islands

Geology

The Nicobar Islands are part of a great island arc created by the collision of the Indo-Australian Plate with Eurasia. The collision lifted the Himalaya and most of the Indonesian islands, and created a long arc of highlands and islands, which includes the Arakan Yoma range of Myanmar, the Andaman and Nicobar Islands, and the islands off the west coast of Sumatra, including the Banyak Islands and Mentawai Islands.

Ecology

The climate is warm and tropical, with temperatures ranging from 22 to 30° C. Rainfall is heavy due to annual monsoons and measures around 3000 to 3800 mm each year. The vegetation of the Nicobars is typically divided into the coastal mangrove forests and the interior evergreen and deciduous Tropical and subtropical moist broadleaf forests. Additionally, several islands contain extensive interior grasslands, though these are thought to result from human intervention.

The Nicobar islands are recognized as a distinct terrestrial ecoregion, the Nicobar Islands rain forests, with many endemic species.

As a result of lower sea levels during the ice ages, the Andaman Islands were linked to the Southeast Asian mainland, but it is not believed that the Nicobar islands ever had a land bridge to the continent. Lower sea levels did link the islands to one another: Great Nicobar and Little Nicobar were linked to each other, and Nancowry, Chaura, Katchall, Trinka, Camorta, and the nearby smaller islands were linked to one another as well.