NATURE’S INVISIBLE BARRIER
What is the ‘Wallace Line’ & how did it shape Southeast Asia’s evolution?
The longstanding puzzle of a gigantic evolutionary line has been explained more than 160 years after the boundary was first drawn up
The Wallace Line, also known as the Wallace’s Line, is a significant biogeographical boundary in Southeast Asia that was first identified by the British naturalist Alfred Russel Wallace in 1859. It refers to an imaginary line that separates the fauna of the Asian and Australian regions, specifically between the islands of Bali and Lombok in Indonesia. The line continues eastward through the Makassar Strait, between Borneo (Kalimantan) and Sulawesi, and then further north between the Philippines and the islands of the Celebes Sea.
During his exploration of the Indonesian archipelago, Alfred Russel Wallace observed a striking contrast in the animal species between the two sides of the line. To the west, on islands like Bali and Borneo, the fauna bore similarities to mainland Southeast Asia, boasting species like tigers, rhinoceroses, and monkeys. On the eastern side, encompassing islands like Lombok and Sulawesi, the fauna exhibited a closer affinity to Australia, showcasing marsupials and other unique…
