The Wallace Line is a boundary line that separates the fauna of Asia and Australia. It is named after Alfred Russel Wallace, a British naturalist who first discovered the line during his travels in the 19th century. The line runs through the Indonesian archipelago, and separates two biogeographical regions – the Oriental region to the west and the Australian region to the east.
The Wallace Line is a significant biological boundary, as it marks the point where two distinct groups of animals from Asia and Australia meet. To the west of the line, animals such as tigers, elephants, and monkeys are found, while to the east, marsupials such as kangaroos, wallabies, and possums are prevalent.
The reason for the difference in fauna can be traced back to the geological history of the region. Millions of years ago, the landmasses of Asia and Australia were connected, forming a supercontinent called Gondwana. As the continent broke apart and the sea level rose, the land masses of Asia and Australia drifted apart, and a deep oceanic trench was formed between them. This separation created a barrier that prevented the movement of many animal species between the two regions, leading to the distinct fauna on either side of the Wallace Line.
The Wallace Line is not a fixed boundary, and there are several islands in the Indonesian archipelago that are located on both sides of the line. These islands, known as the Wallacea region, have a unique blend of both Asian and Australian species, making them an important area for biodiversity conservation.
The Wallace Line is a fascinating example of the complex relationship between geography, geology, and biology. It has played a significant role in shaping the biodiversity of the region, and is a reminder of the incredible diversity and complexity of our planet’s natural history.