The Wallace Line: The Invisible Barrier

The Wallace Line is a fascinating biogeographical boundary that separates the distinct ecosystems of Southeast Asia from Australia and New Guinea. First identified by Alfred Russel Wallace in the 19th century, this invisible barrier has puzzled scientists for over a century.

Key Facts About the Wallace Line 

 • The Wallace Line runs through the Malay Archipelago, dividing Asian fauna from Australian fauna. • Despite the narrow waterways, species from either side rarely cross the boundary.

Why Do Species Not Cross the Wallace Line?

 • Climate & Evolutionary Adaptation: Asian species evolved in tropical climates, making them more adaptable to islands near the Wallace Line.

Australian species, adapted to cooler, drier conditions, struggled to establish themselves in tropical Southeast Asia.

• Geographic Isolation:

 The deep ocean trenches between Borneo and Sulawesi act as a natural barrier, preventing migration.

Scientific Significance 

 • The Wallace Line helps scientists understand species distribution and evolutionary pathways.