Wallace Line

The Wallace Line (or 'Wallace's Line') is a boundary that separates the ecozone of Asia and the Australasian ecozone. The transitional zone is sometimes called Wallacea.

Plants and animals related to Asian species are found to the north-west. Australasian species are found mainly to the south-east, with some Asian species. The line is named after Alfred Russel Wallace, who noticed this clear dividing line during his travels through the East Indies in the 19th century.

The line runs through Indonesia, between Borneo and Sulawesi (Celebes); and through the Lombok Strait between Bali (in the west) and Lombok (in the east).

The distance between Bali and Lombok is only about 35 kilometers. Surprisingly, the distributions of many bird species observe the line, because many birds do not cross even the smallest stretches of open ocean water. Some bats have distributions that cross the Wallace Line, but other mammals are generally limited to one side or the other; an exception is the Crab-eating Macaque. Other groups of plants and animals show differing patterns, but the overall pattern is striking and reasonably consistent.

The term 'Wallace's Line' was first used by Huxley in 1868.^[1]

1. ↑ Cite error: The named reference Mayr44 was used but no text was provided for refs named (see the help page).