The Wallace’s Line distinguishes or separates the flora and fauna between

The Wallace’s Line is a significant biogeographical boundary proposed by Alfred Russel Wallace in 1859 [1]. It serves as a faunal demarcation line that separates the distinct biological realms of South-East Asia and Australasia [1]. Specifically, it distinguishes the Asian fauna—characterized by placental mammals like primates, elephants, and carnivores—from the Australian fauna, which is dominated by marsupials. Geographically, the line follows the edge of the Sunda shelf, passing between the islands of Bali and Lombok and between Borneo and Sulawesi. This boundary highlights the deep evolutionary divergence between the Oriental and Australian biogeographic regions, where even narrow deep-water channels prevented the migration of many species during periods of lower sea levels [3].

Sources

1. [1] https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/wallace-line
2. [2] https://en.wikipedia.org/wiki/Wallace_Line
3. [3] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 4: BIODIVERSITY > Himalayas and east and south east Asia > p. 9