Abstract:

Background & Aims: The regions of Southeast Asia are recognized as global biodiversity hotspots that require conservation priority. Since the mid-19th century, Southeast Asia has been widely considered as one of the most important foundations of biogeography. This recognition stems from the groundbreaking field works of Alfred Russel Wallace, who spent eight years to extensively explore the regions and proposed the geographic distribution patterns of fauna in Malesia (or the Malay Archipelago). Wallace’s works in Southeast Asia, such as the famous “Wallace Line” and its distinct distribution patterns, established the region as a crucial cradle and frontier of biogeography. Also, such renowned works have garnered significant attention from numerous biogeographers and ecologists. Additionally, the unique geomorphology and abundant biodiversity in Southeast Asia have sparked a growing scientific interest, leading to an increasing number of studies that explored the biodiversity and geographic distribution patterns in the regions. The comprehension of geographic distribution patterns of biodiversity in Southeast Asia can enhance our understanding of the origination, evolution, and response of global biodiversity to environmental and climatic changes.

Progress: In this review, we have undertaken a comprehensive synthesis of the primary biogeographic investigation conducted in Southeast Asia, spanning from the era of Alfred Russel Wallace to the present day. The main biogeographic studies in Southeast Asia are retrospectively reviewed and the existing problems are considered here.

Conclusion: Several key findings of biogeography in Southeast Asia with the most important distribution patterns are listed as follows. Firstly, Southeast Asia, based on the boundary or delimitation, encompasses the Indochina Peninsula and Malesia, which consist of four distinct bioregions: Indochina, Sundaic, Philippines and Wallacea. Secondly, the biogeographic patterns with these regions, as well as the biogeographic relationships or patterns among regions are primarily influenced by the mechanism of vicariance, migration and dispersal. Thirdly, the difference in biogeographic boundaries, particularly along the Wallace Line, can be attributed to variations in the migration and dispersal capacity of plants and animals. Lastly, the biogeographic connections between Southeast Asia and Sahul are mainly driven by the exchanges of flora and fauna, with elements from both regions have been migrated to and from each other. This review presents some ideas and offers recommendations to address the unresolved challenges of the field of biogeography in Southeast Asia. In all, we hope this review serves as a link between past and future, intends to throw out a minnow to catch a whale, and facilitates the flourishing development of biogeography in Southeast Asia.

Key words: biogeography, Southeast Asia, geographic boundary, biodiversity, geographic distribution patterns, Wallace Line