Southeast Asia as One of World's Primary Sources of Biotic Recolonization Following Anthropocene Extinctions

The plight of Southeast Asia's animals, plants and ecosystems in the face of unsustainable exploitation and habitat destruction has been illustrated in several recent studies, despite often falling outside the global discourse on global conservation priorities. Here, we collate biogeographic and phylogenetic information to argue that this beleaguered region is one of world's primary macrorefugia, and possibly its best chance of regaining its natural biodiversity distribution patterns after the current Anthropocene upheaval. The region uniquely combines top diversity values in (a) ancient lineage diversity and (b) cosmopolitan lineage diversity, suggesting that it has acted in the past as a biodiversity museum and source of global colonization. This is at least partly due to the interplay between latitudinal diversity gradients and continental connectivity patterns. However, the peak values in South China/North Indochina for cosmopolitan tetrapods and their sister lineages suggest that a key feature is also the availability of diverse climatic conditions. In particular, the north-south orientation of the mountain ranges here has allowed for rapid recolonization within the region following past climatic changes, resulting in high survival values and overall exceptional relict lineage diversity. From this starting point, global colonization occurred on multiple occasions. It is hoped that, with urgent action, the region can once again fulfill this function.

Automated summary

The region of Southeast Asia, despite often being overlooked in global conservation discussions, is highlighted as one of the primary macrorefugia of the world with rich ancient lineage diversity and cosmopolitan lineage diversity. It is considered a biodiversity museum and a source of global colonization, with its unique combination of top diversity values attributed to latitudinal diversity gradients and continental connectivity patterns. The availability of diverse climatic conditions, particularly in South China/North Indochina, has facilitated rapid recolonization within the region following past climatic changes, resulting in high survival values and exceptional relict lineage diversity.