Borneo and Indochina are Major Evolutionary Hotspots for Southeast Asian Biodiversity

Abstract

Tropical Southeast (SE) Asia harbors extraordinary species richness and in its entirety comprises four of the Earth's 34 biodiversity hotspots. Here, we examine the assembly of the SE Asian biota through time and space. We conduct meta-analyses of geological, climatic, and biological (including 61 phylogenetic) data sets to test which areas have been the sources of long-term biological diversity in SE Asia, particularly in the pre-Miocene, Miocene, and Plio-Pleistocene, and whether the respective biota have been dominated by in situ diversification, immigration and/or emigration, or equilibrium dynamics. We identify Borneo and Indochina, in particular, as major "evolutionary hotspots" for a diverse range of fauna and flora. Although most of the region's biodiversity is a result of both the accumulation of immigrants and in situ diversification, within-area diversification and subsequent emigration have been the predominant signals characterizing Indochina and Borneo's biota since at least the early Miocene. In contrast, colonization events are comparatively rare from younger volcanically active emergent islands such as Java, which show increased levels of immigration events. Few dispersal events were observed across the major biogeographic barrier of Wallace's Line. Accelerated efforts to conserve Borneo's flora and fauna in particular, currently housing the highest levels of SE Asian plant and mammal species richness, are critically required.

DNA Barcoding Indonesian freshwater fishes: challenges and prospects

“…Pseudomystus) and Sisoridae (Glyptothorax) fostering the settlement of high level of endemism for those groups. De Bruyn and colleagues [35], for instance, have demonstrated that Borneo's diversity (including Kalimantan in Indonesia and Sabah and Sarawak provinces in Malaysia) resulted not only from the accumulation of immigrants but also from in situ diversification that further enabled the dispersal of species to other islands in Sundaland including Java and Sumatra. Dispersal among Sundaland islands has been made possible by eustatic changes during glacial times through the Pleistocene that created connections between the islands of Sundaland but also with the continent [9,10,34,46].…”

“…The main reasons for this exceptional diversity are the important fragmentation of the rivers across the numerous islands of the archipelago, together with the occurrence of several major biogeographical boundaries in the country including the Wallace and Lydekker lines ( Fig. 1) and complex palaeoecological and geological histories [33][34][35][36][37].…”

Mapping Distinct Forest Types Improves Overall Forest Identification Based on Multi-Spectral Landsat Imagery for Myanmar’s Tanintharyi Region

“…The complex geological and bioclimatic history of Southeast Asia has resulted in an exceptionally rich biodiversity [1] and some of the highest concentrations of endemic species in the world [2]. The floristically-distinct forest types that occur in the region vary in their species assemblages, vulnerability to habitat conversion or degradation, conservation value, and representation within protected area networks [3,4].…”

Molecular systematics and biogeography of the Hemigalinae civets (Mammalia, Carnivora)

“…Within the Sundaic region, climate-induced sea-level changes have altered the topography repeatedly, exposing and flooding land corridors between the mainland and different islands, and ecological factors played a role in restricting movements of species across this region. For instance, during the Last Glacial Maximum (LGM), the central part of the Sundaland might have been covered by open habitat (Bird et al 2005;Meijaard 2003;de Bruyn et al 2014; but see also Woodruff 2010), which could have limited the exchanges of forest-dependent species between Borneo and the rest of the Sundaic region (Veron et al 2014;2015c), and this could have affected the Hemigalinae civets.…”