Historical distribution of Sundaland's Dipterocarp rainforests at Quaternary glacial maxima.
The extent of Dipterocarp rainforests on the emergent Sundaland landmass in Southeast Asia during Quaternary glaciations remains a key question. A better understanding of the biogeographic history of Sundaland could help explain current patterns of biodiversity and support the development of effective forest conservation strategies. Dipterocarpaceae trees dominate the rainforests of Sundaland, and their distributions serve as a proxy for rainforest extent. We used species distribution models (SDMs) of 317 Dipterocarp species to estimate the geographic extent of appropriate climatic conditions for rainforest on Sundaland at the last glacial maximum (LGM). The SDMs suggest that the climate of central Sundaland at the LGM was suitable to sustain Dipterocarp rainforest, and that the presence of a previously suggested transequatorial savannah corridor at that time is unlikely. Our findings are supported by palynologic evidence, dynamic vegetation models, extant mammal and termite communities, vascular plant fatty acid stable isotopic compositions, and stable carbon isotopic compositions of cave guano profiles. Although Dipterocarp species richness was generally lower at the LGM, areas of high species richness were mostly found off the current islands and on the emergent Sunda Shelf, indicating substantial species migration and mixing during the transitions between the Quaternary glacial maxima and warm periods such as the present.
Naturalis Biodiversity Center, 2333 CR Leiden, The Netherlands; niels.raes@naturalis.nl.
Niels
http://orcid.org/0000-0002-4329-4892
N
Raes
Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Yunnan 666303, China; Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409;
Charles H
CH
Cannon
Department of Environmental Science and Policy, University of California, Davis, CA 95616;
Robert J
RJ
Hijmans
Institute Biology Leiden, Leiden University, 2300 RA Leiden, The Netherlands;
Thomas
T
Piessens
Forest Research Institute Malaysia, Kepong, 52109 Kuala Lumpur, Malaysia; and.
Leng Guan
LG
Saw
Naturalis Biodiversity Center, 2333 CR Leiden, The Netherlands; Institute Biology Leiden, Leiden University, 2300 RA Leiden, The Netherlands;
Peter C
PC
van Welzen
Faculty of Science, University Brunei Darussalam, Gadong, BE 1410, Brunei.
J W Ferry
JW
Slik
D002980:Climate; D065928:Forests; D008296:Malaysia
Dipterocarpaceae; Quaternary; Sundaland; last glacial maximum; species distribution model