Professor of Geosciences, Pennsylvania State University
Origins and Paleoconservation of Southeast Asian Rainforests
Abstract: Southeast Asia’s hyperdiverse, endangered tropical rainforests have assembled from multiple sources, reflecting the region’s dynamic history and geological complexity. Our multinational paleobotanical team is working to advance biogeographic understanding of SE Asian rainforest origins, using fossil floras from Patagonia and Australia (Gondwana); India and Pakistan (Indian Plate); Vietnam, Yunnan, and Tibet (continental Eurasia); and Sumatra and Borneo (Malay Archipelago). Concurrently, we are developing a computer-vision application for fossil-leaf identification as a breakthrough tool for the project and general paleobotany. This seminar will spotlight our recent discovery of the first fossil-leaf floras from Brunei (northern Borneo), representing the first study of Cenozoic compression floras in the Malay Archipelago for ca. 100 years. Our two Pliocene sites are each dominated by remains of dipterocarps, the defining life form of SE Asian forests and an iconic group in SE Asian biogeography, ecology, forestry, and conservation. Strikingly, the rich pollen floras from the same strata as the leaves have almost no dipterocarp pollen, underscoring the significance of macrofossils for understanding the evolutionary history of dipterocarp-dominated ecosystems. Today, there are more than 160 endemic dipterocarp species in Borneo, of which more than 60% are threatened. Along with other discoveries from the new sites, our work shows that the principal structural, compositional, and environmental features of northern Borneo’s lowland vegetation have changed little for at least 4–5 million years, raising the conservation significance of their highly threatened yet still strikingly diverse and ecologically foundational living analogs. The presentation will conclude with a look at how the austral components of the SE Asian flora, as known from Gondwanan fossils, inform conservation and illuminate the high-risk biogeography of Anthropocene SE Asia.