Resilience of Southeast Asian Lowland Rainforest to large-scale climatic changes
Dipterocarp forests of Southeast Asia are one of the oldest and most diverse forests on the planet. Due to their high timber value they have been reduced to only 50% of their previous range and continue to have world’s highest deforestation rates. Projected climate change is expected to exacerbate current threats to these forests.
The nature and extent of the impacts of climate change on biota is difficult to forecast as most of our data on species distribution and dynamics have been collected in recent past (<150 years). Unlike palaeoecological records, observational datasets rarely encompass climatic changes comparable to those projected for the future. Thus, long-term ecological data play a crucial role in improving our understanding of the potential response of species and ecosystems to the upcoming climate change. Virtually nothing is known about the long-term dynamics of Dipterocarp forests and their capacity to persist under changing climates. The aim of this project is to provide valuable insights on the subject by generating the first paleorecord of Dipterocarp forest dynamics, spanning the last 2,000 years.
More specifically, I aim to answer some of the long-standing questions about the ecology of Dipterocarp forests. For instance, how do large-scale changes in El Nino/ Southern Oscillation (ENSO) variability affect supra-annual mast fruiting events in these forests? To what extent major changes in drought and fire regimes influence forest composition and structure? What are the mechanisms underlying the resilience of Dipterocarp forests to large scale climatic changes? To tackle these questions, I will be taking a multi-proxy approach, examining fossil pollen, macrocharcoal, leaf wax compounds and geochemical signatures from the sedimentary sequence of Bulusan lake, Philippines. These records will allow direct measurement of the rate and magnitude of Dipterocarp forest responses to a range of environmental disturbances such as drought, fire and volcanic eruptions. The sediments have been collected in April 2013 and the described analyses are underway.