The dominant deciduous trees of tropical Asia (i.e., Tectona grandis, Shorea robusta, and Dipterocarpus turbinatus) form a mono-specific canopy and extend into the deciduous forests of South and Southeast Asia. They play an important role in the economy of many South and Southeast Asian countries being one of the primary species harvested for timber export. However, these deciduous trees and forest ecosystems are under threat from continuing deforestation, land use change and global climate change. Direct impacts of climate change have not been widely considered in this region due to the lack of availability of robust inventory data of trees. Therefore, we applied a bioclimatic modelling approach to three ecologically and economically important timber trees of South and Southeast Asian deciduous forests. We used presence-only records of tree species combined from field data, online database ‘global biodiversity information facility’ and literature records and nine bioclimatic variables that were most representative for the current distributions of selected deciduous trees. We selected two climatic scenarios (RCP6.0 and RCP8.5) and compared the distributions of current, 2050 and 2070 using MaxEnt.
Results/Conclusions
The key predictor variables that had significant contribution to explain the current and future climate suitability of Tectona grandis, Shorea robusta and Dipterocarpus turbinatus were land cover types (20.5%), temperature seasonality (25.5%) and annual precipitation (34.7%) respectively. Overall, Dipterocarpus turbinatus dominated forests will be the most affected, losing 38% of their climate space in 2070 under the extreme climate scenario. Although Shorea robusta will gain some climate space (5%) in 2050 under RCP6.0, it is likely to lose climate suitability in 2050 and 2070 under RCP8.5. The shifts are observed towards the northern and eastern part in India for Shorea robusta forests which indicates the suitability of alluvial soils and red loam soils in that region due to higher water holding capacity and greater moisture content. The least affected species Tectona grandis are likely to gain 4% of their climate space in 2050 under RCP 6.0 across the South and Southeast Asia. The deciduous forests of Bangladesh, Myanmar, and Cambodia are likely to suffer most due to global climate change. The quantitative findings of this study could be tailored to suit a decision making process by identifying critical habitats, selecting reserves and translocating endangered species.