Current and future floral biodiversity patterns in Thailand

This study used botanical records to investigate the effects of climate change on species richness patterns in the continental part of Southeast Asia, defined by the latitudes 1°–23.5° N and longitudes 92°–109.6° E. Collection records of 15032 species of the 48 largest plant families currently described in the Flora of Thailand project were used to develop Species Distribution Models (SDMs) with MaxEnt, based on bioclimatic and edaphic conditions at known species occurrence sites. Bias-corrected null-models were used to test the SDMs for significant deviation from random expectation. Stacked ranges of 4048 significant SDMs (27% of species) indicated that current areas of high species richness are located in the southern part of the Malay Peninsula, the northern parts of Laos and Vietnam, as well as in southern China. To predict the impact of future climate change on species richness in mainland Southeast Asia the SDMs were projected to multi-model ensemble means of bioclimatic conditions for the most optimistic (RCP2.6) and worst case (RCP8.5) development scenarios of global climate change for the year 2070. High species losses were predicted for the species-rich areas in the north and south of the study area, while areas to the west and east showed an increase in species richness. High species turnover rates were found in western Myanmar (border effect likely) and at a narrow stretch connecting eastern Myanmar with southern Vietnam. These regions should get the highest priority for protection of botanical diversity.