Extended Data Fig. 1: Distribution of tree species richness across Southeast Asia for all 1498 species, 11 species groups, and for all species across our study period.
From: Conserving Southeast Asian trees requires mitigating both climate and land-use change
(a) The projected distribution of weighted tree species richness across SEA based on a dataset of 1498 species. Weighted richness was calculated by weighting the presence of each species based on the size of their respective species group—each species group contributed equally—before min-max scaling the values (1 represents the presence of all 1498 species). Lower data availability in Sundaland meant a smaller fraction of known tree species from that region could be modelled, as compared to Indo–Burma and subtropical East Asia. (b) The projected distribution of tree species richness for each group, which was scaled to 0-1 for consistency in values across panels. A total of 11 spatially distinct species groups were identified. Species groups were labelled based on expert knowledge and quantitative examinations of underlying environmental conditions. (a, b) Projections were under climate conditions for the year 1960 and an undisturbed land use scenario. (c) The projected distribution of weighted tree species richness in 1960 and 2019 and the loss of, and gain in, weighted richness from 1960 to 2019, due to past climate and land use changes. Projected gains followed a realistic migration rate. Within richness maps, blacked out areas indicated non-forested areas that persisted from 1960 to 2090, across SSPs. Colour gradients for weighted richness, and the loss of, and gain in, weighted richness, were scaled to 0–0.34 for clarity, with 0.34 representing the highest weighted richness value observed across grid cells, scenarios, and time periods. Climate-related changes in weighted richness was less distinct because climate change impacts among species (groups) were more spatially variable; for more detailed spatial trends see group-specific maps (Supplementary Figs. 7–17). Maps follow a transverse cylindrical equal-area projection with grid cells of 5 km by 5 km.
