Yunnan province, southwest China, is one of the most diverse floristic regions on Earth and forms a major part of the Indo/Burma biodiversity hotspot. A wide range of forests distributed across steep environmental gradients are found in Yunnan. Climate change could profoundly change these forests by affecting species ranges. Predicting how the woody flora will respond to these changes is necessary to adapt regional conservation strategies so as to minimize or mitigate the climate change impact on the plant diversity of Yunnan.
Dr. ZHANG Minggang and his teachers of Xishuangbanna Tropical Botanical Garden (XTBG) conducted a study to focus on how climate change will affect the woody plant species distribution patterns of Yunnan in the context of developing conservation strategies. Their aims were to (1) evaluate species extinction risk and range change under two extreme assumptions about species dispersal (no dispersal vs. full dispersal); (2) examine the vulnerability of the different floristic regions of Yunnan to climate change; and (3) determine which environmental variables are responsible for current species richness and future local extinction.
Using MaxEnt, they modeled current distributions of 2319 woody plant species, corrected for collecting bias and found that 1996 had significant spatial association with environmental factors. Using three General Circulation Models (GCMs: CGCM, CSIRO and HADCM3) for the years 2070–2099 (2080s), based on three emission scenarios for each GCM (A1b, A2a and B2a), they predicted the future geographic position of suitable habitat for each species.
Their results implied that establishment of latitudinal migration corridors would not make a large contribution to woody plant species conservation into the future under changing climate. Their results also showed that most woody plant species in Yunnan would lose considerable amounts of their range due to the difficulty of moving northwards to track climate change, which might lead to considerable genetic erosion of those plant populations over time. At the local scale, in those areas that have been identified as essential for the conservation of Yunnan's woody plant flora (the conservation hotspots), conservation efforts should focus on providing ample elevational migration possibilities. Strategic reforestation in areas predicted to suffer most from increasing climate instability should therefore be considered to prevent a negative feedback between climate change and habitat degradation as has been observed in many other regions in the world.