A comparative assessment of climate change effect on some of the important tree species of Hindu-Kush Himalayas, using predictive modelling techniques

A comparative assessment of the effect of global climate change on some the ethno-medically and socio-economically important tree species was carried out in the Hindu-Kush Himalayan mountains. The primary study site chosen was the Swat Valley of Northern Pakistan, which is a unique biodiversity hotspot supporting some important ethnomedicinal plant species. The species assessed for the future climate change effects were: Acacia modesta Wall., Abies Pindrow (Royle ex D.Don), Pinus wallichiana A. B. Jackson, Royle. and Taxus baccata L. The Maximum entropy (MaxEnt) modelling technique of species prediction and distribution was used, applying HADCM3 (Hadley Centre Coupled Model, version 3) which is a coupled atmosphere-ocean general circulation model (AOGCM) and A2a global climate change scenario. Results suggest that by the year 2080, there will be a significant change in the distribution and density of these species. It was found that Acacia modesta will have significantly higher density, expanding to the southern and central parts of the Valley, i.e. the lower basin of Himalayas. The remaining three species have produced opposite results to Acacia modesta, as they will significantly reduce in their density and restrict in their distribution in the Valley. The results show that all species will have altitudinal movement to the northern cooler climatic regions of the Himalaya/Hindu-Kush. Results related to the validity of the models indicate “good model” for all species in both present and future predictive models attaining very high AUC values, i.e. 0.989, 0.98, 0.95, and 0.961 for training data for Acacia modesta, Abies pindrow, Pinus Wallichiana, and Taxus baccata, respectively. The results suggest that in the future, some of the species will have increased population density, probably at the expense of other useful plants while other will get confined to very small sub-climatic regions. These changes will alter the socio-ecological environment of the fragile Himalaya-Hindu-Kush Mountains which can ultimately result in food and medicine scarcity not just for the inhabitants of the area but in the entire network of national and international supply chain.