Potential distribution of Abies, Picea, and Juniperus species in the sub-alpine forest of Minjiang headwater region under current and future climate scenarios and its implications on ecosystem services supply

Abstract

Mountain forest ecosystems provide us with life-supporting ecosystem services that are valuable for local, regional, and global communities. Ecological niche-based models have been used extensively, with remarkable success, in understanding the influence of climate change on potential distribution of species. In this study, we used maximum entropy (MaxEnt) modelling to predict the potential distribution of ecologically important tree species, Abies, Picea, and Juniperus, at the eastern edge of the Tibetan Plateau in China. The potential distribution of tree species was modelled and predicted on genus level for current and three representative concentration pathway (RCPs) based future (2050s and 2070s) climate conditions. The model performed well and gave reliable results for current and potential species’ distribution. Precipitation of wettest month was the most important environmental variable for determining the habitat suitability of all tree species, with 30.3% (Abies), 51.2% (Picea), and 57% (Juniperus) contribution to model output, respectively. Temperature seasonality, temperature annual range, and soil type also made the most significant contribution to model outputs. Model projections under current climate highlight that the total suitable habitats, which included regions with different probability of species occurrence, for Abies (3234.2 km2) was much higher than Picea (2003.7 km2) and Juniperus (1784.8 km2). However, projections of habitat suitability under current climate scenario projected onto future climate change scenarios for all concentration pathways in 2050s and 2070s, showed a clear decline in potentially suitable habitats for all three species. The shifts in geographic distributions under future climate scenarios showed an unusual pattern, with slight downward shift of the mean elevation with high habitat suitability for the occurrence of tree species in most RCPs, accompanied by a decrease in the elevational range of suitable habitats. The results of this study highlight the urgent need for forest management strategies to conserve the habitats of these species. Our study offers base-line information on the impact of climate-change on major tree species which can aid in guiding adaptation strategies for forest conservation and management in order to sustain the delivery of ecosystem services in the future.