Abstract:This study obtained 108 sampling sites through specimens and field investigation of Picea purpurea, and screened 13 environmental variables and 3 climate scenario models in the future provided by CMIP6 for analyzing the changes of P. purpureas distributions under different climate conditions based on MaxEnt model and GIS. Meanwhile the response curves of main environmental variables affecting the growth of P. purpurea were obtained and the environmental conditions suitable for the P. purpureas survival were described quantitatively. The results showed that: (1) MaxEnt model for predicting the distributions had high credibility because of high AUC values of both training data and test data. The distributions of P. purpurea are mainly concentrated in the eastern edge of Qinghai-Tibet Plateau, including northwestern Sichuan, southern Gansu, southeastern Qinghai and eastern Tibet. (2) It indicated that high distributions were mainly located in the northwestern Sichuan, southwestern Gansu, which covered an area with 40 937 km2. Medium distributions covered an area of 167 344 km2, extending from high distributions. Low distributions had most widespread with an area of 567 257 km2, occupying more than 73% of distributions. (3) The analysis of Jackknife test and response curves showed that main factors influence on distributions of P. purpurea were altitude (percent contribution was 44%) and precipitation (the accumulative contribution rate was 45.6%, while percent contribution of annual precipitation was 32.1%) firstly, then the temperature (the accumulative contribution rate was 10.3%, while percent contribution of mean temperature of coldest quarter was 5%). Meanwhile, response curves of main environmental variables had significant peaks. The suitable regions for P. purpureas growth were those where altitude, annual precipitation, mean temperature of coldest quarter were around 2 600-4 200 m, 590-820 mm, -9.8--1.4 ℃, respectively, while the most suitable values were 3 600 m, 712 mm, -7 ℃, respectively. (4) In the future, the distributions of P. purpurea extended to west and north compared with contemporary distributions and a few amount of area lost in southern Tibet. Overall, the area of suitable habitat showed a growing tendency, and it covered the largest distributions under the condition of ssp370 in 2081-2100, with an area of 1 091 404 km2.
