Simulation And Prediction Of Ecological Environment In Qilian Mountain National Park Under Climate Change

As one of the first ten pilot national parks in China,Qilian Mountain National Park aims to protect the biodiversity as well as natural ecosystem integrity and authenticity.The Qilian Mountain National Park plays an important role in the implementation of China's "Belt and Road" policy and the construction of ecological civilization.It not only guarantees the health of China's western ecological security barrier,but also accumulates experience for ecological restoration and protection and acts as a reference for the construction of national park systems.In recent years,under the twofold pressure of climate change and human activities,the ecological environment of Qilian Mountain National Park has been facing severe challenges,with some areas experiencing vegetation degradation,soil erosion and glacier retreat.The study is based on the coupling of multi-source data and multi-models to accomplish the simulation and prediction of key elements of the ecological environment in Qilian Mountain National Park.It reveals the spatio-temporal evolution patterns of climate,land use,vegetation dynamics,soil erosion in the region and the possible future development directions.Meanwhile,it also helps to comprehensively reflect ecological environment problems and stresses that the park faces along with conservation effects.The ecological vulnerability evaluation index system is constructed for the characteristics of the ecological environment of Qilian Mountain National Park,and an artificial intelligence algorithm is introduced to build the evaluation model.It can grasp the spatio-temporal change characteristics of ecological vulnerability in Qilian Mountain National Park and predict the development directions of ecological vulnerability under different future scenarios.The results will provide a scientific basis for the construction and high-quality development of Qilian Mountain National Park.The main conclusions were as follows:(1)Based on the meteorological station data and site downscaling data of the Coupled Model Intercomparison Project v5(CMIP5)model,a rasterized simulation of historical-future meteorological factors and dry and wet conditions of Qilian Mountain National Park is realized by combining the thin disk smooth spline interpolation method with elevation as the covariate.The results demonstrate that the climate of Qilian Mountain National Park has experienced general warming and drying in the last 60 years.Particularly,the increased warming and drying under the future scenarios place the ecological sustainability of Qilian Mountain National Park at more risk.The annual maximum temperature,minimum temperature,mean temperature and precipitation in Qilian Mountain National Park indicated a significant increasing trend from 1960 to 2020(p < 0.05).The regional Standardized Precipitation Evapotranspiration Index(SPEI)value reflected a slight downward trend,and the spatial drought trend showed a characteristic of being strong in the east and weak in the west.In the future RCP4.5 and RCP8.5 scenarios,both temperature and precipitation will demonstrate a significant increase trend,and the temperature increase will be more obvious.Under RCP4.5 and RCP8.5 scenarios,the future temperature and precipitation show a significant increase(p < 0.05),and the increase in temperature is more obvious.Meanwhile,the increase in the RCP8.5scenario after 2050 is much higher than that of RCP4.5.The decreasing trend of SPEI under the RCP8.5 scenario is also significantly higher than that of the RCP4.5 scenario,and the drought trend in Qilian Mountain National Park will become more prominent.(2)Based on the regional land use cover historical datasets,the Cellular Automata Markov Chain(CA-Markov)model factor restrictions were adjusted for the specificity of Qilian Mountain National Park to achieve land use cover simulation and prediction under ecological protection scenarios.The results illustrate that the implementation of ecological projects has optimized the landscape pattern of Qilian Mountain National Park.The landscape pattern of Qilian Mountain National Park stabilized under the ecological protection scenario,and the landscape fragmentation was reduced,which contributed to the enhancement of regional ecosystem service functions.However,the glacier retreat caused by warming cannot be ignored.The rate of land use change in Qilian Mountain National Park shows a trend of initial increase followed by decrease.The general land use structure shows a significant decrease in glacier/snow,unused land,and construction land,and a significant increase in forest and grassland.At the landscape level,the fragmentation of the landscape pattern in Qilian Mountain National Park slightly decreases,the process fluctuates more,the landscape shape is more complex,while the level of landscape diversity increases.Under the ecological conservation scenario,the area of woodland in Qilian Mountain National Park increases significantly in the future(2030 and2050),mainly transferred from grassland and unused land,and the area of unused land and glacier/snow decreases.Meanwhile,landscape fragmentation decreases,landscape aggregation increases,and patch shape tends to be regularized.(3)Multi-source remote sensing vegetation index data with different spatial and temporal resolutions were assimilated to obtain long time series regional Normalized Difference Vegetation Index(NDVI)data.The simulation and prediction of vegetation carbon dynamics in Qilian Mountain National Park were obtained by localization and correction of Biome-BGC model parameters.The results show that the existing climatic conditions and ecological protection measures and policies have promoted the improvement of vegetation cover and carbon sequestration capacity in Qilian Mountain National Park.The changes of vegetation carbon sequestration capacity under different emission scenarios in the future are significantly different.The vegetation cover and Net Primary Production(NPP)in Qilian Mountain National Park showed a significant increasing trend from 1982 to 2020(p < 0.05).Precipitation was the dominant meteorological factor affecting vegetation NPP in Qilian Mountain National Park,and climate change and human activities had a positive effect on vegetation dynamics in most areas during the study period.The vegetation NPP exhibited a significant increase trend(p < 0.05)in the future RCP4.5 scenario,while the vegetation NPP showed a decrease trend in the RCP8.5 scenario.(4)Simulation of soil water erosion processes in Qilian Mountain National Park based on Revised Universal Soil Loss Equation(RUSLE)model for historical-future scenarios.A geodetector model was employed to reveal the driving factors of soil erosion under multi-factor coupling.The results indicated that extreme precipitation is the most direct factor affecting soil erosion risk in Qilian Mountain National Park.Although soil erosion is less in most areas of Qilian Mountain National Park,strong erosion in steep slope areas needs to be a focused concern during the implementation of future soil conservation measures.There was a slight or significant downward trend in soil erosion in 62.62%of the study area from 1982 to 2020,but the average soil erosion rate increased in the overall area,mainly because the rate of increase in soil erosion was considerably greater than the rate of decrease.There were significant differences in soil erosion in Qilian Mountain National Park under different future emission scenarios,with significantly higher soil erosion under the high emission scenario(RCP8.5)than the RCP4.5 scenario.(5)The ecological vulnerability index system is established for the ecological environment characteristics of Qilian Mountain National Park,and the ecological vulnerability assessment model of Qilian Mountain National Park is constructed based on the integrated genetic algorithm-projection tracing model.The spatio-temporal simulation and prediction of regional ecological vulnerability were realized by combining the relevant evaluation indexes of multi-model simulation and prediction.The results demonstrate that the implementation of ecological projects and policies has a positive effect on the change of ecological vulnerability in Qilian Mountain National Park,but an aggravation of vulnerability in the southeastern region.The risk of ecological vulnerability,especially under the future high emission scenario,has increased significantly.It is necessary to optimize the protection measures for the area of increased ecological vulnerability in the subsequent construction of Qilian Mountain National Park.