Research On The Evolution Of Ecological Environment In Qilian Mountains National Park Based On Multi-source Data

Qilian Mountain National Park is one of the natural barriers to ensure the ecological balance in northwestern China and one of the first batch of pilot areas of national park system.Hydrothermal resources are two important factors throughout the evolution process of terrestrial ecosystem,which determine the background pattern of ecological environment in the study area.And them also affect the virtuous cycle and sustainable development of regional mountain-oasis-desert system.With multi-source data as input,SPEI,RSEI and CCDM were constructed to study the evolution of the ecological environment of Qilian Mountains National Park,and to explore the coupling and coordination relationship between hydrothermal regime and ecological environment and its future development.It will provide a reference for the ecological environment protection and ecological restoration path of Qilian Mountain National Park.The research results show that:(1)Qilian Mountain National Park has warming and wetting trend,and the periodicity of dry-wet alternation is obvious.Severe drought events mostly occur in summer.The mutation from drought to wet occurred in 2014.Sunan station-Yanniugou station is divided into dry and wet trend boundaries,showing the spatial distribution law of "wet in the west and dry in the east;wet in the middle and dry in the edge".Dry-wet alternation takes 19 years as the cycle.The study area is in the wet period and has a short-term trend of continuous wet in the future.(2)The overall ecological environment of Qilian Mountain National Park experienced a process of deterioration first and then gradual recovery.The change of ecological environment has a polarization trend in space-time angles.From 1989 to 2019,the ecological environment quality in the study area was mainly good,and the type of regional weak ecological land changed to the better ecological environment level.This indicates that the ecological environment is developing for the better.The ecological grade improvement area changed from a dry state to a wet state,which significantly alleviated the regional drought.Because the snow-ice covering area shrinked seriously,people need to focus on it.(3)There are obvious regional differences in hydrothermal status,ecological environment status and their coupling relationship in Qilian Mountain National Park.Except for the drought trend in the region of 1745–2700 m,other altitudinal bands show completely opposite warm-wet trend.In each vertical zone,the ecological environment quality and the coupling relationship gradually decrease with the increase of altitude.At the same time,each altitude band show the process of ecological environment first destroying and then gradually recovering,and the coupling coordination degree show a positive development in different degrees.(4)The hydrothermal regime of Qilian Mountain National Park are constantly coordinated with the ecological environment,and continue to develop well in the future.During the study period,the regional coupling and coordination relationship had experienced three stages: running-in development(1989–2007),transformational development(2007–2016)and coordinated development(2016–2019).At the time of coupling and coordination degree improvement,it is necessary to focus on dysregulated recession areas in Sunan Yugur Autonomous County,Minle County,and Qilian County.The future coupling and coordination relationship,between ecological environment and hydrothermal conditions,will develop exponentially,and enter a highly coupled and coordinated development state around2037.The future study area will have a better environmental foundation in terms of regional development.