The Trade-offs And Synergies Of The Ecological-Production-Living Functions Of Grassland And Its Spatial Pattern Optimization In The Qilian Mountains By Ecological Priority

Grassland is the main body of the Qilian Mountains ecosystem,which plays an important role in the development of animal husbandry production,supporting the herders livelihood and the maintenance the Hexi Corridor oasis stability.However,Grassland degradation has caused increasingly prominent conflict between ecological environment conservation and socioeconomic development in the Qilian Mountains,China.The grassland ecological protection policy of ecological priority has changed the original functional structure of grassland ecosystem and the livelihood mode of herdsmen in Qilian Mountains,resulting in a new trade-off and synergy between ecological protection and social and economic development.Therefore,how to scientifically and effectively trade-offs and synergies to grassland ecological security,animal husbandry production and herdsmen livelihood in the context of ecological priority,and comprehensively consider the coupling coordination between ecological and socio-economic is essential to achieving the sustainable development of the grassland ecosystem in the Qilian Mountains pastoral area.In this study,the analytical framework,evaluation index system and model of grassland ecosystem service function trade-off and synergy and spatial optimization regulation were constructed from the perspective of “ecological-production-living”functions(EPLFs).The purpose was to study the trade-off and synergy of grassland EPLFs and its spatial pattern optimization during the implementation of the Grain to Green Project,the grassland ecological compensation policy and national park construction in Qilian Mountains from 2003 to 2020.This study clarified the temporal and spatial distribution characteristics and the key driving factors of grassland EPLF trade-off and synergy and revealed the formation mechanism of the trade-offs and synergies of the grassland EPLF in the context of ecological priority in the Qilian Mountains.The optimal allocation scheme,regulation countermeasures of the spatial distribution of grassland EPLF were put forward based on the multi-functional collaborative optimization scenario.It provides a scientific basis for national park construction and the sustainable development management decision of grassland ecosystem in the Qilian Mountains.The main results in this study are as following:Firstly,with the implementation of the ecological priority strategy,the production and living space of grassland has been squeezed,resulting in the structure imbalance of grassland EPLF in the Qilian Mountains.The long-term grazing prohibition of grassland was not conducive to the recovery of grassland health and sustainability,increases ecological risks,restricts the economic development of grassland animal husbandry and the livelihood of herdsmen.The sustainable development of grassland ecosystem in the Qilian Mountains is facing great challenges.Therefore,it is the key to realize the coupling and coordinated development of grassland EPLF in the Qilian Mountains to explore the green development mode of grassland ecological protection and livelihood of herdsmen improvement of the Qilian Mountains in the context of ecological priority.Secondly,the construction of national parks had caused a decrease in the number of livestock grazing in rangeland and a decrease in the economic income of herdsmen,which had a significant positive impact on the ecological function of grasslands of the Qilian Mountains.But,it had a significant negative impact on production and living of grassland.Therefore,it is necessary to correctly handle the relationship between the grassland EPLF and the construction of national parks,prevent the "one-size-fits-all" grassland management method,establish a system protection and comprehensive development and utilization mechanism for mountains,rivers,forests,fields,lakes,grassland,ice and deserts,and realize the harmony and sustainable development of man and nature of the Qilian Mountains in the context of ecological priority.Thirdly,the grassland EPLF showed significant spatial-temporal differentiation characteristics in the Qilian Mountains.The ecological function was consistent with the production function,trending upward initially and then decreasing.The living function showed a trend of continuous increase from 2003 to 2020.The spatial pattern of grassland EPLFs showed that the northwest and southeast were more active than the middle of the Qilian Mountains,and the regional gradient difference was apparent.The trade-off and synergy relationships of grassland EPLFs had obvious spatial correlations as well;spatial differences were evident under different conservation policies.With national park construction and strengthen environmental control efforts,the synergistic relationship gradually weakened,and the trade-off relationship gradually strengthened.The result showed that the trade-off was the dominant relationship between the grassland EPLFs in the Qilian Mountains,which was not conducive to the coupling and coordination development of grassland EPLFs in the Qilian Mountains.The study also demonstrated that maintaining moderate grassland grazing pressure and the appropriate number of herdsmen is crucial to sustainably developing the grassland ecosystem in the Qilian Mountains.Fourthly,the grassland EPLFs of Qilian Mountains showed a nonlinear relationship of cross symbiosis,interaction,mutual influence and mutual restriction.The imbalance between supply and demand of grassland ecosystem services,social choice preference and the demand difference of different stakeholders were the main reasons for the formation of the trade-off and synergy relationship of the grassland EPLFs in the Qilian Mountains.With the Grain to Green Project to the construction of the Qilian Mountain National Park,the intensity of trade-offs and synergies of grassland EPLFs in Qilian Mountains was also increasing.It showed significant differences in space.The interaction between natural factors and economic factors was the main driving force for the trade-off and synergy spatial and temporal changes of grassland EPLFs in Qilian Mountains.Fifthly,the results of suitability evaluation based on MCR model showed that the spatial distribution of suitability is dominated by ecological dominance in the Qilian Mountain National Park,coupled coordination in the eastern area,and production dominance in the southern area outside the national park.The ecological suitability is gradually weakened from the east to the northwest,and the northern slope is stronger than the southern slope.According to the identified corridors and nodes of ecological and production and living sources in Qilian Mountains,the spatial layout structure was constructed for "two corridors and four circles" of grassland EPLFs in the Qilian Mountains.Combined with the natural conditions and ecological resources characteristics of the Qilian Mountains grassland,a differentiated grassland EPLFs optimization control strategy and development ecological animal husbandry policy recommendations were proposed.