Ecological Effects And Climatic Responses Of Land Cover Change In Arid Areas Under The The Policy Of Grain For Green Project

Healthy and stable ecosystem is the basis of human survival and development,and also an important guarantee for China’s economic and social development to a high quality in the new era.The policy of converting farmland to forest is a key ecological project in China aiming at stopping cultivation,afforestation,vegetation restoration and preventing and controlling soil erosion.Over 20 years,the policy of Grain for Green Project has played a great role in restoring ecosystem,creating ecological value and helping to alleviate poverty,especially breaking the vicious circle of environmental deterioration and poverty aggravation in fragile ecological areas.However,although the academic circles have discussed the ecological effect assessment of the policy of returning farmland to forest,mature and applicable evaluation system is still a major challenge.Due to the lack of comprehensive monitoring and evaluation technology system,the system of inspection and acceptance and benefit evaluation is not perfect,the implementation effect of policy projects in some regions is poor,so the stability of engineering quality and engineering effect needs to be improved.Under the background of the central government’s proposal to build ecological civilization,strengthen comprehensive land and space renovation and ecological restoration,how to scientifically and reasonably evaluate the impact of the policy on regional ecological environment and further explore the response of climate change is the key link and core of scientific evaluation of the implementation effect of the policy,and further consolidate and expand the achievements of the project to further consolidate and expand the project It is necessary to maintain the regional ecological security and provide reference for exploring the harmonious relationship between human and land in the fragile ecological areas.This study takes Guyuan City of Ningxia Hui Autonomous Region as the research area,and studies the land use cover change in arid and semi-arid areas in Northwest China in the past 20 years since the implementation of the policy of returning farmland to forest from the three dimensions of the structure,quality and function of the ecosystem.Based on this,the ecological effect and climate response characteristics of regional land use change in the past 20 years are further revealed Finally,the paper puts forward the policy suggestions of ecological protection and restoration in the vulnerable areas of resources and environment,and the optimization of the policy of returning farmland to forest.In the research ideas,first,through literature review,the relevant contents and evaluation methods of the implementation evaluation of the policy of converting farmland to forest are sorted out,and the law of land use change in Guyuan City in the past 20 years has been revealed.Further,the service function value,habitat value and habitat of regional ecosystem are analyzed by using landscape pattern index,habitat quality model,current value method and Arc GIS spatial analysis.Finally,taking two key indexes of temperature and precipitation as an example,the paper further explores the response characteristics of climate system to land use change during the implementation of Grain for Green Project,so as to deepen the understanding of the complex role of human and land under the interference of ecological policies in fragile ecological areas;finally,the specific reality of the implementation of the policy of returning farmland to forest in Guyuan city is summarized.In order to realize economic development and ecological environment protection in vulnerable ecological areas,we put forward corresponding policy suggestions including building ecological security barrier,strengthening policy coordination,promoting comprehensive governance and developing green economy.The results show that:(1)in the past 20 years,cultivated land in Guyuan city has decreased obviously,the area of forest and grass has increased,the area and proportion of forest and grass change are the largest in the slope range of 6 °-15 ° and15 °-25 °,the degree of grassland concentration has been improved,but the fragmentation degree of cultivated land increases,landscape diversity and concentration degree increase,but fragmentation has not been found The results showed that the service value of cultivated land ecosystem was improved significantly;(2)under the implementation of the policy,the ESV of woodland and grassland increased by 54 million yuan and 71 million yuan respectively.Affected by the decrease of cultivated land area,the value of food production and other supply services decreased significantly,while the value of soil conservation and biodiversity maintenance and other regulation and support services increased.The increased ESV after the implementation of the project compensated for the loss of ESV caused by construction land expansion and reclamation activities,and ensured the sustainable development of land(3)the ecological quality of vegetation in Guyuan City showed a trend of continuous improvement,the spatial distribution of low value vegetation area decreased sharply,the expansion trend of medium Vegetation cover area was obvious,and the NDVI was improved in spring,summer and autumn.(4)under the background of comprehensive improvement of land space and ecological protection and restoration,ecological protection in ecologically fragile areas should pay attention to the combination of overall protection and systematic restoration,and firmly build the ecological system with key projects Finally,the regional ecological environment is in a continuous virtuous circle.