| Ecological land is the core carrier that provides the function of ecological service and ecological product.It is also an important nature resource to maintain and stabilize the regional ecological balance.The rapid development of social economy and the acceleration of urban expansion continue to occupy the ecological land,leading to the emergence of many environmental problems.At present,the space of rural ecological land is constantly squeezed and destroyed by urbanization and industrialization construction,and the spatial imbalance of ecological functions seriously restricts the sustainable development of rural areas and affects the process of agricultural and rural modernization.It is an important guarantee for ensuring the ecological security,reducing ecological risks and improving the quality of life in rural areas that optimizing the space distribution of rural ecological land and giving full play to its ecological service function.This study takes the traditional agricultural area in the upper reaches of the Yangtze River–the hilly area of Sichuan as an example.Under the guidance of systematic theory and ecology theory,theory of geography and space planning theory,a systematic study was carried out on identification,evaluation and layout optimization of rural ecological land configuration by means of quantitative analysis method,spatial analysis method and mathematical model method.The research contents and results were listed as follows:(1)There are various types of rural ecological land in the hilly area of Sichuan,and the spatial distribution are different.There is a one-to-many correspondence between the types of ecological land and the ways of land use.From 2 aspects of rural ecological land,suitability characteristics and functional characteristics,6 indexes constructs the rural ecological land identification index system,that includes relief amplitude,ecological sensitivity,distribution of geological hazard points,habitat quality,ecological importance and the way of land use,to identify and divide the rural ecological land use comprehensively into 3 types of ecological land,core,auxiliary,and the bottom line.The result shows that the acreage of core,auxiliary and urgent ecological land is 18289.16km~2?30723.51km~2?37974.17km~2,accounting for 20.48%,34.41%and 42.52%of the study area,respectively.The core ecological land is mainly distributed in the deep hilly narrow valley area with complex terrain,and the auxiliary and baseline ecological land is evenly distributed in the shallow hilly and plain area with small topographic undulation.Under the influence of human activities,spatial distribution of geological disasters and differences in landform and physiognomy,there is a one-to-many correspondence between the types of rural ecological land and the types of land use/cover.For example,the core ecological land is dominated by forest land,grassland and water,while the auxiliary and baseline ecological land are dominated by arable land.(2)The rural ecological land in the hilly area of Sichuan has significant horizontal zonality and vertical zonality.As time goes by,the total scale of ecological land is decreasing,but the quantity of local ecological land is increasing and the spatial structure is more stable.From the perspective of horizontal zonality,the core ecological land is mainly distributed in the area 35km away from the city center,25km away from the industrial park and 3.5km away from the main traffic road.The bottom line ecological land is mainly distributed in the area within 10?20km from the city center,5?15km from the industrial park,and 1.5?2km from the main traffic road.From the perspective of vertical zonality,core ecological land is mainly distributed in areas with an elevation greater than700m or a slope greater than 25°.The auxiliary and bottom-line ecological land is mainly distributed in the area with an elevation of 250?700m or a slope of 6?25°.From 2000 to2018,the total amount of rural ecological land in the research area decreased by 283.04km~2.As time goes by,the decrease rate of rural ecological land is accelerating.The decrease trend of ecological land is obvious when the elevation is less than 700m or the slope is less than 25°,mainly for the bottom line and auxiliary ecological land types.From2000 to 2018,the core ecological land distributed in the topographically complex region increased by 131.71km~2,and the structure of the ecological land in this region tends to be stable.(3)The areas‘eco-efficiency has been improved but the overall value remains relatively low in the hilly area of Sichuan.The spatial distribution pattern of regional ecological efficiency value gradually changes from high in the surrounding area and low in the middle to high in the southwest and low in the northeast,and the improvement of ecological efficiency will gradually change from factor driven to technology driven.In this study,from land,capital,labor and other factors,ecological land acreage,fixed assets input,rural labor,ecological adjustment service value,support service value,landscape culture service value,added value of agriculture,forestry,animal husbandry and fishery,and agricultural non-point source pollution are selected to construct a measure index system of rural ecological efficiency.From 2000 to 2018,the average value of rural eco-efficiency has increased from 0.731 to 0.826.But the overall situation is still at a low value,and there is potential to improve the ecological efficiency of rural areas in the future.The spatial agglomeration of rural ecological efficiency is remarkable.As time goes by,the spatial pattern of its efficiency value gradually changes from high around and low in the middle to high in the southwest and low in the northeast.With the overall development of society and economy,the improvement of ecological efficiency will be gradually transformed from factor driven to technology driven,that is,the improvement of regional ecological efficiency mainly depends on the improvement of education level,the investment and application of advanced production technology and capital,the government's macro-control ability and other factors.(4)The pressure of rural ecological environment in the hilly area of Sichuan is always in the upward stage,and the pressure of production in rural areas is higher than the pressure of living.The hilly area of Sichuan has a high degree of ecological constraints,and the degree of regional ecological constraints is significantly related to the type and area of ecological land.From 2000 to 2018,the pressure index of rural eco-environment increased from 0.529 to 0.758,with an increase of 43.29%.Among them,population and economic growth have a positive pulling effect on the pressure of rural ecological environment,while technological progress has a negative reducing effect on the pressure of rural ecological environment.The area proportion of low,median and high value of ecological constraint regionalization in the hilly area of Sichuan is 22.18%,25.18%and52.64%,respectively.The high value of ecological constraint regionalization is mainly distributed in the shallow hills of both sides of Jialing River,Fujiang River and Tuojiang River basin.The low value of ecological constraint regionalization is mainly distributed in the deep hills and low mountains of northeast and southwest of study area.The degree of ecological constraint regionalization is inversely proportional to the core and auxiliary ecological land(woodland,water,grassland)within the region,and positively proportional to the bottom and non-ecological land(farmland and construction land).(5)The optimized layout of rural ecological land based on ecological constraint regionalization will effectively improve the rural ecological efficiency and reduce the pressure of rural ecological environment.Under the natural evolution scenario,the increase of core ecological land mainly occurs in the regions far away from the towns,and the regional ecological environment will be further deteriorated due to the inability to solve the ecological environment problems aggravated by the expansion of towns and industrial development.Under the scenario of ecological optimization,the proportion of core ecological land will be increased in the high-value area of ecological constraint regionalization,and the proportion of non-ecological land will be increased in the low-value area of ecological constraint regionalization,so as to relieve the pressure of rural ecological environment.This study innovatively establishes the system of identification and classification of the rural ecological land based on multivariate data,puts forward and establishes the index system of the rural ecological efficiency evaluation and index system of evaluation rural ecological environment pressure.On the basis of the countryside ecological efficiency evaluation and the ecological environmental pressure evaluation,the study achieves the rural ecological constraint partitions.Based on this,the layout optimization simulation experiment of rural ecological land was carried out.In this paper,a systematic analysis of identification,classification,evaluation and layout optimization simulation of rural ecological land use is carried out.The research results can provide important reference and technical support for the optimization of rural space,the redistribution of land resources,the implementation of rural revitalization strategy and the construction of ecological civilization. |
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