| In the context of China’s rapid urbanization,urban and rural construction land is the most active type of land use change.With the rapid economic and social development,strategies such as new rural construction and rural revitalization have promoted the development of rural construction land mainly based on rural settlements.Since the Three Gorges Reservoir Area was put into operation,it has brought huge benefits in terms of water conservancy regulation,waterway transportation,energy generation,etc.,and promoted the rapid economic and social development of the middle and upper reaches of the Yangtze River.However,the Three Gorges Reservoir Area is also facing geological disasters,water environmental pollution,Ecological and environmental issues such as ecological fragility,the complex mechanism of interaction between the transformation of urban and rural construction land and the regional ecological environment;an in-depth analysis of the characteristics of the transformation of urban and rural construction land in the Three Gorges Reservoir Area and its ecological environmental effects will help achieve overall urban and rural development and build an ecological barrier in the upper reaches of the Yangtze River.Promoting the green development of the economy and society has important strategic significance.From the perspective of land use transformation,based on land use data,DEM data,and ecological environment data in the Three Gorges Reservoir Area.The characteristics of the obvious transformation of urban and rural construction land in the Three Gorges Reservoir Area are revealed from the quantitative characteristics of structure,source and destination,landscape form,and spatial distribution characteristics.Constructing a comprehensive index model of the recessive morphology of urban and rural construction land from the dimensions of urban and rural construction land structure index,efficiency index,and function index,to describe the recessive morphological change process of urban and rural construction land,and quantitatively analyze the characteristics of recessive transformation of urban and rural construction land in the Three Gorges Reservoir Area.Evaluate the habitat quality and the degree of habitat degradation in the Three Gorges Reservoir Area,analyze the temporal and spatial changes of the habitat quality in the reservoir area,and qualitatively judge the relationship between urban and rural construction land and regional habitat quality;construct a pixel-corrected ecological environment quality index to analyze the temporal and spatial characteristics of ecological environment quality changes On this basis,the ecological contribution rate is used to quantitatively analyze the impact of the transformation of urban and rural construction land on the ecological environment,and reveal the ecological environmental effects of the transformation of urban and rural construction land.The main analysis results are:(1)From 2000 to 2018,the scale of urban and rural construction land in the Three Gorges Reservoir Area was as follows: urban land> rural residential land> other construction land;the share of rural residential land and other construction land in the urban and rural construction land of the reservoir area gradually decreased.The reduction of urban and rural construction land includes conversion to other non-construction land and internal conversion of urban and rural construction land;the sources of newly added urban and rural construction land are mainly cultivated land and forest land.The rapid increase in urban land patch area(CA)reflects the rapid expansion of urban land mainly in the "extensional" style,and the rapid increase in the number of rural residential land patches(NP),reflecting the "enclave-like" expansion process of rural residential land.The obvious transformation of urban and rural construction land has obvious spatial pattern characteristics.The areas with the most obvious transformation are concentrated in the main urban area of Chongqing.Affected by urban expansion,the transformation and changes in these areas are mainly due to the rapid and large expansion of urban land.(2)Select indicators from the dimensions of structure index,efficiency index,social function index,economic function index,ecological function index and other dimensions to construct a comprehensive index model of the recessive form of urban and rural construction land to describe the process of recessive form change of urban and rural construction land.From 2000 to 2018,the change rate of the comprehensive index of the recessive morphology of urban and rural construction land in the Three Gorges Reservoir Area has both positive and negative values,reflecting the complex situation of the recessive transformation of urban and rural construction land in the Three Gorges Reservoir Area,both increasing and decreasing;the recessive urban and rural construction land The spatio-temporal pattern of transformation has obvious characteristics,and there are far more areas where the level of implicit transformation has increased than areas that have fallen.The analysis shows that the transformation of urban and rural construction land in the Three Gorges Reservoir Area has problems such as rapid expansion of urban land and waste of land resources,unbalanced spatial distribution of urban and rural construction land and unreasonable structure.(3)The quality of the habitat in the Three Gorges Reservoir Area showed an overall upward trend from 2000 to 2018.The spatial pattern of areas with higher habitat quality is steadily increasing,mainly distributed in major mountain ranges and areas far away from urban and rural construction land.Its effect on the ecological environment quality of the reservoir area is more obvious;low quality grades increase by 3.67%,and the spatial location of expansion Mainly focus on the expansion of urban and rural construction land.The habitat degradation areas are mainly located in the built-up area of the main city of Chongqing,and continue to expand outward.Urban and rural construction land is mainly used for urban land,which has certain negative effects on the habitat quality of the local area of the Three Gorges Reservoir.Impact: The average value of habitat quality "increased first and then decreased",showing an overall upward trend,increasing from 0.6197 in 2000 to 0.6264 in 2018.It reflects that there is a slight decline in local regional habitat quality in the reservoir area,but its impact on the overall habitat quality of the Three Gorges Reservoir Area is not obvious,and the overall habitat quality of the reservoir area is gradually improving.(4)From 2000 to 2018,the quality of the ecological environment in the Three Gorges Reservoir Area gradually increased,with a spatial distribution characteristic of "high in the east and low in the west",and the spatial pattern showed a change in the characteristics of "two expansions".The ecological environment low-quality areas and high-quality areas have expanded significantly.The high-quality areas increased by 7.79%,with an average annual increase of more than 0.4%,and the low-quality areas increased by 2.56%,with an average annual increase of less than 0.14%.The high-quality areas increased significantly higher than the low-quality areas.Area increase rate.This reflects that the quality of the ecological environment in some areas has declined,but the overall ecological environment of the Three Gorges Reservoir Area is obviously showing a trend of improvement.(5)The transformation type that promotes the improvement of local ecological environment quality is mainly from urban and rural construction land to forest land,cultivated land and water area.These land use types contribute to regional biodiversity protection,ecological environment self-purification and restoration,and ecological environment stability,etc.Very important;but this type of transformation area is very small,and its effect on the overall ecological environment quality of the region is limited.The type of transformation that led to the deterioration of the ecological environment quality of the local area where the urban and rural construction land is located in the Three Gorges Reservoir Area is mainly the conversion of cultivated land and woodland to urban and rural construction land.A large amount of ecological conservation value land has been replaced by urban and rural construction land,and the construction land is impermeable and high.Intensive human economic and social activities and other disturbances to the ecological environment have a negative impact on the ecological environment of local areas where urban and rural construction land is located.However,the implementation of a series of ecological environmental policies has weakened the impact of construction land transformation on local areas to a certain extent.The negative impact of ecological environment quality. |
PDF Full Text Request