Study On The Ecological Environment And Spatial Pattern Optimization In The Three Gorges Reservoir Area

Nowadays,global climate change is becoming more and more dramatic,and the rapid development of industrialisation and urbanisation has made the environmental problems of the entire ecosystem increasingly serious.Drought,water pollution and atmospheric pollution have become the focus of discussion among experts and scholars.These ecological problems can have a negative impact on economic development and human health,as well as causing damage to the natural environment.Ecological and environmental problems have now become a global task that needs to be addressed urgently.However,in China,due to the influence of multiple factors such as topography and economy,ecological and environmental problems and spatial pattern optimisation at the macro-regional scale are currently less studied.At this stage,traditional environmental monitoring and the construction of ecological models are mostly used to study and assess ecological and environmental problems and to propose corresponding protection and management measures.The rapid development of computer and RS technology has made it possible to obtain the ecological environment of a study area at a macroscopic scale,but the specific details and drivers of ecological changes in the study area cannot be obtained by using only GIS and RS technology.As an important economic,cultural and ecological centre in China,the Three Gorges Reservoir Area is developing rapidly and has received widespread attention.This paper takes the Three Gorges Reservoir Area as the study area,based on RS,GIS and other means,and selects Landsat data for 1995,2000,2005,2010,2015 and 2020 as the main data source,incorporating socio-economic data such as total population,population density and gross domestic product(GDP)on the basis of the RESI model to enhance the impact of human activities The ecosystem quality of the Three Gorges reservoir area from 1995 to 2020 is analysed objectively and comprehensively in time and space by coupling the Landscape Pattern Index(LPI)method with the Improved Remote Sensing Ecological Index(IRSEI)model to explore the specific details and drivers of ecosystem change.The main findings of this paper are as follows:(1)The Three Gorges Reservoir Area has the largest proportion of forest area from1995 to 2020,with an area share of around 60%,mainly concentrated in the central and southern regions of the Three Gorges Reservoir Area.The main reason for the increase in forest and building land area is the transfer of farmland area.The development of afforestation,return of farmland to forest and urbanisation has influenced the conversion between different land use types.(2)The landscape pattern of the Three Gorges reservoir area has changed significantly,with patches of farmland and building land becoming more spatially dispersed,their shapes becoming more complex,and landscape heterogeneity increasing.Forest patches tend to become more dense,with small patches merging and developing into large patches,and the area of forests greatly increasing.The patches of other land use types are less variable.(3)Among the evaluation indicators of the IRSEI index model,greenness and humidity play a positive role in improving the ecological and environmental quality of the Three Gorges reservoir area,while dryness,heat,total population,population density and GDP play a negative role in improving the ecological and environmental quality of the region.The areas with higher humidity and greenness are concentrated in the central and south-central regions of the Three Gorges Reservoir Area,which are at high altitude and have a higher concentration of land types such as forests,grasslands and farmlands,and are also the areas with more ecological improvements.Areas with high heat and dryness indicators are concentrated in the east and west.In general,the area of the Three Gorges Reservoir Area where the ecological quality has improved is greater than the area where it has declined,and the ecological environment is continuing to advance towards a positive effect.(4)The expansion of the built-up land area will simultaneously change the local ecological environment and encroach on other land use types.The study found that the ecological environment of the urbanised fringe areas is affected by a variety of factors,including natural and human factors,and therefore the variability of the ecological environment quality in different locations of the urbanised fringe areas is significantly different.(5)The ecological environment quality in the Three Gorges reservoir area shows a strong correlation in space and is proportional to spatial aggregation over time.The study area mainly shows the spatial aggregation characteristics of high high and low low.Those in long-term low aggregation characteristics of ecological environment quality include Yuzhong District,Jiangjin District,Yubei District,Jiangbei District and Nanan District,etc.Those in long-term high aggregation characteristics of ecological environment quality include Wushan County,Badong County,Yunyang County and Kai County,etc.