Ecological Risk Assessment And Construction Of Ecological Security Pattern In Guangxi

Guangxi is located in the coastal area of South China.It is an important node in the construction of the Belt and Road and plays an important role in the construction of the Free trade zone and the Pearl River Delta cooperation.Guangxi is known as "Guangxi Basin",the complex mountains and hills,the size of the basin is mixed,the year round climate is warm,abundant rainfall,animal and plant resources are rich.However,limited by the regional karst landform,rocky desertification problem is serious,it is difficult to vigorously develop industry,the economy is relatively backward,and tourism is an important source of economic development in Guangxi,so it is particularly important to maintain the security of regional ecological environment.In recent years,Guangxi has vigorously developed industrial and agricultural clusters,which have caused damage to regional waters,forest and other ecosystems.Therefore,it is necessary to carry out ecological risk assessment and ecological security pattern construction to promote coordinated development of regional economic development and ecological protection,and promote sustainable and high-quality regional development.In this study,firstly,based on land use data,ecological risk assessment model and spatial analysis were used to explore the spatio-temporal changes of land use and ecological risk in Guangxi,and suggestions on ecological risk management were put forward.Secondly,based on the evaluation results of the importance of ecological protection,the appropriate patches were selected as the ecological source,the resistance factors were selected from both natural and human factors to construct the comprehensive resistance surface,and the ecological security pattern of Guangxi was constructed by using the circuit theory.Finally,taking Nanning,a typical high-risk area,as the research area,the spatial scale effects of ecological risk assessment were analyzed,and the PLUS model was used to simulate and predict the ecological risks under different scenarios under the optimal scale in 2036 in Nanning.The results show that:(1)From 2000 to 2018,the proportion of land use type area in Guangxi was woodland > arable land > grassland > construction land > waters > unused land.The construction land increased rapidly and the area was wide,and the ecological risk increased gradually.The overall ecological risks in Guangxi are mainly low risk,medium-low risk and medium risk,but the spatial distribution of ecological risks is significantly different,showing a gradually decreasing trend from the middle to the surrounding area.The ecological risks show a positive spatial correlation,and the spatial clustering and spatial differentiation are weakened.The interaction of natural factors and social economic factors has great influence on ecological risk.(2)The total area of Guangxi ecological source area is 60556.99km2,and there are50 patches,which are distributed in the north and northeast of Guangxi,mainly woodland.There are 115 ecological corridors with a total length of 4004.52 km,among which 41 key corridors account for the largest proportion in quantity but the least in length.The longest corridor is 194.97 km.The spatial distribution of ecological corridors showed a trend of decreasing importance from the periphery to the middle.There are 301 ecological sandwickets,covering an area of 669.44km2.The spatial distribution is scattered and mainly distributed in woodland.There are 286 obstacle points in Guangxi,with a total area of 1,878.75 km2,mostly distributed in important corridors and general corridors in central Guangxi.(3)The spatial grain size of 120 m and spatial amplitude of 7km are the best scales for ecological risk assessment and prediction in Nanning.From 2000 to 2018,the overall ecological risk in Nanning was not high,but the spatial distribution difference was significant.The areas of high risk areas and high risk areas decreased,and they were concentrated in 7 districts under the jurisdiction of Nanning.The ecological protection scenario is more suitable for the sustainable development of Nanning in 2036.