Land Use Ecological Risk Assessment And Its Influencing Factors In The Yellow River Delta

With the steady improvement of urbanization and socio-economic development,the influence of human activities on land ecosystem is more and more significant.Excessive exploitation of resources and unreasonable land use increase the pressure of land ecosystem,which intensifies the regional ecological risk.In order to control the regional ecological risk effectively and realize regional ecological security,ecological risk assessment must be carried out.Therefore,this thesis takes the Yellow River Delta region as the research object and uses the land use data and remote sensing image data in 2000,2005,2010,2015 and 2020.Under the guidance of landscape ecology theory and ecosystem services theory,the index system of land use ecological risk assessment in the Yellow River Delta was constructed based on pressure-state-response(PSR)model.Then establish a land use ecological risk assessment model,and the ecological risk of land use in the Yellow River Delta was evaluated with a grid of4km×4km as the minimum evaluation unit.Then,using software such as Arc GIS10.3 and Geoda,combined with spatial analysis methods such as standard deviation ellipse analysis and spatial autocorrelation analysis,the spatial and temporal evolution characteristics of land use ecological risk assessment results in the Yellow River Delta were studied on the whole and regions.Finally,the Geo-Detector model and decoupling analysis model were used to explore the influencing factors of land use ecological risk in the Yellow River Delta.This thesis divides the ecological risk zones of land use in the Yellow River Delta and puts forward countermeasures and suggestions for different ecological risk zones.The results show that:1)The fluctuation of land use ecological risk index decreased in the Yellow River Delta,and the ecological security situation gradually improved.The values of land use ecological risk in the Yellow River Delta in 2000,2005,2010,2015 and 2020 were 0.5309,0.5415,0.5172,0.5199 and 0.4992,respectively.From 2000 to 2020,the number of low-risk and lower-risk assessment zones increased,while the number of other land use ecological risk zones decreased significantly.2)The spatial distribution of land use ecological risks in the Yellow River Delta was heterogeneous.On the whole,from 2000 to 2020,the standard deviation ellipse of land use ecological risk in the Yellow River Delta region always presents a "northwest to southeast" trend,and the elliptic azimuth does not change much.Therefore,the spatial distribution of land use ecological risk in the Yellow River Delta region is stable on the whole.According to the analysis of characteristic values of standard deviation ellipse center,the ecological risk of land use in the western inland region of the Yellow River Delta is higher than that in the eastern coastal region,the land use ecological risk in the southern region is slightly higher than that in the northern region,and the ellipse shape of standard deviation is gradually narrow and long,indicating that the heterogeneity of the spatial distribution of land use ecological risk in the Yellow River Delta region is increased.Regionally,lower land use ecological risk areas and low land use ecological risk areas are mainly distributed in the middle and north of the Yellow River Delta,and the fluctuation of the risk level of land use ecological risk increases with the distance from the coast.From 2000 to 2020,the spatial distribution of the middle risk area began to shrink and fade,while the lower risk area and low risk area gradually spread to the southwest.The level of land use ecological risk in 19 counties in the Yellow River Delta region has little change,but the value of land use ecological risk showed a downward trend in different degrees.3)The spatial distribution of land use ecological risk in the Yellow River Delta has obvious agglomeration characteristics.The Moran’I of land use ecological risks in the Yellow River Delta in 2000,2005,2010,2015 and 2020 were 0.580,0.493,0.642,0.664 and 0.768,respectively,which indicated there is a significant positive correlation between the spatial distribution of regional land use ecological risks.In other words,the land use ecological risk in the surrounding areas of high land use ecological risk zones is also high,and the land use ecological risk in the surrounding areas of low land use ecological risk zones is also low,showing spatial agglomeration characteristics.From the perspective of local spatial autocorrelation,the land use ecological risk agglomeration patterns in the Yellow River Delta are mainly high-high(HH)agglomeration and low-low(LL)agglomeration.The high-high(HH)clusters were mainly distributed in the western region and the eastern part of the region,and sporadically distributed in the southern region.The low-low(LL)clusters are more concentrated,mainly distributed in the northeast coastal areas of the Yellow River Delta region,while the high-low(HL)clusters and low-high(LH)clusters are scattered and occupy a small proportion.4)The influencing factors and their influence degree of land use ecological risk in Yellow River Delta are different in different periods.The location condition is the dominant factor all the time,the influence degree of social and economic development is deepening,and ecological protection factors have an increasingly important impact on land use ecological risk mainly through the interaction of factors.Specifically,the distance from the coast and the distance from the town are the dominant factors affecting the land use ecological risk in the Yellow River Delta region from 2000 to 2020,and the degree of influence is deepening.In terms of socio-economic factors,population density continues to affect the land use ecological risk assessment in the Yellow River Delta region.Except for the proportion of the output value of the secondary industry and the proportion of the output value of the tertiary industry,the q values of all other factors show varying degrees of fluctuation trend,and the impact on land use ecological risk is deepening.With the continuous transformation of the economy from high-speed development to high-quality development,the influence degree of social and economic factors will become smaller and smaller,and regional socio-economic development will be less and less at the cost of ecological environment.In terms of ecological protection,the q of the proportion of ecological land keeps rising,and it exerts more and more important influence on the land use ecological risks assessment mainly through the cross effect with other influencing factors,which indicates that ecological land can effectively reduce the land use ecological risk,and ecological land should give full play to its important role in ecological environmental protection.5)Based on the decoupling analysis model,the relationship between ecological risk of land use and economic development in the Yellow River Delta region was analyzed,and combined with the evaluation results of land use ecological risk,the Yellow River Delta region was divided into six types of land use ecological risk regulation areas: High risk area of stable absolute decoupling,medium-low risk area of stable absolute decoupling,high risk area of weakening absolute decoupling,medium-low risk area of weakening absolute decoupling,high risk area of absolute decoupling-negative decoupling,and medium-low risk area of absolute decoupling-negative decoupling.According to the characteristics of different types of areas,countermeasures and suggestions were put forward to control the land use ecological risks from the aspects of protecting ecological land to improve the value of ecosystem services,controlling the application of pesticides and fertilizers to control agricultural non-point source pollution,actively adjusting industrial structure to accelerate the realization of high-quality economic development,and stabilizing the industrial base to realize economic recovery as soon as possible.