Evaluation Of Ecological Vulnerability In Shiyang River Basin Based On SRP Model

The ecological environment belongs to a complex ecosystem,and is the collective name for the quantity and quality of various resources.With the development of human society,the impact of the ecological environment on human beings has become increasingly apparent.The imbalance in the distribution of materials and energy in the ecosystem has led to ecological fragility and has gradually become a hot issue of global concern.Therefore,research on ecological vulnerability is also increasing.The Shiyang River Basin is located in Gansu Province,China.Due to the limitation of natural conditions,there is little precipitation and water shortage in the basin,especially the scarce water resources in Minqin County.In addition,dense population and irrational use of land resources have caused the ecological vulnerability in the basin to become increasingly prominent.Scientific evaluation and analysis of the ecological vulnerability of the Shiyang River Basin will not only help to understand the characteristics of the temporal and spatial evolution of ecological vulnerability in the river basin,but also be important for the future governance and improvement of the ecological environment of the Shiyang River Basin and for sustainable social and economic development have Meaning of reference.Based on the current status of the ecological environment in the Shiyang River Basin,by selecting the three years of elevation,slope,soil erosion intensity,landscape diversity index,annual average temperature,annual precipitation,aridity,vegetation coverage,The population density,the proportion of cultivated land,and GDP density,etc.,were constructed using the SRP conceptual model to evaluate the ecological vulnerability of the Shiyang River Basin.With the support of remote sensing and geographic information technology,the principal component analysis method and spatial correlation analysis method were used to compare Systematic and quantitative evaluation and analysis of the ecological vulnerability of the Shiyang River Basin in2005,2010 and 2015.The study reached the following conclusions:?1?The background characteristics of the Shiyang River Basin are the main cause of ecological vulnerability,and the artificial interference factors are the secondary causes of the ecological vulnerability of the Shiyang River Basin.For the three years of 2005,2010 and 2015,although the top four principal components with the largest weights have different contributions in different principal components,they also have a certain regularity:each year is in the first four principal components The main driving factors are almost the same,such as the annual average temperature,vegetation coverage,soil erosion intensity and other indicators have been the main driving factors of ecological vulnerability in the watershed.?2?The overall ecological fragility in the Shiyang River Basin is at a severely fragile level,and the ecological fragility is obviously increasing from upstream to downstream,with obvious vertical zonal characteristics.The average ecological vulnerability index of the Shiyang River Basin in 2005,2010 and 2015 was 7.207.The areas with the largest types of fragile types are all extremely vulnerable areas,with a proportion of more than 48%,and the proportions of slightly fragile and lightly fragile areas are less than 15%.?3?The comprehensive index of ecological vulnerability in the three phases of Shiyang River Basin in 2005,2010 and 2015 was 4.173,4.067,and 4.094,respectively.The overall ecological situation showed a slight improvement,but the ecological vulnerability in the region was significantly different.The difference calculation of the ecological vulnerability index from 2005 to 2010 and 2010 to 2015found that the change was most significant between 2005 and 2010.The ecological vulnerability of different regions in the basin is inconsistent.From 2005 to 2010,the ecological conditions of the central,southern and western parts of the basin,especially the Minqin Oasis area,showed a marked improvement.From 2010 to 2015,the southern part of the basin The differences in ecological vulnerability in the southeast,southeast and parts of the southwest are negative,and the ecological situation is improving.?4?Structural factors are the main reason for the spatial heterogeneity of ecological fragility in the Shiyang River Basin.Random factors also have a certain degree of influence.Geostatistical software GS+10.0 for fitting analysis can truly reflect the correlation of various factors within the basin.The best model for the three-stage ecological vulnerability fitting effect is the Gaussian model.The C₀/C₀+C values of the three phases of 2005,2010,and 2015 were 8.3%,8.2%,and 6.2%,respectively,showing a decreasing trend,indicating that within a sampling distance of6km,random factors affect the ecology of the Shiyang River Basin.Vulnerability impacts are decreasing.Structural factors are the main reason for the heterogeneity of ecological fragility in the Shiyang River Basin.Random factors have a smaller impact.?5?The ecological fragility of the Shiyang River Basin in 2005,2010 and 2015all had significant spatial positive correlation and spatial agglomeration,and the spatial clustering of fragility showed a slowly rising trend."high-high"clusters are mainly distributed in Minqin County,Yongchang County,northern Liangzhou District,and parts of Jinchuan District;"low-low"clusters are mainly concentrated in southwest Yongchang County,Huangcheng Town,Sunan County,Tianzhu County and parts of Gulang County to the west.