Spatio-temporal Differentiation Of Ecological Risk In The Loess Hilly-Gully Region And Its Risk Management Categories

Ecologically fragile regions such as loess hilly-gully region are highly responsive to global changes.Under the vulnerability of natural background and agricultural activities,regional development is on an unsustainable track.The study of ecological risks in this region has become one of the research hotspots of geography and ecology for ecosystem management.Taking Mizhi County for the study of loess hilly-gully region,a comprehensive ecological risk assessment framework for identifying risk probability,habitat sensitivity,and system impairment was established,and multi-source data was integrated at watershed level.The spatio-temporal differentiation of criteria layers and comprehensive ecological risk were analyzed,the dynamic changes of risk agglomeration model and risk centroid were explored.The ecological risk management categories were simultaneously delineated based on the risk dominant factors,and the risk management strategies were formulated in loess hilly-gully region.The results were as follows:(1)The risk probability increased from 0.499 3 to 0.529 2 during 2009-2015.The habitat sensitivity index was 0.611 9,0.600 8,respectively,which was an increase of 1.8%.The system impairment increased from 0.424 5 to 0.456 7 during 2009-2015.(2)The spatial distribution pattern of the high comprehensive ecological risk was high in the middle in the Mizhi County,and the low in the south and north.Between 2009 and 2015,the comprehensive ecological risk index increased from 0.145 2 to 0.152 0.The Moran'I values of ecological risk were 0.461 7 and 0.484 4,respectively,which indicated that the risk values were positively correlated and the degree of autocorrelation was increased.The risk centroid of Mizhi County was distributed in Gaoqu Township in 2009,and jumped into Yinzhou Township in 2015.The main direction of ecological risk evolution was northwest-southeast trend,and kept stable basically.(3)Risk monitoring zones,habitat recovery zones,early warning and recovery zones,and natural regulation zones encompass 7.53%,6.57%,23.86% and 62.04% of the study area,respectively.Risk management categories and its corresponding measures at watershed level can effectively promote risk mitigation and regional sustainable development.