| As an important part of the"Five-in-One"construction goal,the ecological civilization construction emphasizes the interdependence,mutual promotion and coexistence of human and natural environment.However,with the economy and society development rapidly,the disturbance of human activities to the natural environment has intensified,causing the ecological environment quality has declined and the harmonious development of society and nature has been limited.In such context,the regional ecological risks assessment can identify the problems in the ecosystem in time.At the same time,construction the ecological security pattern is of great practical significance to correct ecological problems,maintain the ecosystem stability and realize the ecosystem function improvement.The Qinba Mountain Area are an important ecological function area in China,and also one of the 14 contiguous special hardship areas,where the resident livelihoods are highly dependent on natural resources,leading to the destruction of the ecological environment and a growing conflict between ecological protection and livelihood development.In order to accurately assess the regional ecological risks,construct ecological safety networks,and reasonably plan local ecological resources,this paper took the Qinba Mountain area as the research object,constructed an ecological risk evaluation index system from three aspects:topography and landscape,ecological background,and human interference,explored the spatial and temporal distribution pattern of ecological risks.On this basis,four ecosystem service capacities of water connotation,soil and water conservation,carbon sequestration and oxygen release,and biodiversity maintenance has been calculated,together with the ecological risk evaluation results,determined the ecological source areas in the mountain area.At the same time,the basic ecological resistance coefficient has been determined according to different land use types,and the intensity of human activities within the mountain area has been represented using nighttime light data,and the basic ecological resistance coefficient has been corrected using the intensity of human activities to obtain the ecological resistance surface.Based on the clarification of ecological source sites and ecological resistance surfaces,the ecological corridors been constructed using the MCR model and the gravity model.The ecological corridors were intersected with the local road data to get the intersection point,and the ecological corridors were intersected together to get the intersection point,and these two kinds of points were taken together as the ecological strategic point in the mountainous area.Finally,got the ecological security pattern of the Qinba Mountainous Area.The network analysis method has been used to calculate the connectivity of the ecological network to evaluate the rationality of the ecological network construction.Through this paper,we expect to provide theoretical support for reducing ecological risks,enhancing ecological security and improving ecological resilience in the Qinb a Mountain Area.The main contents and conclusions are as follows:(1)The ecological risk levels of most counties were below the medium level,and the counties with high ecological risk level had a spatial distribution pattern of"a circle layer,a belt and a point".From 2000 to 2020,the mean ecological risk values showed a decreasing trend.The three most significant factors affected the ecological risk level were distance from construction sites,slope and soil erosion.(2)The ecosystem service capacity showed a spatial pattern of low in the north of the mountain area and high in the south of the mountain area.Ten ecological source lands were identified based on ecological risk and ecosystem service capacity,with a total area of 30,302.78 km~2,accounted for 13.47%of the mountainous area.Among them,the land use type with the largest area was forest land,accounted for 96%of the total source land area,followed by arable land.(3)According to the MCR model and gravity model,13 important ecological corridors with a total length of 1305.08 km were identified,this kind of corridors was to link ecological sources with high ecological quality and close spatial distance,while 5 potential ecological corridors with a total length of 1065.21 km were also identified,this kind of corridors to improve the connectivity between ecological sources.These two types of corridors together form an ecological corridor pattern of"two horizontal,one vertical and one cluster".(4)A total of 87 ecological strategic points were identified,of which 76 were intersections of corridors and roads,evenly spaced on each ecological corridor;11ecological strategic points were intersections of ecological corridors,mainly distributed between ecological sources in the southeastern part of the mountains.(5)The constructed ecological network in the Qinba Mountain Area has a network closure(α)of 0.47,a line point rate(β)of 1.64,a network connectivity(γ)of0.67,and a cost ratio(c)of 0.99,which means that the ecological network has a reasonable structure but was expensive to construct. |
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