Application Of Resilient Landscape Function For Water And Soil Conservation In Jiangang Reservoir

As a reservoir for urban flood control and alternate water sources,the Jiangang Reservoir is an important factor in building an ecologically civilized city in Zhengzhou.Landscape function is an important representation of soil and water conservation.Combining the concept of resilient landscape with soil and water conservation landscape function,drawing on landscape ecological modelling methods,establishing models and indicators,using 3S technology and 2m resolution GF-2 remote sensing images and DEM data,taking the Jiangang Reservoir as the object,carrying out analysis of the landscape characteristics of the study area through the division of the Jiangang Reservoir landscape unit,and carrying out analysis of the resilient landscape function of soil and water conservation in the study area The study provides a technical basis for the prevention and control of soil erosion and ecological environmental protection in the reservoir,a methodological reference for the construction of a resilient landscape for soil and water conservation in the reservoir,and a theoretical significance for ensuring ecological security and benign development in the reservoir area.Research conclusions.(1)Through basic conceptual research,forest land,grassland,cropland and watershed are identified as the main components of the soil and water conservation resilient landscape in the study area;through basic theoretical research:within the scope of the defined landscape area,various landscape elements(grassland,forest land,cropland and watershed)with soil and water conservation resilient functions play soil and water conservation resilient landscape functions when they are eroded and destroyed;when the destruction exceeds the maximum resilient value the landscape functions collapse;after the destruction the landscape function gradually returns to the elastic minimum;the basic characteristics of the structure type,spatial distribution and heterogeneity within the landscape have an important influence on the elastic landscape function.(2)A model based on SW soil and water conservation function,EP ecological protection function and NPP ecological production function was established:With woodland,grassland,arable land and watershed as the basis of the resilient landscape function of soil and water conservation,and SW soil and water conservation,EP ecological protection and NPP ecological production as the 3 control indicators of the resilient landscape function,9 evaluation indicators and 15 calculated factor indicators were selected to establish the indicator system.(3)Using Arc GIS software,combined with DEM data map,using the 2019 summer state temporal 2m resolution GF-2 true colour fusion remote sensing image,the study area of Jiangang Reservoir was divided into two soil and water conservation resilient landscape units in the east and west,using the scope of Zhengzhou city in the upstream watershed of Jiangang Reservoir as the landscape area;the total area of the study area was 6143.44hm~2,and 1,577spots of each category were obtained from the interpretation The total area of the study area is6143.44hm~2,and 1,577 maps were obtained,including 436,196,302,48,266,182 and 147maps of forest land,grassland,arable land,water,construction,village and unused land,with an area of 2267.59,326.41,1754.06,173.46,1166.82,240.50 and 214.60hm~2;Landscape Unit No.1(West)has an area of 2909.11hm~2,with 1016.43,176.23,922.31,109.11hm~2of woodland,grassland,arable land and water respectively,accounting for 34.94,6.05,31.70,3.75%of the landscape unit area,with an area ratio of 1:0.17:0.91:0.11 The area of Landscape Unit No.2(East)is 3234.33hm~2,with 1251.16,150.18,831.75 and 64.35hm~2of woodland,grassland,arable land and water respectively,accounting for 38.68%,4.64%,25.71%and1.99%of the area of the landscape unit,with an area ratio of 1:0.12:0.1:0.05.(4)The density of landscape patches in the study area is 3.9 patches/hm~2in the study area,4.73 patches/hm~2in the west unit and 3.36 patches/hm~2in the east unit.The average area of landscape class patches is 4.69km~2/pc in the study area,3.36km~2/pc in the west unit and4.73km~2/pc in the east unit.The landscape fragmentation is higher in the west of the Jiangang Reservoir than in the east,and the average area size of landscape element patches is larger in the east than in the west.(5)The patch shape indices of each category in the study area are 28.87,28.96,23.41,8.71,63.22,18.28 and 7.55 respectively,and the patch sub-dimensions are 1.55,1.62,1.53,1.48,1.67,1.57 and 1.45 respectively,which are all greater than 1.The landscape structure of the study area is relatively complex;the Shannon diversity index is 0.20 on average and 0.30,0.19,0.25,0.07,0.23,0.18,0.16 for each category respectively;diversity index averaged 0.21and 0.36,0.14,0.34,0.09,0.29,0.11,0.10 for each category respectively;evenness averaged0.11 and 0.19,0.07,0.18,0.05 The landscape structure diversity and evenness are low.The dominance of each category in the study area is 0.24,0.06,0.18,0.02,0.13,0.05,0.04,0.21,0.04,0.17,0.02,0.10,0.04,0.03 in the west unit,0.19,0.04,0.14,0.01,0.11,0.03,0.03 in the east unit,and 0.19,0.04,0.14,0.01,0.11,0.03,0.03 in the Jiangang Reservoir landscape.The degree of structural dominance is not obvious,forest land is the largest 0.24,followed by cultivated land 0.18 and unused land the smallest 0.04.(6)The model was applied to calculate the elastic landscape function of soil and water conservation in the study area of Jiangang Reservoir,the maximum value of⊿E is 2.82,the minimum value is 1.435,and the current value is 2.385;the larger the⊿E value,the better the ecology,the smaller the value,the worse the ecology;the elastic landscape function of soil and water conservation is negatively correlated with soil erosion,and positively correlated with ecological protection and ecological production function.The maximum value of 2.21and the minimum value of 0.80 and the status quo value of 1.82 respectively,the maximum value of 3.43 and the minimum value of 2.07 and the status quo value of 2.95 respectively for landscape unit No.2 are greater than those calculated for landscape unit No.1,and the eastern part of the study area of the Jiangang Reservoir is ecologically better than the western part;the maximum value of 3.43 and the minimum value of 0.8 for the two landscape units do not reach the upper threshold of 5 and are lower than the study area The average status quo value of 2.385 indicates that the ecological environment in the study area of the Jiangang Reservoir is good,but due to the proximity of the reservoir to the urban area and the frequent socio-economic activities,there is a small area of ecological vulnerability in the western part of the study area that needs to be strengthened for ecological protection and construction.Taking Jiangang Reservoir as the research object,SW water and soil conservation elastic landscape function⊿E model is used to calculate SW water and soil conservation function,EP ecological protection function and NPP ecological production function.A representative index system that is easy to quantify,has calculated data sources,and is easy to operate is selected to calculate elastic landscape function of water and soil conservation.The elastic landscape function of water and soil conservation in jiangang reservoir is quantified,and then the soil and water loss in the reservoir area is analyzed more pertinently,which provides theoretical support for the work of water and soil conservation in the reservoir.However,soil erosion,ecological protection and ecological production are all complex systems with many influencing factors.Therefore,there is still much room for research on the application of⊿E model to calculate and analyze the elastic landscape functions of soil and water conservation.