| The riparian zone is a special ecosystem on both sides of the river,with obvious edge effects,and there is a significant difference between the vegetation near the water and the highlands.The type,composition,and structure of riparian vegetation have an important impact on the quality of habitats on rivers,banks,and the entire river basin.There are many secondary rivers in the main urban area of Chongqing.The existing problems are:a large number of human disturbances to reduce vegetation coverage,serious soil erosion,and human activities directly polluting riparian zones and rivers.The management of secondary rivers has become an important part of river protection and management projects.Work content and work objects.In this paper,the relevant theories of quantitative ecology and landscape ecology are used to investigate the vegetation of the riparian zone in the Taohuaxi and Changsheng River areas through a layer-by-layer detailed system of plot-sample-square.Statistical analysis of species composition characteristics,community structure characteristics and their relationship with factors such as altitude,terrain,artificial interference type,configuration analysis of typical,natural vegetation artificial improvement typical,natural ecological slope protection and so on.It also proposes semi-naturalized restoration for different sections of ecological slope protection,landscape aesthetics,agricultural production and different sections of rivers with missing functions,and proposes corresponding plant community construction models and species selection.The research results are as follows:(1)Analyze the quantitative characteristics of the species composition of riparian vegetation within the survey area.There are 386 species of plants in the whole region,belonging to 271 genera of 99 families,including 254 species of Taohuaxi,190 genera of 88 families,284 species of Changshenghe,and 213 genera of 83 families.Among the 386 plantations in the whole region,there are 341 native plants,accounting for 88.34%of the total species,Taohuaxi has 215 native plants,accounting for 84.65%of Taohuaxi,and Changshenghe has 252 native plants,accounting for Changshenghe 88.73%of the total plant species.(2)Cluster analysis of riparian plant communities using quantitative classification methods.Using TWINSPAN to perform cluster analysis on 33 plots and 142 plots respectively,the plots in the survey area are divided into 12 types and the plots are divided into 18 types;TWINSPAN divides plants into 17 main groups,Evergreen broad-leaved forests are the main species,and Ficus microphylla and Osmanthus fragrans are the common dominant species,and the mulberry,thorn tree and neem tree are widely distributed.(3)Gradient analysis of community-environment and plant-environment using ranking method.According to the structure of DCA ranking,the relationship between community distribution and environmental factors is suitable for the unimodal model.The community CCA ranking reveals that the vegetation pattern of the plot is mainly affected by function,human disturbance,altitude and aspect.In general,the function and the degree of disturbance have a greater impact on the community distribution.The vegetation distribution pattern of the sample site is mainly affected by the slope position,slope,and interference.It can be seen that the restoration of the riparian zone vegetation needs to fully consider the carrying function and the riparian zone itself May be subject to human interference.In addition,from the plant sorting map,the trees located in the center of the sorting map include yellow pueraria sclerotiorum,sculptural tree,Ficus spinosa,shrub sculptural tree,safflower tree,small wax,etc.These plants are less affected by environmental factors The ecological adaptation range is large and the adaptability is strong,suitable for growing in various environments.(4)Explore the relationship between species diversity and environmental factors at the two levels of sample plots and sample sites.Environmental factors such as human disturbance and altitude obviously affect the species diversity pattern of the community,that,is the disturbance intensity increases and the altitude decreases,and the species diversity of the riparian forest zone decreases accordingly.The species diversity of the tree layer is mainly affected by human disturbance factors,And the shrub layer is greatly affected by altitude.(5)Evaluate and investigate the habitat quality and beauty level of vegetation in the riparian zone.According to the evaluation results,select typical demonstration plots with high comprehensive scores,and analyze their species composition and community configuration.Habitat quality evaluation adopts the analytic hierarchy process,with riparian quality evaluation as the target layer,under which there are 4 criterion layers including vegetation coverage,slope bank conditions,apparent water quality conditions,and human interference.A total of 15 indicators are set under the criterion layer.Each index of each plot is scored and multiplied by the weight obtained by expert rating and AHP to obtain the final score.The evaluation of beauty degree adopts the form of taking photos and grouping for questionnaire survey.The survey experts and the public are satisfied with the beauty degree of the plot,and the score of satisfaction degree is summarized.Four typical demonstration sites with high comprehensive scores were selected and evaluated respectively.According to the existing riparian zone vegetation function division,it puts forward suggestions for the reform of different types of riparian zone and recommends plant configuration.The ecological slope protection type,landscape aesthetic type,and agricultural production type are divided into U-shaped and ladder-shaped according to the cross-section.Corresponding to the flat river valley farmland area and the planned construction area,temporary crops are planted.The flat river valley type avoids cultivation in the decline zone.The area reduces private cultivation;the plant configuration is mainly agricultural products and garden plants with ornamental value and soil and water conservation functions.The function loss category should pay attention to covering bare land area and proper greening to minimize soil erosion. |
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