Study On Plant Landscape Characteristics And Diversity Of Five River Corridors In Beijing

With the development of urban construction,ecological corridor has become an important position for the protection of urban biodiversity.Aiming at the problems of insufficient integrity and connectivity of urban river ecosystem and low natural degree of plant landscape of urban rivers in Beijing at present,based on sorting out the data of river system in Beijing,field investigation was carried out on the North Canal,Yongding River,Yushui River,Huaijiu River,Kunyu River and South Moat,from different river corridors.The differences of species composition,community structure,plant diversity and corridor cross-section structure were compared and analyzed from different angles,such as channel,River reach,cross-section habitat and land use type,in order to explore the construction methods and Strategies of plant landscape in the ecological corridor of Beijing rivers,and to recommend plant species and community patterns suitable for the ecological corridor of Beijing rivers.The main results are as follows:(1)Habitat composition characteristics of river corridors in Beijing are analyzed from different angles of cross-section habitats,land use types and riparian zone types.The results show that the urban section has the most riverbanks,followed by highlands,and the shallow marshes and rivers.The main land use type is park green space,and the water area is less.The main types of land used for corridors of Yongding River,North Canal and Yongshui River in the countryside are woodland.There are obvious differences in the community composition of cross-section habitats.The Yongding River is dominated by rivers and highlands,the North Canal is dominated by riverbanks,and the Yongshui River is dominated by riverbanks and rivers.The cross-sectional habitats in the gorge section are mainly composed of riverbanks and shallow marshes,forestland and water area,and Huaijiu River bank is less.Yongding riparian zone in the urban section is the most natural,followed by the North Canal,and the Kunyu River-South Moat is the most artificial.In the countryside section,the Loushui River bank zone is the most natural,followed by the North Canal,Yongding River is the worst.In the gorge section,Yongding River is more natural than Huaijiu River.Based on four types of riparian zones,the typical structure of Beijing river corridor riparian zone is divided into 13 models(natural type 2,near natural type 4,degenerate type 4,artificial type 3).The cross-sectional habitat and land use type layout structure under the typical model are analyzed.(2)A total of 370 species belonging to 264 genera and 91 families were recorded,including 55 species of trees,47 species of shrubs,258 species of herbs,9 species of vines and 1 species of bamboos.The dominant families are Compositae,Gramineae,Rosaceae,Leguminosae and Labiatae.The analysis of species sources showed that there were 84 species of alien plants,accounting for 22.70%,mainly from foreign countries,of which trees and shrubs were mostly cultivated species.There are 29 invasive plants.The plant species composition of different river corridors,River sections,cross-sectional habitats and land use types are different.Statistical analysis of plant composition in river corridors from different river corridors,River sections,cross-sectional habitats and land use types shows that all plant species except Yongding River Gorge are herbaceous>arbor>shrub,and the number of woody plant species is far less than that of herbaceous plants.Salix matsudana and Setaria viridis are important native plants in the river corridors of Beijing,and they are also important keynote plants in the plant landscape of river corridors.(3)The main types of plant communities in the corridors of rivers in Beijing are arbor-grass type,followed by arbor-shrub-grass type and herbaceous type.Very few communities are shrub-grass type,Arbor-shrub type and Arbor-shrub type.The lack of shrub layer in community structure is obvious.The community composition of cross-sectional habitats and land use types in corridors of different rivers is obviously different.The River corridors in Beijing are mainly pure forest and single-layer forest of the same age.(4)The results of species diversity analysis show that the species diversity in the suburban section is the smallest and the species distribution in the urban section is the most uniform.The species diversity of different cross-section habitats was highland>river bank>shoal marsh>River course.Among different land use types,forest land species diversity is the largest,followed by park green space.The species distribution of accessory green space and protective green space is more uniform,followed by park green space and woodland.The species distribution in water and grassland is relatively uneven.(5)The plant landscape optimization strategies based on the principles of natural native plant communities,supporting functions of biodiversity,site conditions,landscape ornamentality and low intervention and low maintenance were put forward.The plant species and ecological community patterns suitable for the corridors of rivers in Beijing were recommended.It has certain guiding significance for the construction and promotion of plant landscape in urban river corridors in later period.