Community Structure Characteristics And Optimization Of Woody Summer Flowers In Urban Green Space In Shanghai

As an important part of urban ecosystem,urban green space is the product of the combination of urban human landscape and natural landscape,which has the ecological functions of improving urban ecological environment,improving air quality,conserving water and soil,etc.Regulating people’s emotions,improving urban layout,providing recreation places and other social and humanistic services;And beautify the environment,improve the city style and other aesthetic functions.In recent years,Shanghai is a frontier area with intense urbanization and rapid economic development.The quality of its greening reflects the quality of urban construction.In recent years,scholars have found some significant problems in the development of green space,such as the lack of summer flower species and the great difference in seasonal effects of colorful plants.Therefore,this study aimed to study the woody summer flower plant community in Shanghai urban green space,and selected four green space types of park green space,pocket park,road green space and riverside green space to set up 108 samples of 100 square meters for investigation.This paper provides a theoretical basis for species selection and structure optimization of woody summer flower plant communities in Shanghai urban green space,and enrichis and perfectthe plant landscape evaluation system through the investigation of plant community structure characteristics and landscape evaluation.The main research achievements are as follows:(1)Through the investigation and statistical analysis,a total of 318 plant species,belonging to 93 families and 225 genera.Among them,73 species of trees accounted for 22.95%.84 species of shrubs,accounting for 26.42%.145 species of herbaceous plants,accounting for 45.59%.16 species of lianas,accounting for 5.03%.The data showed that in Shanghai urban green space,the woody summer flower plant community was relatively diverse,among which the herb species was the most abundant,accounting for nearly half of the total plant species,while the woody plants accounted for a relatively low proportion.(2)Among woody plants,there are 69 species of summer flowers,21 species of trees,46 species of shrubs and 2 species of lianas.There are 29 evergreen plants and 40 deciduous plants.All are broad-leaved species.The family with the largest number of applied tree species is cyperaceae(a variety of Hydrangea macrophylla varieties,such as’Endless Summer’,’Merveillle’,’Lime Light’,’Annabelle’,’Temaritema’,etc.).Oleaceae plants(Ligustrum lucidum,Ligustrum ovalifolium’Vicaryi’,Ligustrum japonicum’Howardii’,Ligustrum sinense var.variegatum,etc.),Rosaceae(Kerria japonica,many rose varieties,Spiraea siccanea),Lonicera(Viburnum macrocephalum keteleeri,Viburnum macrocephalum,Abelia grandiflora,Weigela’Red Prince’,Weigela florida ’Variegata’,Sambucus williamsii,etc.).(3)The analysis of plant diversity index showed that the trend of tree,shrub and grass diversity index was basically the same among the four green space types.In the tree layer,the species richness of park green space was the highest,the number of dominant species was less,and the species distribution was the most uniform,while the diversity index of road green space was the lowest,and the dominant species were obvious.In the shrub layer,the dominant species in the park green space were obviously distributed intensively and the evenness was lower.The diversity index of the other three green space types is similar,and the distribution is more uniform than that of the park green space.In herb layer,the evenness index of pocket park was the highest,and the herb application was diverse,often showing the form of multiple species mixed in flower border,so the distribution was the most uniform,and there was no obvious dominant species.The park has the most abundant herbaceous plants,and its evenness index is the lowest due to its significant dominant plants,such as Ophiopogon japonicus,Liriope spicata,and Reineckia carnea.(4)Based on the survey,69 representative and good quality photos of plant communities reflecting the characteristics of summer flowers were selected for landscape evaluation.A community evaluation system of woody summer flowers was established by AHP.Finally,15 indicators were selected from the three aspects of ecology,landscape and social service function to conduct comprehensive evaluation by combining qualitative and quantitative methods.In addition,PCA principal component analysis was used for objective weight assignment.Through comparative analysis of the two evaluation methods,the evaluation results were more scientific and objective after verification.Finally,the community with higher comprehensive evaluation ranking was obtained,and the structural characteristics,plant configuration and application forms of the community were summarized.(5)According to the landscape evaluation,the plant communities with low comprehensive score were divided into four types:the first type was single species.The second category is the excessive use of evergreen plants,color collocation is not reasonable;The third type is for the riverside green space,which has a simple structure and cannot highlight the characteristics of the riverside green space;The fourth type is the simple hierarchical structure of road green space,which emphasizes the ecological function of plants but neglects the aesthetic benefit of plant landscape.The evaluation results are consistent with the field investigation results.Finally,based on the field investigation and landscape evaluation results,combined with relevant theoretical research,optimization suggestions were put forward for the construction of woody summer flower plant community in Shanghai urban green space.