Plant Community Allocation In Tropical Coastal Parks Based On Carbon Sequestration Capacity

Urban garden plants are an important part of urban ecosystem,and their reasonable selection of plant species,configuration form,color collocation,space construction and plant community configuration are important ways to achieve carbon neutrality in high-density population areas.Under the "two-carbon" policy and the concept of urban park construction,this paper takes Binhai Park-Wanlu Garden of Haikou City as the research object and typical plant communities as the investigation object to explore the community composition and spatial configuration structure of street tree plants,landscape node plants,riverside coastal plants and other typical plants.The correlation among plant composition,species diversity,community structure configuration and carbon storage of the community was analyzed,and the optimal spatial structure of plant community configuration with high carbon sink,complex community structure and ecological and ornamental value was constructed,so as to continuously enhance the carbon sink capacity of the urban park ecosystem.The results show that:1.There are about 193 species,144 genera and 70 families in Wanluyuan Garden.In the geographical distribution of plant families,the overall distribution is mainly tropical,pantropical distribution of 29 families,accounting for 41.43% of the total number of families.A total of 108 genera were distributed in pantropical regions,accounting for 72.00% of the total genera.2.The analysis of Shannon-Weiner diversity index and richness index of 36 plant communities showed that the species richness in the same community was good,while the evenness index was relatively high,and the diversity index showed a positive correlation.3.The carbon sequestrating capacity of Ficus finica was the highest among all trees,followed by that of Ficus alficus.Carbon storage of an adult ficus finica was between1905.00 and 17426.42 kg,and that of Ficus alficus was between 833.36 and 5244.54 kg.From the perspective of individual shrub,carbon storage of leaf flower,hibiscus and pseudoforsythia was relatively high,and carbon storage of individual shrub was between8.72-13.61 kg.The carbon sequestration capacity of mangrove is the strongest among the waterfront plant communities.The carbon storage in the community was mangrove,arbor,bamboo,shrub,herb and vine from high to low.4.The correlation analysis between carbon storage and biodiversity shows that street trees are mainly trees,and the size of their carbon storage mainly depends on the species of trees.When trees are the same,the richer the plant composition and the higher the species diversity,the higher the overall carbon storage;There was no obvious correlation between species diversity and carbon storage in the other three communities.5.Based on the calculation and correlation analysis of species diversity and carbon storage of typical plant communities,suggestions were put forward to optimize the spatial structure of plant community configuration in tropical gardens,which was characterized by high carbon sink,complex community structure and ecological and ornamental value:(1)For street trees,two aspects of vertical structure hierarchy construction and tree species selection are considered: first,increasing vertical structure hierarchy of street trees,increasing shrub layer,herb layer and plant species can simultaneously improve the species diversity and carbon storage of street trees landscape;The other is to control the application of tree species at different levels on both sides of the road,and control the application proportion of small ornamental trees and tall ornamental trees.(2)For most plant communities in the garden except street trees,it is necessary to increase the richness of plant species and the spatial level of the vertical structure of the community from the perspective of the direct factors affecting the diversity and carbon storage.In addition,it is necessary to increase the proportion of plants with strong carbon sequestration ability in the community from the aspect of carbon storage,increase the proportion of trees in the community,and rationally match annual herbs and shrubs.It can not only enhance the long-term carbon sequestration capacity of garden,but also improve the ornamental value of garden landscape.