Investigation And Risk Assessment Of Alien Invasive Plants In Ningbo,Zhejiang Province

With the acceleration of globalization in recent years,the geographical isolation of biology has been broken,and the spread of alien invasive plants has become more convenient,this causes it easier for alien invasive species to be widespread and uncurbed in the new environment.With the increasing foreign trade and inbound and outbound tourism,the risk of alien invasive plants in the port city of Ningbo has increased sharply.Therefore,it is extremely urgent to investigate the status of invasive plants in Ningbo and carry out risk assessment.There are ten areas in Ningbo:Cixi,Yuyao,Zhenhai,Beilun,Jiangbei,Haishu,Yinzhou,Fenghua,Ninghai and Xiangshan.This study investigated the species and harm degree of alien invasive plants in these ten areas,comprehensively evaluated the risk of alien invasive plants with Analytic Hierarchy Process(AHP),and put forward the countermeasures of prevention and management,providing reference for the ecological security,landscaping and introduction work of Ningbo city.The main research results are as follows:1.According to statistics,there are 93 species of alien invasive plants in Ningbo,belonging to 31 families and 71 genus.The alien plants are rich in species,and the dominant family is obvious.The most alien invasive species belong to Compositae(24 species),followed are Leguminosae(7 species)and Solanaceae(7 species).There are 86 species of herbaceous plants,accounting for 92.47%of the total species.There are 5 species of lianas,accounting for 5.38%,and 2 evergreen shrubs(2.15%).2.46 alien invasive species of Ningbo are introduced intentionally,accounting for 49.46%of all invasive plants.35 species are unintentionally introduced,accounting for 37.64%.The remaining 12 species are nature spread,accounting for 12.90%.62 species come from America,accounting for 66.67%of the total number of alien invasive plants in Ningbo.19 from Europe,accounting for 20.43%.11 from Asia,accounting for 11.83%.5 from Africa,accounting for 5.38%.1 from Oceania(1.06%).In addition,5 from other provinces in China,accounting for 5.38%.3.93 species of alien invasive plants are classified into five invasion levels.Among them,the first-level risk has 16 species as well as the second-level,18 species of the third-level risk invasive plants,26 species of the fourth-level risk invasive plants and 17 species of the fifth-level.Based on the invasive status and risk assessment of alien invasive plants in Ningbo,combined with the characteristics of Ningbo port,put forward some suggestions on law-based management and scientific prevention and control.