The Study On Greenbelt Plant Diversities In Tri-circle Area Of Fuzhou City

The environment quality of urban human settlement are affected by urban biodiversity,especially the plant diversity.Urban greenbelt is an important part of urban ecosystem and carrier of urban biodiversity.With the speeding up of urbanization in our country,urban biodiversity is facing with the troubles of monotonous species composition,complex species origin,and single vertical structure.Besides,urban construction is also destroying the local biont and ecological system.The study of urban greenbelt plant diversity can provide theoretical basis for urban biodiversity protection and construction.In this study,after making a comprehensive investigation on the plants of different types of greenbelt in Tri-circle area of Fuzhou city,the species composition,origin,diversity and community structure were analyzed.In addition,the plants diversities and characters of the four greenbelt types,including parks,dwelling districts,schoolyards and streets were analyzed.The results can be theoretical basis for the urban biodiversity construction of Fuzhou,and the main results were as follows:There are 808 species,belonging to 140 families and 498 genera in Tri-circle area greenbelt of Fuzhou city.They are divided into 221 arbor species,189 shrub species,348 herbage species,28 herbaceous-liana species and 22 ligneous-liana species.Woody plants are formed by more evergreens and less deciduous;more perennials and less annuals consist of herbs.The ranking of four greenbelt types:dwelling district(615 species),park(544),schoolyard(257)and street(41).There are 446 indigenous species(55.20%of the total)and 362 introduced species(44.80%)which contain 86 species introduced from other regions of China(10.64%)and 276 species from foreign countries(34.16%),the native ones are slightly more than introduced.It exists eight invasive species which spread to a wide range of habitats.Park and dwelling district greenbelts contain 235 and 230 introduced species,respectively.The indigenous plants are composed of much more herbs than arbors and shrubs.Schoolyard greenbelts contain 114 introduced species which dominated on the arbor,shrub and herb layers.There are 22 introduced species in street greenbelts,having an advantage over indigenous ones.In the 123 plant communities,the ranking of community vertical structure types are as follow:arbor-shrub-herb structure,arbor-shrub-vine-herb,arbor-shrub,arbor,and arbor-shrub-vine.Different layers are similar in plant disposition and the commonly plants are used frequently.Almost natural-forest communities appear in historic parks or near the mountains.The community structures of old parks and dwelling district greenbelts are more complex than new ones.The street community structures of the city center are more complex than that near downtown area.The Margalef Index of greenbelt plants is quite high in Fuzhou tri-circle area.The shrub layer gets the highest species Margalef Index,then the herbage and arbor,and interlayer is the lowest.The shrub also gets the highest Shannon-Wiener index and Simpson index,then the arbor,interlayer and herbage.Most arbor layers of greenbelts get the highest Pielou Index,and then the shrub.In different types of greenbelt,dwelling districts has the highest species Margalef Index,Shannon-Wiener index and Simpson index in different levels,which are the lowest in streets.In general,the species diversity level of arbor and shrub are higher,interlayer and herbage are lower.Besides,the species diversity level of parks and dwelling districts are higher,schoolyards and streets are lower.As the main part of city greenbelt system,park greenbelts get the highest Margalef Index in shrub layer,followed by arbor,shrub and herb.The Shannon-Wiener index and Simpson index of arbor and shrub are higher than interlayer and herb.Arbor gets the highest Pielou Index,followed by shrub,interlayer and herb.