Study On Vegetation Characteristics Of Remnant Hills In Old City Zone Of Nanjing

Taking the vegetation on the12remnant hills in old city zone of Nanjing as the researchobject, based on the investigation of36typical plant community plots, vegetation characteristicsof remnant hills were studied systematically in terms of flora, community types, species diversityand the dominant population dynamics of Shizishan in this paper, which aimed to know thecurrent features of the vegetation, predict the dynamic change trend of the vegetationcommunities and provide scientific basis for restoration and reconstruction of zonal urbanvegetation of Nanjing. The main research contents and conclusions were as follows:(1) There were totally83families,171genera,214species of tracheophytes which arerecorded at the typical plant community plots of the remnant hills in old city zone of Nanjing.Statistics analysis of family areal-types and genera areal-types of its species composition showedthat tropical elements had obvious advantages, there were few temperate elements relatively, butmost of them were the main compositions of the vegetation of the remnant hills in old city zone.(2)36community plots were classified into15formations by using the method of fuzzycluster analysis, they were: Form. Alangium chinense, Form. Celtis sinensis, Form. Robiniapseudoacacia+Broussonetia papyifera, Form. Sabina chinensis, Form. Ligustrum lucidum+Pinusthunbergii, Form. Cinnamomum camphora, Form. Pterocarya stenoptera+Dalbergia hupeana,Form. Viburnum awabuki, Form. Cedrus deodara, Form. Michelia chapensis, Form. Liquidambarformosana, Form. Quercus acutissima+Celtis sinensis, Form. Osmanthus fragrans+Trachycarpusfortunei, Form. Ginkgo biloba, and Form. Castanea henryi. Plot number belonging to Form.Robinia pseudoacacia+Broussonetia papyifera were16. This indicated that Form. Robiniapseudoacacia+Broussonetia papyifera was the main type of vegetation communities in theremnant hills in old city zone of Nanjing.(3) Using the method of measuring different growth form respectively, species diversityindices of tree layer, shrub layer, herb layer and interlayer plants in different community typesand different remnant hills in old city zone of Nanjing were analysised and comparisoned. Theresults showed that the species richness index and the species diversity indices of all growth formof natural or seminatural plant communities were higher generally than those of artificial plantcommunities besides the evenness indices of tree layer and shrub layer.(4) Structures and dynamic features of the main three population in plant communities onShizishan of Nanjing which are Alangium chinense, Celtis sinensis and Broussonetia papyiferawere studied with the method of size class substituting for age class. The results indicated thatAlangium chinense population was the increasing type structure of L type, its population densitywas the biggest one, but there was no large diameter-class plant because it invaded later and it was limited by its life form, as it existed high mortalities at every age class, its population densityas a whole showed a gradual downtrend; Celtis sinensis population was obviously the mature andstable type structure of inverse J type, its population density was the smallest one, seedlings had ahigh mortality, its large diameter-class plant density was the biggest one because there werestable low mortalities after the age class Ⅲ, its population density decreased firstly and thenincreased; Broussonetia papyifera population was close to L type structure, which belonged to bea transitional type from increasing type to stable type, as it existed high mortalities at every ageclass, its population density and dynamic were the medium of the two mentioned above.