Study On Ruderal Community Diversity And Distribution Under Different Land Use Type In Suburban Of Shanghai

The ruderal communities were investigated under seven land use types included abandoned lands,farms,roads,factories,residential areas,units and parks in spring and autumn in suburban of Shanghai.The total community number of spring is 394, and autumn is 444.The distribution pattern of species composition among different land use types was analyzed firstly in this article.Secondly the community distribution and the relevance between community types and biotopes were analyzed and discussed.Shannon-Wiener index was used to calculate community species diversity under different land use types;Jaccard index was used to calculate the community similarity of species;the community types were clustered in the PC-ORD by the farthest neighbor method;the relevance was analyzed by CCA in PC-ORD. Lastly the species composition and community diversity were compared among the urban,suburban and Sheshan area of Shanghai,to clarify the effect of urbanization on ruderals.The main conclusions are as follows:1)The species richness under seven land use types is different from each other,the highest is abandoned lands,then are the roads,residential areas,factories,farms,units and parks.The effect of land use type on species level is the most obvious.On the flora composition,besides the cosmopotian,the largest two types are pantropic and north temperate.And the temperate type ratio is higher than the proportion of tropical. On life form composition,the proportion of annual species is more than the perennial. Referred to the annual species,the ratio of winter annual to summer annual is different from each land use type;the highest ratio is road,followed by abandoned lands,factories,farms,residential areas,units and parks.On seasonal variation,in spring the main species are winter annuals and the autumn are summer annuals.But the species appeared both in spring and autumn are more than the one season appearance,and the annual ones accounted for a high proportion.Due to the urbanization,the temperature,precipitation and soil factors have been changed,the ruderal species' phenology occurred disorder.2)The communities' species diversity is different from each land use types.In spring, parks' diversity is the highest,followed by farms,factories,residential areas,units, and abandoned lands and roads.In autumn,parks' diversity is still the highest, followed by residential areas,units,roads,abandoned lands,factories and farms. Abandoned lands and farms,residential areas and units,roads and factories have the high species similarity because of the similar human interrupt and habitat condition. The similarity is lowest between abandoned lands and parks.3)394 communities of spring were clustered into 72 community types,include 6 wide-adapted types,with the ratio of 8.3%;33 part-adapted types,with the ratio of 45.8%;33 single-adapted types,with the ratio of 45.8%.The environment factors affected the distribution of spring communities are soil hardness,soil salinity,light conditions and soil moisture.444 communities of autumn were clustered into 64 community types,included 8 wide-adapted types,with the ratio of 12.3%;28 part-adapted types,with the ratio of 43.1%;29 single-adapted types,with the ratio of 44.6%.The environment factors affected the distribution of autumn communities are light condition,soil hardness and soil pH.4)The species diversity,the proportion of annuals and the types of communities showed that suburban is more abundant than both urban and Sheshan area of Shanghai,appeared the unbalanced single-peak distribution pattern.This was decided by suburban's broad growing space,abundant land use type,complex habitat conditions and multiple human disturbances.