On Species Diversity,Niche Breath and Interspecies Association in Communities Invaded by Spermacoce latifolia Zhejiang Province

According to the data collected from ten typical plots in Zhejiang Province,we analyzed the diversity of the communities invaded by alien plant Spermacoce latifolia using species richness index,Simpon Index,Shanon-Wiener Index and Pielou Index.In order to test its competition,relative association,and the position with other species in the communities,the niche breadths,niche overlaps,multi-interspecies association,and pair-interspecies association of S.latifolia with other 20 species were determined.The results were as follows:(1) The diversity of the communities decreased with the invasion of S.latifolia;(2) The widest in niche breath of S.latifolia dropped a hint that it could survive in any environments and easily compete with other species in the community;(3) S.latifolia had greatest niche overlaps with Digitaria ciliaris,followed by those with Conyza bonariensis and Cyperus rotundus;(4) The χ2 analysis indicated that no species in the community had a significant relationship with S.latifolia,which only had a positive relationship with D.ciliaris,C.bonariensis and a negative relationship with C.rotundus,Commelina communis and Lindernia crustacea.