Influence of Azadirachta indica Plantation upon the Native Plant Diversity in Yuanmou County,Yunnan

Native plant species were studied in the neem(Azadirachta indica) plantation in Yuanmou County of Yunnan by analying the genus areal-types and four diversity indexes (Gleason index,Simpson's diversity index,Shannon-Weiner index and Pielou's evenness index). According to the genus areal-types, the main areal-types were Pantropic and Cosmopolitan, indicating that the tropical component was the most abundant.It was consistant with the climate of the Dry-Hot Valley in Yuanmou County. Four diversity indexes showed the same results: (1)the species richness, diversity indices and evenness declined with the increase of coverage of neem plantation; (2)the number of species and the number of each species were not influenced evidently by the shadow of neem plantation in low coverage(40%),while this influence was very evident in high coverage(40%); (3)the growth of other plant species was restrained by the defoliatation and deadwood of neem in the neem plantation, some species grew very well.