Studies On Population Ecology Of Paeonia Ludlowii In Xizang

Paeonia ludlowii is endemic plant in Xizang, it is precious resources. Because of the destruction of natural vegetation and predatory logging, Paeonia ludlowii population decline and is endangered in nature, now it has been classified as second-class protected plant. The studies primarily deal with population ecology of this species, including flowering phenollogy; pattern of distribution;niche and biodiversity, ect., in order to provide theoretic evidence for culturing and protecting Paeonia ludlowii .The blooming phenophase and flowers organs of Paeonia ludlowii in different area were investigated in this paper.By using type place investigation method and C index,I index,M* index,K index,M*/M index,spatially distributed pattern of Paeonia ludlowii population,an important shrub growing in a small strip of area, belonging to the middle reaches of the Yarlung Tsanpo River in Xizang of China was studied.Detailed ananlysis demonstrated that the spatiale distributed pattern of Paeonia ludlowii population from different plots is clumped in seedling and adult shrub stage.this kind of pattern is caused probably by strong tiller ability,falling seeds around parent shrub and light like strait in Paeonia ludlowii.Based on the data from the field investigation, the Levins formula and the niche proportional similarity formula were used to calculate the niche breadth, niche proportional similarity and the niche overlaps among eleven populations of Paeonia ludlowii Community in the South-eastern Tibet. The result shows that the order of niche breadth is:Paeonia ludlowii, Geranium wilfordii, Dryopteris silaensis,Berb-eris hemsleyana, Parasenecio souliei, Rosa sericea, Sambucus adnata, Elsholtziafru-itcosa, Amygdalus mira, Hippophae rhamnoides,Malus rockii . The niche proportional similarities and the niche overlaps among Paeonia ludlowii and other populations are low. The competition for resources is not intensive. Paeonia ludlowii became dominant species and plays an important role in the maintenance of the diversity and stability of the community.Based on the quadrate method,the species diversity of Paeonia ludlowii Community in the South-eastern Xizang was studied. The results show that Astera-ceae, Dryopteridaceae, Labiatae,Caprifo- liaceae,Rubiaceae,Ranunculaceae,Rosaceae,Paeoniaceae Berberid- aceae, Labiatae were the dominant families in Paeonia ludlowii Community.The 12 sample plots are all absolutely dominant,the importance value came up to 64.45% on average,and it is far higher than the others. the abundance index,Simpson index,Shannon-Wiener index, probability of inter-specific encoun- terand species evenness show the similar results. The diversity indexes of tree layer,shrub layer and herb layer is varied in the 12 plots community, the variation in herb is significant, but relaively less in the tree layer and shrub layer.