Population Dynamic Comparison Of Abies Chensiensis Van Tienghem And Abies Fargesii Franch

Abies chensiensis, an endangered plant, is a classâ…¡typical endemic species in China. In order to puzzling one efficient plan for protecting the species and making use of the natural resource sustainedly, probing into the endangered mechanism of this population, In this paper, we compared the individual characters, biomass, population dynamics, species diversity of its communities and Niche characteristics of Abies chensiensis and its relative Abies fargesii at the similar habitats. The results showed as the followings:Firstly, The similarity of families genera and species is large in Abies chensiensis and Abies fargesii community. Especially, the discrepancy of species Composition was the largest.There were only 34 plants which were altogether existed in Abies chensiensis and Abies fargesii community, and occupied 17% in the total number of Abies chensiensis and Abies fargesii community plants. According to geographical elements of family and genera analyses results, temperate plays an important role in the Abies chensiensis and Abies fargesii community. The geographical components were multiformer than Abies fargesii community. The dominant families and genera were not prominent. The number of monotype species and oligotype species were very large in Abies chensiensis and Abies fargesii community.Secondly, the species richness, diversity indexes and evenness indexes of the Abies chensiensis community in Cloudy slope were higher than other slopes. The result showed that the stabilization of Abies chensiensis community were more. The arbor layer species richness of Abies chensiensis community were higher than Abies fargesii community in every slope. But the shrub layer and herb layer species richness in Abies chensiensis community were lower than Abies fargesii community in every slope.Thirdly, growth yield of young Abies chensiensis was bigger than Abies fargesii at different slopes.Both the roots and truck of Abies chensiensis were larger than Abies fargesii. That showed than Abies chensiensis could endure bad environment. The leaves biomass of Abies fargesii was larger 11% than Abies fargesii.Fourthly, The dynamics, sizes and structures of Abies chensiensis and Abies fargesii which had grown in the habitats sitting on sunny slopes, semi-sunny slopes, semi-shady slopes and shady slopes, were systematically studied and their static life tables and survival curves and death curve of the populations were accordingly worked out. The results showed that Abies chensiensis in different habitats standing Mt.Qinling basically belonged to a declination type contain less young population members and more middle-aged or old population members. The population density and number of Abies chensiensis were lower than Abies fargesii. The life table of Abies fargesii population indicated that the death rates and killing powers were minus. We should increase numbers of Abies chensiensis, and keep the stability of communityFifthly, the niche breadth of Abies chensiensis were lower than Abies fargesii at different slopes. Niche overlaps extents of main populations in Abies chensiensis community were lower than Abies fargesii., indicated that the environmental resource could be shared by every population and the community was comparative stabilization.By using Hegyi, competition index model for individual tree the intraspecific and interspecific competition in Abies chensiensis community were investigated. The results showed that intraspecific competition of Abies chensiensis was more intensive than interspecific competition. The competition intensity of competitive tree against objective tree and the size of objective tree fit power function CI=ADB, and competition intensity decreases with the increase of the size of objective tree. The model can simulate and predict the intraspecific and interspecific competition among Abies chensiensi community in Mt. Qinling.