The Study On Species Diversity And Relationships Of Forest Communities In Pangquangou Nature Reserve In Shanxi Province

Ecosystem Systems of Larix principisrupprechtii and Picea in Pangquangou Nature Reserve in Shanxi province are the representative forest plant groups in the Loess Plateau region. Applying quadrat methods, forest community in Pangquangou Nature Reserve were analyzed by the qunantitative statistic method in the work, including species composition, species diversity of different communities, niche of main secondary forest populations and of secondary forest in the forest region of association of tree species. Objective to provide scientific basis for forest management protection and sustainable utilization of wildlife habitat biodiversity.The results were as follows:Base the plant species in core area of Pangquangou Nature Reserve, it was known that there were 6 species of fern in the region, which belonged to 5 genera and 4 families, and 285species of seed plants in the region, which belonged to 165 genera and 56 families. Among seed plants there were about 2 families 5 genera 6 species in Gymnospermae, and 54 families 160 genera 279 species in Angiospermae.According to statistical area of distributions wood species, the basal area distributions of dominant wood species were also positively skewed. There were relatively significant different among wood species on degree of skew: Betula albosinensis>Salix sinica>Betula platyphylla>Larix principisrupprechtii.The herb layer has the highest species richness index, followed by those of the shrub layer and the arbor layer. As far as the slope degree, the relationship of the determination of soil parameters and species diversity study shows that the relationship between the species richness and total nitrogen content, available Kalium content, organic content, pH of soil conformed well to significant conic curves respectively at the sunny slope. The relationship between the species richness and total nitrogen content, available potassium content, organic content of soil conformed well to negative conic, and the species richness has exponent relation available Kalium content at the shady slope.Larix principisrupprechtii and spruce forest are as the main building species in Pangquangou Nature Reserve. They are with big niche breadth. The values overlap of niche generally smaller, but niche stocks are higher degree of differentiation between arbor species. So the competition between species in a relatively weak, and community is considerablly stable in general. Lonicera maackii and Cotoneaster multiflorus et al. are with big niche breadth in shrub layer. There is less dominant species than in the arbor layer. The resource sharing are the inevitable trend in shrub layer.In the forest communities, there are 171 species parirs formed by 19 species among which 23 pairs showed signification positive interspecific association(α=0.01), 15 species pairs showed positive interspecific association(α=0.05), respectively account 13.5 percentage, 8.8 percentage, and 10 pairs showed signification negative interspecific association, 26 species pairs showed negative interspecific association, respectively account 5.9 percentage, 15.2 percentage. The interspecific association is not significant.