The Study Of Species Diversity, Interspecific Association And Correlation In The Midst Of Taihang Mountain

Hongyan Mountain, the highest peak in the middle part of Taihang Mountain, is located at Zuoquan county, the southeast part of Shanxi province. It's altitude is 2089m: Its hypsography slopes from northwest to southeast, the former being lower than the later. The altitude of most area is over 1200m. Its climate belongs to the warm temperate zone. There are some villages in this district, so grazing and minerals exploitation have damaged vegetation.This paper selected the middle part of Taihang Mountain as study area. The species diversity, interspecific association and correlation, and niche breadth and niche overlap were studied. The community types, community structure, ecological relationships between species diversity and community types, environmental variables were analyzed in details.X2 test with 2×2 contingency table and Ochiai indices were used to analyze the interspecific association of 12 dominant species of meadow community and 20 dominant species of scrub community and 18 dominant species of tree community. Pearson's correlation coefficient and Spearman's rank correlation coefficient were also applied to calculate correlations between species. The results indicted that species with positive association have similar biological characteristics and demand similar habitats, and the relationships among species-pairs are of significant difference in different types of community. The x2 test is lower, and the Spearman rank correlation test is better than Pearson test.68 quadrats were divided into 8 types of communities by TWINSPAN, which can be treated as one-dimension resource states. The niche breadths and overlaps of main dominant species were measured using a series of indices proposed by Levins, Shannon-wiener and Petraitis. The results indicated that the greater the niche breadth of a species was, the stronger the ability of adaptation to environment and using resources was. The greater the niche overlap value for some species-pairs, the more similar the environmental requirements and resource use. The species with wide niche breadth may have high overlap value with species with narrow niche breadth, and low on the contrary. Species of greatest niche breadth isn't always the constructive species of community.By using of the richness, diversity and evenness indices, combined with TWINSPAN, DCA, DCCA, multi-factors regression, correlation analysis techniques and so on, species diversity and diversification mechanism were studied. The communities were classified into eight types by TWINSPAN. The first axis of DCA indicated basically the diversification of soil water, while the second axis indicated basically the disturbance degree by people.The correlations between N, organic matter, elevation and the first axis are negative association, and the others are positive. The angle between Cu, PH and the first axis is very small, shows significant positive association. The angle between Mn, electrical conductivity and the second axis is also small, showing significant association, and the correlations between P and the second axis are significantly negative.