Study On Quantitative Ecology Of Castanea Mollissima Communities In Taikuan River Nature Reserve

Taikuanhe Nature Reserve, belonging to Zhongtiao Mountains, is situated in 111°19'--111°30'E,34°58'--35°13'N in the south of Shanxi. It has a typical warm-temperate continental climate with abundant plant resources and higher biodiversity. As an endemic and high economic plant to China, Castanea mollissima is distributed in many moutains. Based on the datasets from the field in Taikuanhe Nature Reserve, Shanxi, Castanea mollissima community were studied by using quantitative ecology methodology, including community classification and ordination, species diversity and interspecific relationship. The object of this study were to provide some theoretical basis so as to protect this endangered species from damage, recover population and utilize sustainable for the resource.The community structure, species composition, distribution of C. mollissima communities and the relationship between community and environmental factors were investigated by using TWINSPAN and DCA. The classification reflected the relationship of C. mollissima communities'types and environmental gradient.The results were as following:Castanea mollissima communities were classified into 11 Associations by TWINSPAN, and the main factors that restricted community distribution were disturbance, aspect and soil organic matter. The ordination results of DCA indicated that the main factors that restricted community distribution were aspect, terrain and soil type. The first axis of the DCA ordination indicated the influence of the slope and aspect gradient on the communities. The second axis that reflected the relationship between communities and the environment is not obvious, but the diagonal of the DCA ordination identified the changes of the communities, the ground layer and Soil organic matter content. The ordinations of the 37 dominant species and 42 quadrats showed the similar results. the distribution pattern of the dominant species determined the type of the communities.The relationships between species diversity, community types, community structure and environmental factors were studied by using the richness indices, diversity indices and evenness indices. the extent of differences between the diversity indices were analyzed. The results showed that:Associations ofⅤandⅪhave higher species diversity, community types, but The two indices were small in Associations ofⅢ,Ⅷ, andⅨ. The analysis of variance results showed that the various groups'richness indices, diversity indices and evenness indices were not significant differences.Tree layer, shrub layer and herb layer were also too. C. mollissima communities diversity mainly decided by the diversity of the shrub layer.The interspecific relationships of 37 dominant species in the communities were analyzed by usingχ2-test and Spearman's correlation coefficient. The results fromχ2-test showed that the association or correlation of species-pairs in the shrub layer was obvious more than that in the tree and herb layers. The results were more sensitive than that ofχ2-test was higher when we used Spearman's correlation analysis. This suggested that the community was in fluctuate period of succession. Based on the result of TWINSPAN and the characteristics of plants ecological adaptation, the 37 dominants were divided into four ecological species groups:Castanea mollissima ecological species group, Forsythia suspensa ecological species group, Rosa multiflora ecological species group and Cotoneaster acutifolius ecological species group.