Community Classification, Composition And Species Association Of Dioscorea Nipponica Naturally Distributed In Shanxi

On the basis of investigation of natural distributions of Dioscorea nipponica in Shanxi province, community classification was conducted by systematic clustering methods. Then the species diversity of each community, interspecific association and niche of dominant species were analyzed. The results were as follows:(1)There were 256 plant species from 182 genera,83 families in plots of Dioscorea nipponica in Shanxi province. This speices was mainly found in 6 kinds of communities. Two were Shrub types of Vitex negundo var. heterophylla mixed with Macleaya cordata, and Spiraea pubescens mixed with Agrimonia pilosa; Four communities were Koelreuteria paniculata-Spiraea pubescens-Thalictrum aquilegifolium, Betula platyphylla-Rosa davurica-Phlomis umbrosa, Populus cathayana-Spiraea pubescens-Iris tenuifolia, Quercus wutaishansea -Cotoneaster multiflorus-Carex lanceolata.(2)The total diversity of the six communities in Dioscorea nipponica was that, Spiraea pubescens-Agrimonia pilosa shrub's species diversity is the highest, and Quercus wutaishansea-Cotoneaster multiflorus-Carex lanceolata community's species diversity is the lowest. There were no significant difference of total diversity between the shrub typeVVitex negundo var. heterophylla-Macleaya cordata) and Populus cathayana-Spiraea pubescens-Iris tenuifolia community. The total diversity of three communities were similar:Koelreuteria paniculata-Spiraea pubescens-Thalictrum aquilegifolium community, Betula platyphylla-rosa davurica-Phlomis umbrosa community and Populus cathayana-Spiraea pubescens-Iris tenuifolia community.(3)Dominant species of Dioscorea nipponica community were positively correlated, but the correlation degree was not significant. The number of significantly positive species-pair was more than the number of significantly negative species-pair. Dioscorea nipponica was positively correlated with most species. Competition between the dominant species was not fierce, so community of Dioscorea nipponica was of certain stability in short term.(4)The average value of Dioscorea nipponica in soil nutrient resource dimension was the highest and the niche width of soil PH resources of the dominant species was relatively low. Niche overlap between dominant species was not high, Dioscorea nipponica had relatively adequate resources to expand. The soil nutrient resource was not yet saturated by current species, interspecific competition was still weak, and so the development of Dioscorea nipponicat will not be restricted presently.