Studies On The Community Structure And Diversity Of The Forest Plant And Arthropod In Wuling Mountain

The Wuling Mountain is located in a floristic region that is a transition from the warm-temperate deciduous broad-leaved forest to the temperate coniferous and broad-leaved mixed forest. Its natural forests were featured by both of the two forest types, and had complex vegetation forms, obvious altitudinal zones and various influencing factors. In order to seek for the varying regulations of the forest biocoenose under the natural condition, the constitution, structure, diversity, stability and the relationship between diversity and stability of the plant community and the arthropod community in the natural secondary forests in Wuling Mountain were being studied by field community investigating methods and multivariate analyzing techniques. The main results are as follows:(1) The varying regulations of the constitution, structure and diversity of the plant communities. In the natural secondary forests of Wuling Mountain, the plant community represented different varying regulations under various factors such as stand type, stand age, altitude and human disturbance degree. Under the effect of the stand type, comparing the different species abundances, the stands with complex plant constitutions were higher than the pure stands, and the natural stands were higher than the artificial stands; comparing the various individual amount of the plant community, the bushes, the meadows and the stands with lower crown density were higher than the stands with orderly forest form and higher crown density; the artificial stands were higher than the natural ones. Concerning the diversity and evenness of the plant community and the herbaceous layer, the stands with orderly forest form and higher crown density were higher than the bush and the stands with lower crown density. Concerning the diversity and evenness of the tree layer and the shrub layer, the mixed stands were higher than the pure stands, while the natural stands were higher than the artificial stands. Considering the functions of different stand layers, the tree layer was a critical group and layer, its species, amount profoundly influenced the plant community structure and function, however, as the herbaceous layer had numerous small individuals, it seriously influenced the variation of the community diversity. From the effect of the stand age, the species abundance of the plant community increased with the increasing stand age, but the specie amount of the herbaceous layer decreased with it. The individual amount also had a trend of decrease with the increasing stand age, while the diversity and evenness had a regulation of increase with the increasing stand age. As the altitude rising, the species abundance and the diversity of the plant community represented a varying form of the bell carve, while the individual amount showed a decreasing trend. With the increase of the human disturbance, the speciesabundance,individual amount and diversity of the plant community were all decreased.(2) The arthropod community structure and diversity influenced by the forest type. The arthropod community constitution, structure and diversity were significantly influenced by the constitution and stand type of the natural secondary forest in the Wuling Mountain. The more complicated the stand constitution was, especially, the more abundant predatory and parasitic natural enemy species its arthropod community had, the more proportion the top arthropod species accounted for, and the more intricate the community vertical structure was. The arthropod community diversity increased with the enhancement of the stand constitution complexity, however, the natural enemy group had the most significant augment. It indicated that the plant community constitution and type had a close correlation with the arthropod community constitution, structure and diversity.(3) The influence on the arthropod community structure and diversity imposed by the stand age. As the stand age increased, the family and species number of the arthropod community were increased, and the parasitic natural enemy, pre...