Effects of Human Disturbance on Species Diversity and Community Structure of Symplocos sumuntia Secondary Forest in Bifengxia in Western Sichuan

Abstract:

To understand the community structure and species diversity of Symplocos sumuntia secondary forest of Bifengxia in western sichuan under human disturbances, the community structure, composition of species and species diversity character of Symplocos sumuntia community were studied. The results showed that there were 151 vascular species, belonging to 58 families and 98 genera, in 12 plots with total area of 7200 m², in which Lauraceae, Symplocaceae and Rosaceae were dominant. One-Way ANOVA analysis showed that there were not significant difference (P>0.05) in diameter class and height class of tree layer under different human disturbance. And the diameter class structure of tree layer was single peak type, its height class structure conform to inverse J-shape, which suggested strong capacity of natural regeneration. The species composition and number of dominant species in each layer were different under human disturbances. The number of dominant species in tree layer had significant difference under disturbances with in order of slight disturbance > middle disturbance > severe disturbance, while the number of species in shrub layer and herb layer was in order of middle disturbance > slight disturbance > severe disturbance. The diversity indexes, such as S, H, H', and J_sw, decreased with the increament of human disturbance, indicating a decrease of species diversity. There was negative relationship between human disturbance and species diversity in tree and herb layer, while the species diversity increased in shrub layer at middle disturbance. As a whole, these indexes were in the order of shrub layer > tree layer > herb layer.