Abstract: The evergreen broadleaved forest communities in East China have been subject to extensive disturbances such as changing landuse, agricultural development and logging. To describe the character of species diversity of the degraded evergreen broadleaved forests around Tiantong National Forest Park, their α diversity indices were compared with those of nearby mature evergreen broadleaved forest communities. Multiple stepwise regression was used to determine which factors, such as elevation, aspect, slope, land use type, soil depth, human impact intensity and distance to natural vegetation, road and village, affected the species richness of degraded communities. Overall the α diversity of the evergreen broadleaved forest communities was higher than that of the degraded communities. In the degraded communities, the depth of soil and land use type, together with distance to natural vegetation were the main factors influencing the species richness. We also found a positive correlation between the species diversity of degraded communities and soil depth, but distance to natural vegetation was negatively correlated with diversity, in abandoned orchard the species diversity was higher than that of other land use types. The nine influencing factors can be divided into three groups, which include habitat factors, landscape elements and human disturbance activities. All three groups are important in determining species richness in the degraded communities. However, habitat factors alone play an important role in contributing species richness in shrub communities, while both habitat factors and human disturbance activities are significant in the conifer forests.

Key words: species diversity, stepwise multiple regression, environmental and land use factors, degraded communities, species diversity, stepwise multiple regression, environmental and land use factors