DYNAMICS OF DIVERSITY, DISTRIBUTION PATTERNS AND INTERSPECIFIC ASSOCIATIONS OF UNDERSTORY HERBS IN THE CITY-SUBURB-EXURB CONTEXT OF WUHAN CITY, CHINA

The dynamics of herb diversity, distribution patterns and interspecific associations of dominant herbs in natural forests at three growing stages in a city-suburb-exurb context in Wuhan City were studied using a fixed plot. The results show that the composition, diversity indices, mean and total richness gradually increased with the city-suburb-exurb gradient. Codominant species across temporal dynamics in Qinglong Mountain were stable, however, there were remarkable changes in the city-suburb context. Qinglong Mountain (exurb context) had the densest codominant herbs, Woodwardia japonica, Spider brake and Parathelypteris glanduligera, throughout the growing season. However, Shizi Mountain (suburb context) and Hongshan Mountain (urban context) had low-density and monodominant herbs at three stages. The overall strength of associations among herbs increased with the city-suburb-exurb context, and pairs of positive associations and significant associations (r>0.5 or r<-0.5) were more frequent on Qinglong Mountain. Therefore, the exurb-suburb-city landscape context in response to urbanization had a notable effect on the features of the understory herb layer.