The re-vegetation and changes in species diversity in hilly and gully regions on loess plateau——As seen by the case study in Wuqi county

On the base of the research on natural and man-established vegetation communities in Wuqi county, the species diversity of those communities were analyzed. The results show that the communities at early and balanced stages of natural restoration had a higher diversity and evenness index, yet the peak value of abundance index appeared in the middle stage of the succession. The species diversity of bush communities was higher than grass communities while it decreased after a fixed number of year and the bush communities degraded to certain degree. Species diversity can be used to estimate the vegetation's functions in conserving soil and water indirectly, but when estimated, species abundance and evenness in spatial distribution should be taken into consideration.