关键词: 黄土丘陵区, 沙棘, 群落, 物种多样性, 封育

Abstract: Traits of plant diversity in a hillclosed and afforested sequence of Hippophae rhamnoides stands in Ziwuling mountains were preliminarilly analyzed. The results showed that species richness and species diversity indexes of different layers in the forest stands are as follows: herb layer>shrub layer. D and H′of species diversity indexes of identical layer are different, but it has basically the same tendency in different growth stages of Hippophae rhamnoides community. Species diversity indexes of shrub layer increase with increasing time. Species diversity indexes of herb layer in one yearly stage is bigger and in the other stage they decline with time increasing. The similarity of Hippophae rhamnoides communites is increased with time increasing. On the whole , different plants and families have impeoved greatly and ecology dominance of communities have improved and communities are stabilized greatly. The limited human disturbances is the effective measure for Hippophae rhamnoides community recovery.

Key words: Loess Hilly Region, Hippophae rhamnoide, community, species diversity, hillclosed and afforested