Studies on diversity and structure of plant communities in early succession stage in abandoned land at different landforms on the Loess Plateau

The species component, similarity, diversity of plant communities at early succession stage in abandoned land at different landforms on the Loess Plateau were studied by sampling methods. The results showed that the structure of plant life forms was different among landforms and the number of hemicryphtophytes or annual plants were more than others. The similarity of top slope communities to north-facing slope communities was higher and it was in the same situation between south-facing slope and bottom slope. There were certain differences at community diversity among different landforms, and the differencs of community evenness were not significant. The significant level of diversity differencs with four different landforms were dissimilar, the diversity of top slope was the highest, and the south-facing slope the lowest. It could be concluded that, the plant communities of top slope and north-facing slope would develop toward perennial plant communities, and the plant communities of bottom slope and south-facing slope would develop toward the annual plant communities in the future. Therefore, the ecological characteristics of abandoned land needed to be studied in longterm, and this might provide more scientific foundations for the vegetation restoration and rehancement on the Loess Plateau.