宁夏盐池沙地3种植物群落的数量特征

Quantitative Characteristics of Three Plant Communities in Yanchi of Ningxia,China

采用样线法和样方法对盐池沙地典型植物群落牛枝子群落、牛枝子-黑沙蒿群落、黑沙蒿群落数量特征进行了研究。结果表明:从牛枝子群落经牛枝子-黑沙蒿群落至黑沙蒿群落,物种组成变化较大,优势种的相对重要值也发生了较大的变化;植物种从占优势地位的草原种,逐步让位于耐旱、抗风蚀的多年生和一年生草本植物,并最终被沙生、一年生草本植物和灌木、半灌木取代;土壤沙化程度逐渐加重。从生活型组成看,从牛枝子群落经牛枝子-黑沙蒿群落至黑沙蒿群落,地面芽植物和地下芽多年生草本植物种类数和重要值所占比例逐渐下降,一年生植物种类数和重要值所占比例逐渐增加。牛枝子-黑沙蒿群落的物种α多样性指数最高,黑沙蒿群落最低。β多样性指数变化反映出植物群落组成已发生分化,物种出现根本性的变化。

The quantitative characters of Lespedeza potaninii community, Lespedeza potaninii-Artemisia ordosica community and Artemisia ordosica community in Yanchi couty, located at the southwestern edge of Mu Us Sandy Land, was investigated. The results showed that： From Lespedeza potaninii community to Artemisia ordosica community, via Lespedeza potaninii-Artemisia ordosica community, Species compo- sition were various, while the relatively importance value of dominant species changed significantly. The main species of plant lost their dominant position gradually to those drought-and-wind resistant perennial and annual herbs, and eventually replaced by those desert annual herbs and shrubs. The composition of life form showed that the number of perennial cryptophytes and their importance value decreased, while the number of annual species and their importance value increased. The diversity index reflected the great differentia- tion of species composition in the three plant communities.