盐池县草地不同沙化阶段植物群落特征

Characteristic of plant community of different desertification grassland stages in Yanchi County

以宁夏盐池县5种不同沙化类型草地:潜在沙化草地、轻度沙化草地、中度沙化草地、重度沙化草地和极度沙化草地为研究对象,通过野外调查,分析植被物种组成和群落物种多样性的变化,以探讨沙化对草地植被的影响.结果表明:随着沙化程度的加重,旱生多年生草本植物逐渐被沙生一年生草本植物及沙生灌木、半灌木取代;物种丰富度指数、多样性指数自潜在沙化草地至极度沙化草地均逐渐下降,群落趋向于简单和不稳定,物种的替代率升高;群落相似性系数以重度沙化草地与极度沙化草地之间最高,而潜在沙化草地与极度沙化草地之间最低.

The vegetative composition and species diversity in potential desertification grassland, light desertification grassland, medium desertification grassland, severe desertifieation grassland and extreme desertification grassland in Yanchi County were investigated and analyzed to explore the influence of desertification on grassland vegetation. The results showed that the perennial species were replaced gradually by the psammophyte annuals, shrubs and semi-shrubs. With aggravation of desertification degree, the species richness index and diversity index were gradually decreased. Plant communities tended toward simple and instability, the substitution rates of species were gradually increased. The coefficient of community similarity between severe desertification grassland and extreme desertification grassland was the highest, while the coefficient of community similarity between potential desertification grassland and extreme desertification grassland was the lowest.