退化羊草草原在浅耕翻处理后植物多样性动态研究

Dynamic of Plant Diversity of Degraded Leymus chinensis Steppe after Shallowly Ploughing

利用多年样方资料的统计分析,对退化草原群落浅耕翻处理后恢复过程中的生物多样性变化规律及引起这些变化的主要植物种群进行研究,结果表明:退化羊草草原在浅耕翻恢复过程中其多度分布特征表现为个别种个体的快速富集(建群种)和少数种随演替进程的富集(优势种),多度很少的种类(偶见种和伴生种)增加的过程,以上特征与恢复过程中羊草的增加密不可分。退化羊草草原在浅耕翻恢复过程中出现多样性指数的3个高峰期,但多样性指数总变化趋势为开口向上的抛物线状。物种多样性可作为丰富度与均匀度的一个综合反映,在退化草地改良恢复过程中均匀度起着更主导的作用。均匀性指数的整体趋势与多样性指数相似。群落主要植物种群与多样性指数存在着显著的相关关系,其中羊草、冷蒿、冰草、针茅、糙隐子草、变蒿、星毛萎陵菜的密度和生物量与多样性指数具有显著或极显著的线性回归关系。黄蒿的生物量、双齿葱的密度与多样性指数呈显著的线性关系。

Having analyzed the quadrat data of several years, the paper studied the dynamic rules of biodiversity during restoration process of grassland after shallowly ploughing, and also studied the main plant populations which caused the changes. The abundance characteristics of degraded steppe of Leymus chinensis showed that the individuals of several species （edificatory） became abundant quickly, and a few species （dominant） got abundant during the process of restoration and the whole species of low abundance （accidental species and companion species） increased. These characteristics were closely related with the increase of Leymus chinensis. The diversity index of degraded steppe of Leymus chinensis showed three climaxes during restoration process. But the variation trend of diversity index was a parabola opening upwards, which showed that biodiversity index could be regarded as the comprehensive reflection of richness index and evenness index, and the evenness index played a more important role. The evenness index was similar to diversity index in this study. Its whole trend during restoration process was also a parabola opening upwards. The main plant populations and diversity index had a significant correlation. Some populations, such as Leymus chinensis, Artemisia frigida, Agrogyron sibiricum, Stipa grandis, Cleistogenes squarrosa, Artemisia pubescens, and Potentilla acaulis, the linear regression relation between their density, biomass and diversity index was significant or extremely significant. The biomass of Artemisia scoparia had a significant linear relation with diversity index, so did the density of Allium bidentatumm.