山西霍山灌丛空隙草本植物物种多样性与更新

采用物种重要值和物种多样性指数,分析了山西霍山灌丛空隙内主要草本组成及其多样性随灌丛空隙面积梯度的变化规律。结果表明:在自然状况下形成的10 m2的灌丛空隙最多,占51.2%。灌丛空隙内草本植物的重要值高于灌丛下草本,且以10~20 m2的空隙为最高。主要草本可分为3类:(1)对灌丛空隙更新反应不明显的草本,(2)对灌丛空隙有正更新反应的草本,(3)对灌丛空隙有负更新反应的草本。灌丛空隙内的物种丰富度、多样性指数和均匀度指数均高于灌丛下,而生态优势度均小于灌丛下,呈现"单峰型"的变化趋势,且在10~20 m2达到峰值。因此,适宜大小的灌丛空隙是森林生态系统草本层植物多样性维持的重要途径。

Herbaceous Plant Species Diversity and Regeneration in Shrub Gaps in Huoshan Mountain of Shanxi Province

To better understand the effects of shrub gaps on the herbaceous species community in Huoshan Mountain, species importance value and diversity index were employed to analyze the change of the herbaceous plant species composition and diversity across a gradient of gap sizes. The results showed that the proportion of shrub gaps whose area size less than 10m2 were the highest under the natural state, accounting for 512%. The importance value of herbaceous plant was larger in shrub gaps than in non gaps and it was the highest in shrub gaps from 10 to 20m2. The dominant herbaceous species could be classified into three groups: positive response, negative response, and non sensitive. The species richness, diversity index and evenness index in shrub gaps were higher than those in non gaps, while dominance index in shrub gaps was lower than that in non gaps. In addition, they showed hump shaped curves with increasing gap size, and the maximums appeared in shrub gaps from 10 to 20m2. Therefore, the appropriate size of shrub gap is an important way to maintain the species diversity of herbaceous plant in the forest ecosystems.