南长山岛草本植物多样性及影响因子

Diversity and its impact factor of herbaceous plant on Nanchangshan Island in Shandong Province,China

由于特殊的地理位置和有限的规模大小,海岛生态系统具有明显的脆弱性特征,植物多样性对维护海岛生态系统稳定具有基础性作用.以山东南长山岛草本植物为研究对象,在现场调查的基础上,分析多样性及其空间分布,通过CCA排序和方差分析,辨识地形、土壤、人工林和海洋因子对草本植物多样性的影响.结果显示:(1)调查记录南长山岛草本植物85种,各样地Shannonwiener指数和Pielou指数平均值分别为2.16和0.838,相邻环境梯度区间的Jaccard指数均小于0.5;(2)不同样地Shannon-wiener指数和Pielou指数由林缘至林内均呈降低趋势,且在土壤pH、含水率、全磷、全钾较低以及海拔较高的位置总体较高;在海拔较高和坡度较小的区域,相邻梯度区间的Jaccard指数总体较低;(3)地形、土壤和人工林均对南长山岛草本植物多样性具有显著影响,其中海拔、全磷和距林缘距离是最主要的影响因子.

Island ecosystem is vulnerable due to its limited area and isolated space, and biodiversity plays an important role in maintaining the stability of the ecosystem. Herbaceous plant is one of the widely distributed plants on island which is highly diversified and respond well to environment. It is vitally significant for biodiversity conservation to reveal the diversity and its impact factor of herbaceous plant on island. Related studies have indicated that herbaceous plant on island is not only affected by topographic and soil factors, but also probably associated with plantation and ocean. In this study, herbaceous plant on Nanchangshan Island was studied through field investigation and sampiing. Species composition and biodiversity were calculated. Then, the impact factor of herbaceous plant diversity was identified using the method of canonical correspondence analysis （CCA） and analysis of variance （ANOVA）. The results showed that the number of herbaceous species recorded in the field investigation was as high as 85 species and the plants belonged to 75 genera of 31 families. The average Shannon-wiener Index and Pielou Index were 2.16 and 0. 838, respectively, and the Jaccard Index between adjacent environmental gradient ranges were all lower than 0.5. The Shannon-wiener Index and Pielou Index tended to reduce from the edge to center of the forest and the 2 indices were generally higher where soil pH, moisture content, total phosphorus and total potassium were low and altitude was high. Meanwhile, the Jaccard Index between adjacent gradi- ent ranges was generally lower where altitude was high and slope was low. Terrain factors, soil factors and plantation factors had played important roles in biodiversity of herbaceous plant on Nanchangshan Island, and altitude, total phosphorus and distance to forest edge were the most important factors.