亚高山草甸植物群落植物物种数与取样面积的关系

Relationships between plant species number and sampling area for sub-alpine meadow plant communities

采用巢式样方法统计出随样方面积增大物种数量的累积数,分析东祁连山亚高山草甸植物群落植物物种数与取样面积的关系,并选择10条曲线模型对亚高山草甸植物群落种-面积曲线进行拟合,采用相关指数(CRI)作为模型拟合优劣的评价指标。结果表明:取样面积>16 m2时,4个样方植物群落物种数目的增加幅度明显减小并基本保持同一水平,而且每个样方中植物群落物种数目都超过了本样方总物种数的75%;取样面积达到32m2左右时,高产样方Ⅰ、Ⅱ和低产样方Ⅰ、Ⅱ的物种数基本都保持在某一特定的水平,分别占本样方总物种数的88%、89%、84%和92%;除模型S=aln(A-1)和S=a(1-e-bA)外,其他8个模型的拟合效果均比较好,CRI值均≥0.9,其中S=(b+alnA)c和S=c/(a+A-b)最好,其次是S=aln(bA+1)、S=b+alnA、S=aAb、S=c-ae-bA。

In this paper, nested plots were used to alpine meadow plant communities in the Eastern investigate the plant species number of sub- Qilian tween plant species frequency and sampling area were Mountains of China. The relationships be- analyzed, and the species-area curves of the plant communities were fitted with ten selected models. Correlation index （CRI） was then used to test the fitness of the models. The results showed that when the sampling area increased over 16 m2, the related increase of species number in four quadrats decreased significantly, and basically maintained at the same level. Furthermore, the species number in each quadrat was more than 75% of the total species number in the quadrat. When the sampling area reached about 32 m2, the species number in high-yield quadrats I and II and in low-yield quadrats I and II were basically maintained at a certain level, accounting for 88%, 89%, 84%, and 92% of the total species number in the quadrats, respectively. With a CRI of ≥ 0.9, eight of the ten models had good fitness. Models S= （b＋alnA）c and S=c/（a＋A-b） were the best, followed by models S=aln（ bA＋1 ） , S=b＋alnA, S=aAb, and S=c-ae-hA, and only models S=aln（ A-1 ） and S=a（1-eTM） had bad fitness.