关键词: 青海云杉人工林, 草本层, 生态位宽度, 生态位重叠度, 生态响应

Abstract: The herb layer of spruce plantation in the Qilian Mountains was selected as the object of this study. Data of 60 plots in the spruce plantations were obtained from investigation. The niche breadth and overlapping of dominant herbal species within plantation communities were measured by means of levins niche breadth, Shannon-wiener niche breadth and pianka niche overlapping indices. Results showed that both Polygonum viviparum and Fragaria orientalis had greater niche breadth than other ones, which were the dominant species of herb layer due to their extensive adaptation to environment of spruce plantation. The niche overlapping index suggested that the herbaceous species with larger niche breadth in the spruce plantation didn't always have bigger niche overlapping. There was no positive direct liner relationship between niche breadth and niche overlapping of herbaceous species. This phenomenon perhaps resulted from patchiness of species distribution and high spatial heterogeneity of environmental resources in spruce plantation. Niche overlapping of herb layer in spruce plantation is relative low. The herb layer of spruce plantation has lower similarity of resource utilization. Geranium pylzowianum and Pedicularis were more aggressive than other species based on their eco-response rate and they will develop as the dominant species of herb layer in spruce plantation for future development.

Key words: Spruce plantation, Herb layer, Niche breadth, Niche overlapping, Ecological response