祁连山青海云杉人工林草本层生态位及生态响应研究

Niche and Ecological Response of Herb Layer in Spruce plantation of Qilian Mountains

对祁连山区青海云杉(Picea crassifolia)人工林草本层植物群落的60个样方进行调查,运用Levins和Shan-non-Wiener生态位宽度指数及Pianka生态位重叠度指数,对该人工林下草本层各植物种群的生态位宽度及生态位重叠度进行定量研究。结果表明:珠芽蓼(Polygonum viviparum)和东方草莓(Fragaria orientalis)的生态位宽度最大,是青海云杉人工林下草本层的优势种,表明这2种物种在该人工林下具有广泛的适应性。生态位重叠指数表明:在青海云杉林下生态位宽度较大或较小的草本种群,他们之间的生态位重叠既有较大的,也有较小的,草本种群的生态位宽度和生态位重叠程度无相关性,可能是由于该区草本物种分布的斑块性和环境资源的高度空间异质性造成的。总体上看,青海云杉人工林下草本层的生态位重叠相对较低,对资源利用的相似度较低;从生态响应速率来看,高山老鹳草(Geranium pylzowianum)和马先蒿(Pedicularis)的发展性最强,在今后的演替过程中将会发展为青海云杉人工林下草本层的优势种群。

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.