洮河自然保护区大峪沟林区紫果云杉群落木本植物种群生态位特征

基于群落调查数据，以样地代表多种资源的综合状态，物种重要值作为生态位的计测指标，利用Levins和Shannon生态位宽度，Schoener生态位相似和Pianka生态位重叠对洮河自然保护区大峪沟林区的紫果云杉群落木本植物种群生态位进行定量研究。结果表明：紫果云杉群落乔木层共有树种8种，隶属于4科6属，紫果云杉占绝对优势，岷江冷杉为次优势种；灌木层共有植物50种，隶属于16科25属，忍冬科的蓝靛果、葱皮忍冬和唐古特忍冬等以及蔷薇科的峨眉蔷薇和银露梅等构成了灌木层的主体，紫果云杉幼苗优势不明显，但生态位宽度最大。本研究表明，生态位宽度受物种生态特性及其分布和生境共同影响，重要值大的物种生态位宽度一般较大，生态位宽度大的物种之间生态位相似性和重叠性一般较大，并与其它物种重叠的概率高、重叠程度大，生态位宽度小的物种集中出现时也会出现较大的生态位重叠，同科或同属的物种间常有较大生态位相似和重叠。生态位宽度反映着种群的扩散潜力，生态位相似反映着群落的稳定性，生态位重叠反映着物种间存在或潜在的竞争程度。紫果云杉在乔、灌木层均有最大的生态位宽度，生态适应性最强，群落结构稳定，具有进一步扩散的可能。

Niche of woody plant populations of Picea purpurea community in Dayugou forest area, Taohe Nature Reserve, Gansu Province

Based on the plant community investigation data, and with plots representing the comprehensive status of multiple resources, and species importance values as measurement indicators of niche, the niche characteristics of woody plant species in the Picea Purpurea Community in Dayugou forest area of the Taohe Nature Reserve were quantified with the indices of Levins niche breadth, Shannon niche breadth, Schoener niche similarities and Pianka niche overlap. The results showed that there were 8 tree species in the tree layer of the picea purpurea community, belonging to 4 families and 6 genera, among which the picea purpurea was the absolute dominant species, and the Abies faxoniana was the subdominant species; the shrub layer had a total of 50 species of plants belonging to 16 families and 25 genera, among which Lonicera caerulea, Lonicera ferdinandii and Lonicera tangutica of the Caprifoliaceae and Rosa omeiensis and Potentilla glabra of the Rosaceae are the dominant species of the shrub layer, and the picea purpurea seedlings did not have obvious advantages but they had the widest niche breadth. This study indicated that the niche breadth was affected by the ecological characteristics of species as well as their distribution and habitat. The species with large important values generally had larger niche breadth, and the species with large niche breadth generally had the larger niche similarity and overlap, and had higher probability and degree of overlap with other species; there were also large niche overlaps when species with small niche breadth were concentrated, and the species of the same family or genus often had larger niche similarities and overlaps. Niche breadth reflected the population dispersal potential, the niche similarity reflected the stability of a community, and the niche overlap reflected the degree of the existing or potential competition among species. Picea Purpurea had the widest niche breadth in both the tree layers and shrub layers, the strongest ecological adaptability, the stable community structure, and thus the possibility of further dispersal.