黄土沟壑区狼牙刺群落优势种群生态位研究

运用Levin公式和百分率相似公式，对狼牙刺群落中13个优势种群的生态位宽度、生态位相似性比例及其生态位重叠值进行了研究.结果表明,生态位宽度依次为狼牙刺(0.964)、茭蒿(0.775)、铁杆蒿(0.664)、黄背草(0.508)、远志(0.485)、狗尾草(0.472)、狗牙根(0.399)、白羊草(0.393)、达乌里胡枝子(0.327)、长芒草(0.321)、杠柳(0.292)、灌木铁线莲(0.251)、糙隐子草(0.234).狼牙刺与其他种群的生态位相似比在0.21～0.76之间，生态位重叠值较高，其他种群与狼牙刺之间的重叠值较低，表明狼牙刺与其他种群之间对资源的竞争并不十分激烈，因而能成为黄土沟壑区狼牙刺群落中利用资源能力和生态适应性最强的优势种群，并在维持群落的物种多样性和相对稳定性中发挥重要作用.

Niche characteristics of dominant populations of Sophora davidii community in loess gully region

Based on field investigation data and employing Levin and niche proportional similarity formulae,this paper calculated the niche breadth,niche proportional similarity,and niche overlap of 13 dominant species ofSophora davidii community in loess gully region.The results showed that the niche breadth of the dominant populations of Sophora davidii community decreased in order of Sophora davidii(0.964),Artemisia giraldii(0.775),Artemisia gmelinii(0.664), Themeda triandra var.japonica(0.508),Polygala tenuifolia(0.485),Setaria viridis(0.399),Cynodon dactylon(0.393),Bothriochloa ischaemum(0.327), Lespedeza davurica(0.321),Stipa bungeana(0.472),Periploca sepium(0.292), Clematis fruticosa(0.251),and Cleistogenes squarrosa(0.234).The niche proportional similarity between Sophora davidii and other species was 0.21～0.76,while the niche overlap was not high,which meant that there was no severe competition between them.It could be concluded that Sophora davidii was the dominant population in the community,with most resources utilization and most adaptability to the ecosystem.