黄土高寒区浅山人工林植物群落生态位特征研究
Niche Characteristics of Plant Communities in Shallow Mountain Plantations in Loess Alpine Region

生态位理论在研究植物群落物种组成、种间关系、结构功能、生物多样性等方面具有重要意义。本文以黄土高寒区大通县安门滩流域林草植被为研究对象，通过Shannon-Wiener指数和Pianka指数分别计算不同立地类型下典型人工林及林下草本的生态位宽度及生态位重叠。结果表明：乔木层在阴坡条件下，华北落叶松(Larixprincipis-rupprechtii May)生态位宽度最大(44.13、42.69、42.99)；阳坡条件下，油松(Pinus tabuliformis Carr)和青杨(Populus cathayana Rehd)生态位宽度最大(39.56、40.22)。草本层中，白莲蒿(Artemisia sacrorum Ledeb)和早熟禾(Poa annua L)在不同立地下，生态位宽度均较高，说明二者适应能力较强，能够利用的资源位多。有建群效果树种的种对在不同立地下生态位重叠值范围在0.17~0.29间，说明混交林中，不同树种利用的资源位不同，种间竞争不强烈。草本层生态位重叠值，在阴坡受坡度影响较高，在阳坡受坡度影响较小。
Niche theory is of great significance in the study of plant community species composition, interspecific relationship, structure and function, biodiversity and so on. In this paper, the niche width and niche overlap of typical plantations and herbs under different site types are calculated by Shannon-Wiener index and Pianka index, respectively, taking the forest and grass vegetation in Datong County of Datong County as the research object. The results show that the niche width of Larixprincipis-rupprechtii May is the largest (44.13, 42.69, 42.99) under the condition of shady slope. Under the condition of sunny slope, the niche breadth of Pinus tabuliformis Carr and Populus cathayanais the largest (39.56, 40.22). In the herbaceous layer, the niche breadth of Artemisia sacrorum Ledeb and Poa annua L is large in different site conditions, which indicate that the two have universal adaptation and more resources could be utilized. All kinds of trees with the effect of building groups overlap in different underground niche. The range of value is 0.17 - 0.29, which indicates that the resource position of different tree species is different and the competition among species is not strong in the mixed forest. The niche overlap value of herbaceous layer is more affected by slope in shady slope and less affected by slope in sunny slope.