云南松林不同层植物分布与地形、气候因子的关系

植物群落由植物与环境共同作用形成,其中地形与气候因子对植物群落的形成与发展又有极为重要的影响。本文在群落调查的基础上,利用去趋势典范对应分析(detrended canonical correspondence analysis,DCCA)排序方法分析了各地形、气候因子对云南松林中不同层的物种数量、分布结构及多样性的影响及其相互关系。结果表明:乔木层、灌木层、草本层的DCCA排序效果均为极显著(P<0.01)。从排序图可以看出,对乔木层分布影响较大的依次有夏季平均降雨量、气温年较差、年均降雨量等环境因素;而灌木层的主要影响因子为夏季平均降雨量、年均降雨量、无霜期;对草本层物种分布影响大的有无霜期、海拔、夏季平均降雨量。人为干扰对乔木层和草本层影响不明显,而对灌木层影响则相对较大。

Relationships of plant species distribution in different strata of Pinus yunnanensis forest with landform and climatic factors

Plant community is formed under the combined action of plant and environment. In the formation and development of plant community, landform and climatic factors play important roles. On the basis of plant community investigation, and by using detrended canonical correspondence analysis (DCCA), this paper analyzed the effects of each landform and climatic factor on the plant species number, distribution structure, and diversity in different strata of Pinus yunnanensis forest. The DCCA ordination efficiency for the tree layer, shrub layer, and herb layer was very significant (P<0.01). The effects of environmental factors on the plant species diversity and distribution were in the order of mean precipitation in summer (from May to Sept.), annual temperature range, and mean annual precipitation for tree layer, mean precipitation in summer, mean annual precipitation, and frost-free days for shrub layer, and frost-free days, elevation, and mean precipitation in summer for herb layer. Human disturbances had great effects on shrub layer but little effects on tree and herb layers.