甘肃小陇山暖温带针阔混交林物种组成和群落结构

处于暖温带与亚热带过渡区的甘肃小陇山是我国重要的生物多样性保护区域之一。以甘肃小陇山建立的6 hm²暖温带针阔混交林森林动态样地为基础,以样地中所有胸径(DBH)≥1 cm的木本植物为对象,分析群落结构和物种组成,探讨物种对不同生境的选择偏好。结果表明: 样地内共有木本植物41735株,除去分枝和萌生的独立个体有29251株,共计124种,包含33科65属,其中重要值≥1的树种有28个,占总多度的82.9%。样地中重要值最大的前4个种依次是锐齿槲栎、白桦、小叶乌药和榛,也是该群落乔木层与灌木层的优势树种。样地内所有植株的径级分布整体表现为倒“J”型,群落自我更新良好。指示种分析发现,样地中有11个物种对不同生境表现出一定的偏好,其中2个物种(铁木和四蕊枫)表现出明显的生境偏好。冗余分析和偏分析表明,样地内的物种多度分布主要受地形影响。

Species composition and community structure of coniferous-broadleaved mixed forest in Xiaolong Mountain,Gansu Province,Northwest China

Xiaolong Mountain, located in warm temperate subtropical transition zone, is one of the important biodiversity conservation areas in China. We analyzed species composition, community structure, and habitat preferences of all woody plant species with DBH (diameter at breast height)≥1 cm in a 6 hm² plot in Xiaolong Mountain, Gansu Province, Northwest China. A total of 29251 individuals (41735 stems) belonging to 33 families, 65 genera, and 124 species were recorded. The 28 species with importance value ≥1 contributed 82.9% to the total abundance. The top four species with the highest importance value were Quercus aliena var. acuteserrata, Betula platyphylla, Lindera aggregata var. playfairii and Corylus heterophylla. The structure of DBH size class of all stems showed an inverse ‘J' type, indicating a successful regeneration tendency in the understory. Results from the indicator species analysis showed that 11 species had significant habitat prefe-rences, an two species (Ostrya japonica and Acer stachyophyllum subsp. betulifolium) had the most obvious preferences. Results from the redundancy analysis and partial methods showed that topographic factors played a dominant role in determining species distribution.