小五台山森林群落优势种的生态位分析

研究河北小五台山森林群落优势种的生态位宽度和生态位重叠,运用广义可加模型拟合各个优势种对环境梯度变化的响应规律.结果表明: 在148个样方中,共记录到维管植物75科222属392种,分别从乔木层、灌木层、草本层中选取重要值较大的36个优势种进行分析.乔木层的红桦、白桦、华北落叶松、油松,灌木层的土庄绣线菊、六道木、美蔷薇、毛榛,草本层的青绿薹草、野青茅、地榆、宽叶薹草在森林群落中生态位宽度较大,竞争力及环境适应力较强.在同一片层中,生态位重叠指数高的物种喜好相似生境,各个优势种在共生或伴生的同时存在着一定的竞争关系.色木槭和辽东栎存在高度重叠,由于资源丰富,竞争并不强烈;白桦与色木槭、辽东栎、水榆花楸等多种杂木树种存在重叠,有限的资源导致该群落中竞争较为强烈.各物种对不同环境因子的适应能力存在差异.多数优势种对海拔的响应表现出单峰曲线,分布在一定海拔范围内;部分优势种对海拔的响应呈线性升高或降低,集中分布在高海拔或低海拔区,各个优势种对坡位的响应情况与海拔相似.各优势种沿坡向多呈线性变化,与土壤温度呈显著正相关,物种表现出喜阴或喜阳的特性.红桦、六道木、东陵绣球、青绿薹草、兴安升麻等优势种对凋落层厚度和土壤厚度的响应呈线性升高.华北落叶松、红桦、金露梅、野青茅等优势种对土壤湿度的响应呈线性升高,而对土壤导电率的响应呈线性降低.大多数优势种对土壤pH和干扰程度表现出单峰曲线,部分优势种呈线性降低.

Niche analysis of dominant species of forest community in Xiaowutai Mountain,China

This paper analyzed the niche breadth and niche overlap of dominant species of forest community in Xiaowutai Mountain, and fitted the response patterns of dominant species to the environment gradients by generalized additive models. The results showed that a total of 392 species of vascular plants, belonging to 222 genera, 75 families were recorded in 148 quadrats. A total of 36 dominant species were selected from the tree layer, shrub layer and herb layer by importance va-lues. Betula albosinensis, Betula platyphylla, Larix principis-rupprechtii, Pinus tabuliformis at the tree layer, Spiraea pubescens, Abelia biflora, Rosa bella, Corylus mandshurica at the shrub layer, Carex breviculmis, Deyeuxia arundinacea, Sanguisorba officinalis, Carex siderosticta at the herb la-yer had higher niche breadth, and these species had greater competitiveness and stronger environmental adaptability. In the same layer, niche overlap index was high indicating that species had similar habitats, and there was competitive relationship between them. Although Acer momo and Quercus wutaishanica had high niche overlap, their competition was not strong in the condition of rich resources. There was niche overlap between B. platyphylla and a variety of mixed tree species including A. momo, Q. wutaishanica, Sorbus alnifolia, and limited resources leaded to strong competition in these communities. The adaptability of each species to environmental factors was diffe-rent. The response of most dominant species to altitude showed a single peak curve, and they distri-buted within a certain altitude range. The response of some dominant species to altitude was linearly increased or decreased, and concentrated at high altitudes or low altitudes. The response of dominant species to slope position was similar to altitude. The dominant species showed a linear change along the slope, showed significantly positive correlation with soil temperature, and showed the cha-racteristics of shade-requiring or sunny-requiring. The response of B. albosinensis, A. biflora, H. bretschneideri, C. breviculmis, C. dahurica to litter layer thickness and soil thickness showed linearly increased. The response of L. principis-rupprechtii, B. albosinensis, P. fruticosa, D. arundinacea to soil moisture showed linearly increased, while linearly decreased to soil electrical conductivity. Most dominant species to soil pH and environmental disturbance showed a single peak curve, and the others showed linearly decreased.