中亚热带侵蚀黄壤坡地润楠次生林的群落结构特征

Community Structures of Machilus pingii Secondary Forestry after Vegetation Restoration on Erosion Yellow Soil Slope Region in the Middle Subtropics

为了探讨中亚热带侵蚀黄壤坡地植被恢复模式的群落结构,以武陵山区女儿寨小流域为例,运用群落生态学的研究方法对润楠次生林的垂直层次结构、种群水平分布格局、乔木层直径与树高分布结构进行了研究。结果表明:润楠次生林群落层次结构分化明显,可分为乔木层、灌木层、草本层及层外植物4个基本层次,物种数量排序为灌木层(23种)>草本层(19种)>乔木层(16种)。乔、灌、草重要值在10以上的主要种群有7个,其水平分布格局以聚集分布占绝对优势,占主要种群的71.43%。β分布和Γ分布能较好地模拟乔木层直径与树高分布结构,径阶与树高分布曲线反映乔木层中小径阶、矮小林木占多数。多数种群的聚集分布有利于促进黄壤坡地的植被恢复与重建过程,但润楠次生林林分质量较低,应辅之以积极的人工措施来改善群落结构,以充分发挥其坡地水土流失治理等功能。

In the case of Nverzhai watershed in Wulin mountain region, community structures ot Machilus pingii secondary forestry were studied in the yellow soil slope region of middle subtropics, which included vertical layer structure,distribution patterns of dominant populations and DBH ＆ height structure of tree layer. It was found that the vertical layer structure was obviously divided into tree layer,shrub layer,herbaceous layer and cross-layer plants. In different layers the species number was the biggest in the shrub layer followed by the herbaceous layer and the tree layer. There were 7 plant populations （IV〉10） in different layers with distribution patterns aggregated distribution predominantly, which the percentage of all main populations was 71.43. β and Г distributions were fitted for simulating DBH and height structures. Forest qualities were worse because DBH in middle or small ranks and lower trees were dominant showed by distribution curves of DBH and height ranks. Aggregated distribution was effective for promoting the process of vegetation restoration in yellow soil slope region, however, some measures should be taken to improving community structures to play full role in its ecological functions, such as controlling water and soil loss in the slope region.