木林子次生林中典型群落的结构及多样性研究

在野外群落调查及双向指示种分析的基础上，对木林子自然保护区川陕鹅耳枥+青冈-水马桑群落及其10个优势种群的物种组成、结构和多样性特征进行探讨。结果表明：胸径≥ 1.0 cm的木本植物共149种8 051株，植株密度为13 418.3株/hm²，分属39科81属，区系成分以热带分布科属占据优势，具有温热带过渡的性质；低林层的物种更加均匀和多样，更新层物种丰富度占整个群落的59.8%；整个群落中，常绿与落叶树种的物种丰富度比为0.44 : 1，多度比为0.39 : 1，在更新层中常绿与落叶树种的物种丰富度比为0.52 : 1，多度比为0.60 : 1；群落的10个优势种群中，仅盐肤木、亮叶桦种群的幼龄个体较少，植株径级呈纺锤型，属衰退型种群，其他种群均为增长型。因此，多数优势种群自然更新良好，小径级个体增长迅速，群落中落叶树种占优势地位，在高林层中优势尤其明显。

The Typical Forest Community Structure and Diversity of the Secondary Forest in Mulinzi

Based on investigating field community and using two-way indicator species analysis (TWINSPAN), we had investigated the species composition, construction and diversity features of the Carpinus fargesiana + Cyclobalanopsis glauca - Weigela japonica community and its 10 dominant populations in Mulinzi Nature Reserve. The result showed there were 8 051 individuals of ligneous plants altogether whose diameter at breast height (DBH) ≥ 1.0 cm, belonging to 149 species, 81 genera and 39 families. The tropical plant families was more dominant and had tropical-temperature intersection trends properties. In community, species were more abundant and diverse in laigh height layer, and species richness of regeneration layer take up 59.8% of whole community. In community, the species ratio of evergreen with deciduous species numbers was 0.44 : 1, the quantity ratio of evergreen with deciduous species′ individuals was 0.39 : 1. In the regeneration layer, the species ratio of evergreen with deciduous species numbers was 0.52 : 1, the quantity ratio of evergreen with deciduous species′ individuals numbers was 0.60 : 1. Among the top 10 species in importance value, only Rhuschinensis and Betula luminifera population was declining and other populations belong to the growth form. The arborets exhibit significant positive association to adult trees in dominant populations but in Litsea cubeba and Clethra cavaleriei population are less pronounced. In general, most dominant populations had well natural regeneration, small diameter class individuals grew quickly. the deciduous species had still occupied the dominant position and it had more advantage in high height layer of community.