Abstract:

Taking the evergreen and deciduous mixed forest in the Fuchun River-Xin’an River National Scenic Area of Jiande City, Zhejiang Province as the research object, this study analyzed its community structure and interspecific relationships, clarified the characteristics of the community and predicted the direction of succession, aiming to provide a scientific basis for the positive succession and human regulation of this type of forest. In the study area, a 1 hm² plot and eight 0.04 hm² subplots were established, and all woody plants with a diameter at breast height (DBH)≥1.0 cm were surveyed. Twenty-one dominant species with importance values≥1% were identified. Niche breadth, Pianka’s niche overlap index, variance ratio method, chi-square (X ²) test, and random forest models were used to analyze species’ niche characteristics and interspecific associations. Results show that woody plants in the plot belong to 85 species, 62 genera, and 36 families. The top five species by importance value are Liquidambar formosana, Dalbergia hupeana, Loropetalum chinense, Cunninghamia lanceolata, and Castanopsis sclerophylla. The Pianka’s niche overlap index (O_ik) for 210 species pairs ranges from 2.95×10⁻³ to 0.82. The X ² test indicates that among 210 species pairs, the proportion of positive and negative associations is 0.45, with dominant tree species mainly showing negative or no association. Combined results from the X ² test and random forest model suggest that the dominance of Liquidambar formosana, Dalbergia hupeana, and Cunninghamia lanceolata is declining, while evergreen broad-leaved species are likely to become dominant in the future. Overall, the community is in the middle stage of succession and has not yet stabilized. In the future, conservation of seedlings such as Castanopsis sclerophylla, Castanopsis jucunda, and Quercus glauca is recommended, along with moderate planting of evergreen broad-leaved trees, to promote the early formation of a climax community of evergreen broad-leaved forest.

Key words: niche, interspecific association, random forest, mixed forest, community succession

摘要：

以浙江省建德市富春江－新安江国家级风景名胜区常绿落叶混交林为对象，解析其群落结构及种间关系，阐明该群落特征并预测演替方向，旨在为探索该类型森林的正向演替与人为调控提供科学依据。在研究区设置并全面调查1个1 hm²和8个0.04 hm²森林样地中胸径≥1.0 cm的所有木本植物，筛选出重要值≥1%的21个优势种，运用生态位宽度、Pianka生态位重叠指数、方差比率法、X ²检验及随机森林模型，分析物种生态位特征与种间联结性。结果表明，样地中胸径≥1.0 cm的木本植物隶属于36科62属85种；重要值前5位分别为枫香树Liquidambar formosana、黄檀Dalbergia hupeana、檵木Loropetalum chinense、杉木Cunninghamia lanceolata、苦槠Castanopsis sclerophylla。样地中210对Pianka生态位重叠指数（O_ik）为2.95×10⁻³－0.82。X ²检验显示210对种对中，正负联结比例为0.45，优势树种种间关系以负关联和无关联为主。综合X ²检验、随机森林模型分析，表明群落中的枫香树、黄檀、杉木的优势地位呈下降趋势，而常绿阔叶树种将作为最终的优势种。综上，该群落正处于演替中期，尚未达到稳定状态。今后可对苦槠、乌楣栲Castanopsis jucunda、青冈栎Quercus glauca等幼苗进行保育，同时适度补植常绿阔叶树，促进常绿阔叶林顶极群落的及早形成。

关键词: 生态位, 种间联结, 随机森林, 混交林, 群落演替