湖南青羊湖国家森林公园针阔混交林主要种群生态位特征

摘要

生态位是解释自然群落中种间共存与竞争机制的基本理论，对了解植物群落构建及其与环境因子的耦合关系具有重要意义。在群落调查的基础上，运用Levins生态位宽度、Pianka生态位重叠指数，对湖南青羊湖国家森林公园针阔混交林群落7种乔木、10种灌木和7种草本的种群生态位特征进行了分析。结果表明：（1）乔木树种生态位宽度从大到小依次为南酸枣（0.716）＞杉木（0.662）＞马尾松（0.648）＞青冈（0.551）＞枫香（0.530）＞槲栎（0.447）＞油茶（0.164）；灌木树种中青冈（0.784）的生态位宽度最大，其次是白栎（0.683）和海桐（0.660）；而草本层生态位宽度最大的是鳞毛蕨（0.751）和苔草（0.664）。（2）群落各层优势种群间生态位重叠程度较高，生态位分化不明显，利用性竞争较为激烈，群落处于演替阶段，群落结构与物种组成不稳定。（3）针阔混交林群落内，各层植物种群的生态位宽度与其重要值呈典型正相关关系，且相关性均达到显著水平（p＜0.05），相关系数分别为0.832、0.770和0.964。（4）乔木、灌木和草本层各优势种的生态位宽度与其重要值变异系数呈极显著负相关关系（p＜0.01），相关系数均为-1.000。%The niche theory has been successfully used to explain competition mechanisms among the coexisting species in natural communities, which is significant for understanding of the coupling between plant community construction and environmental factors. Based on community survey, by using the formulas of Levins niche breadth and Pianka niche overlap,the niche characteristics of 7 trees,10 shrubs and 7 herbs within mixed broadleaf-conifer forest in Qingyanghu national parkwere analyzed.The results showed that (1) In the tree layer,the niche breadth from high to low in order for Choerospondias axillaris(0.716)>Cunning hamialanceolata(0.662)>Pinus massoniana(0.648)>Cyclobalanopsis glauca(0.551)>Liquidambar formosana(0.530)>Quercus aliena(0.447)>Camellia oleifera(0.164);species with large niche breadth was Cyclobalanopsis glauca(0.784), followed by Quercus fabri(0.683) and Pittosporum tobira(0.660) in the shrub layer;and Dryopteridaceae (0.751) and Carex tristachya(0.664)in the herb layer.(2)The niche overlaps of 24 main populations in the mixed broadleaf-conifer forest were all higher, niche differentiation is not obvious, the resources utilizing competition was strong.The communities stayed in the stages of succession, and the community composition was not stable.(3)The niche breadth of 24 main populations and its important valuehad a significant positive correlation (p<0.05), the correlation coefficients were 0.832,0.770 and 0.964.(4)The niche breadth and the important value of the coefficient of variation of 24 main populations showed a significant negative correlation(p<0.01), the correlation coefficients were-1.000.