神农架南坡小叶青冈+曼青冈常绿阔叶林主要木本植物生态位与种间联结

为揭示神农架南坡代表性常绿阔叶林主要木本植物的种间生态联系及群落演替趋势,以小叶青冈+曼青冈群系20个主要木本植物的190组种对为研究对象,通过生态位测定并区分生态位特化种和生态位泛化种以及种间联结性检验,分析该群落主要物种生态位与种间联结特征。主要结果:(1)该常绿阔叶林群落物种丰富,群落组成复杂,小叶青冈(Cyclobalanopsis myrsinifolia)的重要值(11.13%)和生态位宽度(58.3)均最大,占绝对优势,生态位宽度排序和重要值排序不一致,分布频度对生态位宽度影响较大。(2)将20种主要木本植物划分为生态位特化种(6种)、生态位泛化种(3种)、中性类群(11种),生态位分化程度较高,资源利用差异以及生境适应性是影响生态位分化的主要因素。(3)生态位宽度大的物种其生态位重叠和相似度较高,生态位重叠指数总体略低,大部分物种对环境或资源需求相似,但相似度不高,种间竞争较弱,种间关系比较稳定。(4)主要木本植物总体正联结显著(P ＜ 0.05),χ²检验、联结系数AC、Spearman秩相关检验结果均显示种间正联结作用占优势,但大多数种对联结不显著,物种趋于独立分布。(5)通过聚类分析,将20种主要木本植物划分三大生态种组:建群种组,共生种组和边缘种组。研究表明,神农架南坡小叶青冈+曼青冈常绿阔叶林目前正处于相对稳定的演替中后期阶段,群落发育较成熟,生态位分化、生境选择以及资源需求互补或互利是影响该群落物种共存的主要原因。研究阐明了神农架南坡代表性常绿阔叶林主要物种之间实际相互作用以及群落特征,为深入理解群落物种共存原因以及群落演替规律提供依据。

The ecological niche and interspecific association of main woody plants in the evergreen broad-leaved forest of Cyclobalanopsis myrsinifolia+C. oxyodon on the south slope of Shennongjia

In order to elucidate the ecological relationships among the principal woody plants within the representative evergreen broad-leaved forest on the southern slope of Shennongjia and unveil the trajectory of community succession, we selected 190 species groups from 20 main woody plants in the Cyclobalanopsis myrsinifolia+C. oxyodon group as the focal subjects of our research. The determination of their ecological niche involved distinguishing specialized species from generalized ones and assessing interspecific connections. Subsequently, we analyzed the ecological niche and interspecific connections of the primary species within the community. The main results show that: (1) The evergreen broad-leaved forest community exhibits species richness and a complex composition. Cyclobalanopsis myrsinifolia, with the highest importance value (11.13%) and ecological niche width (58.3), emerges as the dominant species. Notably, the inconsistency between ecological niche width ranking and importance value ranking is attributed to the pronounced influence of distribution frequency on ecological niche width. (2) The classification of the 20 primary woody plants reveals six specialized species, three generalized species, and eleven neutral taxa. The notable degree of ecological niche differentiation arises from variations in resource utilization and habitat adaptability, constituting the principal factors influencing this differentiation. (3) Species with expansive ecological niche widths exhibit the substantial overlap and similarity in ecological niches. Despite a slightly low overall ecological niche overlap index, most species share comparable environmental or resource requirements but display low similarity. This suggests weak inter-species competition and relatively stable inter-species relationships. (4) The comprehensive network of primary woody plants exhibits significantly positive linkage (P ＜ 0.05). Results from the χ² test, connection coefficient AC, and Spearman rank correlation test collectively indicate a prevalence of positive linkage between species, though the majority of species do not exhibit significant linkage and tend towards independent distribution. (5) Employing cluster analysis, the study categorizes 20 principal woody plants into three significant ecological species groups: the building community species group, the symbiotic species group, and the edge species group.The findings indicates that the evergreen broad-leaved forests, featuring Cyclobalanopsis myrsinifolia+C. oxyodon, on the southern slope of Shennongjia are presently in a stable later stage of succession, demonstrating a relatively mature community development. The primary factors influencing species coexistence in this community encompass ecological niche differentiation, habitat selection, and complementary or mutualistic resource requirements.The study elucidates genuine interactions and community characteristics among the principal representative species within the evergreen broad-leaved forests on the southern slope of Shennongjia. It offers a foundation for more profound comprehension of the factors driving species coexistence and the governing principles of community succession.