湖北木林子保护区山矾属植物空间分布格局及其关联性

物种共存机制是生态学研究的重要问题。以同属物种山矾、光叶山矾为研究对象,分析其空间分布格局和种内、种间关联性特征。将山矾、光叶山矾分为4个径级,分别归属幼树、小树、中树和成年树4个生长阶段。采用单变量成对相关函数分析空间分布格局特征;双变量成对相关函数分析种内、种间关联性。结果显示:山矾和光叶山矾径级结构基本一致,均属增长型种群。在完全空间随机模型下,山矾和光叶山矾主要呈聚集分布,逐渐过渡为均匀分布;在异质泊松模型下,只在小尺度上聚集,较大尺度范围呈随机分布。种内关联上,山矾各生长阶段主要呈正关联,逐渐向无关联过渡,光叶山矾除小树与成年树外,其余均呈正关联;排除生境异质性影响后,小尺度呈正关联,其余尺度无关联。种间关联上,在幼树、小树物种对中主要呈负关联,中树、成年树物种对中多为无关联。研究表明,同属物种山矾和光叶山矾呈种内聚集、种间分离的空间构型,在竞争排除作用下实现同属共存,有利于亚热带常绿落叶阔叶混交林群落结构稳定和物种多样性维持。

Spatial distribution pattern and intraspecific and interspecific relationships of genus symplocosin Mulinzi Nature Reserve, Hubei Province

The mechanism of species coexistence is an important issue of ecological research. The spatial distribution pattern and intraspecific and interspecific relationships of Symplocos sumuntia and Symplocos lancifolia were analyzed in this paper. All Symplocos sumuntia and Symplocos lancifolia trees were divided into four diameter classes which represented four growth stages:sapling, small tree, medium tree and adult tree. The spatial distribution pattern of Symplocos sumuntia and Symplocos lancifolia were analyzed by single-variable pair-correlation function, and bi-variate pair-correlation function was used to analyze the intraspecific and interspecific interactions. The results showed that the diameter structure of Symplocos sumuntia and Symplocos lancifolia was basically the same, and two populations were growing populations. Symplocos sumuntia and Symplocos lancifolia populations were aggregated distribution characterized by the complete spatial randomness model, and gradually become to a uniform distribution; Under the heterogeneous Poisson model, the two species only presented aggregation in small-scale and showed a random distribution in the larger scale range. According to the intraspecific relationships, each growth stage was positive association of Symplocos sumuntia, and gradually changed into uncorrelated relations; in addition to the small trees and adult trees, the other two growth stages were positively associated with each other for Symplocos lancifolia. There was positive association in the small scale, and no association in other scales after excluding habitat heterogeneity. The sapling and small trees mainly displayed negative association of interspecific relationships, while no association for middle trees and adult trees. The results showed that Symplocos sumuntia and Symplocos lancifolia presented intraspecific aggregation and interspecific segregation patterns of the spatial configuration, and showed coexistence under the action excluded competition from the same genus. It would be beneficial to the stability of community structure and keep maintaining species diversity in subtropical evergreen deciduous broad-leaf mixed forest.