Data from: Localized neighborhood species mingling is correlated with individual tree size inequality in natural forests in South China

Context: Numerous hypotheses such as Janzen–Connell and herd immunity effects have been proposed to explain the coexistence of diverse species in plant communities. However, these mechanisms for maintaining diversity have been studied primarily through the lens of species diversity, whereas tree size diversity or relationships between size and species diversity resulting from local interactions have rarely been investigated. Aims: We aimed to identify relationships between spatial species mingling and tree size inequality using extensive plot data from species-rich forest ecosystems. Methods: We applied neighborhood-based methods and explored relationships between spatial species mingling and size inequality indices in 22 large forest plots (30 ha in total) in subtropical and tropical China. Results: Forest communities with low species mingling, or segregation of heterospecific trees, exhibited increased segregation of trees with dissimilar sizes. In most plots, large trees (e.g. dbh > 30 cm) were extensively associated with high species mingling, and individual-tree neighborhood species and size diversity were closely correlated. Conclusion: Our findings suggest that both the spatial patterns of conspecific dispersal and neighborhood interactions play an important role in determining the spatial patterns of tree size and species diversity and eventually in shaping the structure of forest communities.

背景：已有诸多假说被提出以解释植物群落中多样物种的共存现象，例如扬岑-康奈尔效应（Janzen–Connell）与群体免疫效应。然而，此类维持物种多样性的机制主要从物种多样性的视角开展研究，而针对树木大小多样性，或是由局部相互作用所引发的大小与物种多样性之间的关联，相关研究却极为匮乏。
研究目标：本研究旨在借助中国亚热带与热带地区的大规模样地数据，厘清空间物种混交度（spatial species mingling）与树木大小不均性之间的关联。
研究方法：我们采用基于邻域的分析方法，对中国亚热带及热带地区的22处大型森林样地（总面积达30公顷）中的空间物种混交度与大小不均性指数之间的关联进行了探究。
研究结果：物种混交度较低的森林群落，即异种树木呈现聚集分离的群落，其不同大小树木的分离程度显著升高。在绝大多数样地中，胸径（dbh）大于30厘米的大树普遍与较高的物种混交度相关联，且单木邻域的物种多样性与大小多样性呈紧密相关。
研究结论：本研究结果表明，同种个体的扩散空间格局与邻域相互作用，在决定树木大小与物种多样性的空间分布格局，乃至最终塑造森林群落结构的过程中均发挥着关键作用。

搜集汇总

背景与挑战

背景概述

该数据集基于中国南方22个大型天然林样地（总面积30公顷），研究了局部邻域物种混合与个体树木大小不平等之间的相关性。研究发现，物种混合较低的森林中，大小不相似的树木分离更明显，且大树常与高物种混合相关，表明同种扩散和邻域相互作用共同影响森林结构和多样性模式。