群落物种共存机制是生态学家长期关注的核心科学问题之一。负密度制约机制通过维持种内负作用强度大于种间负作用强度来促进群落物种的稳定性共存。以往的研究表明负密度制约机制在热带森林群落中普遍存在，但是该类研究通常只考虑种间的生态学差异，即假设种内个体在生态学上等价，而忽略了种内个体间的差异在种内和种间个体共存上的作用。那么种内变异又是如何促进群落物种共存的呢？

中国科学院西双版纳热带植物园热带森林生态学重点实验室群落构建与物种共存研究组的博士研究生邵晓娜在研究员林露湘和副研究员李巧明的指导下，与德国卡尔斯鲁厄理工学院科研人员Calum Brown、美国马里兰大学科研人员Nathan Swenson等合作，开展种内个体间遗传距离、种群空间分布与个体生长和存活的关系研究。以椆琼楠（Beilschmiedia roxburghiana）为例的阶段性研究发现，遗传距离较近的个体在空间上呈聚集分布，同时，目标个体与遗传距离较近的同种个体为邻时生长率下降。该研究证实了散布限制通过降低局域尺度的遗传多样性来提高负密度制约强度，种群通过遗传距离调节种内个体之间的负相互作用，从而促进群落种内和种间个体的共存。未来的研究需要建立更多的类似研究案例，并进一步探讨遗传距离与负相互作用之间关系的机理。

相关研究结果以Intra-specific relatedness, spatial clustering and reduced demographic performance in tropical rainforest trees 为题已在线发表于国际生态学期刊Ecology Letters上。该研究得到中科院B类先导科技专项培育项目（Grant No. XDPB0203）、国家重点研发计划项目（Grant No. 2014CB954100）、国家自然科学基金（31370445, 31570430, 31370267）、中科院东南亚生物多样性研究中心（Grant No. 2015CASEABRI004）和版纳植物园“一三五”专项突破一（No. 2017XTBG-T01）的资助以及中科院热带雨林生态系统研究站提供的数据支持。（来源：中国科学院西双版纳热带植物园）

Intra-specific relatedness, spatial clustering and reduced demographic performance in tropical rainforest trees

Abstract  Intra‐specific negative density dependence promotes species coexistence by regulating population sizes. Patterns consistent with such density dependence are frequently reported in diverse tropical tree communities. Empirical evidence demonstrating whether intra‐specific variation is related to these patterns, however, is lacking. The present study addresses this important knowledge gap by genotyping all individuals of a tropical tree in a long‐term forest dynamics plot in tropical China. We show that related individuals are often spatially clustered, but having closely related neighbours reduces the growth performance of focal trees. We infer from the evidence that dispersal limitation and negative density dependence are operating simultaneously to impact the spatial distributions of genotypes in a natural population. Furthermore, dispersal limitation decreases local intra‐specific genetic diversity and increases negative density dependence thereby promoting niche differences and species coexistence as predicted by theory.

原文链接：https://onlinelibrary.wiley.com/doi/epdf/10.1111/ele.13086