Climate change has been modifying precipitation and temperature in many regions of the world, prompting changes in plant communities. It also affects soil microbial communities, indirectly influencing plant species distribution through plant-soil feedbacks. Here we report an experiment designed to test seed germination responses to global change, addressed through the interaction between increased temperature and soil microbial communities in a tree species in the Atlantic rainforest, a global biodiversity hotspot. Our objective was to test plant-soil feedbacks in an early colonizer tree species, Schizolobium parahyba, and their interaction with warming. We assessed the role of increased air temperature and soil microbiota in controlling seed germination as a function of distance to mother tree. Higher germination percentages were recorded with extracts of soil microbial communities from the edge of the canopy than with microbial extracts obtained closer to the trunk. These manipulations evidenced that soil microbiota influenced seed germination, being responsible for Janzen–Connell effects. Warming produced major changes in microbial composition but the effect on germination was unclear. Our results may help understand species distribution and coexistence in secondary patches of Atlantic rainforest under warmer conditions, and may contribute to the design of successful restoration programs.

气候变化一直在改变世界许多地区的降水和温度，促使植物群落发生变化。它还影响土壤微生物群落，通过植物-土壤反馈间接影响植物物种分布。在这里，我们报告了一项旨在测试种子萌发对全球变化的反应的实验，该实验通过全球生物多样性热点大西洋热带雨林中一种树种中温度升高与土壤微生物群落之间的相互作用来解决。我们的目标是测试早期殖民树种Schizolobium parahyba中的植物-土壤反馈，以及它们与变暖的相互作用。我们评估了气温升高和土壤微生物群在控制种子萌发中的作用，作为与母树距离的函数。从树冠边缘提取的土壤微生物群落的发芽率高于靠近树干的微生物提取物。这些操作证明土壤微生物群影响种子发芽，是造成 Janzen-Connell 效应的原因。变暖导致微生物组成发生重大变化，但对发芽的影响尚不清楚。我们的研究结果可能有助于了解温暖条件下大西洋热带雨林次生斑块的物种分布和共存，并可能有助于设计成功的恢复计划。