Impact of soil negative feedbacks on plant-species diversity

最近的研究表明，植物-土壤反馈可能有助于解释群落中植物物种相对丰富的很大一部分，从而有助于解释物种共存的机制。我们希望利用生物多样性探索站的框架来检验两个主要假设：（1）具有大的个体生物量生产的植物物种不是本地优势的，最强烈地受到特定的负土壤反馈的限制;（2）潜在的入侵植物物种在其新栖息地缺乏特定的土壤负反馈。这两个假设将通过两组不同的植物物种进行检验，这两组物种显示了所检验的性状的相关变异性，即（1）生物量和相对丰度，以及（2）在探索站中沿着南北梯度出现的情况。在这些测试中，我们将使用来自所有50个实验草地的土壤微生物样本。在温室实验中，我们还将通过检查不同的土壤组分，包括丛枝菌根真菌，根病原真菌和微生物混合物（病原体和saprobes的混合物），提供关于土壤（负）反馈性质的机械分辨率。此外，我们还将测试FTIR，这是一种新型的高通量快速分析根系材料的方法，随后也可用于Exploratories面临大量样本的其他项目。通过我们的大规模和遗传多样性筛选，我们希望为植物物种共存和生物多样性机制的研究做出前所未有的贡献;这些知识可以与其他土壤生物区系和以植物为重点的项目相结合。

Recent research indicates that plant-soil feedbacks may contribute to explaining a large proportion of the relative abundance of plant species in communities and therefore to mechanisms enabling species coexistence. We wish to use the framework of the Biodiversity Exploratories to test two main hypotheses: (1) that plant species with large individual biomass production that are not locally dominant are most strongly limited by specific negative soil feedbacks; and that (2) potentially invasive plant species profit from the absence of specific soil-negative feed-backs in their new habitat. These two hypotheses will be examined by two different sets of plant species, which show the relevant variability in the traits examined, i.e. for (1) biomass and relative abundance, and for (2) occurrence along a South-North gradient in the Exploratories. For these tests, we will use soil microbial samples from all 50 experimental grassland plots. In greenhouse experiments, we will additionally provide mechanistic resolution regarding the nature of the soil (negative) feedback, by examining different soil fractions, including arbuscular mycorrhizal fungi, root pathogenic fungi, and a microbial mish (mixture of pathogens and saprobes). Additionally, we will test FTIR, a new and high-throughput fast analysis of root material, which could subsequently be utilized also for other projects in the Exploratories that are faced with large sample numbers. With our large-scale and phylogenetially diverse screening, we hope to make an unprecedented contribution to the study of mechanisms enabling plant species coexistence and biodiversity; this knowledge can be integrated with other soil biota and plant-focused projects in the Exploratories.