Aboveground-belowground interactions drive the relationship between plant diversity and ecosystem function

植物多样性和生态系统功能之间的正向关系很可能是由地上-地下多营养相互作用共同决定的。因此，考虑和操纵这种相互作用可能会显著提高对BEF关系的机械性理解。本提案全面调查了长期(4年)植物多样性对不同生态系统(草原和森林生态系统)和全球变化背景(大气二氧化碳浓度升高、氮沉积、气候变暖和干旱)下土壤微生物、线虫和其他土壤无脊椎动物的影响，以提取一般机制。将进行互补性和针对性良好的实验室实验，以模拟植物多样性引起的土壤食物网变化所产生的土壤反馈效应。这一新的方法将使人们能够调查土壤负反馈和正反馈效应之间的平衡以及对生态系统功能的影响。对地上和地下过程的变化和相互作用的全面了解，对于预测植物群落简化对生态系统功能的长期影响至关重要。试验性工作将与先前工作的荟萃分析相辅相成，以协调先前不一致的发现。与一些世界领先的国际科学家在BEF研究方面的合作，将产生对BEF关系的独特机械见解。本建议的主要任务是理清植物多样性对土壤生物群的影响的驱动力以及随后对植物的正反馈和负反馈效应。为实现这一目标，本项目有四个主要目标：(I)调查多种环境下植物多样性对土壤生物群和功能的长期影响，以得出一般性结论(Ii)调查植物多样性诱导的正反馈和负反馈效应对植物性能的意义(Iii)调查人为应激源效应是否加强了植物多样性对土壤生物群的影响和随后的土壤反馈效应(Iv)综合结果和进行荟萃分析，以了解和协调先前关于植物多样性对土壤生物群影响的不一致研究结果，并将土壤食物网随后的变化与生态系统功能的变化联系起来。

The positive relationship between plant diversity and ecosystem functioning is likely to be co-determined by aboveground-belowground multitrophic interactions. Considering and manipulating such interactions thus is likely to significantly improve the mechanistic understanding of BEF relationships. The present proposal comprehensively investigates long-term (>4 years) plant diversity effects on soil microorganisms, nematodes and other soil invertebrates across different ecosystems (grassland and forest ecosystems) and global change contexts (elevated atmospheric CO2 concentrations, N deposition, warming and drought) in order to extract general mechanisms. Complementary and well-directed laboratory experiments will be conducted to simulate soil feedback effects resulting from plant diversity-induced changes in soil food webs. This novel approach will allow investigating the balance between negative and positive soil feedback effects and the consequences for ecosystem functioning. This holistic knowledge of changes in and interactions of above- and belowground processes is crucial to predict the long-term consequences of plant community simplification for ecosystem functioning. Experimental work will be complemented with the meta-analysis of previous work in order to reconcile prior inconsistent findings. Collaborations with some of the world‘s leading international scientists in BEF research, at the TU München and the Helmholtz Zentrum München will yield unique mechanistic insights into the BEF relationship. The main task of the present proposal is to disentangle the driving forces of plant diversity effects on soil biota as well as subsequent positive and negative feedback effects on plants. In order to achieve this, the present project has four major goals:(i) Investigate long-term plant diversity effects on soil biota and functions across multiple settings in order to derive general conclusions(ii) Investigate the significance of plant diversity-induced positive and negative soil feedback effects on plant performance(iii) Investigate if anthropogenic stressor effects reinforce plant diversity effects on soil biota and subsequent soil feedback effects(iv) Synthesize results and perform meta-analyses in order to understand and reconcile inconsistent findings of previous studies on plant diversity effects on soil biota, and relate subsequent changes in soil food webs to alterations in ecosystem functioning.