SP03: Root trait diversity

生物多样性可以被视为地球减缓气候变化的安全网，因为众所周知，生物多样性可以提高生态系统的功能和稳定性。人们经常假设，草原物种丰富度的增加会增加植物群落对干旱的抵抗力和恢复能力。尽管由于世界范围内干旱的频率和强度不断增加，这一主题具有紧迫性，但这些有益的生物多样性影响的基本机制尚未得到充分理解。具体来说，我们对植物功能性状的组成和多样性如何驱动干旱后的抗性和恢复有一个不完整的观点。在这个子项目中，我们的目标是提供一个综合的角度对植物功能性状-重点是根性状-推进我们的机械理解植物群落对干旱的反应。我们将建立在最近开发的植物性状框架上，首次整合了地上和地下植物功能性状，并将其扩展为1）植物水力性状，因为这些尚未在框架中实施，2）根系生物量分配，因为增加根系生物量分配到深层土壤层的潜力可能是理解植物对干旱反应的基础。首先，我们将选择最相关的芽，根，和水力性状在一个研讨会上与一个多元化的国际专家团队在这个主题（WP 1）和实验量化这些拟议的性状在物种水平上的微观实验（WP 2）。然后，我们将从植物物种到群落水平，以解开平均性状组成和多样性对干旱抗性和恢复的影响。我们将在ResCUE实验（WP 3）中这样做，并在主实验（WP 4）中分析整个季节的微型电子图像。最后一步将通过将性状组成和多样性与主要实验（WP 5）20年序列中严重干旱的抵抗力和恢复联系起来，测试这些新见解。总之，这套多样化的工作包将阐明植物性状组成和多样性在社区一级对抗旱和干旱后恢复的重要性。这种关于植物功能性状的知识对于设计和恢复适应气候变化的植物群落至关重要。

Biodiversity can be considered as the earth’s safety net for mitigating climate change, as biodiversity is known to increase ecosystem functioning and stability. It is often hypothesised that increased species richness in grasslands increases resistance and recovery of plant communities to drought. Despite the urgency of the topic due to the increasing frequency and intensity of droughts worldwide, the underlying mechanisms of these beneficial biodiversity effects are not fully understood. Specifically, we have an incomplete perspective of how plant functional trait composition and diversity drive resistance to and recovery after drought. In this subproject, we aim to provide an integrated perspective on plant functional traits – with a focus on root traits – to advance our mechanistic understanding of plant community responses to drought. We will build on a recently developed plant trait framework, that for the first time, integrated above- and belowground plant functional traits, and will expand it with 1) plant hydraulic traits, as these have not been implemented in the framework yet, and 2) root biomass allocation, as the potential to increase root biomass allocation to deeper soil layers might be fundamental for understanding plant responses to drought. First, we will select the most relevant shoot, root, and hydraulic traits in a workshop with a diverse team of international experts on this topic (WP1) and experimentally quantify these proposed traits at the species level in a microcosm experiment (WP2). Then, we will scale from the plant species to the community level to disentangle effects of average trait composition and diversity for resistance to and recovery after droughts. We will do so in the ResCUE Experiment (WP3) and by analysing minirhizotron images throughout the season in the Main Experiment (WP4). The final step will test these new insights by linking trait composition and diversity to resistance to and recovery from severe droughts in the 20-year sequence of the Main Experiment (WP5). Taken together, this diverse set of work packages will elucidate the importance of plant trait composition and diversity at the community level for resistance to and recovery after droughts. This knowledge on plant functional traits will be essential to design and restore plant communities that are resilient to climate change.