SP03: Root trait diversity

生物多样性可以被视为减缓气候变化的地球安全网，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力。尽管由于全世界干旱的频率和强度越来越高，这一专题的紧迫性，但这些有益的生物多样性影响的潜在机制并未得到充分了解。具体地说，我们对植物功能性状组成和多样性如何推动抗旱性和旱灾后恢复的看法不完整。在这个子项目中，我们的目标是提供一个关于植物功能特征的综合视角--重点放在根特征上--以促进我们对植物群落对干旱的反应的机械性理解。我们将建立在最近开发的植物特性框架的基础上，该框架首次整合了地上和地下植物的功能特性，并将通过1)植物水力特性扩展该框架，因为这些特性尚未在该框架中实现，以及2)根生物量分配，因为增加根生物量分配到更深的土壤层的潜力可能是理解植物对干旱的反应的基础。首先，我们将在与不同的国际专家团队就这一主题(WP1)举行的研讨会上选择最相关的地上部、根和水力特征，并在微观实验(WP2)中在物种水平上对这些提出的特征进行实验量化。然后，我们将从植物物种到群落水平来分析平均性状组成和多样性对抗旱和旱灾恢复的影响。我们将在救援实验(WP3)中这样做，并在主要实验(WP4)中通过分析整个季节的迷你加速器图像来做到这一点。最后一步将通过在20年的主要实验序列(WP5)中将性状组成和多样性与对严重干旱的抵抗和恢复联系起来，来检验这些新的见解。总而言之，这套不同的工作方案将阐明在社区一级植物特性组成和多样性对于抗旱和干旱后恢复的重要性。这些关于植物功能特征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.