Data from: Resistance of plant–plant networks to biodiversity loss and secondary extinctions following simulated environmental changes

1. Plant interactions are fundamental processes for structuring plant communities and are an important mechanism governing the response of plant species and communities to environmental changes. Thus, understanding the role played by the interaction network in modulating the impact of environmental changes on plant community composition and diversity is crucial. Here, we aimed to develop a new analytical and conceptual framework to evaluate the responses of plant communities to environmental changes. 2. This framework uses functional traits as sensitivity measures for simulated environmental changes and assesses the consequences of microhabitat loss. We show here its application to an alpine plant community where we recorded functional traits (specific leaf area [SLA] and leaf dry matter content [LDMC]) of all plants associated with three foundation species or the surrounding open areas. We then simulated primary species loss based on different scenarios of environmental change and explored community persistence to the loss of foundation species. 3. Generally, plant community responses differed among environmental change scenarios. In a scenario of increasing drought alone (i.e. species with lower LDMC were lost first) or increasing drought with increasing temperature (i.e. species with lower LDMC and higher SLA were lost first), the plant community resisted because drought-tolerant foundation species tolerated those deteriorating conditions. However, in a scenario with increasing nitrogen input (i.e. species having lower SLA were lost earlier), foundation species accelerated species loss due to their early primary extinctions and the corresponding secondary extinctions of species associated to their microhabitat. 4. The resistance of a plant community depends on the driver of environmental change, meaning that the prediction of the fate of this system is depending on the knowledge of the main driver of environmental change. Our framework provides a mechanistic understanding of an ecosystem response to such environmental changes thanks to the integration of biology-informed criteria of species sensitivities to environmental factors into a network of interacting species.

1. 植物相互作用是构建植物群落的核心过程，亦是调控植物物种与群落响应环境变化的关键机制。因此，阐明植物相互作用网络在调节环境变化对植物群落组成与多样性的影响中所发挥的作用至关重要。本研究旨在构建一套全新的分析与概念框架，用以评估植物群落对环境变化的响应。
2. 该框架以功能性状（functional traits）作为模拟环境变化的敏感性指标，并用以评估微生境（microhabitat）丧失所带来的后果。本研究将此框架应用于一处高山植物群落：在此群落中，我们记录了与3个建群种（foundation species）相关联的所有植物，以及周边开阔区域内植物的功能性状，即比叶面积（specific leaf area, SLA）与叶片干物质含量（leaf dry matter content, LDMC）。随后，我们基于不同环境变化情景模拟了物种初级消失过程，并探究了建群种丧失后群落的持久性。
3. 总体而言，不同环境变化情景下植物群落的响应存在显著差异。在仅干旱加剧的情景（即叶片干物质含量更低的物种率先消失），或是干旱加剧叠加温度升高的情景（即叶片干物质含量更低、比叶面积更高的物种率先消失）中，植物群落表现出抗性，这是因为耐旱建群种能够耐受这些恶化的环境条件。然而，在氮输入增加的情景（即比叶面积更低的物种更早消失）中，建群种会加速物种消失过程：这是由于建群种率先发生初级灭绝，进而引发与其关联的微生境中物种的次级灭绝。
4. 植物群落的抗性取决于环境变化的驱动因子，这意味着对该系统命运的预测依赖于对环境变化主要驱动因子的认知。本框架通过将基于生物学的物种对环境因子敏感性判定标准整合到相互作用物种网络中，为理解生态系统对这类环境变化的响应提供了机制层面的认知。