• Some commonly reported trait–trait relationships between species, including the leaf economic spectrum (LES), are regarded as important plant strategies but whether these relationships represent plant strategies in reality remains unclear.
• We propose a novel approach to distinguish trait–trait relationships between species that may represent plant strategies vs those relationships that are the result of common drivers, by comparing the direction and strength of intraspecific trait variation (ITV) vs interspecific trait variation. We applied this framework using a unique global ITV database that we compiled, which included 11 traits related to LES, size and roots, and observations from 2064 species occurring in 1068 communities across 19 countries.
• Generally, compared to between species, trait–trait relationships within species were much weaker or totally disappeared. Almost only within the LES traits, the between-species trait–trait relationships were translated into positive relationships within species, which suggests that they may represent plant strategies.
• Moreover, the frequent coincidental trait–trait relationships between species, driven by co-varying common drivers, imply that in future research, decoupling of trait–trait relationships should be considered seriously in model projections of ecosystem functioning. Our study emphasizes the importance of describing the mechanisms behind trait–trait relationships, both between and within species, for deepening our understanding of general plant strategies.

中文翻译：

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物种内部和物种之间性状-性状关系的全局分析

• 一些常见的物种间性状-性状关系，包括叶片经济谱（LES），被认为是重要的植物策略，但这些关系是否代表现实中的植物策略仍不清楚。
• 我们提出了一种新方法，通过比较种内性状变异 (ITV) 与种间性状变异的方向和强度，来区分可能代表植物策略的物种之间的性状-性状关系与那些由共同驱动因素导致的关系。我们使用我们编译的独特的全球 ITV 数据库应用了这个框架，其中包括与 LES、大小和根相关的 11 个特征，以及来自 19 个国家的 1068 个社区的 2064 个物种的观察结果。
• 一般来说，与物种之间相比，物种内的性状关系要弱得多或完全消失。几乎只有在 LES 性状中，种间性状-性状关系才转化为种内正向关系，这表明它们可能代表植物策略。
• 此外，由共同变化的共同驱动因素驱动的物种之间频繁的巧合性状-性状关系意味着在未来的研究中，应在生态系统功能的模型预测中认真考虑性状-性状关系的解耦。我们的研究强调了描述物种之间和物种内部性状-性状关系背后机制的重要性，以加深我们对一般植物策略的理解。