The leaf economic spectrum is a widely studied axis of plant trait variability that defines a trade-off between leaf longevity and productivity. While this has been investigated at the global scale, where it is robust, and at local scales, where deviations from it are common, it has received less attention at the intermediate scale of plant functional types (PFTs). We investigated whether global leaf economic relationships are also present within the scale of plant functional types (PFTs) commonly used by Earth System models, and the extent to which this global-PFT hierarchy can be used to constrain trait estimates. We developed a hierarchical multivariate Bayesian model that assumes separate means and covariance structures within and across PFTs and fit this model to seven leaf traits from the TRY database related to leaf longevity, morphology, biochemistry, and photosynthetic metabolism. Although patterns of trait covariation were generally consistent with the leaf economic spectrum, we found three approximate tiers to this consistency. Relationships among morphological and biochemical traits (specific leaf area [SLA], N, P) were the most robust within and across PFTs, suggesting that covariation in these traits is driven by universal leaf construction trade-offs and stoichiometry. Relationships among metabolic traits (dark respiration [Rd ], maximum RuBisCo carboxylation rate [Vc,max ], maximum electron transport rate [Jmax ]) were slightly less consistent, reflecting in part their much sparser sampling (especially for high-latitude PFTs), but also pointing to more flexible plasticity in plant metabolistm. Finally, relationships involving leaf lifespan were the least consistent, indicating that leaf economic relationships related to leaf lifespan are dominated by across-PFT differences and that within-PFT variation in leaf lifespan is more complex and idiosyncratic. Across all traits, this covariance was an important source of information, as evidenced by the improved imputation accuracy and reduced predictive uncertainty in multivariate models compared to univariate models. Ultimately, our study reaffirms the value of studying not just individual traits but the multivariate trait space and the utility of hierarchical modeling for studying the scale dependence of trait relationships.

中文翻译：

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叶片经济范围是否在植物功能类型之内？贝叶斯多元性状荟萃分析。

叶片经济谱系是植物性状变异性的一个广泛研究的轴，它定义了叶片寿命与生产力之间的权衡。尽管已在全球范围内对它进行了研究，但在健壮性方面和地方性方面（通常都存在偏差）进行了研究，但在植物功能类型（PFT）的中等规模上，它受到的关注较少。我们调查了地球系统模型通常使用的植物功能类型（PFT）的规模内是否还存在全球叶片经济关系，以及该Global-PFT层次结构可用于约束性状估计的程度。我们开发了一个分层的多元贝叶斯模型，该模型假设PFT内部和之间具有独立的均值和协方差结构，并使该模型适合TRY数据库中与叶片寿命，形态，生物化学和光合代谢。尽管性状协变的模式通常与叶片经济范围一致，但我们发现了三个大致的层次来达到这种一致性。形态和生化性状（特定叶面积[SLA]，N，P）之间的关系在PFT内和跨PFT最牢固，这表明这些性状的协变是由普遍的叶构造权衡和化学计量驱动的。代谢性状之间的关系（暗呼吸[Rd]，最大RuBisCo羧化速率[Vc，max]，最大电子传输速率[Jmax]）之间的一致性稍差，部分反映了它们的稀疏采样（特别是对于高纬度PFT），但同时也指出了植物代谢组中更具弹性的可塑性。最后，涉及叶子寿命的关系最不稳定，这表明与叶片寿命相关的叶片经济关系主要由跨PFT差异决定，叶片内部寿命的PFT内变化更为复杂和特质。在所有特征中，这种协方差是重要的信息来源，与单变量模型相比，多元模型中的插补精度提高和预测不确定性降低证明了这一点。最终，我们的研究重申了不仅研究个体性状的价值，还重申了多元性状空间的价值以及分层模型在研究性状关系的规模依赖性方面的作用。这种协方差是重要的信息来源，与单变量模型相比，多元模型中的插补精度提高和预测不确定性降低证明了这一点。最终，我们的研究重申了不仅研究个体性状的价值，还重申了多元性状空间的价值以及分层模型在研究性状关系的规模依赖性方面的作用。这种协方差是重要的信息来源，与单变量模型相比，多元模型中的插补精度提高和预测不确定性降低证明了这一点。最终，我们的研究重申了不仅研究个体性状的价值，还重申了多元性状空间的价值以及分层模型在研究性状关系的规模依赖性方面的作用。