Data from: Scaling functional traits to ecosystem processes: towards a mechanistic understanding in peat mosses

1. The role of trait trade-offs and environmental filtering in explaining the variability of functional traits and ecosystem processes has received considerable attention for vascular plants but less so for bryophytes. Thus, we do not know whether the same forces also shape the phenotypic variability of bryophytes. Here we assess how environmental gradients and trade-offs shape functional traits and subsequently ecosystem processes for peat mosses (Sphagnum), a globally important plant genus for carbon accumulation. We used piecewise Structural Equation Modeling (SEM) to understand how environmental gradients influence vital processes across levels of biological organization. 2. We gathered data on functional traits for 15 globally important Sphagnum species covering a wide range of ecological preferences. Phenotypes lie along well-established axes of the plant economic spectrum characterizing trade-offs between vital physiological functions. Using SEM we clarified the mechanisms of trait covariation and scaling to ecosystem processes. We tested whether peat mosses, like vascular plants, constrain trait variability between a fast turnover strategy based on resource acquisition via fast traits and processes, and a strategy of resource conservation, via slow traits and processes. 3. We parameterized a process-based model estimating ecosystem processes linking environmental drivers with architectural and functional traits. In our SEM approach the amount of variance explained varied substantially (0.29 ≤ R2 ≤ 0.82) among traits and processes in Sphagnum, and the model could predict some of them with high to intermediate accuracy for an independent dataset. R2 variability was mainly explained by traits and species identity, and poorly by environmental filtering. 4. Some Sphagnum species avoid the stress caused by periodic desiccation in hollows via resource acquisition based on fast photosynthesis and growth, while other species are adapted to grow high above the water table on hummocks by slow physiological traits and processes to conserve resources. 5. Synthesis. We contribute to a unified theory generating individual fitness, canopy dynamics and ecosystem processes from trait variation. As for vascular plants, the functional traits in the Sphagnum economic spectrum are linked into an integrated phenotypic network partly filtered by the environment and shaped by trade-offs in resource acquisition and conservation.1. 性状权衡与环境过滤在解释维管植物（vascular plants）功能性状与生态系统过程变异中的作用已受到广泛关注，但在苔藓植物（bryophytes）中相关研究仍较为匮乏。因此，我们尚不清楚相同的驱动力是否同样塑造了苔藓植物的表型变异。本研究聚焦于泥炭藓属（Sphagnum）——这一在全球碳固存中具有重要地位的植物类群，旨在探究环境梯度与性状权衡如何塑造其功能性状，进而影响生态系统过程。我们采用分块结构方程模型（piecewise Structural Equation Modeling, SEM），解析环境梯度如何影响不同生物组织层级的关键生态过程。 2. 我们收集了覆盖广泛生态偏好的15种全球重要泥炭藓物种的功能性状数据。这些物种的表型分布于植物经济谱（plant economic spectrum）的经典轴线上，该轴线表征了关键生理功能间的权衡关系。通过结构方程模型，我们阐明了性状协同变异与向生态系统过程缩放的机制。我们验证了泥炭藓是否与维管植物类似，存在两种约束性状变异的策略：一类是以快速性状与过程实现资源获取的快速周转策略，另一类是以缓慢性状与过程实现资源保存的保守策略。 3. 我们构建了一个基于过程的模型，用于估算连接环境驱动因子与结构及功能性状的生态系统过程。在本研究的结构方程模型中，泥炭藓各性状与生态过程的解释方差存在显著差异（0.29 ≤ R² ≤ 0.82），且该模型可对独立数据集的部分指标实现中等到较高精度的预测。R²的变异主要由性状与物种身份解释，环境过滤的贡献则相对较弱。 4. 部分泥炭藓物种通过快速光合与生长的资源获取策略，规避了湿地洼地周期性干旱带来的胁迫；而另一些物种则依靠缓慢的生理性状与过程来保存资源，以适应在地下水位以上较高的丘地生境。 5. 总结。本研究为整合性理论提供了支撑，该理论可通过性状变异推导个体适合度、冠层动态与生态系统过程。与维管植物类似，泥炭藓经济谱中的功能性状被整合为一个统一的表型网络，该网络部分受环境过滤塑造，并由资源获取与保存的性状权衡所驱动。