• Forest understorey plants are sensitive to light availability, and different species groups can respond differently to changing light conditions. A plant trait tightly linked to light capture is specific leaf area (SLA). Studies considering the relative role of within‐ and among‐species SLA variation across different species groups (e.g. specialists and generalists) are rarely implemented in temperate forest understories varying in their maturity.
• We examined community‐level SLA patterns of beech forest understories along a light availability gradient, and for habitat specialists and generalists separately. We then disentangled and quantified the contribution of intraspecific trait variability and interspecific trait differences in shaping SLA patterns.
• We revealed that the increase in community‐level SLA with decreasing light availability was primarily driven by beech forest specialists (and, to a lesser extent, by forest generalists), and this pattern was mainly determined by specialists’ high intraspecific variability. Community‐level SLA was therefore formed by different responses at different organizational levels, i.e. within and among species, and for separate species groups.
• This study provides insights into factors shaping the shade tolerance strategy in beech forest understorey plants; specialists persistence under putative less favourable conditions (i.e. high irradiation) may be fostered by their ability to adjust their light capture strategies intraspecifically.

中文翻译：

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特定叶面积的种内变异性促进了下层专家在光照可用性梯度上的持久性

• 森林下层植物对光的可用性很敏感，不同的物种组对变化的光照条件会有不同的反应。与光捕获紧密相关的植物性状是比叶面积（SLA）。考虑到内和之间的物种变异SLA的在不同的物种群体（相对作用的研究如专家和通才）温带森林understories在他们的成熟度不同，很少实施。
• 我们研究了沿光可用性梯度分布的山毛榉林林下层的社区级SLA模式，并分别针对了栖息地专家和通才。然后，我们解开并量化了塑造SLA模式时种内性状变异性和种间性状差异的贡献。
• 我们发现，社区级别的SLA随可用光的减少而增加，主要是由山毛榉森林专家（在较小程度上是由森林专家）驱动的，而这种模式主要由专家的种内高变异性决定。因此，社区级别的SLA是在不同组织级别（即，在物种内部和物种之间，以及单独的物种组。
• 这项研究提供了对影响山毛榉林下层植物耐荫策略形成因素的见解；专家们可以在种内条件下调整其光捕获策略，从而在假定的不利条件下（即高辐射）坚持不懈。