Data from: No evidence for larger leaf trait plasticity in ecological generalists compared to specialists

Aim: Phenotypic plasticity is hypothesized to contribute to a species’ capacity to occupy broader ranges of conditions and to optimally exploit resource-rich environments. Although this is supported by case studies of individual species, we do not know whether larger plasticity in functional traits is generally associated with ecological characteristics of species such as their niche breadth or niche position. Here, we test whether there is such a relationship for plasticity in leaf functional traits.
Location: Central Europe.
Methods: We surveyed 110–132 grassland plant species for plasticity in five leaf traits [leaf thickness, leaf greenness, specific leaf area, leaf dry matter content (LDMC) and plant height] and for biomass changes in response to experimental fertilization, shading and waterlogging. Trait plasticity and changes in biomass were compared with species niche characteristics along three environmental axes (light, nutrient and soil moisture) derived from a vegetation-plot database.
Results: Although response of several traits to experimental treatments correlated with niche position and breadth (change in leaf thickness, greenness and biomass in response to fertilization; change in LDMC due to shading; and change in plant height and biomass due to waterlogging), we did not find evidence that species with broader niches or species from resource-rich environments are more plastic. Ecological generalists even turned out to be less plastic in some traits, including leaf thickness after fertilization and waterlogging. Generalists also displayed smaller plastic response averaged across all five traits (‘composite plasticity’), though the relationship was not statistically significant. This composite plasticity was positively related to absolute change in biomass in all experimental treatments.
Main conclusions: Our results suggest that larger species-level plasticity in leaf traits is not necessarily associated with a capacity to occupy a broader range of environments or with growth in resource-rich habitats; rather, it may indicate species’ sensitivity to environmental changes.

Aim: 表型可塑性（Phenotypic Plasticity）被假设可提升物种占据更广环境范围的能力，并使其能够最优利用资源富集的生境。尽管已有单个物种的案例研究支持这一假说，但目前仍不清楚功能性状（functional traits）的更高可塑性是否普遍与物种的生态位宽度（niche breadth）、生态位位置（niche position）等生态特征相关联。本研究旨在探究叶片功能性状（leaf functional traits）的可塑性是否存在此类关联。
Location: 中欧。
Methods: 我们针对110至132种草地植物，测定了5种叶片性状的可塑性——叶片厚度、叶片绿度、比叶面积（specific leaf area）、叶干物质含量（LDMC）以及株高，并记录了其在实验性施肥、遮阴和淹水处理下的生物量变化。随后，基于植被样方数据库（vegetation-plot database）得到的光照、养分、土壤水分三个环境轴的物种生态位特征，我们将性状可塑性与生物量变化进行对比分析。
Results: 尽管部分性状对实验处理的响应与生态位位置和宽度存在相关性——如施肥处理下叶片厚度、绿度及生物量的变化，遮阴处理下叶干物质含量的变化，以及淹水处理下株高与生物量的变化——但我们并未发现证据表明，生态位更宽的物种或来自资源富集生境的物种具有更高的可塑性。甚至，生态泛化物种（ecological generalists）在部分性状上的可塑性更低，包括施肥和淹水处理后的叶片厚度。此外，泛化物种在全部5种性状的平均可塑性（即“综合可塑性（composite plasticity）”）也更低，尽管该关联未达到统计学显著性。综合可塑性与所有实验处理下的生物量绝对变化呈正相关。
Main conclusions: 本研究结果表明，物种水平上更高的叶片性状可塑性，未必与物种占据更广环境范围的能力或在资源富集生境中的生长相关；相反，这或许反映了物种对环境变化的敏感性。