Data from: Genotypic diversity and trait variance interact to affect marsh plant performance

1. Intraspecific diversity can have important effects on population, community and ecosystem processes, yet we have little understanding of the relative importance of genetic- vs. trait-based measures of intraspecific diversity. 2. I conducted a manipulative field experiment of plant (Spartina alterniflora) genotypic diversity and trait diversity to examine their independent and interactive effects on plant performance and community structure. I focused on variation within and among genotypes in plant stem height, a trait that varies substantially across environmental gradients and can be an important predictor of plant competition intensity. 3. Trait and genotypic diversity interactively affected multiple metrics of plant performance. Both stem density and spatial spread increased with genotypic diversity in the low trait diversity combinations, yet there were negligible to weak negative effects in the high trait diversity treatments. S. alterniflora percent cover also varied with genotypic and trait diversity, but not in a clear linear pattern. 4. There were no effects of trait or genotypic diversity on associated macrofauna above-ground, yet they interactively affected below-ground measures. Infaunal abundance and sediment oxygen availability mirrored the idiosyncratic response of plant percent cover. 5. Despite the interactive effects of genotypic and trait diversity, high trait diversity consistently increased plant performance in genotypic monoculture. 6. Synthesis: The effects of intraspecific plant trait diversity on a range of plant and community responses in this study reinforce the premise that functional differences underlie ecological effects of genetic diversity and suggest that readily measured trait variance may serve as a valuable predictor of plant performance.

1. 种内多样性（intraspecific diversity）可对种群、群落及生态系统过程产生显著影响，但目前学界对种内多样性的基于遗传与基于功能性状的两类测度的相对重要性仍缺乏深入认知。
2. 本研究以互花米草（Spartina alterniflora）为对象，开展了基因型多样性（genotypic diversity）与功能性状多样性（trait diversity）的控制野外实验，以探究二者对植物表现（plant performance）及群落结构的独立与交互效应。本研究聚焦于植物茎高这一性状在基因型内及基因型间的变异——该性状沿环境梯度存在显著变化，且可作为植物竞争强度的重要预测因子。
3. 功能性状多样性与基因型多样性对植物表现的多项指标存在交互效应。在低性状多样性组合中，茎密度与空间扩展范围均随基因型多样性升高而增加；而在高性状多样性处理组中，二者则呈现可忽略至微弱的负效应。互花米草（S. alterniflora）的盖度同样随基因型与性状多样性发生变化，但未呈现明确的线性规律。
4. 性状多样性与基因型多样性对地上伴生大型无脊椎动物（macrofauna）无显著影响，但二者对地下相关指标存在交互效应。底内动物丰度（infaunal abundance）与沉积物氧有效性（sediment oxygen availability）的变化趋势与植物盖度的独特响应相一致。
5. 尽管基因型多样性与性状多样性存在交互效应，但在基因型单培养体系中，高性状多样性始终可提升植物表现。
6. 综合结论：本研究中植物种内功能性状多样性对多项植物及群落响应的影响，进一步佐证了"功能性状差异是遗传多样性产生生态效应的核心基础"这一前提，并提示易测定的性状变异可作为植物表现的有效预测因子。