Data from: The underappreciated role of life history in mediating the functional consequences of biodiversity change

Biodiversity is changing on both global and local scales, motivating research to understand the consequences of these changes for how communities and ecosystems function. Here, we explore the role of life history strategies in mediating biodiversity and ecosystem functioning. In particular, we evaluate how the composition, biomass (% cover), and richness of perennial (persistence ≥ 1 year) and ephemeral (persistence < 1 year) species change along a gradient of increasing seaweed species richness on a rocky shoreline. We show that the majority of biomass is comprised of perennial species, especially where overall richness is low, whereas the majority of species are ephemeral, especially where overall richness is high. We then present and discuss the results of an 18-month field manipulation quantifying the factorial effects of tidal elevation, wave exposure, herbivore removals, thermal and desiccation stress amelioration, and nutrient additions on perennial vs. ephemeral species. In particular, the diversity of ephemeral species was strongly affected, relative to perennial species, by tidal elevation, wave exposure, and herbivory; herbivores reduced diversity of ephemeral species relative to perennials. Relative to perennial cover, ephemeral cover was greater higher on the shore, in more wave-exposed habitats, and where herbivores were removed, plots were unscreened, and/or nutrients were added. Thus, perennials and ephemerals responded differently to environmental context and experimental manipulation. We compared nitrate uptake and photosynthesis rates of ephemeral and perennial species and found that maximum nitrate uptake and photosynthesis rates of ephemerals were twice as high as those of perennials. These results highlight the disproportionate roles that ephemeral species play in mediating ecosystem-level processes. In combination with our comparisons of the diversity and cover of perennial and ephemeral species along a biodiversity gradient, these results demonstrate the utility of incorporating life history traits into our efforts to understand the functional consequences of biodiversity change.全球与局地尺度上的生物多样性均在发生变化，推动学界开展相关研究以解析此类变化对群落与生态系统功能的影响。本研究旨在探讨生活史策略（life history strategies）在调控生物多样性与生态系统功能中的作用。具体而言，我们针对岩岸潮间带，分析海藻物种丰富度沿梯度升高时，多年生物种（perennial species，存活时长≥1年）与短命物种（ephemeral species，存活时长<1年）的组成、生物量（盖度百分比）及物种丰富度的变化规律。研究结果显示，生物量主要由多年生物种构成，尤其在总物种丰富度较低的区域；而物种总数则以短命物种为主，尤其在总丰富度较高的区域。随后，我们呈现并讨论一项为期18个月的野外操控实验（field manipulation）结果，该实验量化了潮位（tidal elevation）、波浪暴露度（wave exposure）、植食动物移除、热与干燥胁迫缓解以及营养盐添加等因子对多年生与短命物种的交互效应。具体而言，相较于多年生物种，短命物种的多样性显著受潮位、波浪暴露度与植食作用调控；植食动物会降低短命物种的多样性（相较于多年生物种）。相较于多年生物种盖度，短命物种盖度在潮间带更高位置、波浪暴露更强的生境，以及植食动物被移除、样地未遮罩或添加了营养盐的区域中更高。由此可见，多年生与短命物种对环境背景与实验操控的响应存在显著差异。我们对比了短命与多年生物种的硝酸盐吸收速率与光合速率，发现短命物种的最大硝酸盐吸收速率与光合速率均为多年生物种的两倍。上述结果凸显了短命物种在调控生态系统级过程中所发挥的不成比例的重要作用。结合我们沿生物多样性梯度开展的多年生与短命物种多样性及盖度对比研究，上述结果证实了将生活史性状纳入研究框架的价值，有助于我们深入理解生物多样性变化的功能效应。