Data from: Simultaneous exposure to a pulsed and a prolonged anthropogenic stressor can alter consumer multifunctionality

Ecosystems face multiple anthropogenic threats globally, and the effects of these environmental stressors range from individual-level organismal responses to altered system functioning. Understanding the combined effects of stressors on process rates mediated by individuals in ecosystems would greatly improve our ability to predict organismal multifunctionality (e.g. multiple consumer-mediated functions). We conducted a laboratory experiment to test direct and indirect, as well as immediate and delayed effects of a heat wave (pulsed stress) and micropollutants (MPs) (prolonged stress) on individual consumers (the great pond snail Lymnaea stagnalis) and their multifunctionality (i.e. consumption of basal resources, growth, reproduction, nutrient excretion and organic-matter cycling). We found that stressful conditions increased the process rates of multiple functions mediated by individual consumers. Specifically, the artificial heat wave increased process rates in the majority of the quantified functions (either directly or indirectly), whereas exposure to MPs increased consumption of basal resources which lead to increases in the release of nutrients and fine particulate organic matter. Moreover, snails exposed to a heat wave showed decreased reproduction and nutrient excretion after the heat-wave, indicating the potential for ecologically relevant delayed effects. Our study indicates that the immediate and delayed effects of stressors on individual organisms may directly and indirectly impact multiple ecosystem functions. In particular, delayed effects of environmental stress on individual consumers may cumulatively impede recovery due to decreased functioning following a perturbation. Reconciling these results with studies incorporating responses at higher levels of biological complexity will enhance our ability to forecast how individual responses upscale to ecosystem multifunctionality.

全球范围内的生态系统正面临多重人为威胁，此类环境胁迫因子的影响跨度从个体水平的生物体响应，直至生态系统功能的改变。明晰胁迫因子对生态系统中个体介导的过程速率的综合影响，将极大提升我们预测生物体多功能性（multifunctionality）的能力，例如消费者介导的多重生态功能。本研究开展了一项室内控制实验，以探究热浪（脉冲胁迫，pulsed stress）与微污染物（micropollutants, MPs，长期胁迫，prolonged stress）对个体消费者——大椎实螺（*Lymnaea stagnalis*）——及其多功能性的直接、间接、即时与延迟效应。该多功能性涵盖基础资源摄食、生长、繁殖、营养排泄与有机质循环。研究发现，胁迫环境会提升个体消费者介导的多项生态功能的过程速率。具体而言，人工热浪会直接或间接提升绝大多数量化生态功能的过程速率；而微污染物暴露会提升基础资源摄食量，进而促进营养物质与细颗粒有机质的释放。此外，经历热浪胁迫的椎实螺在胁迫结束后出现繁殖与营养排泄水平下降的现象，表明存在具有生态学意义的延迟效应。本研究表明，胁迫因子对生物体的即时与延迟效应，可通过直接或间接途径影响多项生态系统功能。尤为值得关注的是，环境胁迫对个体消费者的延迟效应，可能会因扰动后生态功能下降而累积阻碍生态系统恢复。将本研究结果与纳入更高生物复杂度层级响应的相关研究相结合，将进一步提升我们预测个体响应如何向上尺度推演至生态系统多功能性的能力。