Data from: The adaptive capacity of lake food webs: from individuals to ecosystems

Aquatic ecosystems support size structured food webs, wherein predator-prey body sizes span orders of magnitude. As such, these food webs are replete with extremely generalized feeding strategies, especially among the larger bodied, higher trophic position taxa. The movement scale of aquatic organisms also generally increases with body size and trophic position. Together, these body size, mobility, and foraging relationships suggest that organisms lower in the food web generate relatively distinct energetic pathways by feeding over smaller spatial areas. Concurrently, the potential capacity for generalist foraging and spatial coupling of these pathways often increases, on average, moving up the food web toward higher trophic levels. We argue that these attributes make for a food web architecture that is inherently ‘adaptive’ in its response to environmental conditions. This is because variation in lower trophic level dynamics is dampened by the capacity of predators to flexibly alter their foraging behavior. We argue that empirical, theoretical, and applied research needs to embrace this inherently adaptive architecture if we are to understand the relationship between structure and function in the face of ongoing environmental change. Toward this goal, we discuss empirical patterns in the structure of lake food webs to suggest that ecosystems change consistently, from individual traits to the structure of whole food webs, under changing environmental conditions. We then explore an empirical example to reveal that explicitly unfolding the mechanisms that drive these adaptive responses offers insight into how human-driven impacts, such as climate change, invasive species, and fisheries harvest, ought to influence ecosystem structure and function (e.g., stability, secondary productivity, maintenance of major energy pathways). We end by arguing that such a directed food web research program promises a powerful across-scale framework for more effective ecosystem monitoring and management.水生生态系统支撑着体型结构化的食物网，其中捕食者与猎物的体型跨度可达数个数量级。此类食物网普遍存在高度泛化的取食策略，尤其在体型更大、营养级位置（trophic position）更高的类群中更为显著。水生生物的运动尺度通常也随体型与营养级位置的提升而增大。综合上述体型、运动能力与取食模式的关联关系，食物网中较低营养级的生物会在更小的空间范围内取食，由此形成相对独立的能量通路（energetic pathways）。与此同时，随着营养级（trophic levels）向上移动至更高层级，泛化取食与这些通路的空间耦合潜力平均而言往往会有所提升。我们认为，这些特征共同塑造了一种在响应环境变化时内在具有“适应性”的食物网架构。这是因为捕食者具备灵活调整取食行为的能力，可缓冲低营养级动态变化的波动。我们主张，若要在环境持续变化的背景下厘清食物网结构与功能间的关联，实证研究、理论研究与应用研究都需要接纳这种内在的适应性架构。为此，我们先讨论湖泊食物网结构的实证模式，以说明在环境变化的条件下，生态系统会从个体性状到完整食物网结构发生一致的改变。随后我们通过一个实证案例展开分析，揭示出阐明驱动这些适应性响应的机制，能够帮助我们理解人类活动驱动的影响——如气候变化、入侵物种与渔业捕捞——将如何作用于生态系统的结构与功能（例如稳定性、次级生产力（secondary productivity）、关键能量通路的维持）。我们最终提出，这类针对性的食物网研究计划，有望为更高效的生态系统监测与管理提供一套跨尺度的有力分析框架。