Gutgesell Marie, McMeans Bailey C, Guzzo Matthew M, de Groot Valesca, Fisk Aaron T, Johnson Timothy B, McCann Kevin S
Integrative Biology, University of Guelph, Guelph, Ontario, Canada.
Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada.
Ecology. 2022 Dec;103(12):e3817. doi: 10.1002/ecy.3817. Epub 2022 Sep 22.
Global change is fundamentally altering flows of natural and anthropogenic subsidies across space and time. After a pointed call for research on subsidies in the 1990s, an industry of empirical work has documented the ubiquitous role subsidies play in ecosystem structure, stability, and function. Here, we argue that physical constraints (e.g., water temperature) and species traits can govern a species' accessibility to resource subsidies, which has been largely overlooked in the subsidy literature. We examined the input of a high-quality, point-source anthropogenic subsidy (aquaculture feed) into a recipient freshwater lake food web. Using a combined bio-tracer approach, we detect a gradient in accessibility of the anthropogenic subsidy within the surrounding food web driven by the thermal preferences of three constituent species, effectively rewiring the recipient lake food web. Because aquaculture is predicted to increase significantly in coming decades to support growing human populations, and global change is altering temperature regimes, then this form of food web alteration may be expected to occur frequently. We argue that subsidy accessibility is a key characteristic of recipient food web interactions that must be considered when trying to understand the impacts of subsidies on ecosystem stability and function under continued global change.
全球变化正在从根本上改变自然和人为补贴在空间和时间上的流动。在20世纪90年代对补贴研究发出明确呼吁之后，一个实证研究领域记录了补贴在生态系统结构、稳定性和功能中所起的普遍作用。在此，我们认为物理限制因素（如水温）和物种特性能够决定一个物种获取资源补贴的能力，而这一点在补贴文献中很大程度上被忽视了。我们研究了一种高质量的点源人为补贴（水产养殖饲料）输入到一个受纳淡水湖泊食物网中的情况。使用一种组合生物示踪方法，我们在周围食物网中检测到由三种组成物种的热偏好驱动的人为补贴可获取性梯度，这有效地重新构建了受纳湖泊食物网。由于预计水产养殖在未来几十年将显著增加以支持不断增长的人口，并且全球变化正在改变温度格局，那么这种食物网改变形式可能会频繁发生。我们认为补贴可获取性是受纳食物网相互作用的一个关键特征，在试图理解补贴在持续全球变化下对生态系统稳定性和功能的影响时必须加以考虑。
