Abstract Fish growth in river ecosystems is influenced by a multitude of environmental drivers, including the heterogeneity of these drivers. Globally, river ecosystems are subject to anthropogenic stressors that can simplify riverine landscapes, homogenize riverine communities, and favor nonnative fishes. Yet, how anthropogenically driven simplification of riverine landscapes affects fish life-history traits remains largely unknown. The aim of this study was to examine the character of fish growth along the entire main channel of an Anthropocene River. We collected four species of potamodromous fish from different functional feeding guilds, from each of six functional process zones (FPZs) – unique large-scale hydrogeomorphic patches – along the entire length of the Illinois River (Illinois, USA), and calculated three growth metrics: growth rate (k), maximum size (L∞), and a relative growth index. The majority (7 of 12) of species-growth metric combinations did not differ among FPZs. Of the five species-growth metric combinations that were different, none exhibited more than three distinct groups of values. The limited difference in growth along the main channel of the Illinois River reflects a homogenization of ecosystem function, and is associated with the systemic simplification of physical heterogeneity of the river channel. The fishes studied from the Illinois River also tended to have faster growth rates (k) and smaller maximum sizes (L∞) relative to other North American freshwater ecosystems. Our results reveal spatial constraints to life-history traits and changes to ecosystem interactions, which are evidence of being in a new regime or state. This has implications for the reproductive output and resilience of native fishes in Anthropocene Rivers.

中文翻译：

---

从复杂到简单：伊利诺伊河网络沿线的鱼类生长

摘要 河流生态系统中的鱼类生长受到多种环境驱动因素的影响，包括这些驱动因素的异质性。在全球范围内，河流生态系统受到人为压力因素的影响，这些因素可以简化河流景观，使河流社区同质化，并有利于非本地鱼类。然而，人为驱动的河流景观简化如何影响鱼类的生活史特征仍然很大程度上未知。这项研究的目的是检查人类世河流的整个主要河道上鱼类生长的特征。我们从伊利诺伊河全长（美国伊利诺伊州）的六个功能加工区 (FPZ)（独特的大型水文地貌斑块）中的每一个中收集了来自不同功能性饲养行会的四种马齿鱼，并计算了三个生长指标：增长率 (k)、最大尺寸 (L∞) 和相对增长指数。大多数（12 个中的 7 个）物种生长指标组合在 FPZ 之间没有差异。在五个不同的物种生长指标组合中，没有一个表现出超过三组不同的值。伊利诺伊河主河道沿线增长的有限差异反映了生态系统功能的同质化，并与河道物理异质性的系统简化有关。与其他北美淡水生态系统相比，从伊利诺伊河研究的鱼类也往往具有更快的增长率 (k) 和更小的最大尺寸 (L∞)。我们的研究结果揭示了生活史特征的空间限制和生态系统相互作用的变化，这是处于新制度或状态的证据。