In alluvial plains, where shallow lakes are subject to inputs of sediments, the impact of turbidity on predator–prey interactions needs to be studied. We conducted an in situ mesocosm study in a shallow floodplain lake during 36 days to evaluate the main and interactive effect of fish predation and turbidity on the abundances, composition and habitat selection of a natural aquatic assemblage, including zooplankton and plant-associated invertebrates, and the cascading effect on phytoplankton biomass. Four treatments were involved: clear water (C), clear water plus fish (CF), turbid water (T), and turbid water plus fish (TF). In each mesocosm, free-floating macrophytes were included to provide environmental heterogeneity, so organisms could display habitat selection. Fish predation was the main factor in structuring the abundances and assemblages composition regardless of turbidity condition. This was explained in part, because turbidity alone did not cause structural changes in the assemblage composition, but produced disorientation of prey organisms, weakening the effect of macrophyte roots as a refuge and favoring the consumption by fish in TF. Therefore, the trophic link between fishes and their prey was the same for zooplankton and stronger for amphipods and chironomids under turbid conditions than in clear waters. Fish caused a cascading effect on phytoplankton biomass, but it was partially counterbalanced under turbid condition due to the negative effect of clay particles on the planktonic algae due to light attenuation. Our results suggest that, within a specific turbidity range, there should be no mismatch in the trophic link between fish and phytoplankton.

在冲积平原上，浅湖是沉积物输入的地方，需要研究浊度对捕食者与猎物相互作用的影响。我们在36天的浅滩中进行了原位介观研究，以评估鱼类捕食和混浊度对包括浮游生物和与植物相关的无脊椎动物在内的天然水生鱼类的丰度，组成和生境选择的主要和相互作用的影响，以及对浮游植物生物量的级联效应。涉及四种处理：清水（C），清水加鱼（CF），混浊水（T）和混浊水加鱼（TF）。在每个中观世界中，都包括自由漂浮的大型植物以提供环境异质性，因此生物可以展示栖息地的选择。鱼类的捕食是构成丰度和组合组成的主要因素，而与浊度条件无关。可以部分解释这是因为仅浊度不会引起组合物组成的结构变化，而是会使猎物有机体迷失方向，削弱大型植物根作为避难所的作用，并有利于鱼类在TF中的消费。因此，在浑浊的条件下，鱼类和它们的猎物之间的营养联系对于浮游动物是相同的，而对于两栖动物和鳞翅目动物则比在清澈的海水中更强。鱼对浮游植物生物量产生了级联效应，但由于光衰减导致粘土颗粒对浮游藻类的负面影响，在混浊条件下鱼得到了部分抵消。我们的结果表明，在特定的浊度范围内，