Understanding how biological communities respond to climate change is a major challenge in ecology. The response of ectotherms to changes in temperature depends not only on their species-specific thermal tolerances but also on temperature-mediated interactions across different trophic levels. Warming is predicted to reinforce trophic cascades in linear aquatic food chains, but little is known about how warming might affect the lower trophic levels of food webs involving extensive fish omnivory, a common scenario in subtropical and tropical waterbodies. In this study, a mesocosm warming experiment was conducted involving a pelagic food chain (fish–zooplankton–phytoplankton) topped by the omnivorous bighead carp [Aristichthys nobilis (Richardson)]. We found that temperature elevation significantly enhanced the growth of fish and suppressed zooplankton, including both metazooplankton and ciliates, while abundances of phytoplankton, despite disruption of temporal dynamics, did not increase correspondingly—likely due to fish predation. Our results suggest that trophic cascades are less unlikely to be reinforced by warming in food chains involving significant omnivory. Moreover, we found that warming advanced the spring abundance peak of phytoplankton abundance and that of the parthenogenetic rotifer Brachionus quadridentatus; whereas, it had no effect on the only sexually reproducing copepod, Mesocyclops leuckarti, presumably due to its prolonged life history. Our study also confirmed that warming may lead to a phenological mismatch between some predators and their prey because of the distinct life histories among taxa, with potentially severe consequences for resource flow in the food chain, at least in the short term.

了解生物群落如何应对气候变化是生态学的重大挑战。等温线对温度变化的响应不仅取决于其物种特定的热耐受性，还取决于不同营养水平上温度介导的相互作用。预计变暖会增强线性水生食物链中的营养级联反应，但是人们对变暖如何影响涉及广泛鱼类杂食性的较低营养网的营养水平知之甚少，这在亚热带和热带水体中很常见。在这项研究中，进行了中上层变暖实验，涉及上层食物链（鱼–浮游植物–浮游植物），上面杂着杂食性big鱼[ Aristichthys nobilis（理查森）]。我们发现，温度升高显着促进了鱼类的生长并抑制了浮游动物，包括后生浮游动物和纤毛虫，而浮游植物的丰度尽管时间动态受到破坏，但并未相应地增加，这可能是由于鱼类捕食造成的。我们的结果表明，营养级联不太可能通过涉及显性杂食动物的食物链变暖而得到加强。此外，我们发现变暖推动了浮游植物丰度的春季丰度峰值和孤雌轮虫Brachionus quadridentatus的春季丰度峰值。然而，它对唯一的有性繁殖的pe足类动物（Mesocyclops leuckarti）没有影响，大概是由于它的使用寿命长。我们的研究还证实，由于分类单元中不同的生活史，变暖可能导致某些捕食者与其猎物之间的物候不匹配，至少在短期内，这可能对食物链中的资源流动造成严重后果。