Abstract Increasing demand for freshwater during the last century has so severely degraded many wetland ecosystems that they are some of the most seriously impacted environments in the world. Environmental flows are used as a management tool to restore parts of the hydrological regime altered by human water use, to rehabilitate these wetlands. Research and monitoring to date has focused on understanding ‘flow-ecology’ relationships, without investigating the mechanisms underlying them. We sought to understand how different basal food sources are incorporated into fish tissue in temporary wetland systems. This study provides a necessary first step toward the development of mechanistic research that investigates the effects of variation in fatty acids (FA) within the food and prey base on top predators. We added different sources of fatty acids to wetland mesocosms by adding extra food sources including redgum leachate to increase planktonic bacteria populations, cyanobacteria, green algae and biofilm matrix to observe how they were incorporated into secondary consumers. Wetland soil and water was added to replicate mesocosms, left for 28 days to produce zooplankton and then Western carp gudgeons added. There was a clear shift in the invertebrate assemblage structure following the introduction of the gudgeons. There was also a clear difference in assemblage structure and nutritional value between benthic and planktonic invertebrates. However, the addition of extra food sources did not generate differing FA profiles between treatments in the substratum fractions, invertebrates or fish after 14 days. We suggest that food sources generated within the mesocosms themselves may have outweighed any treatment effects. Using flooded wetland mesocosms potentially would have provided more realistic knowledge of the food web mechanisms of wetland inundation rather than feeding zooplankton fed specific primary food sources to fish. However, future experiments attempting to identify the mechanisms of the transfer of basal food sources in wetlands to secondary consumers may wish to directly feed fish primary consumers raised on specific basal food sources.

中文翻译：

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使用脂肪酸来识别湿地中观环境中次级消费者的食物来源

摘要 上个世纪对淡水的需求不断增加，使许多湿地生态系统严重退化，成为世界上受影响最严重的环境之一。环境流量被用作管理工具，以恢复因人类用水而改变的部分水文状况，以恢复这些湿地。迄今为止的研究和监测侧重于理解“流动-生态”关系，而没有研究它们背后的机制。我们试图了解如何将不同的基础食物来源纳入临时湿地系统中的鱼类组织。这项研究为机械研究的发展迈出了必要的第一步，该研究调查了食物和猎物中脂肪酸 (FA) 变化对顶级捕食者的影响。我们通过添加额外的食物来源（包括红胶渗滤液）来增加浮游细菌、蓝藻、绿藻和生物膜基质的数量，以观察它们如何被纳入次级消费者，从而向湿地中观生态系统添加了不同的脂肪酸来源。添加湿地土壤和水以复制中世界，放置 28 天以产生浮游动物，然后添加西鲤鱼。引入鱼后，无脊椎动物的组合结构发生了明显的变化。底栖无脊椎动物和浮游无脊椎动物在组合结构和营养价值上也存在明显差异。然而，在 14 天后，添加额外的食物来源并没有在基质组分、无脊椎动物或鱼类的处理之间产生不同的 FA 谱。我们认为，中宇宙本身产生的食物来源可能超过了任何治疗效果。使用淹没的湿地中观可能会提供关于湿地淹没的食物网机制的更现实的知识，而不是喂养以特定主要食物来源为食的浮游动物。然而，未来试图确定湿地基础食物来源向次级消费者转移机制的实验可能希望直接喂养以特定基础食物来源饲养的鱼类初级消费者。