Whole-lake Manipulations of Food Webs and Nutrients: Benthic Community Responses and Benthic-Palagic Coupling

在世界范围内，许多湖泊经历了鱼类数量和营养负荷的巨大变化。这些常见变化的每一种影响对于远洋群落来说是众所周知的，但对于底栖生物群落却鲜为人知。此外，对于鱼类和营养物质在构建底栖动物群落过程中的相互作用，或者这种相互作用对底栖-中上层耦合的影响，我们一无所知。这个项目将测试底栖藻类、大型植物和无脊椎动物对麦迪逊团队创造的三种水平的鱼类捕食和两种水平的营养的反应。底栖生物的响应变量将包括丰度、物种组成、大小结构、生物量以及藻类、大型植物和无脊椎动物的产量。一个中心焦点是底栖生物对鱼类和营养物质的反应将在多大程度上补偿远洋反应。一个中心假设是，渐进的受精将促使初级生产力从海底向中上层迅速、门槛的转变。如果不同时测量浮游和底栖动物的反应，我们对湖泊动态对管理努力的反应的理解将受到影响。湖泊是大多数大陆上的主要景观特征，因此研究结果对广泛的栖息地来说应该是重要的。

Worldwide, many lakes undergo large changes in fish populations and nutrient loading. The impact of each of these common changes is well-known for pelagic communities, but poorly known for benthic communities. Furthermore, nothing is known about the interaction of fish and nutrients in structuring benthic communities, or about the impact of this interaction on benthic-pelagic coupling. This project will test the responses of benthic algae, macrophytes, and invertebrates to the three levels of fish predation and two levels of nutrients created by the Madison team. Benthic response variables will include abundance, species composition, size structure, biomass, and production of algae, macrophytes, and invertebrates. A central focus is the degree to which benthic responses to fish and nutrients will compensate for pelagic responses. A central hypothesis is that progressive fertilization will prompt a rapid, threshold shift from benthic to pelagic primary production. Without the simultaneous measurements of pelagic and benthic responses, our understanding of the response of lake dynamics to management efforts would suffer. Lakes serve as major landscape features on most continents, so the results of the research should be important for a broad array of habitats.