Collaborative Research: Direct and Indirect Effects of Fish Predation of the Freshwater Littoral Benthos

许多生态群落的结构比标准的营养等级结构要微妙和复杂得多，其中有重叠的捕食者层，可能因竞争而交联。根据对海湾山湖（Kingsport， TN）沿岸生物群的9年研究，该项目将确定和测量优势脊椎动物捕食者（redear太阳鱼，Lepomis microlophus），优势无脊椎动物捕食者（蜻蜓Tetragoneuria cynosura的幼虫），和它们的猎物群落。研究这些相互作用的三个组成部分的实验将进行：(1)大围栏实验操纵两个大小类别的鱼；(2)利用小鱼和两年类蜻蜓进行小围栏实验；(3)实验室实验，旨在确定现场结果背后的行为机制，并加强其解释。研究小组将整合来自每个组成部分的概念，以提供构建沿海社区的力量的现实模型。这些研究旨在衡量捕食的直接影响，这可能导致死亡率增加或生长速度下降，或两者兼而有之。捕食的间接影响也将被评估，可能是刺激或抑制特定猎物。干涉和开发竞争是最后一个方面，可能发生在物种内部或物种之间。研究结果将有助于改变我们对社区组织的基本假设，并将提供对一个社区结构的全面理解，包括该结构如何从潜在的行为和生态机制中产生。通过这种合作努力获得的了解将为渔业生物学家和湖泊管理者提供宝贵的信息基础。

Many ecological communities are structured in ways considerably more subtle and complex than can be expressed in the standard trophic hierarchy, with its superimposed layers of predators, potentially cross-linked by competition. Drawing upon nine years of research on the littoral biota of Bays Mountain Lake (Kingsport, TN), this project will identify and measure the critical biotic interactions among the dominant vertebrate predator (redear sunfish, Lepomis microlophus), the dominant invertebrate predator (larvae of the dragonfly Tetragoneuria cynosura), and their prey community. The three component experiments examining these interactions will be conducted: (1) large-enclosure experiment manipulating two size-classes of fish; (2) a small-enclosure experiment manipulating small fish and two-year classes of dragonflies; and (3) laboratory experiments designed to identify the behavioral mechanisms underlying the field results and strengthen their interpretation. Concepts emerging from each component will be integrated by the research team to provide a realistic model of forces structuring littoral communities. These studies are designed to measure the direct effects of predation, which may result in either increased mortality or reduced growth or both. Indirect effects of predation will also be assessed and may be either stimulatory or inhibitory to particular prey. Interference and exploitation competition is the final aspect which may be either within or between species. The results will help change our fundamental assumptions about community organization, and will provide a comprehensive understanding of one community's structure, including how that structure arises from underlying behavioral and ecological mechanism. Understanding gained through this collaborative effort will provide a valuable information base for fisheries biologists and lake managers.