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

许多生态群落的结构比标准营养层次结构要微妙和复杂得多，其重叠的捕食者层可能因竞争而交叉连接。根据对贝斯山湖(田纳西州金斯波特)沿海生物群长达9年的研究，该项目将确定和测量主要脊椎动物捕食者(太阳鱼)、主要无脊椎动物捕食者(蜻蜓Tetraoneuria cynosura幼虫)及其猎物群落之间的关键生物相互作用。检验这些相互作用的三个组成部分实验将进行：(1)操纵两个大小类别的鱼的大型围栏实验；(2)操纵小鱼和两个等级的蜻蜓的小型围栏实验；以及(3)旨在确定实地结果背后的行为机制并加强其解释的实验室实验。研究小组将整合每个组成部分中出现的概念，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，捕食可能导致死亡增加或生长减少，或两者兼而有之。还将评估捕食的间接影响，对特定猎物可能是刺激的，也可能是抑制的。干扰和剥削竞争是最后一个方面，可能是物种内部的，也可能是物种之间的。研究结果将有助于改变我们对社区组织的基本假设，并将提供对社区结构的全面理解，包括该结构是如何从潜在的行为和生态机制中产生的。通过这一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.