COLLABORATIVE RESEARCH: Factors Affecting the Nature and Strength of Indirect Effects: A Modeling and Empirical Approach

合作研究：影响间接效应的性质和强度的因素：建模和实证方法

• 批准号: 0727628
• 负责人: Geoffrey Trussell
• 金额: $ 26.28万
• 依托单位: Northeastern University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-15 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0727628&HistoricalAwards=false
• 关键词: COLLABORATIVE; RESEARCH; Factors; Affecting; Nature

The trophic cascade exemplifies the importance of indirect effects to the dynamics and structure of ecological communities. Classical views of trophic cascades emphasize the positive indirect effect that predators have on basal resources through their consumption of prey. Yet growing evidence indicates that we must refine our view of how different trophic levels are dynamically linked because trophic cascades can also be caused by predator-induced changes in prey behavior such as foraging activity. Despite abundant theory we have a limited empirical understanding of the factors that shape individual foraging decisions that, in turn, dictate the nature and strength of indirect effects in natural communities. Drs. Trussell and Luttbeg will use a model comparison and null hypothesis approach to explore the relative importance of density (DMIIs) and trait-mediated indirect interactions (TMIIs) to trophic cascades on rocky intertidal shores. Using a tri-trophic food chain as a model system, they will manipulate factors predicted to influence prey behavior and thus the relative strength of TMIIs in trophic cascades. The researchers will achieve these objectives by addressing the following questions: 1. How do resource levels, prey state, and predation risk shape prey foraging and growth functions? 2. How do resource levels, prey state, and predation intensity shape prey mortality functions? 3. What model best describes the short-term influence of these factors on prey foraging behavior and the strength of emergent indirect effects? 4. Do models supported by short-term data accurately predict longer-term prey behavior and the strength of emergent indirect effects? The research will make significant intellectual contributions to ecology by exploring whether attention to individual behavior improves our ability to predict the nature and strength of indirect effects in natural systems. By evaluating alternative models with empirical data, our research is novel and will build a stronger connection between ecological theory and its empirical base. Moreover, because species interactions are central to major issues in ecology, such as the use of trophic cascade theory to manage natural systems, it is critical that we understand how behavior is modified by environmental context. Broader impacts are considerable. The research will allow students at all educational levels to pursue their interests in ecology. Graduate and undergraduate training will occur during all phases of the research. As part of Northeastern?s Young Scholars Program they also will offer a summer research internship each year to a high school student from the Coastal Ocean Science Academy (COSA) that is taught by the Marine Science Center?s Outreach staff. These students are largely members of under-represented groups from Boston area public high schools. In addition to providing these students with plenty of field experience, they also will teach them how to (1) conduct basic statistical analyses, (2) write a scientific paper, and (3) develop and deliver an oral presentation on their internship experience to the Marine Science Center community.

营养级联说明了间接效应对生态群落动态和结构的重要性。营养级联的经典观点强调捕食者通过消耗猎物对基础资源的积极间接影响。然而，越来越多的证据表明，我们必须完善我们的观点，不同的营养水平是如何动态连接，因为营养级联也可以由捕食者引起的猎物行为的变化，如觅食活动。尽管丰富的理论，我们有一个有限的经验性的理解的因素，形成个人觅食的决定，反过来又决定了自然社区的间接影响的性质和强度。Trussell和Luttbeg博士将使用模型比较和零假设方法来探索密度（DMIIs）和性状介导的间接相互作用（TMIIs）对岩石潮间带海岸营养级联的相对重要性。使用三营养食物链作为模型系统，他们将操纵预测影响猎物行为的因素，从而影响营养级联中TMIIs的相对强度。研究人员将通过解决以下问题来实现这些目标：1。资源水平、猎物状态和捕食风险如何塑造猎物觅食和生长功能？2.资源水平、猎物状态和捕食强度如何影响猎物死亡率函数？3.什么模型最好地描述了这些因素对猎物觅食行为的短期影响和紧急间接影响的强度？4.短期数据支持的模型能准确预测长期猎物行为和突发性间接效应的强度吗？这项研究将通过探索对个体行为的关注是否能提高我们预测自然系统中间接影响的性质和强度的能力，为生态学做出重大的智力贡献。通过用经验数据评估替代模型，我们的研究是新颖的，将在生态理论与其经验基础之间建立更强的联系。此外，由于物种相互作用是生态学中主要问题的核心，例如使用营养级联理论来管理自然系统，因此我们了解环境背景如何改变行为是至关重要的。更广泛的影响是相当大的。 这项研究将使所有教育水平的学生都能追求他们对生态学的兴趣。研究生和本科生培训将发生在研究的所有阶段。作为东北部的一部分，？的青年学者计划，他们还将提供一个夏季研究实习，每年从沿海海洋科学学院（COSA）的高中生，是由海洋科学中心？s外联工作人员。这些学生主要是波士顿地区公立高中代表性不足的群体的成员。除了为这些学生提供丰富的实地经验，他们还将教他们如何（1）进行基本的统计分析，（2）写一篇科学论文，（3）开发并提供关于他们的实习经验的口头报告海洋科学中心社区。