DISSERTATION RESEARCH: Fish Effects in Stream Ecosystems: A Mechanistic Approach

该建议测试物种多样性生态系统功能的范例，在温带河流鱼类功能群。到目前为止，PI已经表明，单一的鱼类物种可以影响生态系统的属性，如初级生产力（PPR），底栖无脊椎动物的丰度，和有机物处理率在美国中西部的流。此外，鱼类多样性通过功能互补增强生态系统功能。在拟议的研究中，将使用来自三个假定功能组的物种研究鱼类生态系统效应的机制，包括：（1）底栖无脊椎动物，可能通过营养级联增加PPR，（2）表面摄食食虫动物，可能通过营养增强生态系统增加PPR，和（3）底栖无脊椎动物干扰者，可能通过营养级联和生物扰动增加PPR。拟议的实验设计将系统地消除鱼类和生态系统响应之间的每一个潜在的机制途径，提供一个明确的答案，以驱动响应的机制。总体而言，本研究将提供一个更全面的了解具体的鱼类和鱼类多样性如何影响河流生态系统的属性，并扩大多样性和生态系统功能之间的关系的一般知识。

This proposal tests the species diversity-ecosystem function paradigm across fish functional groups in temperate streams. To date the PIs have shown that single fish species can affect ecosystem properties such as primary production (PPR), benthic invertebrate abundance, and organic matter processing rates in midwestern USA streams. Further, fish diversity enhances ecosystem function via functional complementarity. In the proposed research, mechanisms of fish ecosystem effects will be investigated using species from three putative functional groups including: (1) benthic invertivores that may increase PPR through a trophic cascade, (2) surface feeding insectivores that may increase PPR through nutrient enhancement of the ecosystem, and (3) benthic invertivore-disturbers that may increase PPR through trophic cascade and bioturbation. The proposed experimental design will systematically eliminate each potential mechanistic pathway between the fish and the ecosystem response, providing a definitive answer as to which mechanisms drive the responses. Overall, this research will give a more comprehensive understanding of how specific fishes and fish diversity affect stream ecosystem properties, and broaden general knowledge of the relationship between diversity and ecosystem function.