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

本研究对温带河流鱼类功能群的物种多样性-生态系统功能范式进行了检验。迄今为止，pi已经表明，单个鱼类物种可以影响美国中西部河流的生态系统特性，如初级生产（PPR）、底栖无脊椎动物丰度和有机物处理速率。鱼类多样性通过功能互补增强生态系统功能。在拟建的研究中，鱼类生态系统效应的机制将通过三个假定的功能群来研究，包括：(1)可能通过营养级联增加PPR的底栖无性动物，(2)可能通过营养增强生态系统增加PPR的食虫动物，以及(3)可能通过营养级联和生物扰动增加PPR的底栖无性动物干扰物。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种潜在机制途径，为驱动响应的机制提供明确的答案。总体而言，本研究将更全面地了解特定鱼类和鱼类多样性如何影响溪流生态系统特性，并拓宽多样性与生态系统功能之间关系的一般认识。

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.