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

这一建议测试了温带溪流中鱼类功能组的物种多样性-生态系统功能范例。到目前为止，PIs已经表明，单一鱼类物种可以影响美国中西部溪流的生态系统特性，如初级生产力(PPR)、底栖无脊椎动物丰度和有机物处理速度。此外，鱼类多样性通过功能互补增强了生态系统的功能。在拟议的研究中，将使用来自三个假定功能组的物种来研究鱼类生态系统影响的机制，包括：(1)可能通过营养级联增加PPR的底栖食肉动物，(2)可能通过增加生态系统营养增加PPR的表面食性食虫，以及(3)可能通过营养级联和生物扰动增加PPR的底栖逆营养干扰物。拟议的实验设计将系统地消除鱼类和生态系统反应之间的每一条潜在的机制途径，为哪些机制驱动反应提供明确的答案。总体而言，这项研究将使人们更全面地了解特定鱼类和鱼类多样性如何影响河流生态系统的性质，并拓宽关于多样性和生态系统功能之间关系的一般知识。

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.