Dissertation Research: Impacts of Biological Diversity on Sediment Transport Conditions in Streams

点击翻译按钮获取中文摘要

Many fields of natural science suggest that organisms both respond to and also directly regulate the physical processes that structure ecosystems, in ways that have major implications for how the current loss of Earth?s biodiversity will affect our planet. A growing number of studies incorporates the influence of organisms into our understanding of biogeochemical cycles, functioning of ecosystems, and formation of habitats. Most of these studies still consider the influence of only one species at a time, ignoring the diverse array of species that might have unique impacts. The project proposed here will explicitly ask how interactions between coexisting species influence the physical process of erosion. In this project, caddisfly (Trichoptera: Hydropsychidae) diversity in experimental streams will be manipulated. Caddisflies are one of the most diverse and widespread groups of insects that live in riverbeds. They construct silken nets across pore spaces between rocks to filter feed, and previous studies have shown that nets from a single species reduce sediment motion during floods. This study will test whether multiple species of caddisfly that coexist in the same stream cause a synergistic decrease in sediment motion compared to any single species alone. Predicting sediment transport has become increasingly important in light of land-use changes, altered flow regimes, and channel-restoration efforts, and this work will help develop a better understanding of one of the most important processes in ecology and geology. Although many researchers have shown that a single biological species can have a substantial impact on abiotic processes, few studies have mechanistically explored how multiple species of animals can synergistically regulate fundamental transport processes in streams. This approach will refine our ability to quantitatively predict erosion.