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

自然科学的许多领域表明，生物体既对构建生态系统的物理过程做出反应，也直接对其进行调节，这种方式对目前地球的丧失具有重大影响。S：生物多样性将如何影响我们的星球？越来越多的研究将生物体的影响纳入到我们对生物地球化学循环、生态系统功能和生境形成的理解中。这些研究中的大多数仍然一次只考虑一种物种的影响，而忽略了可能具有独特影响的各种物种。这里提出的项目将明确询问共存物种之间的相互作用如何影响侵蚀的物理过程。在这个项目中，将对实验溪流中的瓢虫(毛翅目：水虫科)的多样性进行操纵。卡迪蝇是生活在河床上的种类最多、分布最广的昆虫之一。他们在岩石之间的空隙中建造丝网来过滤饲料，之前的研究表明，来自单一物种的网减少了洪水期间的泥沙运动。这项研究将测试与任何单一物种相比，共存于同一溪流中的多个物种是否会导致沉积物运动的协同减少。随着土地利用的变化、水流状态的改变和河道修复的努力，预测泥沙输运变得越来越重要，这项工作将有助于更好地理解生态学和地质学中最重要的过程之一。虽然许多研究人员已经证明了单一生物物种可以对非生物过程产生重大影响，但很少有研究从机械上探索多种动物如何协同调节溪流中的基本运输过程。这种方法将提高我们定量预测侵蚀的能力。

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.