Dissertation Research: How Does Community Structure Affect Ecosystem Function? An Integrative Approach Linking Physiological Peformance and Species Interactions

由于物种丧失、栖息地改变和气候变化，生态系统日益受到威胁。 为了预测这些因素在未来如何影响生态系统，我们必须了解相互作用的生物体（群落）如何处理和吸收能量和物质。 一个重要的问题是，生态系统进程是更多地受到群落中物种的综合效应（生物多样性）的影响，还是受到最适合当地环境条件的少数丰富物种（优势物种）的影响。 淡水贻贝是沉积物居住，滤食性，双壳类软体动物，生活密集，多物种集群。 因为它们是热构象的代谢率随温度而变化，所以它们对材料的处理会对局部温度做出不同的反应。 它们通过过滤水中的生物并将营养物质沉积到底部沉积物中，在河流和湖泊中发挥着重要作用。 河蚌群落对河流功能的相对重要性取决于河流流量、流量和温度。 本研究整合了生理学、群落学和生态系统生态学，探讨了群落结构（贻贝种优势）和环境（温度状况）的变化如何影响河流生态系统过程。 使用实验室流中围生态系统，物种优势将被操纵，以确定是否占主导地位的物种提供生态服务的最高贡献的生态过程在其优惠的温度或促进其他物种在社区。 淡水贻贝是一个高度濒危的群体，本项目的结果将有助于他们的保护和管理。 此外，本研究亦将应用于本科生营养生态学之教学。

Ecosystems are increasingly imperiled due to species loss, habitat alteration, and climate change. To predict how these factors may impact ecosystems in the future, we must understand how groups of interacting organisms (communities) process and assimilate energy and materials. An important question concerns whether ecosystem processes are influenced more by the combined effects of species in the community (biodiversity) or by the effects of a few abundant species (dominant species) best suited to local environmental conditions. Freshwater mussels are sediment-dwelling, filter-feeding, bivalve mollusks that live as dense, multi-species aggregations. Because they are thermo-conformers whose metabolic rate varies with temperature, they process materials differently in response to local temperature. They serve important roles in rivers and lakes by filtering organisms from the water and depositing nutrients to the bottom sediments. The relative importance of mussel communities to river function depends on river volume, flow and temperature. This study integrates physiology, community and ecosystem ecology to ask how variation in both community structure (mussel species dominance) and environment (temperature regime) affect ecosystem processes in rivers. Using laboratory stream mesocosms, species dominance will be manipulated to determine if dominant species contribute ecological services by providing the highest contribution of ecological processes at their preferential temperature or by facilitating other species in the community. Freshwater mussels are a highly imperiled group and results of this project will contribute to their conservation and management. In addition, this research will be used for teaching trophic ecology to undergraduate students.