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，生态系统正日益受到威胁。为了预测这些因素在未来可能如何影响生态系统，我们必须了解相互作用的有机体(群落)群体是如何处理和吸收能量和材料的。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(生物多样性)的综合影响，还是受到少数最适合当地环境条件的丰富物种(优势物种)的影响。淡水贻贝是栖息在沉积物中的滤食性双壳软体动物，以密集的多物种聚集体形式生活。因为它们是热异构体，其代谢率随温度而变化，它们处理材料的方式因局部温度的不同而不同。它们在河流和湖泊中扮演着重要的角色，通过过滤水中的生物并将营养物质沉积到底部沉积物中。贻贝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。本研究结合生理学、群落和生态系统生态学，探讨群落结构(贻贝优势种)和环境(温度状况)的变化对河流生态系统过程的影响。利用实验室溪流中隔系统，物种优势度将被操纵，以确定优势物种是通过在其适宜的温度下提供最高的生态过程贡献，还是通过促进群落中的其他物种来贡献生态服务。淡水贻贝是一个高度危险的群体，该项目的结果将有助于它们的保护和管理。此外，本研究还将用于向本科生讲授营养生态学。

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.