Dissertation Research: How does biodiversity influence resource subsidy flux? A test with freshwater mussels and aquatic-terrestrial linkages

物种丧失、栖息地改变和气候变化正在导致生态系统的多样性和功能发生巨大变化。这个项目探讨了物种的数量如何影响生物体之间营养物质和能量的转移。先前的实验表明，贻贝在夏季低流量季节为溪流提供氮。氮供应的增加可以引发藻类丰度的增加，从而引发食草水生昆虫的增加。更重要的是，当更多的贻贝物种是目前这种转移的氮增强，这表明贻贝组合的多样性增加了营养补贴的数量。氮补贴的影响可能会超出流本身，成年水生昆虫是一个重要的食物来源，在河岸森林陆地捕食者。实验将进行使用淡水贻贝，以调查淡水贻贝组合的多样性如何影响贻贝社区提供给河流生态系统和陆地捕食者的营养物质的速率。现场和实验室实验将被用来看看成年水生昆虫的出现率和河岸蜘蛛的丰度增加时，更多的贻贝物种。稳定的氮同位素将被用来量化营养补贴，并确定贻贝衍生的营养补贴如何通过河流和河岸食物网移动。这项研究将有助于我们理解生物多样性和生态系统功能之间的关系，这将最终帮助科学家预测生态系统过程中的干旱和气候变化的后果。它还将提高我们对淡水贻贝这一全球濒危动物的生态重要性的认识。

Species loss, habitat alteration, and climate change are causing dramatic changes in the diversity and function of ecosystems. This project asks how the number of species present influences the transfer of nutrients and energy among organisms. Previous experiments suggest that mussels provide nitrogen to streams during summer low-flow seasons. Increased nitrogen availability can trigger increases in the abundance of algae and, subsequently, of grazing aquatic insects. Importantly, when more species of mussels are present this transfer of nitrogen is enhanced, suggesting that the diversity of mussel assemblages increases the quantity of nutrient subsidies. Effects of nitrogen subsidies may extend beyond the stream itself, as adult aquatic insects are an important food source for terrestrial predators in riparian forests. Experiments will be conducted using freshwater mussels to investigate how the diversity of freshwater mussel assemblages influences the rate at which the mussel community makes nutrients available to the stream ecosystem and to terrestrial predators. Field and laboratory experiments will be used to see if the emergence rates of adult aquatic insects and the abundance of riparian spiders increase when more mussel species are present. Stable nitrogen isotopes will be used to quantify nutrient subsidies and determine how mussel-derived nutrient subsidies move through stream and riparian food webs. This research will contribute to our understanding of the relationship between biodiversity and ecosystem function, which will ultimately help scientists predict the consequences of extinctions and climate change on ecosystem processes. It also will enhance our understanding of the ecological importance of freshwater mussels, a globally threatened fauna.