DISSERTATION RESEARCH: Ecosystem response to nutrient subsidies from annual salmon migrations in streams- an inter-biome comparison

太平洋鲑鱼是北方环太平洋地区原产地溪流中重要的营养补充，最近的引进已经将其影响扩大到其他地区，如五大湖。在每年的鲑鱼洄游和产卵期间，鲑鱼衍生的营养物质（SDN）进入河流并影响生物体和生态系统功能。例如，溪流藻类和大型无脊椎动物在鲑鱼洄游期间增加，腐烂的鲑鱼尸体在溪流中提供了长期的SDN储存。以往的研究表明，SDN在溪流中的作用并不总是一致的，而是依赖于溪流结构和区域气候模式。在这项研究中，一套生态系统规模的指标将在五大湖地区的溪流进行测量，以补充阿拉斯加东南部的类似数据集。这两个地区有不同的河流结构和气候，比较将提供一个基本的控制，确定生态系统响应SDN补贴的理解。由于人类活动，一些溪流减少了鲑鱼的流量，特别是由于水坝或过度捕捞，而另一些溪流则由于孵化场放养而获得越来越大的流量。因此，深入了解流结构和气候条件如何决定SDN补贴的影响是必要的，以有效管理目前的鲑鱼运行在本地和引进的范围。比较生物群落间的方法将允许管理人员评估和预测SDN补贴对一系列河流生态系统的反应，提高河流恢复和鲑鱼保护项目的潜在成功。调查结果将分发给适当的联邦机构和非政府组织，如大自然保护协会。

Pacific salmon are an important nutrient subsidy in streams in their native range throughout the northern Pacific Rim, and recent introductions have expanded their influence to other regions such as the Great Lakes. During annual salmon migrations and spawning, salmon-derived nutrients (SDN) enter streams and influence both organisms and ecosystem function. For example, stream algae and macroinvertebrates increase during salmon runs and decaying salmon carcasses provide for longer-term SDN storage in streams. Previous research has shown that the effect of SDN in streams is not always consistent, but dependent on stream structure and regional climate patterns. In this study, a suite of ecosystem-scale metrics will be measured on streams in the Great Lakes region to complement a similar dataset from Southeast Alaska. These two regions have differing stream structure and climate, and the comparison will provide an understanding of the underlying controls that determine ecosystem response to SDN subsidies. As a result of human actions, some streams have diminished salmon runs, particularly from dams or over-fishing, while others receive increasingly larger runs as a result of hatchery stocking. Therefore, a thorough understanding of how stream structure and climatic conditions determine the influence of SDN subsidies is necessary for effective management of current salmon runs in both native and introduced ranges. The comparative inter-biome approach will allow managers to assess and predict the response of SDN subsidies on a range of stream ecosystems, enhancing the potential success of stream restoration and salmon conservation projects. Results will be disseminated to appropriate Federal agencies and non-governmental organizations such as The Nature Conservancy.