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

太平洋三文鱼是整个北太平洋沿岸其原生范围内溪流的一种重要营养补贴，最近的引进已将其影响扩大到其他区域，如五大湖。在一年一度的鲑鱼迁徙和产卵期间，鲑鱼衍生的营养物质(SDN)进入溪流，影响生物和生态系统功能。例如，在鲑鱼捕捞期间，溪流藻类和大型无脊椎动物数量增加，腐烂的鲑鱼身体提供了溪流中较长期的SDN储存。以往的研究表明，SDN在河流中的影响并不总是一致的，而是取决于河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河流上进行测量，以补充来自阿拉斯加东南部的类似数据集。这两个区域具有不同的河流结构和气候，比较将有助于了解决定生态系统对SDN补贴反应的基本控制措施。作为人类活动的结果，一些溪流减少了鲑鱼流，特别是来自大坝或过度捕捞的鲑鱼流，而另一些溪流由于孵化场的放养而获得了越来越多的鲑鱼流。因此，彻底了解溪流结构和气候条件如何决定SDN补贴的影响，对于有效管理当前本地和引进区域的鲑鱼捕捞是必要的。生物群间比较办法将使管理人员能够评估和预测SDN补贴对一系列河流生态系统的反应，提高溪流恢复和鲑鱼养护项目的潜在成功。结果将分发给适当的联邦机构和非政府组织，如自然保护协会。

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.