RAPID: Contrasting Ecological Gradients Before and After Dam Removal

19世纪，在五大湖地区建造了数千座小型磨坊水坝。大坝上下的生态群落变得截然不同。考虑到公共安全，现在需要拆除许多水坝，并开辟一条可以改变生态相互作用的迁徙走廊。这个项目的重点是最近在威斯康星州布里格斯维尔附近的大泉溪拆除大坝和水库。上游社区包含一个典型的冷水鱼类组合，主要是溪鳟，棘鱼，雕刻鱼和溪俱乐部。大坝下面的河段主要是典型的温水组合——大口黑鲈、蓝鳃鱼、黄鲈和白吸盘鱼。监测水温、鱼类群落结构和食物网结构的季节性变化将检验两个问题提出的备选结果：1。冷水是否会取代温水鱼类，并允许冷水组合向下游扩展？大坝的拆除是否会让上游的大型捕食者（鲈鱼）和竞争对手（吸盘鱼）入侵，从而减少和取代冷水鱼群落？在过去的十年里，威斯康星州计划拆除400多座小型水坝。公众对结果的兴趣始终很高。这项研究的结果将为类似的大坝拆除所导致的生态变化提供指导和预期。该项目将为一名研究生和四名本科小时工提供支持。它还将作为威斯康星大学麦迪逊分校鱼类生态学课程（48名学生）的示范点。

Thousands of small mill dams were constructed in the Great Lakes region during the 1800's. The ecological communities above and below these dams become quite different. Public safety concerns now require removal of many dams and open a migration corridor that can change ecological interactions. This project focuses on a recent dam and reservoir removal in Big Spring Creek near Briggsville, Wisconsin. The upstream community contains a typical cold water fish assemblage dominated by brook trout, sticklebacks, sculpins and creek chubs. The reach below the dam is dominated by a typical warm water assemblage--largemouth bass, bluegill, yellow perch and white suckers. Monitoring seasonal changes in water temperature, fish community structure and food web structure will test the alternative outcomes posed in two questions:1. Will the colder water displace the warm water fishes and allow the cold water assemblage to expand downstream?2. Will the dam removal allow upstream invasion by large predators (bass) and competitors (suckers) that can reduce and displace the coldwater fish community?More that 400 small dams are scheduled for removal in Wisconsin during the current decade. Public interest in outcomes is always high. Results of this study will offer guidance and expectation of the ecological changes that result from similar dam removals. This project will provide support to a graduate student plus four undergraduate hourly employees. It will also serve as a demonstration site for the Ecology of Fishes class (48 students) at UW-Madison.