Over the past two decades, dam removal has become an increasingly important aspect of aquatic ecology. The motivation for the removal broadly ranges from purely ecological terms, restoring stream or river connectivity, through safety concerns, as a result of crumbling infrastructure, to economic concerns, increasing local tourism, recreational fishing, or canoeing and kayaking. As a result of this work, ecological studies have arisen that monitor the changes to the riverine ecosystem as a result of removal. Unfortunately, given the uncertain nature of funding and public concerns over dam removal, long term longitudinal studies that cover multiple trophic levels are difficult to find. Fortunately, the University of Michigan Biological Station has been involved in the ecological monitoring of a headwater river (the Maple River) in the northern part of the lower peninsula of Michigan. Through the tremendous intellectual resources available at the station, the physical, chemical, and some biological aspects of this river’s ecology has been measured for eight years prior to the dam removal, during the dam removal, and for two years post-dam removal. The results presented here show that the ecology of the river recovered within this two-year period, but had a different ecological state driven. This new state is primarily driven increases in flow, ammonia, silica, and increases in the populations of the macroinvertebrate feeding guilds of filterers and scrapers. In addition, decreases in stream pH and water temperature contributed to this new state. The results and observations presented here may provide some guidance for other long term monitoring studies.
