Summary
One of the main goals of dam decommissioning and removal is the recovery of aquatic and riparian ecosystems. But it is difficult to predict how an entire ecosystem will recover after dam removal, which can lead to unforeseen challenges when managing the recovering ecosystem. Ryan Bellmore, a scientist with the USDA Forest Service's Pacific Northwest Research Station and his colleagues synthesized data from many studies on dam recovery and ecological theory into models that identify the key physical and biological links underlying ecosystem response to dam removal. The models identified potential ecological transitions in three distinct areas: upstream of the reservoir, within the reservoir, and downstream of the dam. They determined that multiple pathways and feedback loops among physical and biological forces guide the recovery of ecosystems after dam removal. These forces can result in dynamic, non-linear recovery trajectories and ecosystems that arefundamentally different from pre-dam ecosystems. These models can be used by managers to trace the important causal pathways that determine ecosystem recovery after dam removal.
