Ecosystem experiments are arguably the most direct method available for predicting a population or environmental response to management and have contributed greatly to our understanding of ecological processes within watersheds. Often the experiments involve a large disturbance to be applied to a watershed (e.g. timber harvest, acid rain), and then evaluate how the system responds to the loss of an ecological service. Stream restoration has been used extensively throughout the world to improve fish population performance; however, the reach level scale at which they are often applied provides too small of an effect size to the target population, or more commonly are never monitored. Stream restoration could be implemented at a large enough scale to potentially produce an increase in population production, while maximizing learning if conducted in an ecosystem experimental fashion. These concepts have led to the development of Intensively Monitored Watershed (IMW) studies to evaluate anadromous salmonid population level responses to large-scale restoration efforts the Pacific Northwest United States. The goal is to develop a network of IMWs to assess limiting factors, develop actions aimed at restoring ecosystem processes, and evaluate the effectiveness of different actions or a suite of actions on fish populations across a range of watershed types. These large-scale experiments include detailed monitoring to not only detect changes but to identify the mechanisms of response to help generalize results. We summarize the monitoring, implementation plan, and experimental designs of two of these studies we are currently conducting. In these examples, pre-restoration information of salmonid abundance, growth, and survival across multiple life-stages has been collected using seining, electroshocking, weirs and PIT tag technologies. In addition, physical habitat has been assessed using aerial photography, aerial and ground-based LiDAR, and GPS and total station survey techniques. Restoration actions will be implemented in a staircase fashion in treatment reaches and watersheds, while control analogs remain unmanipulated. The monitoring techniques and experimental design provide a powerful means to compare the baseline condition to expected changes in physical habitat quality and quantity and ultimately in salmonid population processes.
Available at: http://works.bepress.com/joseph_wheaton/99/