Evaluating responses of freshwater ecosystems to experimental water management

The availability of fresh water to meet the demands of a growing human population and simultaneously ensure ecosystem integrity has emerged as one of the world’s primary resource issues (Postel and Richter, 2003; Alcamo et al. 2008). Water management for people and ecosystems remains an open scientific question (Acreman and Dunbar 2004, Arthington et al.2006) that is being answered with experimental approaches to releasing water from dams and other control structures for ecological benefits in rivers, floodplains, and estuaries. Flow experiments present an unrivaled opportunity to evaluate large-scale experimental approaches in ecosystem management because of shared scientific approaches. We propose bringing scientists together in a working group to integrate the site-specific results of large-scale flow experiments and synthesize general lessons to guide future large-scale experiments and ecosystem management in other places. We will: 1) test the limits of extrapolation across scales and integration across sites in drawing general conclusions about ecological responses to flow experiments; 2) identify criteria for attributing immediate, direct responses and long-term changes in the status of populations, communities, and ecosystems to experimental manipulation; and 3) develop innovative approaches that facilitate the ransfer of knowledge from large-scale experiments to broader applications.