The Conceptual Basis for Ecological Responses to Dam Removal

Effects of Stronach Dam removal on fluvial geomorphology in the Pine River, Michigan, United States

“…Much of the existing literature focuses on the administrative, legal, and socioeconomic aspects of executing dam removals (Born et al, 1998; River Alliance of Wisconsin and Trout Unlimited, 2000;Smith et al, 2000, Graber et al, 2001Trout Unlimited, 2001;Bowman, 2002;Johnson and Graber, 2002). Using analogies from various disciplines, some researchers have developed general hypotheses of river ecosystem responses to dam removals Gregory et al, 2002;Pizzuto, 2002;Shafroth et al, 2002;Whitelaw and MacMullan, 2002), while others have hypothesized the outcomes of specific proposed dam removals (Shuman, 1995;Freeman et al, 2002;The Heinz Center, 2002). Despite an emerging conceptual basis for the effects of dam removals, this field continues to lack the empirical information that is needed to verify these hypotheses, calibrate preexisting models for use with dam removal, and generate novel insights into the effects of dam removal (Bushaw-Newton et al, 2002;Doyle et al, 2002;Graf, 2003;Hart et al, 2003).…”

Conflicts Associated with Dam Removal in Sweden

“…For example, by fragmenting channels and modifying flows, they affect the productivity of wetlands, floodplains, and deltas; disrupt the migration and dispersal of riparian and aquatic organisms as well as sediment dynamics; and cause freshwater species numbers to decline Poff 2002, WWF 2004). Many dams with large reservoirs, especially those that have hypolimnetic release of water, also modify the http://www.ecologyandsociety.org/vol14/iss2/art4/ temperature regime of downstream reaches and lead to shifts in biota (e.g., Gregory et al 2002). In general, impounded rivers are considered to favor the invasion of non-native species, thus exerting further pressures on the biota (Stanford et al 1996, Johnson et al 2008.…”

Introduction to the special issue: Understanding and linking the biophysical, socioeconomic and geopolitical effects of dams

“…Aging structures, which can pose a risk to public safety, are increasingly removed under new policies and funding sources to support removal projects (Heinz Center, 2002). Dam removal is also emerging as a promising option for restoring continuums and reconnecting habitats for migratory fish species, including anadromous salmon, that are federally listed as threatened or endangered in the United States (Gregory et al, 2002). However, there is a great deal of uncertainty about the consequences of dam removal (Aspen Institute, 2002;Hart et al, 2002), particularly the unknowns related to the extent, magnitude, and timing of physical and ecological outcomes (Heinz Center, 2002;Hart et al, 2002).…”