The renaissance of ecosystem integrity in North American large rivers

Large rivers throughout the world historically provided the necessary resources for civilizations to establish and prosper. In modern times, large rivers provide essential ecosystem services needed for economic prosperity and quality of life (Austin 2013). Rivers are culturally significant and also serve as political borders (Postel & Richter 2003). Although rivers have provided the security needed for much of the world’s colonization by humans, humans have made their mark on large rivers throughmany reoccurring actions, such as damming or diverting water, clearing and developing the floodplain and riparian zones, reductions in water quality, species introductions, and exploitation of the river’s biotic and other natural resources (Karr et al. 1985; Foley et al. 2005). As a result of these perturbations, the world’s large rivers are often impaired from performing their historical ecosystem services and need restoration and remediation actions to improve ecosystem integrity and resilience (Loomis et al. 2000). Restoration of large river systems is occurring globally, aimed toward restoring the natural state and ecological function, biodiversity, recreation, flood management, landscape development and sustaining human habitability (Palmer et al. 2005; Arthington et al. 2010). Each large river is globally unique, due to the large volume, diversity of habitats and fauna and colorful history of each river. As a consequence, the restoration and management of large rivers are often distinctive, and require large scale and scope of management actions, partnerships and financial investment. Given the large and complex scope of large river restoration projects, communicating the details of individual restoration programs across the global scientific community can improve effectiveness of existing and future river restoration programs, through adaptive feedback and sharing collective ideas and resources (Kania & Kramer 2011). Large river ecosystems of North America possess a complex array of instream and riparian habitat features that support diverse wildlife communities. In addition, these ecosystems provide an array of human services including fisheries, transportation, industry, drinking water, power generation, and agriculture that have often resulted in perturbations to ecosystem integrity and function (Loomis et al. 2000). Riparian lands were desirable to humans who required water for transportation, industry, and fisheries. Over time, human uses degraded aquatic habitat in large rivers through development on land (e.g. urbanization, industrialization and associated pollutants) and channel modifications, such as dredging and diking. Habitat degradation included the loss of fish spawning grounds and wetland nursery areas, invasive species introductions, and disruption of fluvial connectivity (Karr et al. 1985). Many aquatic habitats were destroyed, made inaccessible, and were disconnected from natural function. Restoration plans for large river ecosystems most often focus on reconnecting main channels, backwaters and riparian floodplains (Palmer et al. 2005). Whereas many local and regional restoration efforts have showed successes, or potential successes, at small spatial scales (e.g. Beechie et al. 2015; Phelps et al. 2015; Piazza et al. 2015), ecosystem-wide (i.e. large-scale or basin-wide) restoration and management efforts are urgently needed and often involve inter-jurisdictional cooperation and collaboration featuring mutual objectives (Palmer et al. 2005; Kozak & Piazza 2015). The goal of this special section of Restoration Ecology on “The Renaissance of Ecosystem Integrity in North American Large Rivers” is to highlight the development, implementation and lessons learned from research, management, and monitoring programs designed to improve riparian and instream habitat and water quality in North America’s large rivers. Impetus for this special section was derived from a symposium dedicated to “The Renaissance of Ecosystem Integrity in North American Large Rivers” at the Fifth National Conference on EcosystemRestoration held near Chicago, Illinois, in August 2013. The proceedings of this symposium, and other invited papers, constitute this special section. The special section is presented in two parts. The first (this issue) will include six articles covering the importance of lateral connectivity and habitat complexity (Nack et al. 2015; Phelps et al. 2015), improved juvenile fish habitat and environmental conditions (Beechie et al.