The desire to “rewild” countryside with native species extirpated by humans and the restoration of ecological function are two primary reasons behind species reintroductions. Efforts to return a species to their native range is further aided by legislation, such as the EU Habitats Directive 92/43/EEC, which provides a framework for assessing the feasibility and desirability of a reintroduction. Research at ICER has assessed the feasibility and impact of species reintroductions within a freshwater context.