Re‐establishing and assessing ecological integrity in riverine landscapes

Abstract

1. River–floodplain systems are among the most diverse and complex ecosystems. The lack of detailed information about functional relationships and processes at the landscape and catchment scale currently hampers assessment of their ecological status. 2. Intensive use and alteration of riverine landscapes by humans have led to severe degradation of river–floodplain systems, especially in highly industrialised countries. Recent water‐related regulations and legislation focussing on high standards of ecological integrity back efforts to restore or rehabilitate these systems. 3. Most restoration projects in the past have suffered from a range of deficits, which pertain to project design, the planning process, the integration of associated disciplines, scaling issues and monitoring. 4. The so‐called `Leitbild' (i.e. a target vision) assumes a key role in river restoration and the assessment of ecological integrity in general. The development of such a Leitbild requires a multistep approach. Including explicitly the first step that defines the natural, type‐specific reference condition (i.e. a visionary as opposed to an operational Leitbild), has great practical advantages for restoration efforts, primarily because it provides an objective benchmark, as is required by the European Water Framework Directive and other legal documents. 5. Clearly defined assessment criteria are crucial for evaluating ecological integrity, especially in the pre‐ and postrestoration monitoring phases. Criteria that reflect processes and functions should play a primary role in future assessments, so as to preserve and restore functional integrity as a fundamental component of ecological integrity. 6. Case studies on the Kissimmee River (U.S.A.), the Rhine River (Netherlands and Germany), and the Drau River (Austria) are used to illustrate the fundamental principles underlying successful restoration projects of river–floodplain systems.