Estuarine, coastal and marine ecosystem restoration: Confusing management and science – A revision of concepts

This review presents recent concepts, understanding and experience of the restoration, recovery and human-mediated modification of estuarine, coastal and marine ecosystems. It shows that these can be divided into four categories: natural recovery from a natural or anthropogenic change (whether adverse or otherwise); anthropogenic interventions in response to a degraded or anthropogenically changed environment; anthropogenic responses to a single stressor; and habitat enhancement or creation. A conceptual framework for restoration and recovery of marine marginal and semi-enclosed areas is presented after exploring and refining the plethora of terms used in restoration science and management. Examples of management action are given including managed realignment and the restoration of docks, biogenic reefs, saltmarsh, seagrass, beaches and upper estuarine water quality. We emphasise that although recovery techniques are worthwhile if they can be carried out, they rarely (if ever) fully replace lost habitat. Moreover, while they may have some success in marginal or semi-enclosed areas such as coastal bays, estuaries and fringing habitats, they are less relevant to open coastal and marine habitats. Therefore the best option available in the latter can only be to remove the stressor, as the cause of any change, to prevent other stressors from operating and to allow the conditions suitable for natural recovery. This review emphasises that whereas some ecological concepts related to restoration are well understood, for example, the nature of ecosystem structure and functioning, others such as carrying capacity, resilience and ecosystem goods and services are still poorly quantified for the marine and estuarine environments. The linking between these ecological concepts and the management framework is also relatively recent but is required to give a holistic approach to understanding, managing and manipulating these environments.