Restoration of temperate marine and coastal ecosystems: nudging nature

Abstract

1. The main impacts on marine ecosystems are summarised and the potential for their restoration is discussed in relation to their key features. Rocky shores, seagrass beds and disused docks are focused on. 2. The term restoration is used to describe intervention in the recovery process of a marine ecosystem, with a view to enhancing the process, but not necessarily forcing the system to recover to its original condition. 3. Rocky shore systems are subject to shellfish and seaweed exploitation, point source pollution, diffuse impacts such as tributyl tin and acute impacts such as oil spills. The consideration of whether to employ restoration or allow natural recovery is discussed in relation to these systems. 4. Seagrass systems have suffered serious declines in many parts of the world due to the direct and indirect effects of human impacts. In the North Atlantic a wasting disease first noted in the 1930s caused a serious decline in the subtidal seagrass Zostera marina. The link between this disease and the marine slime mould Labrynthula zosterae is now well established. Human impacts on seagrass systems allow the disease to gain a foothold. Attempts at restoring seagrass beds have met with some success, but it is suggested that the action of conservation of remaining beds and better management of human activities may be the best approach. 5. Disused docks occur in many parts of Britain and Europe. Active management of the physical environment by mixing and biomanipulation by filter feeding organisms have led to improvements in water quality and ecosystem function. Thus healthy marine ecosystems have been restored to inner city areas, although these artificial marine lakes have few natural equivalents and are different from the original ecosystem at the site. 6. When compared to freshwater ecosystems, the scope for coastal and marine restoration is limited although the capacity for recovery is greater.