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.

Response and recovery dynamics of seagrasses Thalassia testudinum and Syringodium filiforme and macroalgae in experimental motor vessel disturbances

“…Once an anthropogenic disturbance occurs, few techniques for intervention exist beyond stopping the impact and waiting for natural recolonization (Hawkins et al 1999). When prevention fails, cost-effective, easily implemented techniques must be found for restoration of marine ecosystems and the services they provide.…”

Experimental ecology and coastal conservation: conflicts on rocky shores

“…Some of the best examples of combining field experimentation with conservation and resource management-driven research come from Chile (Castilla and Duran, 1985;Castilla and Bustamente, 1989;Duran and Castilla, 1989). Here field experiments helped to explain the changes taking place when various conservation measures were instigated (see figure 2 in Hawkins et al, 1999). Harvesting of limpets led to a switch to algal-dominated shores, which in turn were exploited (see Paine, 1994 for review).…”

Exploitation promotes earlier sex change in a protandrous patellid limpet, Patella aspera Röding, 1798

“…In a time when over 28% of all the world's fish stocks are either overexploited or depleted and when another 61% is fully exploited and in imminent danger of overexploitation (FAO 2014), it is paramount that the impact of fishing on the ecology of marine populations, communities, and ecosystems is better understood. Arguably, the largest anthropogenic impact in the Macaronesia intertidal is the overexploitation of patellid limpets (Hawkins, Allen, & Bray, 1999;Hawkins, Côrte-Real, Pannacciulli, Weber, & Bishop, 2000); similar exploitation of limpets occurs in Hawaiian islands (e.g. McCoy, 2007).…”

“…However, introduction of snorkeling and scuba diving in the early 1980s together with the increase of the commercial value of limpets (e.g. tourism and exports to the USA) led to a prompt increase in limpet exploitation (Hawkins, Allen & Bray 1999;Ferraz, Menezes, & Santos, 2001).…”