State of the knowledge on marine habitat restoration and literature review on the economic cost and benefits of marine and coastal ecosystem service restoration. Deliverable 1.3. MERCES Project.

Anthropogenic activities have had an accelerating impact on the marine world over the last 100years. Increasing industrialisation, increasing use of resources, plus a build-up of populations onthe coastline has put a high degree of pressure on the marine environment causing widespreadhabitat change, particularly coastal or near coastal, exacerbated by climate change. Thecontinuing loss of biodiversity linked to habitat degradation, may lead to the unprecedentederosion of natural capital. It has been widely recognised that a range of different restorationactions are essential to halt further habitat decline, and reverse the current trends of degradationand species loss. This has led to the recognition of the needs for conservation and protection inseveral key habitat types, and latterly, within the Convention on Biological Diversity and EUBiodiversity Strategy for 2020, for 15% restoration targets of degraded ecosystems.

The scope of the MERCES D1.3 Report is to review the state of the knowledge of habitatrestoration to support the work surrounding restoration-related activities in the MERCES project.In order to carry out the general objective, several reviews have been carried out, including: areview of unassisted restoration (spontaneous regeneration), a structured review/synthesis ofpeer-reviewed publications on active restoration, a state-of-the-art summary of the MERCES keyhabitats/species/ecosystems with respect to restoration, a review of recent European and iconicworld-wide projects concerning marine restoration, and a structured review of the costs andbenefits in marine restoration. In addition, several relevant issues concerning restoration areaddressed, including; artificial reefs, restoring key structural species, removal of threats, No NetLoss within a mitigation hierarchy, nature-based solutions, technologies and innovation, andrestoration feasibility.

There had been little consensus among scientists and practitioners as to what restoration is, withmany terms used interchangeably, including restoration, remediation, reparation, recuperation,reconstruction, rehabilitation, and even re-creation. The Society of Ecological Restoration (SER)defines ecological restoration as “the process of assisting the recovery of an ecosystem that hasbeen degraded, damaged, or destroyed”. A major dichotomy is also often described betweenunassisted restoration or spontaneous regeneration (also called passive restoration) and so-calledactive restoration involving direct human intervention. Recent approaches to deal with degradedecosystems call for the application of a family of restorative activities that can be carried outsimultaneously or sequentially. The first step to allow for natural recovery is the removal ofthreats. This can be perceived as preventing harmful activities through regulatory management (from controlling/banning specific activities to creating Marine Protected Areas), or removing/adding barriers in an intervention to protect an ecosystem from further harm.