Restoration of urban marine ecosystems through Nature-based Solutions

Cities need to protect, conserve and restore urban marine ecosystems to preserve well-being and progress sustainably.

On the 13th of June 2023, a technical meeting was held in Barcelona on urban marine ecosystems restoration. This meeting was organised in the framework of the UN Restoration and Ocean Decades and the controversial forthcoming EU Restoration Law. EUROPARC’s policy and project manager Teresa Pastor took part in the event.

The meeting was hosted by the Institut de Ciències del Mar (Sea Science Institute). In 2021, they launched the Ocean Cities initiative – an international network of 27 institutions to promote sustainable ocean cities in a context in which resilience of coastal cities to climate change is a critical challenge for the coming decades.

At present, there are three reference frameworks in Europe to restore sea ecosystems in cities.

• UN Ecosystem Restoration Decade 2021-2030.
• EU Green (&Blue &Brown) Infrastructure Strategy (objective 2 of 2010-2020 Biodiversity Strategy)
• EU Nature Restoration Law – a key piece of the European Green Deal, that sets legally binding targets to rehabilitate degraded habitats, and which is currently under vote in the EP.

The invited speakers gave insight into the topic from different perspectives.

Main highlights of the meeting

The main highlights were:

• We need to protect and restore biodiversity, because both our health and economy heavily depend on it.
• The first priority should be protection– we need to protect effectively what is left.
• The second priority should be restoration – soundly applying the principles of conservation biology.
• The third priority should be effective management – applying an ecosystem-based management approach.
• Restoring marine ecosystems should go beyond introducing artificial substrates (e.g. concrete blocks) to enhance biodiversity. The aim should be to recover the fully functioning ecosystem, i.e. the whole community that was there before urbanisation.
• However, there is a lack of reference ecosystems due to the extreme exploitation oceans have been submitted causing the shifting baseline syndrome (Pauly 1995).
• With restoration projects, ecosystems can be restored to a high degree, but hardly ever to their original state, as for this we are dealing with unknowns.
• Therefore, a new concept has emerged in conservation and restoration ecology: novel ecosystems, which are ecosystems that due to human influence differ from those that prevailed historically.
• The Society for Ecological Restoration distinguishes three phases in what would be a restoration continuum:

1. Reduction of impacts
2. Rehabilitation – improvement, but not full restoration of the original habitat
3. Ecological restoration

• Effective restoration should focus first on habitat-forming species that can act as ‘climate rescuers’ e.g. seagrasses, salt marshes, mangroves, kelp forests, coral reefs and shellfish reefs, which form natural coastal protection and thereby help to adapt to increased storminess, seal level rise and flood risks resulting from climate change.
• Secondly, the goal is to recover the whole community to obtain all the potential ecosystem services.

Restoration can be twofold:

1. passive: elimination of the factors of pressure (e.g. removal of ghost nets) and let nature come back
2. active: restoration of vanished species (e.g. fixing coral)

Use of Nature-based Solutions to restore urban marine ecosystems

There are different interpretations of what Nature-based Solutions (NbS) consists of. In order to harmonize the concept, the IUCN has prepared the NbS Global Standard. For further reading, also check out “Planning and delivering Nature-based Solutions in Mediterranean cities: First assessment of the IUCN NbS Global Standard in Mediterranean urban areas. Executive summary” here.