Sustainable management of Posidonia beach systems

Although there is clear scientific evidence and consensus of the ecological role and relevance of Posidonia oceanica and dunes in coastal ecosystems, the lack of a consistent legal framework and existing social perceptions are preventing their sustainable management. Moreover, many municipalities and local stakeholders are demanding sustainable solutions for the management of banquettes. New management approaches are needed, which have to focus on the conservation of the integrated coastal ecosystem, considering how management practices affect the health of the entire ecosystem and the resilience of the coastline.

These Guidelines include a Governance Strategy and Action Plan to address these challenges, by providing:

• An update to the existing perceptions by different stakeholders and the existing policy framework for the management of Posidonia banquettes
• A Guide on existing methods and tools for the sustainable use of seagrass banquettes and associated dune systems; and
• An action framework for the Mediterranean and a locally oriented toolkit with recommendations for the sound management of Posidonia and dune systems.

Technological infrastructure

No technological requirements are specified in the Guidelines.

Training

Personnel should receive training each year on beach cleaning policies, characteristics of the Posidonia littoral zone and how to recognise and mitigate impacts.

Investment

An approximate estimate of the costs associated with each removal option (high-low) is included in the Guidelines.

Concept

The Guidelines include a framework of reference for decision making, particularly for large Posidonia banquettes, that considers beach functions (protection and recreation) and the integration of the ecosystem.

The strategic objective is to achieve the sustainable management of Posidonia beaches, while maintaining the environmental value in some areas (e.g. Protected Areas), and the recreational value in others.

The tactical level reflects beach typologies in order to take into consideration the (local) social expectations and present perceptions while also maintaining the integrity, ecological function and environmental values of the Posidonia coastline.

At the local level, before any activities are undertaken, benchmarking will help to define a base line: the existing dynamics of the coastal zone and the seagrass deposition and formation of banquettes on the beach/es.

At an operational level, measures for managing Posidonia banquettes are identified and implemented:

1. to maintain the ecosystem (minimise interference with the process of sand and nutrient deposition from banquettes);
2. to improve the situation if erosion is present or restoration activities are needed and
3. to limit the impact on the recreational value of surrounding areas and to ensure that existing and planned recreational uses are balanced with maintaining ecosystem integrity.

Feasibility assessments for each option should be carried out for the evaluation. Finally, the monitoring and evaluation of interventions consists of selecting a series of indicators to monitor the status of the coastal environment, including the beaches and associated dunes. Recommendations are included on beach cleaning (avoiding the use of mechanical methods whenever possible), on disposal options, access of transportation vehicles to the beach, use of the banquettes, and on the issue of beach certification schemes.

Recommended implementation frequency

The management framework proposed by these Guidelines should be periodically reviewed to account for any variation in the ecological and socio-economic systems involved in the assessment and the outcomes of Posidonia banquette management.

Each approach to remove Posidonia banquettes may encounter specific limitations, which should be carefully considered in advance. Some of these have been identified in the Guidelines for the following techniques: disposal offshore, relocation to a point higher in the beach, disposal off-site from the beach, use of heavy machinery on sandy beaches, and the use of machinery on dunes.

As an indicative example, the disposal offshore of the banquettes removed from beaches may threaten the persistence and productivity of seagrass and other marine habitats and reduce water quality. As another example, the relocation to a higher point on the beach may reduce the recycling of nutrients and sand back to the sea, with higher maintenance costs.

Quantitative results

The effective implementation of these Guidelines will considerably improve the management of Posidonia banquettes in Mediterranean beaches and dunes.

Transfer potential

These Guidelines may be applied by any Mediterranean MPA manager, as they include general recommendations that are applicable to the whole Mediterranean basin. The Guidelines also include a transnational integrated strategy and action plan, which aims to orient regional and national policies and fund bodies and research institutions towards creating suitable conditions for implementing sustainable beach and coastal management practices across Mediterranean areas.

• Posidonia oceanica forms large meadows that are widely distributed along the Mediterranean coastline between the surface and 44 m depth in the clearest waters. Recent estimates suggest that its overall known distribution is about 12,247 km2 , with more than 50% within EU territory (Telesca et al., 2015).

• It has been estimated that on some Mediterranean beaches, up to 7,000 tonnes of seagrass deposits can be present during the winter