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Restoration of seagrass meadows

ecological engineeringESTECHholder unitPosidonia oceanicarestoration ecologyseagrass planting

Introduction

The invention describes a technique for the reforestation of damaged seabeds, specifically for the restoration of seagrass meadows impacted by human activities. The developed technical solution is based on the use of seedlings obtained from seeds – with zero impact on donor meadows  that allows to maximize the anchoring rate and the adhesion strength of seedlings grown on ad-hoc designed holder units to be transferred to the sea, at the sites chosen for re-planting.

Technical features

In the interventions of repopulation of Posidonia oceanica meadows, when using sprouts produced from seed, it is crucial to increase the probability and strength of anchoring to the substrate of the seedlings during the first weeks of life, to increase their survival until adulthood. For this purpose, a natural stone holder unit, compatible with the ecosystem characteristics of the planting sites was designed. The structure has the shape of a parallelepiped, into whose walls cavities are dug (scale cm) for housing the plant. Optionally, it is possible to tunnel secondary cavities to allow the development of the root system and its anchoring to the unit (scale mm). The cavities are characterized by an inclination “α” between 45 ° and 135 ° with respect to the line parallel to the surface on which the holder unit lies.

The method involves 3 main phases: i) positioning of the seed / seedling in the cavity of the holder unit (in the narrowest point); ii) growth of the seedling in aquaria; iii) transfer of the holder-seedling unit to the planting site.

The dive time required to place the holder units at the sea bottom is short and this reduces costs.

Possible Applications

  • Restoration ecology of coastal areas;
  • Restoration of damaged Posidonia oceanica meadows;
  • Restoration of other seagrass meadows, with similar characteristics of the root system in the juvenile stages, such as Thalassia, Phyllospadix, Enhalus, Halophila etc.

Advantages

  • Maintenance of genetic variability;
  • Greater adaptive capacity and resistance to stress and environmental variability;
  • Reduced environmental impact;
  • Modularity of the holder units;
  • Reduced aesthetic impact of the holder units;
  • Quick installation (no plant anchoring devices needed);
  • Low planting costs.