“Pomis” is a project born in June and July 2018, between the Anton Dorhn Zoological Station of Naples – Dept. of Ecology, Blue Marine Foundation and Aeolian Islands Preservation Fund, for promoting the long-term monitoring and evolution of the Posidonia oceanicaseagrass meadows in Salina Island.
Meadows of the seagrass Posidoniaare distributed along the coasts of the Mediterranean Sea and they represent an indicator of coastal environments’ good state of health, providing important ecosystem services(e.g. production of oxygen, carbon sequestration, protection from coastal erosion, protection for many marine species).
Recent calculations estimated that every hectare of P. oceanica can produce ecosystem services over 1.5 million euros per year: this means that if humans would substitute the benefits coming from P. oceanica meadows, they should spend the equal amount of money cited above.
The Pomis project aims to gather data useful to evaluate the long-term evolution of seagrass meadows around Salina, in support of the management and conservation of this marine habitat in the Aeolian archipelago. This study has an annual basis, taking into account also the presence of invasive species along the coastal areas and their potential effects to native habitats, like Posidonia is.
The SZN scientific team have collected information and observations with a look into the future, with possible involvement of volunteer divers to continue underwater monitoring and improving the level of awareness to this vulnerable habitat. The SZN team selected 11 sites around Salina, including diverse typologies of sea bottoms, different depths and different expositions of the coastline. Sites have also been selected to evaluate potential effects derived from villages (Santa Marina Salina, Malfa, Rinella) and from coastal activities and infrastructures (e.g. harbours and recreational boating). Sites far from direct human influence can be used as control points and as indicators of global climate changes.
The results of the present study showed a marked difference between meadows located along the eastern coast in respect to the western one: the first shows a clear regression of seagrass meadows, mainly because of boat anchoring, as wide and numerous scars are evident in the sandy seabed on this side of the island. Such wounds have active erosions borders inside seagrass meadows, which can enlarge during time because of the mobilisation of sediments and deep currents. The boat impact is also demonstrated by the presence of big fragments of seagrasses, detached but still vital, from the seabed (see fig. 1). Sandy areas that host P. oceanica, also show the presence of invasive species, like the green algae Caulerpa cylindraceavar. racemosa and the seagrass Halophila stipulacea, which seems to find favourable conditions to colonize extended areas.
The Pomis project has been carried out by Dr. Gabriele Procaccini, Director of the Dept. of Integrated Ecology of the SZN, and Dr. Lazaro Marin Guirao (see fig.2), researcher in the same institute, both experts and internationally known for their works on ecology and evolution of seagrassecosystems.
<<Salina has large and thriving seagrass meadows, whose extensions seem to be the widest of the archipelago>> said Dr. Procaccini. <<The Zoological Station is committed by many years in the entire Mediterranean basin for studying this important habitat, whose density is linked to the correct coastal management, and whose state of health can be estimated only towards long-term studies. We cannot afford loosing and damaging such vital marine resource, whose survival depends on the correct management of coastal marine environments, with important consequences on human activities>.
The long-term monitoring will allow discriminating human-induced disturbances from cyclical natural changes, or even climate changes, as well as to monitor the presence and diffusion of invasive species. Such information is crucial for the correct preservation of these precious coastal habitats and for adequate management plans in the Aeolian waters.
