A study has been made of the public's understanding and evaluation of posidonia sea grass, in particular the remains of posidonia that are deposited on beaches. Ana Ruiz, a doctor at Majorca's Mediterranean Institute of Advanced Studies, led the study, which was within the framework of a European project regarding the natural benefits of the so-called "ecosystem service".
Ruiz says that posidonia is fundamental for the conservation of various species, for maintaining the fine and white sand of the beaches, for protection against winter storms and for mitigating the effect of climate change. Posidonia therefore has an economic benefit - one for tourism, as it ensures the transparency of sea water and the quality of beaches.
She explains that it is possible to arrive at the valuation of economic benefits from nature and to therefore design policies that support these benefits. It is also necessary, she observes, to shape the public's perceptions, as there is a lack of understanding of the role that posidonia plays.
The study was divided into two parts. The first gave respondents no information about posidonia. The second provided information before taking responses. In the first part, 45% believed that the benefits of posidonia outweighed drawbacks; 30% felt there were greater drawbacks than benefits; 25% didn't know. Once supplied with information, the 45% shot up to 86%.
Another finding was that only 27% felt that posidonia detritus should be left on beaches over the winter. Once supplied with information, this rose to 50%. The remains of posidonia can be and generally are removed from beaches in time for the summer season. But leaving the remains over the winter months helps to protect the sand and to minimise erosion.
The action of the wind and waves determines the degree to which posidonia accumulates on beaches. In some instances, there are vast banks of remains that may require being removed. However, the same natural action can result in new sand covering up the remains. It is quite possible to walk along a beach where this has happened and experience a sensation of walking on what feels like sponge. If the accumulations are removed, Ruiz stresses, this should be done in such a way that the loss of sand is minimised.