Sustainable management accounting model of recreational boating anchoring in Marine Protected Areas

Recreational boating is a worldwide leisure activity playing an important role in the context of coastal economy but also causing significant damage on the environment, above all in the absence of adequate management measures. Among the damages, the anchoring on sensitive habitats, with the consequent loss of structural complexity, density, cover and specific richness, is widely reckoned and its consequences are long lasting and evident. The aim of this work is to provide an environmentally focused accounting model (SAILOR) to evaluate the net impact of anchoring on sensitive habitats. In this research SAILOR model has been tested on Posidonia oceanica, one among the most vulnerable in Mediterranean. An innovative approach is proposed in order to develop sustainable management strategies for recreational boating in MPAs in the framework of a very strong sustainability. In particular, it starts from the assessment of the natural capital of P. oceanica with the purpose to keep it at least intact. The model procedure is defined considering factors that affect the anchoring damage: type of habitats, seabed compactness, number and size of boats, type of anchor. Considering these data, the net impact is evaluated as surfaces and natural capital (emergy analysis) balancing the anchoring damage and the regenerative capacity. Being recreational boating spatially distributed, the model outputs the results both as values and sustainability maps at different spatial level (overall MPA, protection zones and even smaller), according to management needs. In this way, MPA managers can quickly and easily understand the sustainability status of the MPA, identify suffering areas in order to establish ad hoc actions and develop alternative scenarios. The model, based on a generalized and iterable procedure applicable to any area, is tested on Portofino MPA (Italy): the annual average net impact is 279 m2 (equivalent to 1.51E+11 sej and 1′577 em€ of natural capital), eroding the 0.089% of P. oceanica in the anchorable areas.