A macroecological projection for the future of the Mediterranean marine space management in a Ecosystemic Community Strategy context

Over the past few decades we have witnessed rapid ecological changes that have occurred in the world's oceans and that have mainly affected the resilience and resistance of ecosystems and the vulnerability of communities living in these ecosystems. The real challenge will be to identify and select techniques and approaches based on a macroscopic vision in order to reduce the effect of global warming, the impact of human activities and their consequences on the marine environment. These interactions can generate effects that influence the functioning of oceanic and coastal ecosystems and, consequently, goods and services, such as fishing and aquaculture production. In fact, these activities must be managed and administered responsibly to avoid competition for space which cause numerous conflicts and increase the human impact on ecosystems. In Europe, the Marine Strategy Framework Directive (MSFD) was established in 2008. It represents an important legal instrument for Member States to protect and preserve the marine environment, prevent deterioration and, where possible, restore marine ecosystems in areas where they have been damaged. The directive obliges Member States to determine the characteristics of "Good Enviromental Status" (GES) defined by descriptors, criteria and indicators. This assessment should be carried out in a complementary manner by all Member States, however, in most countries the precise means of implementation of the MSFD are not yet clear. To meet the necessity to increase MSFD implementation, we need to gather organic information in order to better address the decision making process. Here, the chapter 1 proposes an "analysis of the evidence", by which I defined a complete picture of the EU Marine Strategy showing important gaps of the type of approaches and the means to be used for a correct analysis of the state of the environment. Based on this analysis, I selected two MSFD descriptors (D. 2 ―Non-indigenous species‖ and D. 3 ‖Commercial species‖) which were the main subject of the following chapters. Chapter 2 aims to study the effect that climate change, specifically the increase of temperature, had on the presence of non-indigenous species (NIS) in the entire Mediterranean basin. In this basin, complex and fundamental alterations which have consequences on the structure and functioning of the sea and the consequent supply of goods and services, are still underway. Furthermore, threats due to temperature increase may also alter the spread of shellfish aquaculture, hitherto recognized as the best candidate for mitigating the effects of overfishing. This topic was developed in chapter 3. In fact, by using a study carried out along the Italian peninsula, we highlighted the effects of the increase in temperature on the model species, Mytilus galloprovincialis. This was done by measuring the characteristics of the thickness and the condition index. This information will be invaluable for the examination of any possible deviation from natural models due to the increase in temperature and could represent an important context in which to face the future understanding of the feasibility and reliability of the economic activities of shellfish aquaculture. Lastly, in chapter 4, the main objective was to understand and predict the possible impacts of one among the most important human economic activities: aquaculture in coastal habitats. The main question was about the possibility of combining the experimental procedures with the mechanistic bioenergetic models based on functional traits, in order to effectively predict the life history traits of the cultivated species. The need to adopt an ecosystem approach to site selection and the need to define the allocation of areas dedicated to aquaculture activities in the wider context of marine spatial planning, requires the use of modeling tools to support decision-making in aquaculture. Therefore, the main objective of my thesis was that to determine cumulative pressures caused both by the increase in temperature and by human activities, so as to provide useful information for the destination and sustainability of use of Marine Spatial Planning (MSP), in the evaluation of the GES, using an ecosystem-like approach.