Assessing the effects of habitat patches ensuring propagule supply and different costs inclusion in marine spatial planning through multivariate analyses

Marine Protected Areas are considered key tools for conservation of coastal ecosystems. However, manyreserves are characterized by several problems mainly related to inadequate zonings that often do notprotect high biodiversity and propagule supply areas precluding, at the same time, economic importantzones for local interests. The Gulf of Naples is here employed as a study area to assess the effects ofinclusion of different conservation features and costs in reserve design process. In particular eight scenariosare developed using graph theory to identify propagule source patches and fishing and exploitationactivities as costs-in-use for local population. Scenarios elaborated by MARXAN, softwarecommonly used for marine conservation planning, are compared using multivariate analyses (MDS,PERMANOVA and PERMDISP) in order to assess input data having greatest effects on protected areasselection.MARXAN is heuristic software able to give a number of different correct results, all of them near to thebest solution. Its outputs show that the most important areas to be protected, in order to ensure longtermhabitat life and adequate propagule supply, are mainly located around the Gulf islands. In additionthrough statistical analyses it allowed us to prove that different choices on conservation featureslead to statistically different scenarios. The presence of propagule supply patches forces MARXAN toselect almost the same areas to protect decreasingly different MARXAN results and, thus, choices forreserves area selection.The multivariate analyses applied here to marine spatial planning proved to be very helpful allowing toidentify i) how different scenario input data affect MARXAN and ii) what features have to be taken intoaccount in study areas characterized by peculiar biological and economic interests.