NON-INDIGENOUS SPECIES AND MARINE PROTECTED AREAS

Abstract

The introduction of non-indigenous species (NIS) has been pointed out as a major threat to biodiversity. NIS may in time become invasive (i.e. invasive alien species “IAS”) and may cause biodiversity loss and ecosystem service changes. In the Mediterranean Sea, due to multiple human-borne stressors, the number of recorded NIS has currently reached a number around 1000 NIS. Sicily and its surrounding islands, also including a high number of Marine Protected Area (MPAs), as a consequence of their geographic position and the intense maritime traffic volumes, including fisheries and recreational fleets that foster the introduction of marine alien species, is a region particularly vulnerable and prone to NIS invasions. Since frontiers do not exist in the sea, biological invasions may severely affect MPAs, whose major aim is biodiversity conservation, because they are also located in proximity to ports and marinas or are frequently used by small recreational or fishing boats as well as tourists. Assessing effects that IAS have on MPAs is crucial for planning suitable management activities which also require sound knowledge of the pathways of introduction, the impact and current distribution of IAS. Therefore, the distribution, pathways and spread dynamics of invasive taxa recorded till now in Sicilian MPAs, based on relevant publications, grey literature, unpublished data and in situ observations, is presented here and discussed. Altogether, 18 alien and 3 cryptogenic species have been recorded from Sicilian MPAs. Unexpectedly, even though in the southern coast of Sicily the maritime traffic is more intense, the MPAs located in the north-western coast of Sicily (Egadi Islands MPA with 19 species and Ustica Island with 7 species) are the most affected by this phenomenon. The creation of permanent observatories and alarm systems might be an effective tool in the management of present and future introductions of NIS in MPAs.