Invading the Mediterranean Sea: human-shaped biodiversity patterns

Human activities, such as shipping, aquaculture, and the opening of the Suez Canal, have caused the introduction of nearly 1,000 alien species in the Mediterranean Sea. We investigated how human activities, offering pathways for the introduction of alien species, may shape the biodiversity patterns in the Mediterranean. Richness of Red Sea species introduced through the Suez Canal (Lessepsian species) is very high along the eastern Mediterranean coastline, reaching a maximum of 129 species per 100 km2, and declines northwards and westwards. The distribution of species introduced by shipping is strikingly different with several hotspot areas all over the Mediterranean basin. Two main hotspots for aquaculture-introduced species are observed (Thau and Venice lagoons). Certain taxonomic groups were mostly introduced by specific pathways – fish through the Suez Canal, macrophytes by aquaculture, invertebrates through the Suez Canal and by shipping. Hence the local taxonomic identity of the introduced alien species was greatly dependent on the dominant maritime activities/interventions and the related pathways of introduction. Alien species composition differs among Mediterranean ecoregions; such differences are more intense for Lessepsian and aquaculture-introduced species. The biodiversity spatial pattern of native species differs to that of alien species: overall native species richness declines from the north-western to the south-eastern regions, while the opposite trend is observed for alien species. This opposite gradient of alien species richness reduces the pre-existing gradient of native species richness. In coastal waters, native and alien species richness are negatively correlated. The Mediterranean Sea biodiversity is changing and further research is needed to better understand how the human-shaped new biodiversity patterns will affect the Mediterranean food webs, ecosystem functioning, and the provision of ecosystem services.

KATSANEVAKIS Stylianos Marios;  COLL Marta;  PIRODDI Chiara;  STEENBEEK Jeroen;  BEN RAIS LASRAM Frida;  ZENETOS Argyro;  CARDOSO Ana; 

2014-11-26

Frontiers Media S.A.

JRC90268

2296-7745,   

http://journal.frontiersin.org/Journal/10.3389/fmars.2014.00032/abstract,    https://publications.jrc.ec.europa.eu/repository/handle/JRC90268,   

10.3389/fmars.2014.00032,