Impact of the genus Amphistegina on the benthic foraminiferal association of the Pelagian Islands, an example of invasion in the Central Mediterranean Sea

In recent years the Mediterranean Sea is increasingly subject to colonization by non-indigenous marine organisms, many of which migrate through the Suez Canal. Its opening, which took place in 1869, connected two different biogeographical provinces after millions of years, facilitating the migration of over 600 nonindigenous species, some of which are seriously threatening the native biodiversity. This study shows the results of benthic foraminiferal analyses carried out on algal and sediment samples collected in 2014 around the Pelagian Islands (Lampedusa and Linosa). These islands, starting from 2005 (the year of the first report), are undergoing the invasion of the non-native Indo-Pacific species Amphistegina lobifera Larsen. The obtained data have been compared with those of previous sampling carried out in 2005 and 2009 (Caruso & Cosentino, 2014). This comparison highlights how, in most cases, A. lobifera is increasing its abundance dominating the assemblages with percentages over 50% and causing the drastic decrease of the native species. Its carbonatic tests, accumulated on the Linosa seabed are progressively changing the composition of marine sediments and for the first time are also giving rise to accumulations in the coastal environment, inside pools filled during storm surges, as happens in the Indo-Pacific atolls. These results show how, in just a few years, some non-indigenous foraminifera are capable of massively colonize new environments, modifying native biodiversity and influencing sedimentary processes. Caruso A. & Cosentino C. (2014). The first colonization of the Genus Amphistegina and other exotic benthic foraminifera of the Pelagian Islands and south-eastern Sicily (central Mediterranean Sea). Mar. Micropal., 111, 38-52, https://doi. org/10.1016/j.marmicro.2014.05.002.