Mobile epifauna of the invasive bryozoan Tricellaria inopinata: is there a potential invasional meltdown?

The impact of introduced fouling species and their associated epifauna in ports and marinas is potentially devastating for local biodiversity. The species composition of the epifauna on Tricellaria inopinata in Puerto Am,rica (Cadiz, Spain) was studied over a period of one year. Colonies were sampled bimonthly, and all associated mobile macrofauna was sorted and identified. A total of 19 species was found throughout the study period, including the introduced Caprella scaura and Monocorophium sextonae (Amphipoda) and Paracerceis sculpta (Isopoda). These three species represented over half of the individuals found throughout the study period, and there were significant differences between the abundance of native versus introduced species, though the direction of differences was not consistent. Whether the specific morphology and annual cycle of T. inopinata is favouring the establishment of other introduced species like those found here, and hindering other native species, is discussed, and future lines of research to address this phenomenon are proposed.