Lessons from the South: Dominance of NIS on artificial structures in cold-temperate areas

GIACHETTI, CLARA B.; BATTINI, NICOLÁS; CASTRO, KAREN LIDIA; TATIAN, MARCOS; SCHWINDT, EVANGELINA

Baltimore, Maryland

Conferencia; XI International Conference on Marine Bioinvasions; 2023

In urbanized coastal areas, artificial structures are inhabited by fouling communities with a large richness of NIS, compared with natural rocky shores. Among these species, ascidians are one of the most successful invasive species worldwide. The goal of this study is to understand the ecological patterns and processes that determine the colonization success of NIS on different artificial structures. Through field and aquarium experiments, we showed that predation pressure varies among types of artificial structures, between juveniles and adult ascidians, and across species. However, this differential predation pressure on invasive ascidians cannot explain, by itself, the abundance patterns of dominant ascidian species: Ascidiella aspersa keeps a constant but larger abundance only exceed by Ciona robusta’s abundance during fall. Studying their reproductive ecology through histological analyses, we observed that A. aspersa presents a seasonal cycle different from its native range, while C. robusta has a similar reproductive ecology in both invasive and native range. Our results showed that a differential predation along the life cycle of ascidians and variations in their reproductive ecology might be shaping the colonization success of these organisms on cold-temperate regions. Comprehending these factors might help us to predict and prevent future impacts on urbanized coastal areas.