Community interactions of the invasive colonial ascidian Didemnum vexillum in a natural and an anthropogenic rocky intertidal
By: Nicole (Patricia) Cristales, Meredyth Duncan, Nitchamon Chuajedton, and Geoffrey Schroeder
Department: Ecology
Faculty Advisor: Dr. C. Sarah Cohen
Didemnum vexillum is an invasive marine colonial tunicate that is capable of quickly overgrowing and smothering other sessile organisms. This global invader has been shown to have negative ecological consequences in natural habitats and significant economic impacts in aquaculture. It is now found in rocky intertidal habitats on the California coast, where it threatens to change species abundance and community composition, potentially leading to a loss of native species diversity. This research aims to better understand how some native predators of California’s rocky intertidal may support biodiversity by preying on D. vex or injuring the colonies, as well as gain insight about the spread of D. vex and the organisms it overgrows. To accomplish this, predation experiments are run with Tegula funebralis, Pisaster ochraceus, and Strongylocentrotus purpuratus. Photos of fouling panels at Fort Baker taken over time are analyzed for recruitment and spread of D.vex to reveal interspecific interaction and competition. At Point Bonita, colonies are removed and overgrown organisms are identified and counted. Anemone interactions with D. vex are analyzed at this site and in the lab for their potential to limit D. vex spread by damaging competing colonies with their nematocysts.