Invasive macroalgae in native seagrass beds - vectors of spread and impacts.

Our results show limpets support S. muticum as an epibiont and may act as a previous unreported transport mechanism introducing invaders into sensitive habitats. S. muticum reduced phenolics production in Z. marina which may weaken its defensive capabilities and facilitate proliferation of S. muticum. The effect of S. muticum on Z. marina photosynthesis requires further work but having no effect on the capacity of Z. marina to sequester nutrients suggests a degree of resilience to this invader.