The introduction of non-native algae becoming invasive is a driver of ecosystem change in many coastal areas, and understanding the ecological consequences of these introductions is important. Here we use a trait-based approach to demonstrate potential differences between native and invasive algal communities. A set of functional traits was applied to the most commonly occurring native and invasive algal species. We included the recently discovered alga Chondria tumulosa A.R. Sherwood & Huisman (2020) to predict its potential invasiveness on the local algal assemblages. The results indicate that invasive macroalgae have introduced certain novel functional traits to algal communities in the Main Hawaiian Islands. These algae occupy and share a specific part of the trait space, which has two key implications, either that invasive algae can alter the functional composition of local assemblages by introducing new trait values and outcompete the native flora, or, if their traits differ from those of native species, invaders might occupy habitats or utilize resources in a way that instead complement native species. An evaluation of C. tumulosa showed that this species has a high potential of becoming invasive and causing declines in the functional diversity of coastal habitats. Moreover, this study illustrates that trait-based analysis can provide a useful tool for evaluating the invasive potential of algal species and increasing understanding of ecological consequences of such invasions.
