Effects of macroalgal identity on epifaunal assemblages: native species versus the invasive species Sargassum muticum

Abstract

Seaweeds are a refuge from stressful conditions associated with life on rocky intertidal shores, and there is evidence that different macrophytes support different assemblages of mobile epifauna. Introduction of nonindigenous macroalgae may have a great impact on associated epifaunal assemblages and ecosystem processes in coastal areas. Previous studies have reported conflicting evidences for the ability of epifauna to colonize nonindigenous species. Here, we analyzed epifaunal assemblages associated with three species of macroalgae that are very abundant on intertidal shores along the Galician coast: the two native species Bifurcaria bifurcata and Saccorhiza polyschides and the invasive species Sargassum muticum. We collected samples of each species from three different sites at three different times to test whether variability of epifaunal assemblages was consistent over space and time. Epifaunal assemblages differed between the three macroalgae. Results suggested that stability and morphology of habitat played an important role in shaping the structure of epifaunal assemblages. This study also showed that the invasive S. muticum offered a suitable habitat for many invertebrates.

Mobile epifaunal assemblages associated with <em>Cystoseira</em> beds: comparison between areas invaded and not invaded by <em>Lophocladia lallemandii</em>

“…This finding agrees with those described for other introduced seaweeds, suggesting that, while macroalgal invasions strongly affect diversity of sessile assemblages (Ribera and Boudouresque 1995, Piazzi et al 2001, Schaffelke and Hewitt 2007, Baldacconi and Corriero 2009, Zuljevic and Nikolic 2008, the effects of invasions on mobile organisms are more related to changes in the structure of assemblages (Vázquez-Luis et al 2009, Gestoso et al 2012, Janiak et al 2012, Pacciardi et al 2011, Engelen et al 2013. Differences between invaded and non-invaded beds were not evident five months after the disappearance of L. lallemandii.…”

“…Epifaunal assemblages associated with C. crinita were characterized by high abundance and diversity, compared with those described for other seaweed habitats (Gestoso et al 2012, Janiak et al 2012, Engelen et al 2013. Macroalgal assemblages associated with Mediterranean Cystoseira beds are well known (Boudouresque 1972, Sales and Ballesteros 2010), while epifaunal assemblages have been less investigated and knowledge is limited to particular taxa (Arrontes and Anadon 1990, Chemello and Milazzo 2002, Fraschetti et al 2002.…”

Diversity, distribution and ecology of the family Syllidae (Annelida) in the Portuguese coast (Western Iberian Peninsula)

“…McKenzie and Moore (1981) recorded a total of 77 species, while in our study, considering Syllids alone, we reported a total of 33 species. Gestoso et al (2012) comparing the epifaunal assemblages in native and invasive seaweed species found mostly gastropods (45 % of the total taxa), polychaetes and ophiuroids in S. polyschides.…”

Epiphytic macroalgae mediate the impact of a non-native alga on associated fauna

“…The impacts of non-native macroalgae on fauna have been difficult to generalise as they vary in direction and magnitude depending on a number of factors, e.g. the species in question, where it is growing, and the time of year (Wernberg et al, 2004;Buschbaum et al, 2006;Lutz et al, 2010;Gestoso et al, 2012;Engelen et al, 2013).…”