Fig 1.
Study sites and sampling design.
Map of the sites on the Spanish coast: Rocas Blancas (RB), Peizas (P), La Griega (LG), Vidiago (V) and timeline of the experiment.
Table 1.
Parameter estimates and standard errors of the GLM models for the excess E of 15N and 13C atoms in native macroalgae.
Table 2.
Diversity and biomass of the macroalgal assemblages.
Fig 2.
Estimates of macroalgal physiological traits.
Mean (SE) gross primary production (a-c) and nitrogen uptake rate (d-f) of the 3 dominant native macroalgae in S. muticum—removed (-S) and control rock pools (+S) at each site (P, RB, LG, V, as indicated in Fig 1 legend).
Table 3.
Parameter estimates of the GLS models and t-tests for gross primary production and nitrogen uptake rate of the native macroalgae.
Fig 3.
Macroalgal carbon and nitrogen pools.
Mean (SE) mg 13C-carbon and 15N-nitrogen retained by the assemblage of the 3 native species (B. bifurcata, Corallina spp and Ceramium spp.) and S. muticum. The average contribution of each species to these pools is indicated in different colors. P, RB, LG, V, as indicated in Fig 1 legend.
Table 4.
Parameter estimates of the GLS models and t-tests for mg of 13C-carbon and of 15N-nitrogen stored in thalli.
Fig 4.
Cumulative contribution to carbon and nitrogen pools.
Average percentage mg of 13C-carbon (a) and of 15N-nitrogen (b) of the native species (Co = Corallina spp., Bb = Bifurcaria bifurcata, Ce = Ceramium spp.) and of the invader Sargassum muticum (Sm) in control (+S) and S. muticum—removed (-S) rock pools at each site.