Abundance patterns of macrofauna associated to marine macroalgae along the Iberian Peninsula.

Abstract

macroalgae were studied on a spatial scale along the Iberian Peninsula. Nineteen
\nstations and four dominant algae were selected (intertidal zone: Corallina
\nelongata and Asparagopsis armata; subtidal zone: Stypocaulon scoparium and
\nCladostephus spongiosus). Five environmental factors were also considered
\n(seawater temperature, conductivity, dissolved oxygen, turbidity and pH). The
\nAtlantic coast was characterized by lower temperature and conductivity as well
\nas higher values of oxygen and turbidity than the Mediterranean coast. A total
\nof 106274 macrofaunal specimens were sorted and examined (68% arthropods,
\n27% molluscs, 4% annelids and 1% echinoderms). Crustaceans were the dominant
\ngroup in all the macroalgae (ca. 80% in C. elongata and A. armata, ca.
\n50% in S. scoparium and C. spongiosus) followed by molluscs, which were
\nmore abundant in the subtidal algae (ca. 40%) than in intertidal ones (ca.10%).
\nAbundance patterns of macrofauna along the Iberian Peninsula were similar in
\nthe four studied algae. Most of crustaceans belonged to the order Amphipoda,
\nwhich showed high densities (>1000 ind/1000 ml algae) along the whole Peninsula;
\nisopods showed the highest abundances in the Atlantic, while tanaids,
\ncumaceans and decapods were more abundant in the Mediterranean. Among
\nmolluscs, gasteropods showed highest abundances along the Atlantic coasts,
\nwhereas bivalves showed higher densities along the Mediterranean