Macroalgae ecosystem engineering effects mediated by an invasive reef-builder polychaete in a Southwestern Atlantic coastal lagoon

BAZTERRICA, MARÍA CIELO; ALVAREZ, MARÍA FERNANDA; IRIBARNE, OSCAR; BOTTO, FLORENCIA

JOURNAL OF SEA RESEARCH

ELSEVIER SCIENCE BV

Año: 2021 vol. 167

1385-1101

acroalgaein Mar Chiquita coastal lagoon (37° 40′ S, 57° 23′ W, Argentina) settle onsmall-hard substrates on sediments and complex reef-like structures with tubesand crevices of the invader polychaete Ficopomatus enigmaticus(Fauvel, 1923) acting as ecosystem engineers with multiple communitystructuring effects. In this study, we compared the structural effects ofmacroalgae generating new habitat for other organisms in two systems withoriginally different structural complexity. Therefore, we hypothesized thatmacroalgae relative importance as an ecosystem engineer providing new habitatand refuge for other organisms would be higher in flat soft-sediments than onreefs. Through sampling and experimental studies, results showed thatmacrofaunal assemblages were different between areas with and withoutmacroalgae in both reefs and sediment. Experimental results on macroalgae andmacroalgae-mimics to separate structural effects in both reefs and sedimentshowed that macroalgae affect macrofauna on both systems but, structuralmechanisms did not prevail in the reefs or sediment. The effect varied onspecies responses and physical gradients (i.e., depth) of each type of area.Therefore, our results did not support our hypothesis and suggest thatmacroalgae effects are the result of a summary of their multiple effects ininteraction with species and habitat type.