A shift of ecosystem engineers during the succession of an intertidal benthic community associated with natural and anthropogenic disturbances

Abstract

Temporal variation and sewage pollution were assessed on the recruitment of two benthic ecosystems engineer species during an experimental succession. The re-colonisation of the spionid polychaete Boccardia proboscidea and the mussel Brachidontes rodriguezii reached a maximum cover recruitment of 80 % after 12 and 20 weeks, respectively in plots cleared in spring. While in plots cleared in autumn B. proboscidea remained dominant from the initial re-colonisation to final successional stages. The settlement of the green algae Ulva hookeriana was facilitated by B. rodriguezii. The spionid polychaete had an abundance peak during spring, replacing B. rodriguezii and dominated the sewage-polluted area. However, the mussel returned to be the dominant species after a wind-wave–storm. An environmental disturbance like the documented storm was an important structuring factor of the studied community, with implications on the intertidal diversity, as it may change the dominance of the ecosystem engineers in the local sewage-impacted area.