The influence of the predatory starfish Heliaster helianthus on colonization by a dominant mussel at a central Peruvian coast

HIDALGO F.J.,; FIRSTATER F.N.,; BETINA JUDITH LOMOVASKY; IRIBARNE O.

MARINE ECOLOGY PROGRESS SERIES

INTER-RESEARCH

Año: 2011 vol. 432 p. 103 - 114

0171-8630

In this paper, three experiments (i.e. exclusion of starfish from the edge of mussel beds; exclusion from areas on bare substrate; and exclusions on recruitment mediators) were used to assess the effects of Heliaster helianthus on the colonization of the dominant mussel Semimytilus algosus in a rocky intertidal of central Peru. The exclusion of H. helianthus resulted in increased cover of S. algosus in the three experiments. However, the colonization of the available space was more evident when facilitated by recruitment mediators (i.e. macroalgae) or by migration from the edge of mussel aggregations, than when colonization occurred during succession starting from bare substrate. By the end of the study period, however, increased S. algosus abundance, which coincided with the end of the cold phase (i.e. La Nina, LN) of the El Nino-Southern Oscillation (ENSO), overwhelmed the effects of starfish. We suggest that periodic oceanographic fluctuations are also important in controlling community dynamics in Peruvian rocky intertidals, highlighting the variation in the relative importance of top-down vs. bottom-up control when longer temporal scales are considered.