Patterns of substrata use by the invasive acorn barnacle Balanus glandula in Patagonian salt marshes

MENDEZ MM; SCHWINDT E; BORTOLUS A

HYDROBIOLOGIA

SPRINGER

Lugar: Berlin; Año: 2013 vol. 700 p. 99 - 107

0018-8158

Balanus glandula is a common acorn barnacle of the rocky shores in the west coast of North America. Nowadays, forty years after its introduction in Argentina, this species dominates the high intertidal of rocky shores and, also, it was reported successfully colonizing soft bottom salt marshes. In this work, we described and characterized the substrata where B. glandula recruits and we experimentally studied if its success in colonizing salt marshes is based on the active selection of a particular substratum. Salt marshes were carefully covered and the substrata where B. glandula recruited were recorded. As well, the proportion of available substrata was determined. For the selection experiment, the most utilized substrata were offered in the field. Results show that barnacles utilized more than ten types of substrata in different frequency. Mussel valves was the most frequent type utilized in one marsh while in other one, where mussels are not highly abundant, the dominant halophyte Sarcocornia perennis was the substratum most utilized. Nevertheless, when the substrata were experimentally offered, the shrub Limonium brasiliense showed the highest density of recruits and the largest barnacles. Density and size of the barnacles were similar to the observed in rocky shores, suggesting that this exotic species successfully colonize the salt marshes mainly based on the active selection of halophytes as recruitment substrata. Therefore, rocky shores should not be the only environments that take the attention for potential invasions, and soft-bottom environments must be included in early detection plans focusing on B. glandula and similar species.