Habitat shifts: invader ecosystem engineer barnacle selectively recruits and survives on salt marsh plants

MENDEZ MM; SCHWINDT E; BORTOLUS A

Congreso; 2nd World Conference on Biological Invasions and Ecosystem Functioning; 2011

Grieta

Balanus glandula is a characteristic acorn barnacle of the rocky shores in the west coast of North America. This species invaded the SWA Atlantic coast more than 40 years ago dominating the high intertidal. Surprisingly, the specie has also colonized soft bottom environments as the salt marshes. In these environments, B. glandula colonize the salt marsh plant species Sarcornia perennis, Spartina and Limonium brasiliense, rest of organic materials, living mussels, epifaunal organisms, gravels and trash (like bottles, plastic materials, fishing nets, etc). In this work we experimentally study if exists active selection of one or more of the substrata utilized by B. glandula to recruit in salt marshes. To address this question, the five most utilized substrata were offered in the field without changing its original shape and size. These substrata were: Spartina (n = 12), Sarcocornia perennis (n = 12), Limonium brasiliense (n = 11), gravels and mussel valves (n = 10 for each). An inorganic substratum was added in order to evaluate if exists preference between natural and artificial substrata (portion of hard plastic, n = 12). A control treatment was also added (n = 12). The experiment was performed in “Punta Ameghino” (42°36’S, 64°52´W), lasted one year and at the end the variables measured were density of barnacle recruits and barnacle size frequency distribution. Limonium brasiliense showed the highest density values and also contained the biggest barnacle. Both variables were consistent with ones of rocky shores showing that this salt marsh plant could have the optimal surface for B. glandula recruitment.