Structure of intertidal sessile communities before and after the invasion of Isognomon bicolor (C.B. Adams, 1845) (Bivalvia, Isognomonidae) in southeastern Brazil

• Autor(a) principal: Soledad López, María
• Data de Publicação: 2014
• Outros Autores: Lavrado, Helena Passeri, Coutinho, Ricardo
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da Produção Científica da Marinha do Brasil (RI-MB)
• Texto Completo: http://www.aquaticinvasions.net/2014/AI_2014_Lopez_etal.pdf; http://www.repositorio.mar.mil.br/handle/ripcmb/843939
• topic: Bivalve (Molusco)-Brasil, Sudeste; Ecologia marinha

Scientists recognize the importance of ecologi cal data prior to invasion by non-native sp ecies in order to evaluate changes in the recipient community. Here we assess the potential im pact of the invasion of the bivalve Isognomon bicolor (C.B. Adams, 1845) on Brazilian rocky shores through the use of surveys both before and after the arri val of this non–native species. The invader was mostly distribu ted across the mid and low shore levels of the intertidal zone with relative abundance ranging from 9.0 to 36.7 percent cover. The mid shore, previously dominated by the native barnacle Tetraclita stalactifera (Lamarck, 1818), was co-dominated by this barnacle species and I. bicolor after invasion. The relative abundance of these species, and presumably the interaction st rength between them, differed between sites . At the site where I. bicolor reached the highest abundance (aro und 30% on average), the abundance of T. stalactifera decreased on average 70% compared to baseline values obtained before the I. bicolor invasion. Finally, conspicuous and extensive I. bicolor beds such as those observed in this study have not been reported in its original distribution range. Beds of I. bicolor may create a much more intricate biogenic matrix than the extents of bare rock and barnacle clumps it replaced. This bivalve may act as an ecosystem engineer and, thus a functionally different component of the intertidal community in its invaded range compared to its native distribution.