Effects of an invasive reef-building polychaete on the biomass and composition of estuarine macroalgal assemblages

Abstract

Invasive species can transform ecological communities. Their profound effects may alter the sources and pathways of primary production. We investigated the effects of the reef forming polychaete Ficopomatus enigmaticus invasion on the biomass and distribution of estuarine macroalgae in a SW Atlantic coastal lagoon (Mar Chiquita, 37°40 0 S, 57°23 0 W, Argentina). Reefs built by this species serve as substrates for macroalgal development and furnish structures that modify physical and biological conditions for the surrounding benthos. We showed that (1) the red macroalga Polysiphonia subtilissima settles and grows almost exclusively on the surface of the reef, (2) the green macroalgae Cladophora sp. and Enteromorpha intestinalis are found almost exclusively in areas without reefs attached to mollusk shells and, (3) no macroalgae occur in the sediment between reefs. Manipulative experiments show that reefs provide a complex substrate for settlement and survival and therefore benefit red macroalga. These experiments also show that the invasive reef builder has negative indirect effects on green macroalgae by increasing grazing and probably by increased sedimentation between reefs. Via these direct and indirect effects, reefs change the relative biomass contribution of each macroalgal species to the overall production in the lagoon. Knowledge of these processes is important not only for predicting net effects on primary production but also because changes in macroalgal species composition may produce effects that cascade through the food web.

Global ecological impacts of invasive species in aquatic ecosystems

“…Additionally, filter feeders are commonly considered ecosystem engineers because of the complex substrate structure they create, which explains the strong increase observed in the abundance of benthic invertebrates in invaded habitats (e.g. Higgins & Zanden, ; Bazterrica et al ., ).…”

“…Additionally, filter feeders are commonly considered ecosystem engineers because of the complex substrate structure they create, which explains the strong increase observed in the abundance of benthic invertebrates in invaded habitats (e.g. Higgins & Zanden, 2010;Bazterrica et al, 2012). Several studies have reported massive reductions in the coverage of submerged macrophytes within a few years of invasion by omnivores such as crayfish (e.g.…”

First record in the Tropical Eastern Pacific of the exotic species Ficopomatus uschakovi (Polychaeta, Serpulidae)

“…The case of Ficopomatus enigmaticus , a serpulid widely dispersed around the world and with a long historical record of invasions, is a well-known example, because it can have dramatic impacts in invaded habitats building large, reef-like colonies in some coastal lagoons that cause major changes in benthic communities, especially in the Lake of Tunis (ten Hove and van den Hurk 1993) and the Mar Chiquita Lagoon, Argentina (Schwindt et al 2001, Luppi and Bas 2002, Bazterrica et al 2012). Rioja (1943) recorded, for the first time, Ficopomatus enigmaticus from Puerto Quequén, south of Mar del Plata, and now the species is widely distributed in the Mar Chiquita Lagoon, forming annular reefs and having several effects on the ecosystem and navigation of fishing boats in this lagoon-system (Schwindt et al 2001, Luppi and Bas 2002, Schwindt et al 2004a, b).…”

Effects of Ficopomatus enigmaticus ecosystem‐engineered habitat structure on population parameters of the amphipod Melita palmata: A NIS‐NIS interaction study

“…Besides, the feeding activity of their individuals generates a strong top‐down control on phytoplankton, increasing benthic–pelagic coupling (Bruschetti, Bazterrica, Fanjul, Luppi, & Iribarne, 2011; Bruschetti, Luppi, Fanjul, Rosenthal, & Iribarne, 2008). Furthermore, reefs provide a hard substrate surface sustaining macroalgae settling and growth, inhibited on nearby sediment (Bazterrica, Botto, & Iribarne, 2012).…”