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

Abstract

The variability of some population (demo) parameters of the gammarid amphipod Melita palmata was associated with contrasting habitat structures created by the non‐indigenous reef‐builder polychaete Ficopomatus enigmaticus in the Mar Chiquita coastal lagoon (37°40 S, 57°23 W, Argentina). Sampling of M. palmata was conducted biweekly during the reproductive period in F. enigmaticus reefs and sediment from reef‐free areas, accounting for the vertical distribution and the presence/absence of macroalgae. Males, females (non‐ovigerous and ovigerous), and juveniles are present in both reefs and sediment, but the abundance of M. palmata is several orders of magnitude higher in reefs. Reefs’ M. palmata population (demo) displays variations in: (a) abundance, (b) mean size, and (c) proportions of demographic categories. In reefs, females show a higher proportion of ovigerous specimens and a female‐biased sex ratio, contrasting the 1:1 ratio observed in sediment. Individuals are more abundant in the surface layer covered with macroalgae in reefs (small sizes) and macroalgae or valves in sediment. The association of M. palmata to F. enigmaticus reefs drives its permanency in the system, enhancing its reproductive potential via different reproductive traits and habitat use, with a reduced potential to spread to marginal areas.

Boccardiella ligerica, an exotic polychaete in a Southwestern Atlantic coastal lagoon: Morphology and abundance variations

“…In particular, in Mar Chiquita species assemblages structure vary within areas with different habitat structures that are created by F. enigmaticus reefs: the reefs, the sediment from areas with reef and the sediment from reef‐free areas (Schwindt et al, 2001, Bazterrica et al, 2012; Martinez, 2019). This habitat gradient leads to different structuring mechanisms (top‐down and bottom‐up control: Bruschetti, Bazterrica, Luppi, & Iribarne, 2009; Bazterrica et al, 2013; positive interactions: Bazterrica, Bruschetti, Alvarez, Iribarne, & Botto, 2014; variation in species population traits: Bazterrica et al, 2020; different macrofauna assemblages: Martinez, 2019). Therefore, the absence of B. ligerica in sediments may be driven by negative (indirect) effects of F. enigmaticus reefs such as the increase polychaetes predation rates (Schwindt et al, 2004) or negative macrofauna species interactions (e.g., Alvarez et al, 2018), among others.…”

“…Macroalgae grows on reef surfaces and in the valves from sediment in areas without reefs (Bazterrica et al, 2012). Additionally, macrofauna inhabiting reefs and sediments shows not homogeneous vertical distribution (e.g., amphipods; Bazterrica, Baron, Alvarez, & Obenat, 2020).…”

“…Although in this period the F. enigmaticus invasion has been studied in detail (e.g., Bazterrica et al, 2012Bazterrica et al, , 2014Bruschetti et al, 2009Bruschetti et al, , 2011Schwindt et al, 2001Schwindt et al, , 2004, less attention has been given to the species associated with F. enigmaticus reefs (but see Bazterrica et al, 2012;Bazterrica et al, 2020;Méndez Casariego, Schwindt, & Iribarne, 2004;Obenat et al, 2006). F. enigmaticus reefs provide refuge to numerous organisms, including mollusks, other polychaetes, amphipods and crabs (Orensanz et al, 2002;Orensanz & Estivariz, 1971;Schwindt & Iribarne, 2000), many of them being nonindigenous species such as B. ligerica.…”

“…F. enigmaticus reefs provide refuge to numerous organisms, including mollusks, other polychaetes, amphipods and crabs (Orensanz et al, 2002;Orensanz & Estivariz, 1971;Schwindt & Iribarne, 2000), many of them being nonindigenous species such as B. ligerica. As invasive, the ecosystem engineer F. enigmaticus, provides a nonnative habitat to other nonindigenous species, creating a scenario for multiple potential interactions (e.g., invasional meltdown, Heiman, Vidargas, & Micheli, 2008) that need updated monitoring studies (see Bazterrica et al, 2020).…”

Impacts of alien polychaete species in marine ecosystems: a systematic review

“…However, other aspects that are considered as negatives is that F. enigmaticus could be an intermediary in the transmission of parasites (Etchegoin et al, 2012), and facilitates the spread of other alien species (Bazterrica et al, 2020). Another negative aspect of serpulid alien species F. enigmaticus is the dense encrustations on artificial substrates such as concrete marine facilities, buoys and shipping hulls that potentially complicate maritime navigation and marine recreational activities (Davies et al, 1989;Bezuidenhout & Robinson, 2020).…”