Influence of complexity and habitat heterogeneity on macrofaunal assemblages provided by an invasive ecosystem engineer in Mar Chiquita coastal lagoon

MARTINEZ, LORENA E.; BAZTERRICA, M.CIELO; HIDALGO, FERNANDO J.

ESTUARINE COASTAL AND SHELF SCIENCE

ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD

Año: 2020 vol. 246

0272-7714

Invasive ecosystem engineers change habitat attributes and species abundance, affecting the structure of invadedcommunities. In the Mar Chiquita coastal lagoon (37◦ 40′ S, 57◦ 23◦W), the invasive reef-building polychaeteFicopomatus enigmaticus (Fauvel, 1823) generates a heterogeneous environment with habitats of variablecomplexity: the reefs themselves (high complexity), the sediment surrounding the reefs (low complexity), and thesubstrate from the areas without reefs (intermediate complexity). Our objective was to compare the macrofaunalassemblages along the whole complexity gradient. We hypothesized that individuals? abundance, diversity,species richness, and evenness of the macrofaunal assemblages increase with habitat complexity, since morecomplex habitats may represent greater availability of suitable spaces. The composition of the species assemblagewas compared through monthly field samplings in each of the three habitats. Results showed that individuals?abundance increased with habitat complexity. In addition, amphipods were the most abundant group in thereefs, while ostracods were the most abundant group in the sediment surrounding the reefs and that from reeffreeareas. However, community parameters were occasionally similar between the reefs and the sediment fromreef-free areas, depending on the month considered. Our study suggests that the invasion of F. enigmaticuschanged the macrofaunal assemblages and the individuals? abundances by providing a high complexity substrate,but also, and less predictably, by increasing habitat heterogeneity, highlighting the importance of including bothdimensions of habitat structure in the study of invasions by ecosystem engineers