Decline of a non-native ecosystem engineer and its replacement with a native on rocky shores: effects on the diversity and structure of benthic communities

• Published in: Marine biodiversity Vol. 50; no. 1; p. 2
• Main Authors: Pacheco, Aldo S., Andrade, Diego G.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-02-2020; Springer Nature B.V
• Subjects: Animal Systematics/Taxonomy/Biogeography; Benthic communities; Benthos; Biodiversity; Bioengineering; Biogeography; Biomedical and Life Sciences; Coexistence; Community composition; Community structure; Ecosystems; Engineers; Freshwater & Marine Ecology; Human impact; Intertidal environment; Intertidal zone; Introduced species; Invasive species; Life Sciences; Marine invertebrates; Mollusks; Original Paper; Plant Systematics/Taxonomy/Biogeography; Rocky shores; Shores; Species composition; Taxa; Taxonomy; South America; Chile; Indigenous mussels; Invasive ascidians; Human disturbance; Spatial competition; Three-dimensional matrices; Community composition
• ISSN: 1867-1616; 1867-1624
• DOI: 10.1007/s12526-019-01033-y

Ecosystem engineer species create enhanced habitat resources, and therefore host exceptionally diverse communities. We studied the case of two ecosystem engineers: a non-native ascidian,
Pyura praeputialis
, and the native mussel,
Perumytilus purpuratus
, in the rocky shores of Antofagasta Bay, northern Chile.
P. praeputialis
was once dominant in mid- and low-intertidal zones, but human harvesting has severely reduced the extent of the
P. praeputialis
band, allowing for competition from
P. purpuratus
, which subsequently expanded and replaced
P. praeputialis.
We compared the macrobenthic community structure between these two ecosystem engineers at five sites throughout the bay. Our results suggest not only an important share of species composition between the ecosystem engineers (68.1%) but also dissimilarity due to differential changes in taxa abundance. Taxonomic richness and diversity were always high in both ecosystem engineers when analyzing communities in areas without these engineers. Diversity recorded in
P. praeputialis
was slightly higher than those in
P. purpuratus
; however, the re-establishment of the native mussel could prevent a substantial drop in diversity as the invasive bioengineer disappears. From a biogeographical standpoint, all recorded taxa associated with both ecosystem engineers were native, thus allowing us to conclude that
P. praeputialis
did not further facilitate the presence of invasive species; rather, this bioengineer could be considered a reservoir of native fauna. Our study highlights the importance of the coexistence of multiple ecosystems engineers and their interactions in the maintenance of biodiversity in rocky shores, especially in cases where human disturbance reduces the more dominant but invasive ecosystem engineer.