Macrophyte-epifauna associations form structured ecological networks in the Baltic Sea

Marine macrophytes deliver important ecosystem services and are a primary source of nutrition and habitat for a variety of associated species. Shifts in macrophyte distribution due to climate change and other anthropogenic pressures might therefore have substantial secondary impacts on coastal biodiversity. The nature and extent of such impacts depend on the community-wide interaction networks that link invertebrates and other animals to macrophytes. A common assumption in coastal ecology is that most animals associated with macrophyte habitats are generalists, making these systems robust to the loss of or changes in macrophyte diversity. Here, we explore macrophyte-animal associations from a novel perspective, assessing whether non-random associations among taxa promote the emergence of structurally complex ecological networks. For this, we assembled a large data set of macrophyte-animal associations by sampling 430 individual macrophytes and their associated epibenthic invertebrates across 3 sites and 4 time points in the Tvärminne archipelago, Finland. We used null model analyses to identify strong, non-random associations and build local macrophyte-epifauna networks. These analyses identified a total of 99 significant, non-random macrophyte-epifauna associations in the study area. The structure of local macrophyte-epifauna networks varied across both sites and time, with highly structured networks observed at sites hosting structurally diverse macrophyte communities, and the foundation species Fucus vesiculosus playing a key ecological role. Our results demonstrate that marine macrophyte-animal systems are not merely random assemblages. Exploring marine macrophyte-animal associations from a network perspective can therefore enhance our understanding of the ecological processes shaping coastal ecosystems.

MANCA Federica;  NORKKO Alf;  CABEZA Mar;  LLEWELYN John;  HERVÍAS-PAREJO Sandra;  STRONA Giovanni; 

2025-12-19

INTER-RESEARCH

JRC142651

1616-1599 (online),   

https://www.int-res.com/abstracts/meps/v771/meps14942,    https://publications.jrc.ec.europa.eu/repository/handle/JRC142651,   

10.3354/meps14942 (online),