MEPS 657:93-108 (2021)  -  DOI: https://doi.org/10.3354/meps13546

ABSTRACT: Multiple forms of environmental change and anthropogenic pressure co-occur in coastal marine ecosystems. These external forces affect ecosystem structure, functioning, and, eventually, services to humans. Studies that include more than 2 simultaneous stressors are still needed to understand potential interactions among multiple stressors. We evaluated single and interactive effects of density reduction of Zostera marina L. (a habitat-forming species), shading, and sediment nutrient enrichment on the response of Z. marina and its associated epifauna over 10 wk. Shading had the greatest effect on reducing the eelgrass relative leaf elongation rate (RLE), non-structural carbohydrate reserves, and eelgrass shoot density. A reduced eelgrass density sustained higher epifaunal densities and increased the eelgrass RLE. Sediment nutrient enrichment increased eelgrass shoot density but decreased epifaunal richness, diversity, and total abundance. Our disturbance and pair of stressors differed in their influence on diversity measures, but all affected assemblage structure. Most of the changes to the epifaunal assemblage and diversity likely occurred due to altered habitat availability and epiphytic algae load. We observed additive, antagonistic, and negatively synergistic interactions among our treatments, while most of the cumulative effects showed dominance by one stressor over another. Our results highlight the importance of field experiments that are based on multiple disturbances and stressors to determine their interaction type on communities.

KEY WORDS: Habitat complexity · Cumulative effect · Non-additive interaction · Foundation species · Field experimentation · Manipulative study · Shading · Nutrient addition

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Cite this article as: Cimon S, Deslauriers A, Cusson M (2021) Multiple stressors and disturbance effects on eelgrass and epifaunal macroinvertebrate assemblage structure. Mar Ecol Prog Ser 657:93-108. https://doi.org/10.3354/meps13546 Export citation Share:    Facebook - - linkedIn