Benthic Biodiversity and the Assessment of Ecosystem Recovery in Seagrass Meadows: A Critical Narrative Review

Seagrass restoration seeks to recover vegetation, benthic biodiversity, and ecosystem functioning, but these components may recover at different rates. This critical narrative review synthesizes literature identified through 15 September 2026 on canopy-associated and sediment-dwelling fauna, relevant microbial interactions, habitat comparisons, experiments, restoration monitoring, and molecular surveys. Targeted searches and reference checking informed a thematic synthesis, supplemented by descriptive re-expression of published summary estimates and recovery observations. Evidence is dominated by temperate eelgrass and macrofaunal studies, with limited coverage of tropical systems and meiofauna. Seagrass meadows often support greater faunal abundance and diversity than unvegetated sediments, although responses vary with taxa, environmental context, spatial scale, and reference habitat. Some restored meadows rapidly attain community composition and functional traits resembling natural references, but other attributes remain distinct, persistence is uncertain, and no universal recovery timeline is supported. Similarity in community traits does not demonstrate recovery of grazing, secondary production, or nutrient exchange, which require process-specific evidence; carbon storage should be evaluated separately using measurements of carbon stocks and, where relevant, accumulation rates. Environmental DNA broadens detection but is constrained by transport, taxonomic assignment, and sampling completeness. We propose a recovery-assessment framework integrating habitat condition, taxonomic and functional community attributes, directly measured processes, appropriate references, uncertainty, and long-term monitoring. Conservation should preserve complementary meadow habitats and interactions with demonstrated ecological benefits.