Abstract
Abstract
Seagrasses suffer population decline when environmental stress exceeds physiological tolerance. In such instances, seagrass restoration can be successful if stressors are alleviated; however, many stressors cannot be addressed at a local scale. As such, seagrass restoration efforts often fail. In this study, we tested whether artificial oyster reefs—which are comparatively more robust to many environmental stressors—can facilitate the recovery of some lost ecosystem services in bare patches of a fragmented seagrass meadow. From 2021 to 2023, artificial reefs constructed of concrete blocks were installed annually in bare sediment patches of a nearshore estuarine eelgrass (
Zostera marina
) meadow in Prince Edward Island, Canada. In 2023, reefs were sampled to determine benthic and pelagic biodiversity, as well as abiotic environmental conditions adjacent to and away from the reefs. A total of 45 taxa were observed on the artificial reefs. Initial colonization was dominated by oyster (
Crassostrea virginica
) spat. Maximum benthic taxonomic richness was reached within one year of reef installment, and community biomass quadrupled one year thereafter, which was mostly attributable to oyster growth. Short‐term monitoring of pelagic species suggested that numerous fish species actively used 2‐year‐old reefs for both feeding and sheltering, compared to no fishes actively using a reference bare patch; fish diversity and evenness generally increased with reef age. Reefs also appeared to modify localized water quality parameters relative to bare patches by lowering temperature and turbidity, increasing dissolved oxygen, and lowering pH. Together, these results provide support that artificial oyster reefs can facilitate the recovery of lost ecosystem services within fragmenting and declining eelgrass beds. When replacing lost or declining habitat has a low probability of success, shifting restoration efforts away from directly replacing that habitat in a 1:1 manner toward providing different, supplemental habitat comprised of foundational species that can persist will result in more effective restoration programs.