Data Supporting: Artificial Oyster Reefs Facilitate the Recovery of Lost Ecosystem Function in Declining Seagrass Habitat

PURPOSE:
The contents of this dataset serve as supplementary material to an upcoming publication. The paper is from a multi-year project assessing the efficacy of artificial oyster reefs, deployed in bare patches of a fragmented eelgrass bed, to facilitate the recovery of lost ecosystem services within those bare patches. The dataset contains supplementary figures and tables to support the findings contained within the manuscript, R code used for data analysis and figure generation, source datafiles uploaded to R for statistical analyses and figure generation, and a data dictionary to facilitate understanding and comprehension of the source data files. This page will be updated with the complete citation for the article once it is officially published.

DESCRIPTION:
Seagrass populations often decline when environmental stress exceeds tolerance thresholds. In such instances, seagrass restoration can be successful if stressors are alleviated; however, many stressors cannot be addressed at local scale, leading to unsuccessful restoration initiatives.  This study tested whether artificial oyster reefs, which are comparatively more resilient to many stressors, could restore lost ecosystem functions within bare sediment patches of a fragmented eelgrass (Zostera marina) meadow in Prince Edward Island. From 2021 to 2023, artificial oyster reefs constructed of concrete blocks were installed and monitored for biodiversity and environmental effects. By 2023, 45 taxa had colonized the reefs, with rapid oyster (Crassostrea virginica) recruitment driving subsequent increases in richness and biomass. Fish diversity and use were higher around older reefs compared to bare patches. Reefs also locally improved water quality compared to bare patches. These findings indicate that artificial oyster reefs can help recover ecosystem services in declining eelgrass habitats, offering an alternative when 1:1 habitat replacement is unlikely to succeed.

This project was co‑developed with Lennox Island First Nation in close collaboration with Tim Bernard, with the goal of providing accessible tools to support restoration of culturally and ecologically significant habitats in their traditional territory. We gratefully acknowledge the many partners who contributed to this work, including Angela Douglas‑Banks, Randy Angus, Dr. Scott Roloson, Jillian Hunt, staff at the Bideford Shellfish Hatchery, Dr. Barrett Kurylyk and students at Dalhousie University, Chyann Kirby, and Bruce Moore. Project concepts were developed by Jeff Clements, Michael Coffin, and Luke Poirier; methodology was designed by Jeff Clements, Michael Coffin, Luke Poirier, Andre Nadeau, John Davidson, and Kyle Knysh; and data collection and analysis were completed by Jeff Clements, Andre Nadeau, and Kyle Knysh.
            
PARAMETERS COLLECTED:
Biotic data: 
- Diversity, abundance and biomass of various sessile and mobile invertebrates
- Diversity and biomass of various estuarine aquatic plants
- Diversity and abundance of estuarine fish species

Abiotic data: 
- Temperature
- Salinity
- Dissolved oxygen
- pH
- Turbidity

NOTES ON QUALITY CONTROL:
Data were initially collected and input by various field team members including Jeff Clements, Andre Nadeau, and Kyle Knysh. All data files were checked and validated prior to analysis by Jeff Clements. Data were further checked and validated prior to publication by the Centre for Advice, Data and Integration (CADI).

PHYSICAL SAMPLE DETAILS:
Species counts and biomass estimates were obtained from physical samples of species collected from individual concrete blocks; these samples were discarded after processing and data collection.

SAMPLING METHODS:
Artificial reefs constructed of 8-10 concrete blocks were deployed in bare patches of a fragmented eelgrass bed on PEI in 2021 (18 reefs), 2022 (16 reefs) and 2023 (8 reefs). In 2023, samples of biotic and abiotic parameters of reefs from each deployment year were obtained. Three concrete blocks from three separate reefs from each deployment year (n = 27 blocks from n = 9 reefs total) were sampled to measure the biomass and abundance of benthic fora and fauna. Fish biodiversity on reefs from each deployment year was sampled using the analysis of GoPro videos obtained from daytime videos of the reefs taken from August 22-24, 2023. A series of dataloggers were deployed from July 26-August 24, 2023 to monitor abiotic parameters at three locations relative to a reef deployed in 2021: first, directly beside a reef deployed in 2021; second, inside the geographic area where all of the reefs were deployed, but not directly beside a reef; and third, in a reference bare patch well outside the area where all of the reefs were deployed.

USE LIMITATION:
To ensure scientific integrity and appropriate use of the data, we would encourage you to contact the data custodian.

Organization: Fisheries and Oceans Canada | Pêches et Océans Canada