Thermal extremes drive long-term seagrass declines
Author Identifiers
Chanelle Webster's ORCID record ![]()
Kathryn McMahon's ORCID record ![]()
Publication Date
2026
Document Type
Dataset
Keywords
seagrass trajectories, drivers, conservation, climate change, marine heatwaves, thermal stress
Publisher
Edith Cowan University
School or Research Centre
School of Science / Centre of Marine Ecosystems Research
Funders
Western Australian Marine Science Institution
Description
Dataset comprising of seagrass Posidonia sinuosa shoot density observations (n=17935) spanning 3 degrees of latitude across five regions in Western Australia including four marine parks and one industrialised embayment. Data was collected between 2003 and 2024 but note that the start point for monitoring of each region is not necessarily this earliest date. Additionally, it is important to note that in some regions, sites were added at a date late than when the first monitoring was undertaken. The purpose of the dataset was to understand spatial and temporal trends in seagrass trajectories. Additionally, various environmental predictors have been included to further investigate what factors influence these trends and the direction of the relationships to inform current and future management practices.
Research Activity Title
Project 2.2 Pressure-response relationships, building resilience and future proofing seagrass meadows
Research Activity Description
The Pressure-Response Relationships, Building Resilience and Future-Proofing Seagrass Meadows project (Project 2.2) is a research initiative under the multi-million dollar WAMSI Westport Marine Science Program in Western Australia. The project focuses heavily on temperate seagrasses (such as Posidonia sinuosa) in Cockburn Sound, a heavily industrialized embayment. It is designed to evaluate tolerance thresholds and recovery timelines against anthropogenic pressures, such as port dredging and climate change. Key components of the project's sub-studies include: Pressure-Response & Dredging Impacts; Thresholds & Recovery Metrics and Building Resilience.
Methodology
Monitoring employed standardised underwater survey approaches suitable for assessing meadow-scale condition. Surveys were generally conducted during summer months (December–April), coinciding with peak growth of Posidonia sinuosa, and repeated on an annual or biennial basis. Across all programs, shoot density was quantified by scuba divers counting shoots within 0.04 m² quadrats and scaling values to shoots m⁻².
Start of data collection time period
2003
End of data collection time period
2024
Research Project Links
https://westport.wa.gov.au/environment/wamsi-westport-marine-science-program
Language
English
File Format(s)
Excel workbook (.xlsx)
File Size
2682 KB
Contact
Enquiries about the dataset may be sent to Chanelle Webster: chanelle.webster@ecu.edu.au
Citation
Webster, C., McMahon, K., Afrifa-Yamoah, E., Said, N., Ross, C., Hovey, R., Martin, B. & Strydom, S. (2026). Thermal extremes drive long-term seagrass declines. [Data set]. Edith Cowan University. https://doi.org/ 10.25958/35ej-j212