Tracking climate-linked change in Posidonia oceanica at the eastern edge of the Mediterranean – Cape Greco MPA, Cyprus (2026 – Ongoing)

Scope

Cyprus lies at the warm, climate-sensitive eastern edge of the Mediterranean range of Posidonia oceanica, making Cape Greco MPA an especially important location for understanding how this iconic seagrass responds to changing sea conditions. As one of the easternmost monitoring settings for the species in the basin, Cape Greco can provide early signals of climate-linked change that may later become visible elsewhere in the Mediterranean.

Posidonia oceanica meadows are among the Mediterranean’s most valuable marine habitats, supporting biodiversity, nursery functions, shoreline stability and long-term carbon storage. In a region where warming waters and marine heatwaves are an increasing concern, protecting these meadows depends not only on understanding their present condition, but also on tracking how they change through time under real environmental pressure.

This project delivers follow-up monitoring of Posidonia oceanica in Cape Greco MPA, together with the installation of seawater temperature loggers for T-MEDNet integration. Implemented by MER under a Memorandum of Understanding with SPA/RAC, it represents a continuation of the monitoring framework originally established by MER in 2020 under the MedKeyHabitats II project, with MER again engaged to deliver the follow-up phase and ensure consistency with the original baseline.

A key strength of the project is that it returns to the same permanent stations established and surveyed by MER in 2020 , allowing direct comparison with the earlier baseline dataset. This continuity is vital because it helps distinguish short-term variation from real ecological change and provides a stronger basis for understanding whether the meadow is remaining stable, showing early signs of stress, or shifting over time.

The addition of continuous in situ temperature records makes this long-term comparison even more powerful. By linking repeated biological measurements with the actual temperatures experienced by the meadow, the project will help explore whether warming waters and marine heatwaves may be contributing to observed changes in meadow structure, lower-limit condition and overall habitat resilience. Together, these results will strengthen the evidence base for conservation and management in Cape Greco MPA, while connecting Cyprus’s observations with wider Mediterranean monitoring efforts.

Methods at a glance

• Verification and monitoring of the 66 permanent PMN markers (15–19 m) and 18 deep-edge quadrats (30–33 m) established in 2020, including documentation of their condition and minor repairs where needed.
• Repeat PMN monitoring at intermediate depth, including canopy cover, shoot density, rhizome type, shoot exposure/burial, and fixed-position panoramic and vertical photography.
• Resurvey of six deep-edge stations using photo-quadrats, in situ density counts, rhizome-type assessment and evaluation of lower-limit condition.
• Collection and laboratory analysis of sediment samples, leaf biometrics/biomass and past production using methods aligned with the baseline survey.
• Deployment, retrieval, QA/QC and metadata management of seawater temperature loggers at representative depths, with formatted outputs prepared for T-MEDNet submission.
• Preparation of structured spreadsheets, GIS layers and a curated photographic archive to support direct comparison with the 2020 baseline and interpretation of meadow change in relation to measured temperature exposure.
• Reporting and close technical coordination with SPA/RAC, DFMR and T-MEDNet throughout implementation.

Outputs

• An inception note with the final sampling plan, schedule, coordination arrangements and updated inventory of stations, markers and quadrats.
• A field documentation package including completed field sheets, a curated photographic archive and a status note on permanent markers and quadrats.
• Laboratory results and processed datasets for leaf biometrics/biomass, past production, sediment granulometry and organic matter.
• A temperature monitoring package including deployment/recovery metadata, QA/QC notes and a formatted dataset uploaded to T-MEDNet and shared with the relevant authorities.
• A consolidated dataset and GIS/photo archive supporting traceability, reuse and direct comparison with the baseline survey.
• Final scientific reporting, including interpretation of trends, comparison with earlier data and management-oriented recommendations relevant to warming seas, heatwaves and long-term habitat protection.

Turning long-term monitoring into conservation action

This project helps keep Cape Greco’s seagrass monitoring network active as a practical conservation tool at the warm eastern edge of the Mediterranean. By combining repeat meadow observations with temperature time-series and direct comparison with the earlier dataset, it will improve Cyprus’s ability to detect climate-related ecological change early, understand the potential role of thermal stress, and support evidence-based management for one of the island’s most important marine habitats. It also reinforces continuity with the earlier network established under MedKeyHabitats II, ensuring that the same monitoring framework and scientific approach are maintained across survey cycles, and strengthens regional cooperation through SPA/RAC and T-MEDNet.