The Solent waterbody is composed of a myriad of designated sites which are host to ecologically significant intertidal seagrass Zostera species, either as a designated feature in its own right (Solent Maritime Special Area of Conservation (SAC)) or as supporting habitat for bird species (Chichester and Langstone Harbours Special Protection Area (SPA), Solent and Southampton Water SPA and Portsmouth Harbour SPA). This site was last surveyed in 2019 and required an up-to-date mapping of extent and distribution to inform management and conservation measures.
Intertidal surveys were carried out on foot during spring low tides between August and September 2023. GPS tracks were recorded around previously mapped seagrass beds using smartphones with an accuracy of up to 10 m. Once a seagrass bed was located, the extent was mapped by walking along the outer boundary of the bed.
A total seagrass bed coverage of 251.18 ha was recorded across the areas surveyed. Beds of Z. noltii and Z. marina ecotype made up approximately 40% of this total area, covering 101.04 ha, closely followed by mixed beds of Z. noltii and Z. marina which covered a total area of 88.05 ha. Certain areas were inaccessible due to the tidal window, and the report outlines these, recommending them for future surveys. Whilst coverage has remained largely the same to previous surveys, there are notable contractions and expansions across the beds, alongside new beds previously unmapped, and an increase in the average extent of seagrass beds across the Solent and Isle of Wight between 2019 and 2023.