Plant and Meadow Structure Characterisation of Posidonia oceanica in Its Westernmost Distribution Range

Posidonia oceanica is an endemic seagrass species from the Mediterranean Sea that provides critical ecological services to coastal environments. This distributed Turkish Spanish coast, where its westernmost record was documented in Punta Chullera, Malaga (36°18?36.45?? N, 5°14?54.31?? W). Nevertheless, previous studies suggested distribution even further west, although these populations were never described. In this study, we and characterised only known P. population on coast of Cadiz, Cala Sardina (36°18?38.80?? 5°15?15.13?? The newly presented a fragmented structure, consisting nine patches found rocky shallow area surrounded by invasive algae Rugulopteryx okamurae, with total size 61.14 m2. Shoots had relatively small (21.0 ± 2.9 cm) comparison centrally-distributed populations. plants, alongside observed low shoot density (437 42 shoots m?2) leaf index (4.8 0.7 m2 m?2), may indicate meadow could be exposed sub-optimal environmental conditions for plant development. By contrast, showed high production rates (0.03 0.01 day?1 shoot?1) other percentage carbon leaves 38.73 1.38%, while nitrogen C/N 1.38 0.37% 29.93 6.57, respectively. documentation extends making region place highest biodiversity (four species) Iberian Peninsula, potentially Europe. exploratory study baseline examine potential effects climate change, anthropogenic disturbances or presence species.