<p>The abstract serves both as a general introduction to the topic and as a brief, non-technical summary of the main results and their implications. Authors are advised to check the author instructions for the journal they are submitting to for word limits and if structural elements like subheadings, citations, or equations are permitted. This study investigates the influence of seasonal dynamics on habitat structure and biodiversity in Mediterranean wetlands, using the Marchica Lagoon (Morocco) as a case study. Vegetated areas dominated by seagrass meadows (<i>Zostera noltei</i> and <i>Cymodocea nodosa</i>) were compared with unvegetated zones. During winter, organic matter accumulates due to plant senescence and reduced hydrodynamics, highlighting the role of seagrass meadows as natural carbon sinks. In summer, increased hydrodynamic energy leads to a reduction in fine sediment fractions (silt and clay). Morphometric analysis shows that leaf density is the main trait distinguishing the two species, with <i>C. nodosa</i> exhibiting higher biomass and reflecting a perennial growth strategy. Multivariate analyses reveal that the spatial structuring of plant communities results from the interaction between leaf traits and sediment characteristics. Seagrass meadows also act as biodiversity hotspots: they support higher faunal abundance, greater summer diversity, and communities strongly shaped by seasonal variability. By stabilizing habitats and enhancing functional complexity, these vegetated areas contribute to the ecological resilience of Mediterranean wetlands. The results underscore the key ecological role of seagrass meadows and the need for adaptive, seasonally informed management strategies to safeguard them under increasing anthropogenic pressures.</p>