Soundscape analysis is increasingly recognized as a valuable approach in functional marine ecology. Nevertheless, further investigation is needed to clarify how habitat-related characteristics, environmental and biological factors, and anthropogenic pressures affect acoustic metrics. This study examined the influence of seagrass meadow condition, seasonal variability, and human disturbance on soundscape structure and dynamics. To achieve this, the soundscape of Posidonia oceanica meadows was investigated across 16 sites located within two Mediterranean Marine Protected Areas (in Sicily and Sardinia), using 6,600 recordings of 5 minutes each.

The findings highlighted a complex soundscape characterized by strong spatial variability. Diel patterns emerged as the main factor shaping acoustic dynamics, with nighttime periods showing a marked increase in fish vocalizations and invertebrate snapping activity. Several acoustic metrics were positively associated with greater meadow density and intermediate levels of coverage, indicating that structurally complex meadows supported a more diverse acoustic environment. In addition, meadows developed on sandy bottoms negatively affected nearly all acoustic metrics when compared with those growing on rocky substrates, which provide both a higher number of ecological niches for sound-producing organisms and act as reflective surfaces for sound propagation. Boat-generated noise was widespread throughout the study areas and represented the main determinant of low-frequency sound pressure levels, while also causing significant reductions in acoustic complexity and diversity indices. However, dense meadows showed lower low-frequency sound pressure levels suggesting that the seagrass canopy functioned as an acoustic attenuator of noise pollution.

Overall, the acoustic metrics captured the dynamic relationships among habitat structure, biological activity, and anthropogenic influence. These results demonstrate that soundscape analysis represents a robust complementary method for evaluating the functional condition of P. oceanica meadows and support the inclusion of soundscape within conservation and management strategies.