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Description
High-altitude ecosystems are characterized by strong environmental gradients and increasing seasonal anthropogenic pressure, yet their acoustic structure remains comparatively understudied. In this work, the soundscape of an Alpine National Park was investigated during the peak summer period using passive acoustic monitoring across thirteen recording sites on the Nivolet plateau (Gran Paradiso National Park, Italy). A set of ecoacoustic indices was computed from the recordings and summarized through Principal Component Analysis to identify the dominant acoustic gradients. The indices with the highest loadings on the first two components, Acoustic Entropy (H) and the Normalized Difference Soundscape Heterogeneity Index (NDSHI), were retained as representative descriptors of the July soundscape. Spatial and diel patterns revealed marked heterogeneity among sites, with consistently higher nocturnal values of H and site-dependent variations of NDSHI. To investigate directional relationships among recording locations, Transfer Entropy was applied to the selected ecoacoustic descriptors. Only interactions exceeding the 95th percentile of the |ΔTE| distribution were retained, revealing a sparse but spatially structured network of directional information exchanges. These results highlight the potential of combining ecoacoustic indices with information-theoretic metrics to explore the spatial organization of soundscapes in fragile mountain environments.