Vegetation structural complexity is linked to forest soundscapes and informs canopy‐targeted conservation

Understanding how forest vegetation structure shapes acoustic environments is essential for linking biodiversity patterns with ecosystem complexity. However, few studies have systematically examined how fine‐scale three‐dimensional (3D) vegetation features influence soundscape dynamics across diel cycles. Here, we investigated how vegetation structure is associated with acoustic variation over time. We integrated light detection and ranging‐derived 3D vegetation metrics with passive acoustic monitoring across 52 plots in Northeast China Tiger and Leopard National Park. Through a combination of acoustic indices and frequency‐specific power spectral density (PSD) analysis, we examined the associations between six vegetation variables and soundscape characteristics across four diel phases: dawn, day, dusk and night. Canopy structure (e.g. canopy height, crown volume) was most strongly associated with soundscape characteristics during the day and dusk, while understorey openness showed a closer relationship with nocturnal acoustic patterns. Among the acoustic metrics, the Acoustic Evenness Index was especially responsive to vegetation structure variables. PSD results further revealed frequency‐specific vocal stratification, suggesting that different acoustic groups may align their signalling activity with distinct structural layers, a pattern consistent with the ecological niche partitioning hypothesis. Synthesis and applications . Forest soundscapes reflect the composition and activity of local biological communities, both of which are closely linked to vegetation structure. Our findings demonstrate that fine‐scale vegetation heterogeneity is a key correlate of diel soundscape variation, highlighting structural complexity as a key ecological mediator between habitat structure and species behaviour—even in moderately diverse temperate systems. Incorporating 3D structural information into acoustic monitoring provides a robust framework for tracking biodiversity and ecosystem functioning, offering a scalable approach for forest conservation and management.