Remote sensing and passive acoustic monitoring in Riparian Forest: linking habitat structure to bird diversity

Riparian forests play a crucial role in maintaining biodiversity, providing essential habitats for many species, including birds. This study investigates bird biodiversity in riparian forests of South Tyrol, aiming to understand how variations in habitat structure influence species diversity. Data collection was conducted using autonomous acoustic recorders, strategically placed within these forested areas to capture bird activity over extended periods. Additionally, high resolution lidar and multispectral data were utilized to map the structural characteristics of the study areas. By analyzing the relationship between habitat features – such as canopy volume, vegetation density, and landscape complexity – and bird species richness, this research seeks to identify key habitat variables that either promote or limit avian biodiversity. The study findings indicate that structural attributes – such as vegetation greenness, tree density, canopy and understory layering, and vertical heterogeneity – emerge as key determinants of avian presence and community composition in riparian forests. Sites characterized by high canopy volume and multi-layered vegetation supported richer and more specialized bird assemblages, underscoring the importance of mature stand features and structurally diverse habitats for forest-dependent species. From a management perspective, these results highlight the value of maintaining heterogeneous riparian stands through strategies that preserve mature tree cohorts, retain natural understory development, and avoid excessive canopy simplification. Ensuring the structural continuity of riparian corridors may be particularly relevant in fragmented Alpine landscapes, where these systems function as biodiversity refugia and dispersal routes. By linking high-resolution structural metrics with acoustic biodiversity assessments, this work provides an operational framework for integrating remote-sensing indicators into riparian conservation planning and monitoring, with implications for evidence-based habitat restoration and climate-adaptation strategies.