Forest structure mediates topographic effects on salamanders’ abundance in European unmanaged forests

• Detection-corrected salamander abundance estimated using Bayesian N-mixture models. • Topography shapes salamander abundance directly and indirectly via forest structure. • Salamandrina perspicillata peaks in north-facing valley bottoms with open canopies. • Speleomantes strinatii favours mature forests with dense canopy and rocky refugia. • SEM reveals species-specific pathways linking terrain, forest structure, and abundance.