<p>Understanding how landscape structure influences multiple dimensions of biodiversity is crucial for conservation in fragmented ecosystems. We investigated how bird communities respond to landscape composition and configuration across multiple spatial scales in 20 forest fragments in the Atlantic Forest biome, southern Brazil. Using standardized point counts, we assessed 14 bird community attributes related to species richness, composition, and functional diversity. We modeled the effects of forest cover, forest isolation, crop cover, landscape diversity (at 0.5, 1, 2, and 5&#xa0;km radii), fragment size, and the presence of valley bottoms. Forest isolation was the strongest negative predictor, reducing total species richness, abundance, and the number of dietary specialists. However, forest cover and diversity of habitats within landscapes partially mitigated these effects by increasing the specialists-to-generalists ratio and the average abundance per species. Although functional richness and dispersion remained stable, declines in functional evenness and divergence with increasing forest cover, along with higher specialists-to-generalists ratio, indicate a simplification of functional structure driven by generalist species. Bird communities responded most strongly to landscape structure at the 5&#xa0;km scale, suggesting that many species rely on landscape-level connectivity to persist. At the local scale, the presence of valley bottoms decreased functional divergence, suggesting that dominant species in these areas occupy more similar functional roles. These findings underscore the need to maintain and restore forest connectivity and landscape heterogeneity to conserve avian diversity. Conservation strategies should focus on increasing forest cover and restoring ecologically important areas, such as valley bottoms, particularly in simplified agricultural landscapes dominated by monocultures.</p>