Scale-dependent effects of forest area on Atlantic Forest bird occupancy and diversity

Forest area influences bird diversity, although its effects often vary among regions and spatial scales. Understanding these relationships is essential for explaining local biodiversity patterns and informing conservation planning. We evaluated the effects of forest area in highly forested landscapes on bird occupancy, species richness, and β-diversity using a multiscale modeling framework that simultaneously quantified local- and landscape-scale influences in the Argentinian Atlantic Forest. Using in-person point counts and Automated Recording Units, we surveyed 256 points and identified birds across 42,739 min of listening time. We applied multiscale, -multispecies occupancy models, one including 123 bird species and another restricted to 45 endemic species, and used Generalized Dissimilarity Modeling to assess β-diversity with forest area. Overall, even small reductions in forest area negatively affected species richness, with stronger effects observed for endemic and threatened species. Community-level responses masked substantial species-specific variation, and no single spatial scale adequately explained occupancy patterns across the assemblage. Seven possible combinations of positive, negative, and neutral responses across spatial scales were observed. No species were positively associated with forest area at one scale but negatively associated at the other. Community dissimilarity varied among scales: local-scale forest area had stronger effects on β-diversity, whereas landscape-scale forest area determined the conditions under which communities stabilized. We recommend integrating species and region-specific approaches with multiscale environmental variables to better inform conservation and management strategies. Maintaining high forest area across spatial scales appears particularly important for endemic and threatened species, underscoring the need for coordinated cross-scale conservation planning.