The birds of reminiscent and regenerated Semideciduous Atlantic Forest fragments in southeastern Brazil

Abstract

The Botucatu Cuesta region in São Paulo, southeastern Brazil, harbors exceptional avian diversity, with 363 species recorded across just two localities – the Lageado (LEF) and the Edgárdia (EEF) Experimental Farms – representing nearly half of São Paulo’s avifauna. Our study builds upon historical inventories, documenting 32 new species for LEF (bringing the total to 265) and 84 for EEF (now totaling 351). These additions include boreal migrants, such as the Veery Catharus fuscescens, and Atlantic Forest endemics with distributions rarely extending inland, such as the Grey-hooded Attila Attila rufus. Notably, 92% of historically recorded species persist since the 1970s, with losses primarily attributed to wetland degradation (e.g., Rosy-billed Pochard Netta peposaca) and forest-dependent taxa (e.g., Spot-breasted Antvireo Dysithamnus stictothorax). Aquatic species, including the Limpkin Aramus guarauna and Anhinga Anhinga anhinga, have declined due to land-use changes, while others, such as the Spotted Rail Pardirallus maculatus, require further investigation given their likely local rarity. We underscore the urgent need for habitat restoration, particularly wetland management – potentially including the reintroduction of historical rice cultivation – to reestablish suitable habitats for lost species. The Cuesta’s avifauna highlights its conservation priority, yet targeted strategies are essential to counter threats from agricultural expansion and hydrological alterations. This study establishes a critical baseline for future monitoring and emphasizes the region’s pivotal role in conserving Neotropical bird diversity at the Atlantic Forest-Cerrado transition.