Avian composition in the rural ‘Amazon Front Yard’ still retains its humid tropical identity

The Bragantina region is one of the most densely settled regions of the Amazon Basin. Rainforests were clear-cut during the last two centuries and replaced by a tessellated rural landscape of pastures, fields, oil palm plantations, gallery forests, and secondary vegetation. However, the impact of the still ongoing land-use changes on biodiversity has hardly been studied, so the purpose of this paper is to summarize bird observations from the Belém area and its rural hinterland. Audiovisual bird surveys were carried out around Belém, on ten farms in the municipality of Igarapé-Açu, and along the Atlantic coast between 1999 and 2018. Compiled species lists are compared with historical studies of the Bragantina, adjacent Maranhão, and Marajó. To evaluate regional community assembly, non-metric multidimensional scaling (NMDS) was employed and beta diversity was partitioned into turnover and nestedness components. Results indicate that community differentiation is primarily driven by species turnover (replacement) rather than nestedness (species loss), reflecting a significant ecological shift while maintaining high regional richness. Species diversity was further analyzed using Hill numbers ( q = 0, 1, 2) and integrated rarefaction/extrapolation curves to ensure robust regional comparisons independent of sampling effort. In total, 300 bird species (220 genera; 62 families) were reconfirmed. Although the mosaic-like landscape resembles savannas today, the data elucidate that bird composition is still more similar to that of the ancient rainforest biome than to that of adjacent savannas. While robust, widespread neotropical generalists, such as Crotophaga ani and Columbina passerina , became dominant, and Guira guira and Melanerpes candidus established themselves, large understory game birds of pristine rainforests are virtually absent. However, endemic canopy species, such as Xipholena lamellipennis , might survive within the Bragantina if sufficiently large forest patches and mast trees are protected and planted at regular intervals across the whole region. Thereby, it may be more promising to protect robust, common (to rare) Amazonian bird species that can follow dynamic land-use changes than to concentrate on the last remaining pristine forest specialists.