Past, present and future of ecological patterns of birds in response to anthropogenic impacts in the Brazilian Atlantic Forest

• Ano de defesa: 2025
• Autor(a) principal: Navarro, Ana Beatriz
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Anthropogenic impacts; Atlantic Forest. Bird ecology; Ecologia histórica; Espécimes de museus; Historical ecology; Impactos antrópicos; Isotopic niche; Isótopos estáveis; Mata Atlântica, Ecologia de aves; Museum specimens; Nicho isotópico; Stable isotopes
• Link de acesso: https://www.teses.usp.br/teses/disponiveis/38/38131/tde-01092025-161307/

Tropical forests are among the most threatened ecosystems globally, in which the Brazilian Atlantic Forest stands out due to its exceptional biodiversity, high levels of endemism, and a long history of anthropogenic degradation. With only a fraction of its original cover remaining, mostly fragmented and embedded in human-modified landscapes, understanding how such changes have affected animal ecology is both urgent and essential. Birds are excellent indicators of environmental change, yet long-term ecological responses remain underexplored in the Neotropics. In this context, in this thesis I aimed to reconstruct historical shifts in bird ecology in the Atlantic Forest, focusing on changes in habitat use, diet, trophic structure, and isotopic niche dynamics in response to anthropogenic pressures over the past centuries. Through carbon and nitrogen stable isotope analysis of a large dataset of bird feathers from museum specimens, I examined long-term ecological trends across multiple biological scales and two areas of endemism within the Atlantic Forest: Pernambuco and Serra do Mar. Firstly, I conducted a comprehensive review on the development of isotopic ecology in Brazilian ornithology, highlighting the potential of the stable isotopes to address key ecological questions, especially advocating for the use of museum specimens to investigate historical ecological dynamics in neotropical birds. Through 13C and 15N values, I investigated how anthropogenic impacts have affected bird ecology and morphology over time, in which habitat fragmentation and agrochemical use revealed region-specific responses in birds of the Atlantic Forest. Although an increase in the ratio of feathers with fault bars was observed for both Pernambuco and Serra do Mar modern birds, which may be driven mainly by human stressors. The isotopic niche dynamics of bird communities, guilds, and species were also examined across time in this thesis. Community-level niche expansion suggests a broadscale ecological response to environmental change in the Atlantic Forest birds. However, divergent responses at the guild and species levels, which varied by region, highlight the importance of fine-scale processes and local conditions in shaping ecological trajectories. Finally, I explored how generalist and specialist bird communities have responded differently to environmental change in the Atlantic Forest. Generalists showed isotopic niche expansion and increased trophic diversity over time, likely occupying niches left by declining specialists. Conversely, specialists exhibited niche contraction over time, consistent with their greater sensitivity to habitat degradation. These results suggest a future trend toward the generalization of bird communities in the Atlantic Forest. Altogether, this thesis offers a longterm perspective on the ecological impacts of anthropogenic change in one of the worlds most threatened biodiversity hotspots, emphasizing the potential of stable isotope ecology and museum collections in reconstructing and monitoring ecological patterns over time.