Historical anthropogenic stressors affect bird ecology and feather development in neotropical forests

Author(s)

Navarro, Ana B. ; Moreira, Marcelo Z. ; Naka, Luciano N. ; Araujo, Helder F. P. ; Magioli, Marcelo ; Newton, Jason ; McGill, Rona A. R. ; Silveira, Luis F.

• Document type: Journal article
• Source: OIKOS; v. N/A, p. 17-pg., 2025-07-14.

Abstract

Fragmentation and habitat loss driven by agricultural expansion have significantly affected bird ecology. Additionally, the growing use of agrochemicals impacts ecosystems and avian communities. Tools such as isotopic analysis provide reliable proxies for assessing organisms' habitat use and diet, and can also reflect environmental alterations, such as increased input of agrochemicals and shifts in baseline resources. By employing stable isotope analysis of carbon (delta 13C) and nitrogen (delta 15N) on bird feathers over an extensive timescale, we investigated whether human impacts have changed their habitat use, diet, and feather development in two key regions of the Brazilian Atlantic Forest: the Pernambuco and Serra do Mar areas of endemism. We analyzed feathers from 1778 museum specimens, categorized by region, trophic guild and temporal groups (historical and modern). Furthermore, we examined fault bars in the wing and tail feathers of 856 specimens to assess changes in feather development. In Serra do Mar, comparisons showed a significant decline in delta 15N over time, while delta 13C remained stable. These findings suggest that, in addition to habitat loss, agrochemical runoff may indirectly affect bird communities in this region, known for its high agricultural activity. In contrast, isotopic changes in Pernambuco were significant for only a few species, suggesting that habitat use and diet shifts in this region are primarily driven by fragmentation and forest loss. Moreover, we noted a decline in feather quality over time, underscoring the negative effects of human stressors on feather development across the Atlantic Forest birds. (AU)

• FAPESP's process: 20/07619-0 - Past, present and future of habitat use and diet of birds in the face of anthropogenic impacts in the Atlantic Forest of Brazil
• Grantee: Ana Beatriz Navarro
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 22/06791-9 - The ecological and functional role of Xenarthra in the trophic webs
• Grantee: Marcelo Magioli
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 22/06154-9 - Stable isotopes as a tool for understanding bird ecology: a call for Brazilian human resource development
• Grantee: Ana Beatriz Navarro
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• FAPESP's process: 17/23548-2 - Evaluation, recovering and conservation of endangered animal species from the Pernambuco Centre of Endemism
• Grantee: Luís Fábio Silveira
• Support Opportunities: BIOTA-FAPESP Program - Thematic Grants