Abstract
The Blue-fronted Amazon (Amazona aestiva) is a Neotropical parrot with a large distribution in South America, including areas in Brazil, Bolivia, Argentina and Paraguay. A substantial part of the population of this parrot is concentrated in the Pantanal, a large wetland located in the center of South America. There, the clearing of forest and savannas has occurred through the years to accommodate beef-cattle pasture, and crops. Our objective was to understand the direct and indirect effects of time, availability of forest and savannas, and rainfall over the number of nestlings and fledged young of Blue-fronted Amazons inhabiting the southern Pantanal. We surveyed their nests from 1997 to 2018 and counted the number of nestlings produced and the number of fledglings capable to leave the nest in each year. Additionally, we used available data on the area covered by arboreal vegetation, and rainfall data collected at a Meteorological Station located in a central area of the study, as predictors of the numbers of nestlings and fledglings produced every year. Then, we applied structural equation modeling to examine both the direct and indirect effects of time, arboreal habitat availability, and annual cumulative rainfall on the number of nestlings and fledgling per nest. Finally, we estimated the long-term trend of the number of fledglings per nest as a surrogate to the populational trend of Blue-fronted Amazon. We found that none of the variables in our model explained the number of nestlings in nests, but the number of nestlings and the arboreal habitat availability directly and positively affected the number of fledglings. Time indirectly and negatively affected the number of fledglings per nest, whereas rainfall affected it indirectly positively. Additionally, we detected a concerning decrease of about 30% of the fledglings during the 22-years study, which could lead to a change in the species conservational status.
Funder
Centro de Reabilitação de Animais Silvestres – CRAS / Instituto de Meio Ambiente de Mato Grosso do SulIMASUL
Foz Tropicana/Parque das Aves
Refugio Ecológico Caiman
Fundação Grupo Boticário de Proteção à Natureza
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Fundação de Apoio ao Desenvolvimento do Ensino, Ciência e Tecnologia do Estado de Mato Grosso do Sul
Fundação de Apoio ao Desenvolvimento do Ensino, Ciência e Tecnologia do Estado de Mato Grosso do Sul Fundect/CNPq
Conselho Nacional de Desenvolvimento Científico e Tecnológico
Fundação Neotrópica do Brasil
Conservation International do Brasil
SeaWorld and Busch Gardens Conservation Fund
Instituto Arara Azul
Parrots International
McGrath Family
Publisher
Public Library of Science (PLoS)
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