Análise temporal da comunidade de aves em um fragmento de vegetação natural em unidade de manejo florestal
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2019-09-30
Autores
Silva, Guilherme Lima da
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Universidade Estadual Paulista (Unesp)
Resumo
A fragmentação é uma das principais causas da perda de biodiversidade. Conciliar as atividades produtivas e a conservação dos recursos naturais é um dos principais desafios das empresas do setor florestal. Poucos estudos avaliam a composição e estrutura das comunidades em longo prazo, sendo o monitoramento de aves uma ferramenta eficaz para tal finalidade. Este estudo foi conduzido num fragmento de vegetação natural em unidade de manejo florestal no município de Agudos, interior de São Paulo, Brasil. Tem como objetivo verificar se houve alteração na comunidade de aves de um fragmento de no intervalo de 35 anos. Nesse intervalo o fragmento que no estudo inicial era isolado foi conectado a outras áreas de vegetação natural por meio de corredores ecológicos. A captura das aves foi realizada com o auxílio de redes de neblina, dispostas em cinco pontos, com quatro redes por ponto. As amostras foram realizadas por dois dias consecutivos/mês/ponto sendo o estudo inicial, realizado de março de 1982 a janeiro de 1983 e o atual, de novembro de 2017 a dezembro de 2018. No estudo inicial foram capturados 368 indivíduos, distribuídos em 16 famílias e 32 espécies. A diversidade foi de H’ = 2,7. Não houve dominância significativa entre as espécies (J = 0,77). No atual foi constatada diminuição significativa na riqueza e diversidade, sendo capturados 142 indivíduos, de 12 famílias e 18 espécies. A diversidade foi de H’ = 2,2. Não houve dominância significativa entre as espécies (J = 0,78). A curva do coletor no estudo atual não tendeu a estabilização, sendo estimadas 26 espécies (Jackknife1). Os resultados mostram que apesar das estratégias adotadas pela empresa, a avifauna continuou sendo afetada pelos impactos da fragmentação já previstos pela literatura. As alterações na matriz no qual o fragmento está inserido contribuíram significativamente para as alterações identificadas. Estudos de longo prazo são de grande importância, porém foi constatada a necessidade de monitoramentos pontuais e em menores intervalos de tempo. Apesar de não terem sido capturadas no estudo atual, algumas espécies foram registradas na área em estudo forrageando nos estratos mais altos do fragmento, sendo esta mudança de comportamento uma das respostas apresentadas pela avifauna às alterações no habitat. Foram registradas cinco novas espécies com destaque para Eucometis penicillata e Thamnophilus pelzelni, espécies dependentes de ambientes florestais que dificilmente se deslocam por áreas abertas, constatando a efetividade dos corredores ecológicos.
Fragmentation is a major cause of biodiversity loss. Reconciling how productive activities and conservation of natural resources is one of the main challenges for companies in the forest sector. Few studies assess long-term community composition and structure, and bird monitoring is an effective tool for such use. This study was conducted on a fragment of natural vegetation in the forest unit in Agudos, São Paulo State, Brazil. It aims to verify if there was alteration in the bird community of a 35 years interval fragment. In this interval the fragment that in the initial study, was connected to other areas of natural vegetation through ecological corridors. The birds were captured with the aid of five point mist nets with four nets per point. Samples were taken for two consecutives days/month/point with the initial study conducted from March 1982 to January 1983 and the current study from November 2017 to December 2018. No initial study captured 368 individuals, distributed in 16 families and 32 species. The diversity was H '= 2.7. There was no significant dominance between species (J = 0.77). At the moment, there was a significant reduction in richness and diversity, and 142 individuals from 12 families and 18 species were captured. The diversity was H '= 2.2. There was no significant dominance between species (J = 0.78). A collector curve in the current study is not stabilized and an estimated 26 species (Jackknife1). The results show that despite the strategies adopted by the company, an avifauna community continues to be affected by the impacts of fragmentation predicted in the literature. Changes in the matrix in which the fragment is inserted contributed significantly to the identified changes. Long-term studies are of great importance, but have found the need to monitor punctual and at shorter intervals. Although not captured in the current study, some species have been recorded in the study area to stage at the highest levels of the fragment, and this behavior change is one of the responses applied by birds to habitat changes. Five new species were recorded, especially Eucometis penicillata and Thamnophilus pelzelni, species dependent on forest environments that can hardly move through open areas, noting the effectiveness of ecological corridors.
Fragmentation is a major cause of biodiversity loss. Reconciling how productive activities and conservation of natural resources is one of the main challenges for companies in the forest sector. Few studies assess long-term community composition and structure, and bird monitoring is an effective tool for such use. This study was conducted on a fragment of natural vegetation in the forest unit in Agudos, São Paulo State, Brazil. It aims to verify if there was alteration in the bird community of a 35 years interval fragment. In this interval the fragment that in the initial study, was connected to other areas of natural vegetation through ecological corridors. The birds were captured with the aid of five point mist nets with four nets per point. Samples were taken for two consecutives days/month/point with the initial study conducted from March 1982 to January 1983 and the current study from November 2017 to December 2018. No initial study captured 368 individuals, distributed in 16 families and 32 species. The diversity was H '= 2.7. There was no significant dominance between species (J = 0.77). At the moment, there was a significant reduction in richness and diversity, and 142 individuals from 12 families and 18 species were captured. The diversity was H '= 2.2. There was no significant dominance between species (J = 0.78). A collector curve in the current study is not stabilized and an estimated 26 species (Jackknife1). The results show that despite the strategies adopted by the company, an avifauna community continues to be affected by the impacts of fragmentation predicted in the literature. Changes in the matrix in which the fragment is inserted contributed significantly to the identified changes. Long-term studies are of great importance, but have found the need to monitor punctual and at shorter intervals. Although not captured in the current study, some species have been recorded in the study area to stage at the highest levels of the fragment, and this behavior change is one of the responses applied by birds to habitat changes. Five new species were recorded, especially Eucometis penicillata and Thamnophilus pelzelni, species dependent on forest environments that can hardly move through open areas, noting the effectiveness of ecological corridors.
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Fragmentação, Monitoramento, Bioindicadores, Silvicultura, Avifauna, Fragmentation, Monitoring, Bioindicators, Forestry, Avian communities