Ecologia de um psitacídeo introduzido em ambiente urbano
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Data
2017-07-18
Autores
Oliveira, Raquel Colombo [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O processo de urbanização promove a modificação no uso da terra e torna as áreas urbanas em um complexo mosaico de ambientes naturais e antrópicos. A maracanã- pequena (Diopsittaca nobilis - Psittacidae) teve sua população drasticamente reduzida no estado de São Paulo, todavia apresenta diversas populações recentemente estabelecidas em municípios da região sudeste do país, entre os quais, São Paulo. O estudo teve como objetivo avaliar a distribuição, uso de habitat e parâmetros ecológicos de D. nobilis no município de São Paulo, buscando compreender o estabelecimento desta população e o uso do ambiente pela espécie. Foram realizados levantamentos bibliográficos e de dados primários, além de consultas a instituições e especialistas. Quatro campanhas de amostragem foram executadas entre setembro/2015 e julho/2016, em 15 distritos do município, empregando-se o método de “taxa de encontro” em trajetos pré-selecionados. O estudo indica que D. nobilis foi introduzida no município a partir de alguns eventos de soltura, o primeiro deles entre 1987-88, corroborando o Parque Ecológico do Tietê como local e estimando-se um número inicial desta população em 30 a 50 indivíduos. O número inicial de indivíduos, a repetição dos eventos de soltura, realizada com bandos que poderiam ter até 15 indivíduos, e recursos fornecidos pela arborização viária disponível, bem como a suplementação de alimentos no período inicial (soltura branda) devem ter contribuído para o estabelecimento desta população. A distribuição da espécie concentra-se na região central do município, assim como avaliado para o período inicial de estabelecimento, verificando-se progressiva diminuição dos registros à medida em que se afasta do centro. A extensão de ocorrência foi avaliada em 807 km² para São Paulo, chegando a 1074 km² quando considerados registros para a Região Metropolitana. A população de D. nobilis foi avaliada, por meio de censo com contagem simultânea de indivíduos em dormitórios, entre 456 a 524 indivíduos, podendo chegar a 594 indivíduos, ou mais, se consideradas áreas de potencial dormitório ou eventuais dormitórios desconhecidos. A espécie se apresentou como o segundo psitacídeo mais comum na cidade, atrás apenas de Brotogeris tirica. Os bandos registrados variaram entre 1 a 38 indivíduos, com prevalência de casais e bandos com até seis aves, sendo verificada variação circanual no tamanho de bandos, possivelmente refletindo o período reprodutivo da espécie, apontado como de setembro a janeiro. Identificou-se o consumo de frutos, sementes e flores de 12 famílias de plantas, de 22 espécies, predominantemente exóticas. A associação de D. nobilis a palmeiras, verificada para pernoite e sugerida para alimentação e reprodução, deve ser melhor investigada. A espécie distribui-se fundamentalmente pela área urbana, verificando-se sua ausência na região rural do extremo sul do município. A avaliação de uso de habitat indica associação da espécie a Áreas Verdes urbanas, sendo que a população de D. nobilis parece se configurar como uma exploradora do ambiente urbano. Recomenda-se a continuação dos estudos sobre a espécie em áreas urbanas e áreas em que foi introduzida, dando sequência à investigação dos fatores que influenciam a distribuição da espécie em área urbana, mas também abrangendo biologia reprodutiva e tendência populacional.
Urbanization process promotes land use change, creating a complex mosaic of natural and anthropic environments. While the Red-shouldered-macaw (Diopsittaca nobilis – Psittacidae) has had its population severely reduced in the São Paulo state, nowadays it has established several populations in cities in the Brazilian Southeast Region, including the São Paulo city. The present research aimed to evaluate the distribution, habitat use and ecological parameters of the D. nobilis population in São Paulo city, in order to understand the establishment of this species and its environmental use. The research encompassed bibliographic search and personal contact with institutes and experts, besides primary data collection. Field work was conducted between September/2015 and July/2016, in 15 municipal districts, using “encounter rate” method in pre-selected tracks. The research indicates D. nobilis was introduced in the city by some release events, beginning in 1987-88, with initial population size estimated around 30 to 50 individuals. Our study corroborates Tiete Ecological Park as the place where the species was introduced. Some facts such as the initial number of released birds; repeated releases events of groups which could have until 15 individuals, considering this is a gregarious species; and resources provided by urban trees available and soft release may have contributed to the population establishment. The species distribution covers especially the central region of the city, as it was checked for establishment period, noticing a decrease in number of registers as it increases the distance to the central area. The extent of occurrence was gauged in 807 km² in São Paulo city, reaching 1074 km² considering registers available in the Greater São Paulo. D. nobilis population size, evaluated by simultaneous counts of communal roost sites, encompassed between 456 and 524 individuals, which could reach 594 individuals, or even more, considering potential roost areas or unknown roost sites. The species was the second most common parrot in the city, after the most common Brotogeris tirica. Flocks of D. nobilis had between 1 to 38 individuals, and couples and groups of up to six birds prevailed. The flock size presented an annual fluctuation, possibly in response to the reproductive period of the species – between September to January, as indicated by this research. We identify the species feeding of fruits, seeds and flowers of 12 plant family, comprising 22 species, most of them exotic. Association between D. nobilis and palm trees was verified for roosting and it was suggested for feeding and nesting, but it must be better investigated. The species distribution comprised the urban area of the city, being absent in the rural area in the south region of São Paulo. The evaluation of the D. nobilis habitat use indicates an association between the species and urban green areas. D. nobilis population could be classified as an urban exploiter. Further studies are recommended about this species in urban areas and in areas with introduced populations, in order to continue the investigation about factors which influence the distribution of this species in urban areas, but also involving reproductive biology and population trends.
Urbanization process promotes land use change, creating a complex mosaic of natural and anthropic environments. While the Red-shouldered-macaw (Diopsittaca nobilis – Psittacidae) has had its population severely reduced in the São Paulo state, nowadays it has established several populations in cities in the Brazilian Southeast Region, including the São Paulo city. The present research aimed to evaluate the distribution, habitat use and ecological parameters of the D. nobilis population in São Paulo city, in order to understand the establishment of this species and its environmental use. The research encompassed bibliographic search and personal contact with institutes and experts, besides primary data collection. Field work was conducted between September/2015 and July/2016, in 15 municipal districts, using “encounter rate” method in pre-selected tracks. The research indicates D. nobilis was introduced in the city by some release events, beginning in 1987-88, with initial population size estimated around 30 to 50 individuals. Our study corroborates Tiete Ecological Park as the place where the species was introduced. Some facts such as the initial number of released birds; repeated releases events of groups which could have until 15 individuals, considering this is a gregarious species; and resources provided by urban trees available and soft release may have contributed to the population establishment. The species distribution covers especially the central region of the city, as it was checked for establishment period, noticing a decrease in number of registers as it increases the distance to the central area. The extent of occurrence was gauged in 807 km² in São Paulo city, reaching 1074 km² considering registers available in the Greater São Paulo. D. nobilis population size, evaluated by simultaneous counts of communal roost sites, encompassed between 456 and 524 individuals, which could reach 594 individuals, or even more, considering potential roost areas or unknown roost sites. The species was the second most common parrot in the city, after the most common Brotogeris tirica. Flocks of D. nobilis had between 1 to 38 individuals, and couples and groups of up to six birds prevailed. The flock size presented an annual fluctuation, possibly in response to the reproductive period of the species – between September to January, as indicated by this research. We identify the species feeding of fruits, seeds and flowers of 12 plant family, comprising 22 species, most of them exotic. Association between D. nobilis and palm trees was verified for roosting and it was suggested for feeding and nesting, but it must be better investigated. The species distribution comprised the urban area of the city, being absent in the rural area in the south region of São Paulo. The evaluation of the D. nobilis habitat use indicates an association between the species and urban green areas. D. nobilis population could be classified as an urban exploiter. Further studies are recommended about this species in urban areas and in areas with introduced populations, in order to continue the investigation about factors which influence the distribution of this species in urban areas, but also involving reproductive biology and population trends.
Descrição
Palavras-chave
Diopsittaca nobilis, Avifauna, Distribuição espacial, Uso de habitat, Área urbana, Birds, Spatial distribution, Habitat use, Urban area