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Fenologia da floração e biologia floral de bromeliáceas ornitófilas de uma área da Mata Atlântica do Sudeste brasileiro

01/2006; DOI: 10.1590/S0100-84042006000100014

ABSTRACT Flowering phenology and floral biology of some ornitophilous Bromeliaceae of an Atlantic forest area in southeastern Brazil). This study dealt with phenology and flower visitors of some Bromeliaceae species in an Atlantic Forest area at Parque Estadual Intervales, southeastern Brazil. The taxa studied belonged to the genera Tillandsia L. (3 spp.), Vriesea Lindl. (5 spp.), Aechmea Ruiz & Pav. (3 spp.), Billbergia Thunb. (1 sp.) and Nidularium Lem. (2 spp.). Sample transects were established in areas with different succession stages, where the bromeliads were localized and marked. Flowering phenology surveys were made monthly. The bromeliad community showed a sequential flowering all along the year and most species flowered during the rainy season. The floral visitors were recorded by naturalistic observations. Eight hummingbird species visited the bromeliads flowers. Among them, Phaethornis eurynome Lesson and Thalurania glaucopis Gmelin were the most frequent visitors. Bromeliads were divided in two groups by similarity analysis of floral visitors (hummingbirds): a group represented by species visited by Trochilinae hummingbirds and another visited by Phaethornis eurynome (subfamily Phaethornithinae). The competition among bromeliad species for pollinators is reduced due to their spatial distribution and the flowering periods. RESUMO - (Fenologia de floração e biologia floral de bromeliáceas ornitófilas de uma área da Mata Atlântica do Sudeste brasileiro). Foi investigada a fenologia e os visitantes florais de espécies da família Bromeliaceae em uma área de Mata Atlântica, no Parque Estadual Intervales, no Sudeste brasileiro. Os táxons estudados pertencem aos gêneros Tillandsia L. (3 spp.), Vriesea Lindl. (5 spp.), Aechmea Ruiz & Pav. (3 spp.), Billbergia Thunb. (1 sp.) e Nidularium Lem. (2 spp.). Foram estabelecidas transecções amostrais em áreas com diferentes estádios sucessionais, onde foi registrada a localização dos indivíduos nos estratos da vegetação e realizados censos mensais da fenologia de floração. As bromeliáceas apresentaram padrão de floração seqüencial ao longo do ano, com maior número de espécies floridas na estação chuvosa. Os visitantes florais foram registrados por observações naturalísticas. Oito espécies de beija-flores visitaram as flores das bromélias. Destas, Phaethornis eurynome Lesson e Thalurania glaucopis Gmelim foram os visitantes mais freqüentes. A análise da similaridade dos beija-flores visitantes florais indicou a existência de dois conjuntos de espécies de bromeliáceas: o primeiro polinizado principalmente por espécies da sub-família Trochilinae e outro por Phaethornis eurynome (sub-família Phaethornithinae). A distribuição espacial diversa e, sobretudo os diferentes picos de floração foram os principais fatores que minimizaram a competição por polinizadores entre as espécies de Bromeliaceae estudadas.

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