Alcantarea nahoumii occurs exclusively in the state of Bahia, Brazil, and is classifi ed as vulnerable due to deforestation and frequent fi res in the region. Knowledge of fl oral and reproductive biology is fundamental to understanding ecological interactions, as well as the reproductive success of plant species. Th e objective of this study was to evaluate the fl oral and reproductive biology of A. nahoumii in an Atlantic Forest fragment with regard to phenology, pollen viability, stigma receptivity, pollination ecology and reproductive systems, all of which are important parameters for of the development of conservation strategies for the species. Anthesis is diurnal and heterogeneous, starting at 6:30 a.m. and lasting until 8:00 a.m. Highest germination percentages and greatest pollen tube lengths were obtained in BK culture medium. Histochemical tests revealed high pollen viability (89.71 %). Stigma receptivity occurred during anthesis and lasted for up to 24 hours after fl oral opening. Alcantarea nahoumii exhibited preferential allogamy and self-compatibility, and required a pollinator to production of viable seeds. Sixteen species of pollinators were observed visiting A. nahoumii, among which were fi ve hummingbird species. Even though its reproductive system is effi cient, this bromeliad remains threatened mainly due to habitat fragmentation caused by deforestation, burning and predatory extractivism.
The objective of this study was to characterize the spatial distribution pattern at different altitude gradients as well as to investigate the flora associated with A. nahoumii, considered to be endemic and vulnerable. The study was carried out in Serra da Jibóia, Santa Teresinha, Bahia, Brazil. An inventory was conducted of young and adult A. nahoumii specimens along with taxonomic identification and quantification of the associated species. The cover percentage of A. nahoumii, rock slope, organic matter percentage and exposed rock percentage were calculated, as well as the following phytosociological parameters: absolute density, relative density, absolute frequency, relative frequency, and dominance of A. nahoumii. For the spatial distribution, three indices were tested (Morisita, McGuinnes and Payandech). Canonical correspondence analysis was also applied to test the association of the environmental variables with the species in the community. A total of 1,660 individuals were encountered and classified according to taxonomy in 17 families, 25 genera and 28 species. The spatial distribution pattern of the A. nahoumii population is aggregate. The results demonstrate that the population structure of A. nahoumii is stable, but events such as fires and extractive exploitation make the species vulnerable, along with the other species that inhabit the area. Key words: Bromeliaceae, conservation, endemism, dispersion index, floristic survey, plant diversity. ResumoO objetivo deste trabalho foi caracterizar o padrão de distribuição espacial da A. nahoumii em diferentes gradientes de altitudes, bem como realizar o levantamento florístico da vegetação associada a A. nahoumii, considerada endêmica e "Vulnerável". O estudo foi realizado na Serra da Jibóia, Santa Teresinha, Bahia, Brasil. Foi realizado um inventário de plantas jovens e adultas da A. nahoumii, bem como a identificação taxonômica e quantificação das espécies associadas, percentagem de cobertura da vegetação, percentagem de cobertura da A. nahoumii, inclinação da rocha, percentagens de matéria orgânica e rocha exposta. Foram calculados os parâmetros fitossociológicos: densidade absoluta, densidade relativa, frequência absoluta, frequência relativa e dominância da A. nahoumii. Para a distribuição espacial foram testados três índices: Índice de Morisita, McGuinnes e Payandech. Também foi realizada uma Análise de Correspondência Canônica para as variáveis ambientais com as espécies da comunidade. Um total de 1.660 indivíduos foram encontrados e classificados taxonomicamente em 17 famílias, 25 gêneros e 28 espécies. O padrão de distribuição espacial da população de A. nahoumii é agregado. Os resultados demonstram que a estrutura populacional da A. nahoumii está estável, mas eventos como queimadas e exploração extrativista, as tornam vulnerável, juntamente com as demais espécies que habitam a área. Palavras-chave: Bromeliaceae, conservação, endemismo, índice de dispersão, inventário florístico, diversidade de plantas.Spatial distribution and associated f...
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