Spatial distribution and associated flora of Alcantarea nahoumii, a vulnerable endemic species to rocky outcrops of the Serra da Jibóia, Bahia, Brazil

Abstract

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...

Vascular epiphytes on licuri palms (Syagrus coronata (Mart.) Becc.) in a toposequence: Caatinga conservation indicator species

“…At inselberg top and rocky outcrop, there were numerous Bromeliaceae species, some microendemic, such as Tillandsia milagrensis Leme, Dyckia milagrensis Leme and Alcantarea nahoumii (Leme) J.R.Grant. This last species was previously only recorded in the Serra da Jiboia region (Moreira et al 2018), about 35 km in a straight line from the inselbergs of Jatobá.…”

Why do traditional dispersion indices used for analysis of spatial distribution of plants tend to become obsolete?

“…Despite all limitations, the great advantage of the indices discussed in this study is the simplicity of sampling and interpretation when describing the spatial distribution pattern through a simple value (Erfanifard et al, 2016;Szmyt, 2014). This easiness very likely accounts for the great amount of works found in recent scientific literature that use at least one of the dispersion indices and coefficients that were analyzed in this study (Bastos et al, 2018;Bidarnamani & Shabanipoor, 2018;Butturi-Gomes & Petrere Júnior, 2020;dos Santos et al, 2020;Hern andez et al, 2018;Park et al, 2018;Piroozi et al, 2018;Sasaki et al, 2019;Siahaan, Hilwan, & Setiawan, 2019;Sousa & Cunha, 2018;Utami et al, 2019).…”

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“…The spatial distribution pattern of plants can be related to diverse ecological processes, involving endogenous factors, such as mechanisms of dispersion, interspecific interaction, and competition, as well as exogenous factors, such as the soil type, texture, fertility, water availability, light, and temperature (Bastos et al, 2018; Bolker, 2003; Fletcher & Fortin, 2018). Aggregation seems to be the most common pattern among plant species (Butturi‐Gomes & Petrere Júnior, 2020; Legendre & Fortin, 1989; Nascimento et al, 2001; Schulze et al, 2019), and tends to occur in heterogeneous environments, where there can be more favorable places for the establishment of plants (Perry et al, 2006).…”

Epífitas vasculares da Serra de Baturité, Ceará, Nordeste do Brasil

“…According to Zizka et al (2019) about 2/3 (81%) of the 3,503 species of bromeliads in tropical forests may be threatened with extinction. Among the main causes are habitat loss, climate change and, mainly, unsustainable collection (Bastos et al, 2018). This topic deserves more attention, since Baturité Massif receives more than 500 thous and visitors per year (PDITS, 2014), among them the visit of collectors or even local residents, who collect for commercialization.…”