Taxonomia e Ecologia de Cryptanthus na Caatinga, Bahia

Abstract

Cryptanthus Otto &A.Dietr. (Bromeliaceae) is an endemic genus of Brazil, with 78 species, occurring in the phytogeographic domain of the Atlantic Forest, from the southern coast of Rio de Janeiro, to the narrow strip of Atlantic Forest of Rio Grande do Norte. In the Cerrado it occurs mainly in the Rupestres Field, while in the Caatinga it occurs in environments whose vegetation is more humid than in the Savannah Estépica, typical of this region. Cryptanthus is quite demanding as to the quality of the environment where they occur, generally related to the margins of perennial and shady streams. On the other hand, the ChapadaDiamantina Complex, an ecoregion of the Caatingaphytogeographic domain, where due to the altitude and higher precipitation, when compared to the other ecoregions, allows the establishment of ecotonal areas where the larger vegetation can be found in medium the Caatinga is typically hyperxerophilic. In this ecoregion, more precisely in the north of the ChapadaDiamantina, in a junction of semideciduous seasonal Forest between the municipalities of Jacobina (BA) and Miguel Calmon (BA), a new species of the genus Cryptanthus was found in this study described as Cryptanthus euglossinii E. Almeida & JA Siqueira. The specific epithet refers to the bees of the tribe Euglossinii (Apidae), which visit the flowers of C. euglossinii. These collected bees were males of Euglossamelanotricha, Eulaemacingulata and Eulaemanigrita, which scrape the petals of C. euglossinii to collect floral perfumes. The new species includes C. bibarrensis and C. reisii, two sympatric species of the Bahian Atlantic Forest. In addition, in this study, a method was designed to indicate the use of Cryptanthus as an indicator of biological diversity in the Caatinga, using niche modeling, to compare the richness of angiosperm species in the areas of Cryptanthus occurrence with the richness of the areas where this group is absent. In total, 15 plots distributed in four fragments of native vegetation were carried out, eight of them in areas of Cryptanthus occurrence, and seven areas where the genus is absent. An ANOVA (one-way) test was used with a variable predicting the presence or absence of Cryptanthus, and variable response to the richness of angiosperm species of each transect. With result of F (1.15) = 2.75; p = 0.121, refuting the hypothesis that the presence of Cryptanthus infers in a greater richness of angiosperms in their areas of occurrence. This result may be related to the chosen area for the absence of the genus being located in the area of the newly created National Park of Boqueirão da Onça, one of the most conserved Caatinga areas. In addition, the occurrence areas of Cryptanthus showed greater anthropic pressure, with smaller vegetation fragments, and lower vegetation cover around the fragments. Although Cryptanthus is a demanding group of habitat quality, the decharacterization of the relational environmental of seasonal forests where they occur compromises the relationship between the biological diversity indicator and the conservation of the areas