Field work and data from herbaria collections (2686 records) representing 283 taxa (265 species and 18 infraspeciWc taxa) of Bromeliaceae occurring at Minas Gerais state, southeastern Brazil, were analyzed in order to obtain distribution and diversity information, and to determine IUCN (The World Conservation Union) conservation status for each taxon. A map containing 1°£ 1° grid cells was used to identify priority areas for new research collections, areas of high species diversity, and Bromeliaceae conservation status. A clear decrease in Bromeliaceae diversity is observed between the eastern and the western portions of Minas Gerais, and low Xoristic similarities were found between neighboring grid cells. The rocky mountains of Cadeia do Espinhaço are considered the most important area for Bromeliaceae endemics. From the 283 taxa of Bromeliaceae that occur at Minas Gerais, 118 (42%) are considered threatened, and 124 taxa (44% of the total) do not occur inside any protected area. The region of the Quadrilátero Ferrífero in the southern portion of the Cadeia do Espinhaço is the most threatened, and urgent strategies for conservation of this rich Bromeliaceae Xora are needed. Northeastern Minas Gerais, particularly the rocky outcrops or inselbergs located in the Jequitinhonha and Mucuri rivers drainage basins need additional collection eVorts and conservation actions focused on these saxicolous taxa.
The genus Alcantarea comprises near 30 species endemic to rocky outcrops from eastern Brazil. Most species are ornamental and several are threatened due to habitat loss and over collection. In this paper we examine the phylogenetics of Alcantarea and its relationship with the Brazilian members of Vriesea, a genus of which Alcantarea has been treated as a subgenus. We discuss the morphological evolution of the stamen position and its implication for pollination and the occurrence of Alcantarea in the Espinhaço mountain range rocky savanna-like habitat vegetation. DNA sequence data derived from two plastid markers (trnK-rps16, trnC-petN) and from a low copy nuclear gene (Floricaula/Leafy) together with 20 nuclear microsatellite loci were the data source to perform analyses and construct phylogenetic and Neighbor Joining trees for the genus. Alcantarea is well supported as monophyletic in both Bayesian and parsimony analyses, but sections of Vriesea, represented by the eastern Brazilian species, appear paraphyletic. Microsatellites delimit geographically isolated species groups. Nevertheless individuals belonging to a single species may appear related to distinct clusters of species, suggesting that hybridization and/or homoplasy and/or incomplete lineage sorting are also influencing the analysis based on such markers and may be the reasons for some unexpected results. Alcantarea brasiliana is hypothesized as putative hybrid between A. imperialis and A. geniculata. Spreading stamens, a morphological floral characteristic assumed to be related to Chiropterophily, apparently evolved multiple times within the genus, and invasion of rocky savanna-like habitat vegetation by Atlantic rainforest ancestors seems to have occurred multiple times as well.
Aim Pilosocereus is one of the richest and most widespread genera of columnar cacti, extending from south‐west USA to southern Brazil. Most species occur in the seasonally dry tropical forest biome but can also be found in xeric microhabitats inside woody savannas (Cerrado) and moist forests (Brazilian Atlantic forest). The genus exhibits a highly disjunct distribution across the Neotropics. Using a 90% complete species‐level phylogeny, we reconstructed the spatio‐temporal evolution of Pilosocereus to explore the historical factors behind the species richness of Neotropical dry formations. Location South America, Mesoamerica, Caribbean, south‐western North America. Taxon Genus Pilosocereus (Cactaceae, Cactoideae, Cereeae). Methods We used plastid and nuclear DNA sequences and Bayesian inference to estimate phylogenetic relationships and lineage divergence times. Ancestral ranges were inferred within the Pilosocereus subgenus Pilosocereus s. s. clade using the Dispersal–Extinction–Cladogenesis model in a Bayesian framework to account for parameter estimation uncertainty and the effect of geographical distance on dispersal rates. Results Pilosocereus was recovered as polyphyletic, with representatives of other Cereeae nested within. The Pilosocereus subgenus Pilosocereus s. s. clade originated around the Pliocene–Pleistocene transition (2.7 Ma), probably within the Caatinga seasonally dry tropical forest (SDTF) formation. Species divergences were dated in the Middle and Upper Pleistocene, often constrained to the same geographic region but also associated to migration events to other xeric habitats in Mesoamerica and northern South America; dispersal rates were not dependent on distance. Main conclusions Diversification dynamics in the Pilosocereus subgenus Pilosocereus s. s. clade agree with other infrageneric studies in cacti. Species divergence was rapid, driven by in situ diversification and migration events between SDTF dry formations and xeric microhabitats within other biomes and probably linked to Pleistocene climatic changes. This dynamic history differs from that found in woody SDTF lineages, which are older in age and characterized by low‐dispersal rates and long‐term isolation.
Inselberg-adapted species of bromeliads (Bromeliaceae) have been suggested as model systems for understanding the evolutionary genetics of species complexes and radiations in terrestrial, island-like environments. Bromeliads are particularly suitable for addressing the potential roles of interspecific gene exchange during plant speciation and radiation. We have studied populations of five narrowly endemic Alcantarea species adapted to highelevation inselbergs of the Atlantic Rainforest of Brazil with nuclear and plastid DNA markers, estimated outcrossing rates in the giant bromeliad A. imperialis using progeny arrays and carried out a pilot study on the use of next generation sequencing-based genotyping in this group. Our results suggest widespread and asymmetric interspecific gene flow in the studied species complex, which visibly affects patterns of genetic diversity in the phenotypically variable mixed outcrosser A. imperialis. Our data support the hypothesis that gene flow has contributed to the origin of phenotypic forms in the A. imperialis s.l. species complex. We discuss potential conflicts between our neutral marker data and previous taxonomic work and suggest how these might be resolved. We close with a brief outlook on the potential of genomic tools to uncover the hidden links between genotypes, phenotypes and niches in bromeliads and other plant radiations.
Difficulties in identifying Vriesea minarum as well as a conflict of interest among mining companies and local conservationists are pushing this species towards extinction. Vriesea minarum was categorised as data deficient in the Brazilian official plant red list despite earlier works indicating its vulnerability. This species is restricted to the Iron Quadrangle area, Minas Gerais, Brazil, where it grows over iron rock outcrops. Here we use V. minarum to illustrate the importance of taxonomic investigation as well as the presentation of accurate distributional data in order to establish conservation strategies. We emphasize the importance of well-conserved herbaria collections and adequate type material to avoid taxonomic issues that delay the understanding of species limits. This paper presents taxonomic notes and the redefining of V. minarum based on the survey of 22 herbaria collections and fieldwork. The additional material obtained and a morphometric approach allowed us to better delimit the related taxa. The species V. ouroensis is considered to be a new synonym of V. minarum. A map showing the occurrences of populations of V. minarum, pictures of living specimens in the field, as well as its updated conservation status are provided. Historic records housed in herbaria indicate that this species has been progressively losing its area of occurrence.
• Premise of the study: Knowledge about genetic variability in plant populations is one of the main branches of conservation genetics, linking genetic data to conservation strategies. Vriesea minarum is a bromeliad endemic to the Iron Quadrangle region (southeastern Brazil), occurring on mountaintop rock outcrops. It is listed as endangered due to habitat loss, particularly from iron ore mining. Thus, determining the structure and genetic diversity of V. minarum populations could help develop strategies to conserve the species.• Methods: We studied the genetic structure of 12 populations of V. minarum using 10 microsatellite loci transferred from other species of Bromeliaceae. Statistical analyses to compare and describe the genetic diversity of each population were performed, and genetic structure within and among populations, isolation by distance, and Bayesian structure were also analyzed.• Key results: Our results show high inbreeding (G = 0.376) and low population structure (F = 0.088), possibly related to high gene flow due to great pollinator efficiency and/or efficient seed dispersal, thus leading to high connectivity among populations of these fragmented rock outcrops. Two clusters were observed, corresponding to the basins of rivers São Francisco and Doce.• Conclusions: Gene flow among populations is high but, given the rate of habitat loss to mining, most populations are vulnerable and will become increasingly isolated if no action is taken to preserve them. Thus, conservation of this species depends on in situ and ex situ actions, such as controlling overexploitation and creating a germoplasm bank.
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