This study provides a species list of the angiosperms from the Araripe National Forest (ANF) in the south part of Ceará state, northeastern Brazil. The floristic survey recorded 188 species from 55 Angiosperm families. The most species-rich families were Fabaceae (31), Rubiaceae (17), Asteraceae (14), Bignoniaceae (10), Myrtaceae (9), Euphorbiaceae (7), Apocynaceae and Malpighiaceae (7) and Annonaceae and Solanaceae (5). The flora of the ANF is composed of typical species from the vegetation physiognomies of Cerrado sensu lato such as cerradão and cerrado sensu stricto and it is influenced by the northeastern phytogeographic Cerrado province. Furthermore, there are influences of ecotones between these physiognomies, seasonal forests and carrascos within the Caatinga biome. In addition to four threatened species that were recorded, the ANF also harbors species that represent important incomes for local communities because of the non-timber forest products, such as Dimorphandra gardneriana Tul. and Caryocar coriaceum Wittm.
The Cactaceae are known to be amongst the most endangered plant families of the world due to reduction of their habitats and activities of collectors. As the species of the family are dependent on animals to perform cross pollination, and hence seed production, their population performance may be further negatively affected by interrupted biotic interactions. For efficient conservation of rare species, knowledge on reproductive biology and pollinators is of prime importance. In our study we focused on Uebelmannia buiningii Donald, a microendemic cactus from the Serra Negra State Park, Minas Gerais state, Brazil. During four field expeditions to three localities of the species between September 2012 and September 2013, we measured flowers, detected nectar-guides and osmophores and performed pollen viability tests. We studied the reproductive system of the species using manual self-and cross-pollination tests and observed pollinators. Our results revealed that the flowering period takes place during the dry season, between April and October, and that the diurnal flowers open between 7:00 a.m. and 5 p.m. The flowers are shortly tubular with yellow perianth-segments. We found neither nectar nor nectar-guides, and osmophores appeared as glands within the flower tube. Whereas pollen viability was 90.25%, manual crosspollination tests have shown cross-pollination with gametophytic incompatibility. We observed two bee species visiting the flowers and acting as effective pollinators: Dialictus opacus and Plebeia sp. The combination of low reproductive activity with gametophytic incompatibility, together with the reduced number of individuals in a population and low number of populations, makes the endemic cactus U. buiningii a critically endangered species.
This study provides a checklist of the phanerogams and pteridophytes of the Tocantins river middle basin, in northern Goiás state and southern Tocantins state, Brazil. Herbarium samples were collected from 2000 to 2009 and this floristic survey recorded 1572 species from 135 families. The most species-rich families were Fabaceae (217), Poaceae (116), Asteraceae (88), Euphorbiaceae (65), Orchidaceae (58) and Malpighiaceae (56). Furthermore, 14 endangered species and 31 rare species were recorded, mainly associated with the campos rupestres in the Veadeiros Plateau region. The flora mainly from the phytophyisiognomies cerrado stricto sensu, campo rupestre (“rocky fields”), mata de galeria (“gallery forest”), mata ciliar (“riverine forest”) and semi-deciduous seasonal forest comprised typical species of the mid-western Cerrado floristic province, such as the most widely known woody plants Anadenanthera colubrina (Vell.) Brenan (popular name angico), Aspidosperma subincanum Mart. ex A. DC. (guatambú), Astronium fraxinifolium Schott ex Spreng. (gonçalo-alves), Callisthene fasciculata Mart. (pau-jacaré), Dipteryx alata Vogel (barú), Guazuma ulmifolia Lam. (mutamba) and Magonia pubescens A. St.-Hil. (tingui). This study is the first to record a wide floristic list of this important region of central Brazil.
We investigated the effects of geographic distance and environmental heterogeneity on Asteraceae communities in the rupestrian grasslands of the Espinhaço Range, southeastern Brazil. Asteraceae species composition and relative abundance were sampled in 21–1 ha plots distributed across park conservation units, comprising an environmental gradient in soils and relief (elevation and slope). We found high levels of heterogeneity overall in assemblages of herbaceous and woody Asteraceae species at the intermediate spatial scale of this study (10–100 km). We found that both relief and soil properties (texture and total exchangeable bases) explained significant proportions of variation in community composition, suggesting that definitions or expansions of conservation units should span the highest possible variability in observed relief and soil values. We also found that Asteraceae distribution exhibited strong spatial structure independent of environmental variation, reinforcing the need to consider conservation across larger areas. Considering the dystrophic character of the soils found in the Espinhaço Range and the few differences in the fertility observed between the sampling units, our results also support the hypothesis that plant distributions in the tropics are controlled by a hierarchy of environmental gradients, where variables such as altitude and exchangeable bases and Al texture are important predictors in low‐fertility soils. We suggest that Asteraceae could be a model family for conservation planning in other countries and regions because it is particularly well represented in open and montane areas of the Neotropics in general. Abstract in Portuguese is available with online material.
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