The Cerrado is the largest South American savanna and encompasses substantial species diversity and environmental variation. Nevertheless, little is known regarding the influence of the environment on population divergence of Cerrado species. Here, we searched for climatic drivers of genetic (nuclear microsatellites) and leaf trait divergence in Annona crassiflora, a widespread tree in the Cerrado. The sampling encompassed all phytogeographic provinces of the continuous area of the Cerrado and included 397 individuals belonging to 21 populations. Populations showed substantial genetic and leaf trait divergence across the species' range. Our data revealed three spatially defined genetic groups (eastern, western and southern) and two morphologically distinct groups (eastern and western only). The east-west split in both the morphological and genetic data closely mirrors previously described phylogeographic patterns of Cerrado species. Generalized linear mixed effects models and multiple regression analyses revealed several climatic factors associated with both genetic and leaf trait divergence among populations of A. crassiflora. Isolation by environment (IBE) was mainly due to temperature seasonality and precipitation of the warmest quarter. Populations that experienced lower precipitation summers and hotter winters had heavier leaves and lower specific leaf area. The southwestern area of the Cerrado had the highest genetic diversity of A. crassiflora, suggesting that this region may have been climatically stable. Overall, we demonstrate that a combination of current climate and past climatic changes have shaped the population divergence and spatial structure of A. crassiflora. However, the genetic structure of A. crassiflora reflects the biogeographic history of the species more strongly than leaf traits, which are more related to current climate.
The Brazilian Cerrado is the most diverse savanna in the world. Phylogeographical patterns for Cerrado tree species are relatively congruent; however, the causes of these patterns are not clear. Ours aims were to investigate phylogeographical patterns in two co-distributed Annona spp. in the Cerrado and identify the factors responsible for their genetic structure. We sequenced non-coding plastid DNA regions and estimated divergence times using a Bayesian Markov chain Monte Carlo method implemented in BEAST. Generalized linear mixed models (GLMMs) were used to relate genetic divergence with spatial, climatic and phytogeographic data. Annona crassiflora possessed only one haplotype, whereas A. coriacea possessed nine haplotypes constituting two groups: western and eastern. Haplotype diversification first occurred in the Pliocene; the split between eastern and western groups was dated to the Early Pleistocene. GLMMs detected a weak association of genetic distance with current climatic factors, represented mainly by precipitation in the warmest months. In A. coriacea, the north of central Cerrado (around Serra Geral de Goi as) is suggested as a putative Pleistocene refugium. The current climate and dispersal and local adaptation processes probably contribute to maintaining the east-west genetic structure in A. coriacea. Both Annona spp. show idiosyncratic population histories, reminiscent of the complex biogeography of the Cerrado.
Although plant demography, genetics and reproduction are inter-related processes, few studies on rare tropical plants have attempted to integrate them. We used an integrated approach to study two endangered Neoregelia spp. from the Brazilian Atlantic Forest. The floral phenotypes of N. ibitipocensis and N. oligantha are similar, and both species are visited and pollinated only by bumblebees. Flowers of N. ibitipocensis secrete copious nectar, which bees can access only by forcing the corolla to open, whereas flowers of N. oligantha are nectarless. Neoregelia ibitipocensis is self-incompatible and pollen-limited, whereas N. oligantha is self-compatible and sets fruits spontaneously. Population growth rates indicate an increasing population size for both species, although to a lesser extent for N. oligantha. Genetic diversity as a whole was moderate; Bayesian analysis indicated a spatially structured cluster for N. ibitipocensis populations, and genetic diversity was scattered across the distribution of N. oligantha. Despite these differences, vegetative reproduction via clonal growth was the main component of population structuring in both species. Limited seed production in N. ibitipocensis and the risk of genetic drift in N. oligantha seem to be the main threats to their persistence.
Cocalinho é uma comunidade quilombola localizada no norte do estado do Tocantins e, da mesma forma que outras comunidades de ancestralidade africana no Brasil, carece de assistência social adequada e de acesso aos serviços de saúde. Para entender o contexto atual dessa comunidade, vários parâmetros foram analisados: segurança alimentar, frequência de consumo alimentar, dados socioeconômicos e antropométricos, saúde bucal e prevalência de dentes cariados, ausentes e obturados. Os parâmetros avaliados indicaram, como esperado, uma grave falta de acesso à saúde em Cocalinho, o que reforça a necessidade de políticas públicas eficazes para atender às necessidades básicas dessa comunidade. Soluções voltadas ao incentivo da produção agroalimentar e à educação alimentar e nutricional que valorizem os alimentos regionais, além daquelas voltadas à garantia do acesso aos serviços de saúde, constituem estratégias potenciais para reduzir a pobreza e a má nutrição. Coletivamente, os dados destacam a importância de estudos interdisciplinares para melhor caracterizar as comunidades tradicionais, a fim de fornecer dados relevantes para políticas públicas adequadas.
Although there is a consensus among conservation biologists about the importance of genetic information, the assessment of extinction risk and conservation decision-making generally do not explicitly consider this type of data. Genetic data can be even more important in species where little other information is available. In this study, we investigated a poorly known legume tree, Dimorphandra exaltata , from the Brazilian Atlantic Forest, a hotspot for conservation. We coupled species distribution models and geospatial assessment based on herbarium records with population genetic analyses to evaluate its genetic status and extinction risk, and to suggest conservation measures. Dimorphandra exaltata shows low genetic diversity, inbreeding, and genetic evidence of decrease in population size, indicating that the species is genetically depleted. Geospatial assessment classified the species as Endangered. Species distribution models projected a decrease in range size in the near future (2050). The genetic status of the species suggests low adaptive potential, which compromises its chances of survival in the face of ongoing climatic change. Altogether, our coupled analyses show that the species is even more threatened than indicated by geospatial analyses alone. Thus, conservation measures that take into account genetic data and the impacts of climate change in the species should be implemented.
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