Factors affecting the effectiveness of riparian buffers in retaining sediment: an isotopic approach.

Riparian forest width is a major driver of their capacity to retain sediments from agricultural fields. However, the relationship between forest width and ecosystem service provisioning may vary with local environmental conditions such as relief, soil, and vegetation types. In order to assess the effect of forest width, slope, hydraulic conductivity, and land cover (watershed scale) on the effectiveness of riparian buffers in retaining sediment from pastures cultivated with African C4 grasses, we used the natural abundance of carbon stable isotopes (δ13C) in the soil and stream organic sediments as indicators. The study was conducted in small streams of the upper Corumbá River basin, state of Goiás (Cerrado biome), Brazil. We found that slight increases from 2 to 5% mean slope were sufficient to change SOM to a mixture of C3 and C4 carbon sources inside the riparian forests. Therefore, hillslope's steepness and magnitude control soil transport downslope, but after reaching the riparian forest, sediment retention is strongly affected by the forest width. We also found that soil erosion leads to fine sediment deposition in agricultural streams, especially in those watersheds with a high occurrence of degraded pastures. We conclude that sites along the stream course with a combination of steep slopes, narrow forests, and intensive land use are the most vulnerable to sediment inputs and should be the focus of preservation and restoration by landscape managers.

Cerrado ecoregions: A spatial framework to assess and prioritize Brazilian savanna environmental diversity for conservation.

The Brazilian Cerrado is the second largest biome in Latin America, extending over more than 200 million ha and hosts some of the most intensive agricultural activities for grain and beef production in the world. Because of the biodiversity richness and high levels of endemism, Cerrado is considered one of world's hotspot for biodiversity conservation. The objectives of this study are three-fold: to present a comprehensive division of Cerrado into different ecoregions that reflect the environmental heterogeneity within the biome; to analyze the ecoregions in terms of biophysical characteristics, protected areas, environmental liability in riparian permanent protection areas along watercourses, and priorities for biodiversity conservation; and to rank the ecoregions in terms of endangerment for biodiversity conservation and restoration. A previous study that delineated 22 ecoregions using geomorphology, vegetation, soil, geology, and plant diversity maps was revised using topography, vegetation, precipitation, and soil maps. Our new ecoregion map consists of 19 units that are unique in terms of landscape characteristics and has been adjusted to the current official boundary map of Cerrado. Some of the ecoregions consist of only one geomorphological compartment, whereas others are heterogeneous, consisting of up to eight compartments. Ferralsols comprise the dominant soil type in 14 of the ecoregions. The percentage of protected areas within ecoregions ranges from 1.7% to 51.5%. The most endangered ecoregion, where land use change critically threatens habitat integrity, is the Depressão Cárstica do São Francisco (states of Bahia, Minas Gerais, and Piauí), where environmental liability along riparian permanent protection areas amounts to 85.6% of the total area. Our proposed ecoregion map provides a spatial framework for regional and local assessments to improve decision-making processes to reconcile conservation and restoration planning, sustainable agriculture, and provision of ecosystem services. Besides de adjustment of the previous Cerrado's ecoregion map to the official biome boundary (relevant for the implementation of public policies of conservation as those regulated by the Brazilian Forest Code), the new analyses of the ecoregion map represent a substantial improvement in comparison to the ones conducted by the previous study in 2003. In addition, current web resources allow us to make all the information used or derived from this study available to other users. This opens the possibility of additional improvements of our findings by the scientific community or to be used effectively by decision makers.

Data for: Terrain units, land use/cover, and gross primary productivity of the largest fluvial basin in the Brazilian Amazonia/Cerrado ecotone: The Araguaia River Basin.

Integrity of most of tropical wetlands is threatened because they are often considered freely available resources of land and water. The Araguaia River Basin is one of the Brazilian basins most influenced by tropical seasonal floods, in addition to being rich in biodiversity and providing diverse ecosystem services. Here, we propose the analysis of the landscape of Araguaia Basin in terms of terrain units, rainfall, land use/cover and gross primary productivity (GPP). For this, the integration of different databases was made, including the topographic domains, protected areas and indigenous lands; land use/cover map (year 2016); time series of GPP derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor (period of 2000-2015); Shuttle Radar Topography Mission (SRTM) digital elevation models (DEM); and precipitation data produced by the WorldClim version 2 dataset. GPP time serie were processed using statistical methods of decomposition throughout R software. The proposed methodology can assist in new studies aimed at land use changes and carbon cycles.

Late Pleistocene climatic changes promoted demographic expansion and population reconnection of a Neotropical savanna-adapted bird, Neothraupis fasciata (Aves: Thraupidae).

We performed phylogeographic and genetic structure analyses of Neothraupis fasciata joined with species distribution modelling to evaluate whether: (1) the distribution of genetic variability shows a pattern expected by the isolation-by-distance model; (2) the influence of the Pleistocene climate changes on species distribution; and (3) climate/climatic stability (hypothesis of climatic stability) as a predictor of population genetic diversity. Based on two molecular datasets (ND2 and FIB-5), the isolation-by-distance hypothesis was not supported. The mitochondrial haplotype network indicated the existence of historically isolated populations at the southern range of the species distribution, and recent population expansion was identified by both neutrality tests and extended Bayesian skyline plot analysis. Thus, the climatic changes during the Pleistocene might have promoted the reconnection of the partially isolated southern populations, which may have persisted in the plateaus during the cycles of savanna contractions. Subsequently, this species (re)colonized northern areas of the species present distribution, following the continuous vegetation on the São Francisco and Central plateaus about 60 kyr, and also reached the Amazonian savannas likely via the central corridor. Thus, our results indicated that the intrinsic relationship between the relief heterogeneity (plateaus and depressions) and the climatic fluctuations, mainly in the Pleistocene, promoted population reconnection and demographic expansion of N. fasciata.

Variações dos valores séricos do CEA, bilirrubinas e aminotransferases em indivíduos oncológicos / Variations of serum values of CEA, bilirubins and aminotransferases in oncologic individuals

Objetivo: esta pesquisa baseou-se na determinação sérica de marcadores biológicos importantes, em indivíduos oncológicos, para uma possível detecção prognóstica de cân- cer colorretal, tais como o CEA (antígeno carcinoembrionário), as aminotransferases (ALT e AST) e a bilirrubina total (BT) e suas frações direta (BD) e indireta (BI). Métodos: prontuários arquivados de indivíduos (n=80), atendidos no ambulatório e sob internação do setor de oncologia do Hospital Barão de Lucena, localizado em Recife, Pernambuco, Brasil, foram catalogados para análise. O estudo de coorte transversal foi adotado para se avaliar a prevalência de positividade do CEA, correlacionada com os índices séricos eleva- dos das bilirrubinas e aminotransferases. Resultados: o percentual mais elevado de indivíduos com valores alterados, em cada marcador biológico analisado, correspondeu ao sexo masculino, com a maior diferença observada para BI (44,0% vs. 18,2%). O percentual de resultados com alteração para AST, BT, BD e BI foi correspondentemente maior entre os indivíduos que expressaram valores de CEA alterados, com as duas maiores diferenças constatadas para BT (20,6% vs.8,7%) e BI (35,3% vs.19,6%). Conclusão: a associação dos biomarcardores séricos (CEA, bilirrubinas e aminotransferases) não demonstrou resultados significativos. Entretanto, valores do CEA alterados não podem ser desconsiderados, pois, quando averiguados isoladamente, inferem um possível risco de desenvolvimento de neoplasias do sistema digestório, principalmente na região colorretal, assim como da mama, do pulmão e do ovário.

Shallow gas accumulation in sediments of the Patos Lagoon, southern Brazil.

A high resolution seismic survey was conducted in the Patos Lagoon, southern Brazil, aboard of the research vessel LARUS of the Fundação Universidade Federal do Rio Grande (FURG). Around 400 km of 3.5 kHz seismic profiles were collected, which provided acoustic signals of good penetration depth and resolution. Seismic anomalies, including turbidity and pocket gas, revealed that gas-charged sediments are common in several areas of the lagoon. The gas accumulations in the Patos Lagoon are controlled by the spatial distribution of the sedimentary facies. Either in 'curtains' or in 'acoustic turbid zones', the main gas accumulations occur in areas with paleotopographic lows related to fluvial channels and valleys developed in the Rio Grande do Sul coastal plain during regressive/transgressive events of the Quaternary.