The Brazilian Cerrado is recognized as one of the most threatened biomes in the world, as the region has experienced a striking change from natural Cerrado vegetation to intense cash crop production. This paper reviews the history of land conversion in the Cerrado and the development of soil properties and water resources under past and ongoing land use. We compared soil and water quality parameters from different land uses considering 80 soil and 18 water studies conducted in different regions across the Cerrado to provide quantitative evidence of soil and water alterations from land use change. Following the conversion of native Cerrado, significant effects on soil pH, bulk density and available P and K for croplands and less-pronounced effects on pastures were evident. Soil total N did not differ between land uses because most of the sites classified as croplands were nitrogen-fixing soybeans, which are not artificially fertilized with N. In contrast, water quality studies showed nitrogen enrichment in agricultural catchments, indicating fertilizer impacts and potential susceptibility to eutrophication. Regardless of the land use, P is widely absent because of the high-fixing capacities of deeply weathered soils and the filtering capacity of riparian vegetation. Pesticides, however, were consistently detected throughout the entire aquatic system. In several case studies, extremely high-peak concentrations exceeded Brazilian and European Union (EU) water quality limits, which were potentially accompanied by serious health implications. Land use intensification is likely to continue, particularly in regions where less annual rainfall and severe droughts are projected in the northeastern and western Cerrado. Thus, the leaching risk and displacement of agrochemicals are expected to increase, particularly because the current legislation has caused a reduction in riparian vegetation. We conclude that land use intensification is likely to seriously limit the Cerrado's future regarding both agricultural productivity and ecosystem stability. Because only limited data are available, we recommend further field studies to understand the interaction between terrestrial and aquatic systems. This study may serve as a valuable database for integrated modelling to investigate the impact of land use and climate change on soil and water resources and to test and develop mitigation measures for the Cerrado.

Background: Hydropower plants provide more than 78 % of Brazil's electricity generation, but the country's reservoirs are potential new habitats for main vectors of malaria. In a case study in the surroundings of the Manso hydropower plant in Mato Grosso state, Central Brazil, habitat suitability of Anopheles darlingi was studied. Habitat profile was characterized by collecting environmental data. Remote sensing and GIS techniques were applied to extract additional spatial layers of land use, distance maps, and relief characteristics for spatial model building.

No abstract

No abstract

BackgroundIn Brazil, 99% of the cases of malaria are concentrated in the Amazon region, with high level of transmission. The objectives of the study were to use geographic information systems (GIS) analysis and logistic regression as a tool to identify and analyse the relative likelihood and its socio-environmental determinants of malaria infection in the Vale do Amanhecer rural settlement, Brazil.MethodsA GIS database of georeferenced malaria cases, recorded in 2005, and multiple explanatory data layers was built, based on a multispectral Landsat 5 TM image, digital map of the settlement blocks and a SRTM digital elevation model. Satellite imagery was used to map the spatial patterns of land use and cover (LUC) and to derive spectral indices of vegetation density (NDVI) and soil/vegetation humidity (VSHI). An Euclidian distance operator was applied to measure proximity of domiciles to potential mosquito breeding habitats and gold mining areas. The malaria risk model was generated by multiple logistic regression, in which environmental factors were considered as independent variables and the number of cases, binarized by a threshold value was the dependent variable.ResultsOut of a total of 336 cases of malaria, 133 positive slides were from inhabitants at Road 08, which corresponds to 37.60% of the notifications. The southern region of the settlement presented 276 cases and a greater number of domiciles in which more than ten cases/home were notified. From these, 102 (30.36%) cases were caused by Plasmodium falciparum and 174 (51.79%) cases by Plasmodium vivax. Malaria risk is the highest in the south of the settlement, associated with proximity to gold mining sites, intense land use, high levels of soil/vegetation humidity and low vegetation density.ConclusionsMid-resolution, remote sensing data and GIS-derived distance measures can be successfully combined with digital maps of the housing location of (non-) infected inhabitants to predict relative likelihood of disease infection through the analysis by logistic regression. Obtained findings on the relation between malaria cases and environmental factors should be applied in the future for land use planning in rural settlements in the Southern Amazon to minimize risks of disease transmission.

No abstract

No abstract

The carbon cycling of tropical ecosystems has received considerable attention over the last 1–2 decades; however, interactions between climate variation and tropical forest net ecosystem CO2 exchange (NEE) are still uncertain. To reduce this uncertainty, and assess the biophysical controls on NEE, we used the eddy covariance method over a 3 year period (2005–2008) to measure the CO2 flux and energy balance for a 25–28 m tall, mature tropical semideciduous forest located near Sinop Mato Grosso, Brazil. The study period encompassed warm‐dry, cool‐wet, and cool‐dry climate conditions, and based on previous research, we hypothesized that the net CO2 accumulation of the semideciduous forest would be lower during periods of drought. Using time series of the enhanced vegetation index (EVI), a NEE‐light‐use model, and path analysis, we found that the estimated quantum yield (a′, μmol CO2μmol photons−1) was directly affected by temporal variations in the EVI, precipitation, and photosynthetically active radiation (PAR), while the optimal rate of gross primary production (FGPP,opt, μmol m−2 s−1) was directly affected by the EVI and PAR. However, indirect effects of precipitation on the a′ and FGPP,opt were stronger than direct effects because variations in precipitation also lead to variations in the EVI and the atmospheric vapor pressure deficit (VPD). Daytime ecosystem respiration (FRE,day, μmol m−2 s−1) was directly affected by temporal variations in temperature and VPD and indirect effects of other variables were of lesser importance. Net ecosystem CO2 uptake was often higher in the dry season than the wet season, not because of a dry season “green‐up” but because rates of ecosystem respiration declined relatively more than rates of canopy photosynthesis. Over interannual timescales, average daily NEE increased over the 3 year study period and was highest in 2007–2008, which was also the driest year in terms of rainfall. However, 2007–2008 was also the coolest year during the 3 year study period, and the low temperature appeared to compensate for the low rainfall. Overall, our data suggest that the NEE of tropical semideciduous forests is sensitive to temporal variations in surface water availability but that indirect effects of other variables, such as temperature and VPD, are important in controlling CO2 gain and loss. Such interactions will be important for the future NEE under warmer and drier conditions that are anticipated with anthropogenic climate change.