Search

Different mechanisms act to structure metacommunities. Among them, the most studied are those related to environmental and spatial drivers. Also, most studies on metacommunities are based on data obtained in snapshot surveys, hindering the test of other potential mechanisms, including historical effects. Here, we quantified the relative importance of different sets of variables that could potentially structure zooplankton communities in 39 small reservoirs in Midwest Brazil. In addition to local environmental, spatial, and land use variables, as a proxy for potential priority effects, we tested the effect of earlier zooplankton composition on (later) zooplankton metacommunity structure. The relative importance of these sets of explanatory variables varied over time. However, earlier zooplankton community data were, in general, the most consistent predictors (especially for microcrustaceans) of zooplankton community structure. This result may indicate the role of historical effects on later zooplankton metacommunity structure. Our results highlight the importance of considering multiple surveys and past community data in spatiotemporal studies aiming to unveil the determinants of zooplankton metacommunity structure. [ABSTRACT FROM AUTHOR]

The Legal Amazon of Brazil holds vast mangrove forests, but a lack of awareness of their value has prevented their inclusion into results-based payments established by the United Nations Framework Convention on Climate Change. Based on an inventory from over 190 forest plots in Amazon mangroves, we estimate total ecosystem carbon stocks of 468 ± 67 Megagrams (Mg) ha−1; which are significantly higher than Brazilian upland biomes currently included into national carbon offset financing. Conversion of mangroves results in potential emissions of 1228 Mg CO2e ha−1, which are 3-fold higher than land use emissions from conversion of the Amazon rainforest. Our work provides the foundation for the inclusion of mangroves in Brazil's intended Nationally Determined Contribution, and here we show that halting mangrove deforestation in the Legal Amazon would generate avoided emissions of 0.9 ± 0.3 Teragrams (Tg) CO2e yr−1; which is equivalent to the annual carbon accumulation in 82,400 ha of secondary forests. A new study shows that deforestation of Amazon mangroves releases up to four times more carbon dioxide when compared to emissions arising from terrestrial biomes. This study set a foundation for the use of mangroves in Brazil's international policy agreements. [ABSTRACT FROM AUTHOR]

Disasters caused by rainfall extremes represent social challenges in several sectors, especially in climate change scenarios. Along with changes in land use and land cover, this relationship may become more complex. Thus, the present study aimed to detect recent trends in the pattern of rainfall indicators and associate them with records of natural disasters and the evolution of changes in land use and land cover for the state of Espírito Santo, southeastern Brazil. Daily rainfall data from 77 rain gauge stations from 1970 to 2018 were used to analyze climate trends in different rainfall indicators obtained using the RClimDex software. Records of natural disasters from 1991 to 2020 in the state of Espírito Santo were gathered from the Brazilian Integrated Disaster Information System. Additionally, land use and land cover data from 1985 and 2019 were also used. The Mann–Kendall (MK) test and the Sen slope were used to detect and quantify trends. In the Litoral Norte Espírito-santense and Noroeste Espírito-santense mesoregions of the State, trends of drought intensification are expected mainly in the regions further north. Associated with the great recent agricultural expansion in the region, this trend is concerning. The Central Espírito-santense and Sul Espírito-santense mesoregions tend to become wetter, which explains the recent increase in floods and heavy rainfall. No significant trends were found in the other regions studied. The approach adopted in this study has the potential to assist decision-making, implement mitigation and/or adaptation measures, and reduce the impacts of natural disasters in different regions of the world. [ABSTRACT FROM AUTHOR]

Metacommunity studies have demonstrated that local macroinvertebrate communities are structured not only by local environmental conditions but also by spatial processes. Effective bioassessment tools should account for spatial processes while doing so with the least amount of cost. In this study, we applied variance partition techniques based on redundancy analysis to assess the performance of three sets of benthic invertebrate metrics in detecting agricultural land-use effects in a SE Brazil rainforest watershed. Macroinvertebrate data were analyzed separately regarding their taxonomic, functional structure and bioindicator metrics developed for the study region. We stipulated that groups of metrics most sensitive to land-use effects should have the highest amount of variance explained by the joint effects of land use and environmental variation, independently of spatial structuring. Statistical analyses were repeated removing rare taxa in order to assess the effects of their inclusion in the responsiveness of each group of metrics. Traditional bioindicator metrics were more responsive to environmental variation associated with agriculture than taxa abundances and functional attributes. Furthermore, a few common taxa drove a high proportion of the variation observed in invertebrate communities, regardless of how invertebrate data were organized. Similar analytic approaches have the potential to be useful in curtailing sorting and identification efforts when developing macroinvertebrate-based biomonitoring protocols, especially in areas where information regarding the taxonomy of benthic communities is still poorly described. [ABSTRACT FROM AUTHOR]

We analyzed the occurrences of fire foci between years 2001 and 2015 in Mato Grosso state, Brazil. For this, we used remote sensing data and we correlated fire with surface temperature, rainfall, wind speed, air temperature, relative humidity, and vegetation index. The data were analyzed within the state according to use and cover classes. We also spatialize the fire occurrence using Kernel density and analyze trends with the Mann–Kendall test. The year 2015 was the year with the highest average annual air temperature and lowest annual cumulative rainfall, and wet season with the lowest relative humidity and highest surface temperature. Therefore, it was the year with less difference in the number of fire foci between wet (40.53%) and dry (59.47%) seasons. The period 2002–2005 and the years 2007 and 2010 had the highest fire foci, representing about 66.5% of the total from 2001 to 2015. In these years, 80 to 83% of fire foci occurred in the dry season. The classes with the highest density of fire were Mining Area, Urban Area, Temporary Crops, and Pasture. The fire foci in Urbanized Area, Temporary Crops, Pasture and Forestry classes tended to decrease throughout the 15 years evaluated. Fire foci were negatively correlated with rainfall, relative humidity and soil water and positively correlated with wind and surface temperature. This demonstrates that public policies related to combating fires in Brazil must be intensified especially in years with prediction of extreme drought. [ABSTRACT FROM AUTHOR]

The way water resources behave in the face of changes in land use are essential for managing a watershed. The Ibicuí river basin, located in the center of the state of Rio Grande do Sul, Brazil, has great agricultural potential and peculiar characteristics regarding its hydrological regime. Changes in land use and land cover with the purpose of expanding economic activities in this area can generate major impacts on the flow regimes of this watershed. This study shows an analysis of the influence of land use and land cover changes on the flow regime in the Ibicuí river basin from the large-basin hydrological model (MGB-IPH), considering maps of land use history and vegetation cover in the study area. The results were used to analyze the changes in the maximum and minimum annual and monthly average flows. The efficiency of the model was evaluated by the Nash-Sutcliffe coefficient (between 0.636 and 0.801) for peak flows and by the Nash-Sutcliffe log (between 0.682 and 0.863) for recession flows, indicating high correlation and low volume error (- 0.45 to - 8.20%). The greatest change in land use was the forest coverage reduction associated with agriculture land use. As a result, an increase in the average monthly flows and in the reference flow Q90 was verified. In some sub-basins, a significant modification in the reference Q90 flow and maximum flow was verified. The Mann-Whitney test showed that the results were accurate. The results indicated that changes in forest coverage and land use have an impact in the flow regime in the Ibicuí Watershed. [ABSTRACT FROM AUTHOR]

Environmental vulnerability is an important tool to understand the natural and anthropogenic impacts associated with the susceptibility to environmental damage. This study aims to assess the environmental vulnerability of the Doce River basin in Brazil through Multicriteria Decision Analysis based on Geographic Information Systems (GIS-MCDA). Natural factors (slope, elevation, relief dissection, rainfall, pedology, and geology) and anthropogenic factors (distance from urban centers, roads, mining dams, and land use) were used to determine the environmental vulnerability index (EVI). The EVI was classified into five classes, identifying associated land uses. Vulnerability was verified in water resource management units (UGRHs) and municipalities using hot spot analysis. The study employed the water quality index (WQI) to assess the EVI and global sensitivity analysis (GSA) to evaluate the model input parameters that most influence the basin's environmental vulnerability. The results showed that the regions near the middle Doce River were considered environmentally more vulnerable, especially the UGRHs Guandu, Manhuaçu, and Caratinga; and 35.9% of the basin has high and very high vulnerabilities. Hot spot analysis identified regions with low EVI values (cold spot) in the north and northwest, while areas with high values (hot spot) were concentrated mainly in the middle Doce region. Water monitoring stations with the worst WQI values were found in the most environmentally vulnerable areas. The GSA determined that land use and slope were the primary factors influencing the model's response. The results of this study provide valuable information for supporting environmental planning in the Doce River basin. [ABSTRACT FROM AUTHOR]

This article aims is to apply a methodology to identify Trip Generating Territories (TGT) in order to discuss the relationship between transport and land use. To achieve this goal, indirect methods were applied through digital processing of orbital remote sensing images along with spatial analysis, using the Kernel Density Estimation (KDE) method. The image processing results have revealed an overall accuracy of 71% for differentiation and characterization of intra-urban classes use through the adopted typologies. In this way, through data on land use and occupation, it was possible to map out the density of the trip generating territories associated to the main built surfaces and that can indicate a higher potential of trip attraction in the urban area. Additionally, the relationship between land use and public transport system was observed in the city of Petrolina-Brazil, the empirical area of study, and the highest concentration of TGT was observed to be located in the central portion of the city, on its surroundings and on the margins of some arterial roads. Thus, it is possible to extract, in the preliminary analysis, information to support the city's transport and mobility planning. [ABSTRACT FROM AUTHOR]

Mapping priority areas for environmental conservation and restoration is essential to informing policy formulation and decision-making. This study proposes a methodology based on multicriteria analysis and on-site assessment to develop environmental zoning that enhances the provision of water ecosystem services (WES) from Brazil's Água Quente River Basin. Integrated analysis of multiple criteria enabled identification of degrees of susceptibility to degradation, assessment of effects of land-use changes between 1990 and 2020, and validation of the study's methodology via field protocol. The results indicated that the spatial and temporal patterns of WES susceptibility to degradation varied little within the study area with the most critical levels occurring primarily in the Agua Quente's floodplain, where there are sandy textured soils and coverage with a low degree of soil protection. Zoning analysis designates 40% of the basin's area as consolidated use, 28% for environmental conservation, 19% as anthropic use, and 13% for environmental restoration. Field analysis indicates that the occurrence of degraded areas and pollution by solid waste and urban effluents are relevant factors that affect the basin's water resources. Linear regression analysis indicated a good fit between the data modeled by the multicriteria analysis and those observed on-site (R² = 0.6 p < 0.05). The study's method is effective and its structure can be used in other river basins, as its approach is simple and flexible and can be readily adjusted to fit the characteristics of the study site. [ABSTRACT FROM AUTHOR]

Freshwater ecosystems are among the most threatened habitats on Earth, due mainly to anthropogenic pollutants made up of complex mixtures. The Iguaçu River is world famous for the Iguaçu Falls and highlighted by its endemism. Unfortunately, it is considered the second most polluted urban river in Brazil. We aimed to perform an environmental evaluation of Neotropical streams in the Iguaçu River basin, using a multibiomarker approach from a land use and landscape perspective. A set of biomarkers in the fish Psalidodonbifasciatus was analyzed using an Integrated Biomarker Response (IBR) index and correlated with surrounding land uses. Agricultural and urban sites presented more alterations compared to references sites, with elevated protein carbonyls at agricultural sites, increased DNA damage and depletion of glutathione S-transferase at urban sites and decreased glutathione associated with higher histopathological indices at urban and agricultural sites. The IBR shows a consistent increase in negative effects in anthropized areas, with similar values at agricultural and urban sites. The multibiomarker approach, associated with a well-elaborated sample design and a statistical analysis, is an ideal method to obtain more conclusive results about the effects of human activities, revealing the effective result of exposure in the real world. [ABSTRACT FROM AUTHOR]

Loss of native vegetation cover in the watershed is known to affect stream fish communities. However, community response may not occur immediately after land cover change, and may become apparent only years later. In this study, we investigated how a c.a. 30-year (1985–2017) historical trajectory of native vegetation loss affected fish communities in 47 streams of southern Brazilian grasslands. We tested whether current species richness and composition would be more related to past or to recent natural vegetation cover. We then defined trajectories of vegetation loss and tested whether different attributes (frequency, magnitude and duration of disturbance) affected particular species and functional groups. We found that current species richness and composition were more related to past than to current vegetation cover. However, we also observed that responses of particular species and functional groups were dependent on specific trajectory attributes. We concluded that present fish community characteristics may respond not only to past watershed conditions but also to how watershed conditions have changed over the time. Exploring land use trajectories seems a promising approach for improving our understanding of landscape effects on stream ecosystems, as well as the predictability of present landscape management and planning on freshwater communities. [ABSTRACT FROM AUTHOR]

In this study, we explored the association between land use and fish species richness on 52 coastal lagoons in Southeast and South Brazil. We measured the proportion of agriculture and urbanization around lagoons over 26 years and used the coefficient of variation (CV) as a surrogate of the temporal land cover variability. We compiled species occurrences from primary data, from the literature and from museum records, and assigned each recorded species to different habitat use groups: benthic/bottom or water column, and littoral or limnetic zones. In the Southeast, where most lagoons are subject to marine influence, richness was negatively associated to agriculture and positively associated to urbanization. In the South, where freshwater lagoons predominate, richness was negatively associated to urbanization and positively associated to agriculture. The results suggest that fish communities from freshwater coastal lagoons are more sensitive to land use than brackish lagoons. Differently from brackish lagoons, that are colonized by both freshwater and marine species, freshwater lagoons rely on neighboring lagoons as species donors. However, this apparent resilience of the brackish lagoons must be regarded with caution, since the increase in marine connections due to artificial sandbar openings may impair freshwater species with time. [ABSTRACT FROM AUTHOR]

Although global climate change is receiving considerable attention, the loss of biodiversity worldwide continues. In this study, dynamics of land use/land cover (LULC) change in the Paraguai/Jauquara Basin, Mato Grosso, Brazil, were investigated. Two analyses were performed using R software. The first was a comparative study of LULC among the LULC classes at the polygon scale, and the second was a spatio-temporal analysis of moving polygons restricted to the agricultural regions in terms of topology, size, distance, and direction of change. The data consisted of Landsat images captured in 1993, 1997, 2001, 2005, 2009, 2013, and 2016 and processed using ArcGIS software. The proposed analytical approach handled complex data structures and allowed for a deeper understanding of LULC change over time. The results showed that there was a statistically significant change from regions of natural vegetation to pastures, agricultural regions, and land for other uses, accompanied by a significant trend of expansion of agricultural regions, appearing to stabilize from 2005. Furthermore, different patterns of LULC change were found according to soil type and elevation. In particular, the purple latosol soil type presented the highest expansion indexes since 2001, and the elevated agricultural areas have been expanding and/or stabilizing since 1997. [ABSTRACT FROM AUTHOR]

Low-order streams are important places for river formation and are highly vulnerable to changes in terrestrial ecosystems. Thus, the land-use/land-cover plays an important role in the maintenance of water quality. However, only land-use/land-cover composition may not explain the spatial variation in water quality, because it does not consider land-use/land-cover configuration and forest cover pattern. In this context, the study aimed to evaluate the forest cover pattern effects on water quality on low-order streams located in an agricultural landscape. Applying a paired watershed method, we selected two watersheds classified according to their morphometry and average slope to discard other physical factors that could influence the water quality. Land-use/land-cover pattern was analyzed for composition and forest cover configuration using landscape metrics, including the riparian zone composition. Water quality variables were obtained every two weeks during the hydrological year. This way, watersheds had similar morphometry, slope, and land-use/land-cover composition but differed in forest cover pattern. Watershed with more aggregated forest cover had a better water quality than the other one. The results show that forest cover contributes to water quality maintenance, while forest fragmentation influences the water quality negatively, especially in sediment retention. Agricultural practices are sources of sediment and nutrients to the river, especially in steep relief. Thus, in addition to land-use/land-cover composition, forest cover pattern must be considered in management of low-order streams in tropical agricultural watersheds. [ABSTRACT FROM AUTHOR]

Developing conservation strategies to mitigate cumulative impacts requires the understanding of historic land use and land cover changes at the regional scale. By using a multisensory and multitemporal approach, we identified the major changes driving cumulative impacts on native vegetation in northeastern Amazon. Comparing two regions, one with mining as the key driver and another where mining is associated with other industrial activities (cellulose), we explore the land use and land cover historic dynamics and derive implications for the assessment of cumulative impacts. Transitions of forest cover to pastureland, silviculture, and urban expansion were mapped in detail over a 20-year period, revealing that silviculture growth cleared more forests than pastureland expansion when associated with pulp mill activities and kaolin mining. In contrast, in a region with gold and iron mining, pastureland expansion was more relevant, clearing mainly areas surrounding new roads. This research shows that the interplay of major mining and industrial investments can produce cumulative losses of native vegetation, depending on the associated industries and infrastructure required for the project development. Our findings emphasize that the definition of spatial and temporal boundaries for the assessment of cumulative impacts must consider different trends in impact accumulation and changes in their spatial distribution over time. [ABSTRACT FROM AUTHOR]

The development process in Brazil has impacted the landscape over the years, causing, especially, changes in land cover. A critical topic in global studies on environmental issues. As a counterpoint to this process, the Brazilian State opted for the delimitation of protected natural spaces, with the argument of improving biodiversity conservation, ecosystem services, human subsistence and the well-being of current and future generations. The article assesses changes in the biodiversity of a protected area, considered as a global biodiversity hotspot, in the Brazilian Cerrado. We used the environmental arguments associated with its creation and a 30-year time series analysis. That identified and quantified land uses, levels of landscape degradation and their environmental suitability in relation to permanent protection areas according to the Brazilian Forest Code. Forestry over 10 years (1987–1997) increased by 8%, but decreased to around 5% in subsequent periods (2007–2017). Degraded pasture areas decreased between periods of expansion of forestry. There was a reduction in the area occupied by pastures, which went from 39 to 31% in the period from 1987 to 1997, but increased by 6% in the following years (2007–2017). The results showed that the expansion of silviculture from 1987 to 1997 occurred in areas previously occupied by moderately degraded pastures, evidencing, on the other hand, an improvement in the quality of the pasture areas in the following period. In addition to forestry and pasture, there was also an expansion of irrigated agriculture in the region, as well as conflicts related to water scarcity. The study, in addition to investigating the conservation conditions of the vegetation cover in the Protected Area, can also be used as a reference in the evaluation and formulation of management plans and social coexistence strategies, which are still very limited in protected areas around the world. [ABSTRACT FROM AUTHOR]

The investigation of land use changes by anthropic processes, spatially and temporally, is a fundamental tool to establish correlations between landscape patterns and processes and management of the buffer zone of Conservation Units. This study aimed to analyze the forest fragmentation and land use dynamics in the buffer zone of the Rio Doce State Park (PERD), located in Minas Gerais, Brazil, for the year 2015. Its buffer zone was delimited to a radius of 10 km, covering a total area of 128.893,36 ha. Land use classification was based on Landsat 8 image, orbit 217, point 73 and 74, and two types of ecosystems were identified: natural and anthropic. In the thematic mapping, the pressure of the anthropic use over the natural was notified, as well as the high number of forest fragments, which is a negative impact on the resilience required for the conservation of biodiversity and the local Atlantic forest. The fragments have different shapes and sizes and are distributed throughout the buffer zone of the PERD. There is a need to adopt conservation strategies, such as environmental education, reforestation techniques, recovery of degraded areas and ecological corridors. Even with a worrying current scenario, this finding makes it possible to establish an optimistic point for biodiversity conservation, associated with a tendency to reduce the forces of direct changes on natural systems. [ABSTRACT FROM AUTHOR]

Upland forest cover in the Amazon basin has been reduced by land use changes, e.g., the establishment of hydropower plants. Such plants cause permanent flooding and may produce periodic flooding in adjacent upland forests. We determined the short- and long-term effects of artificial flooding on the soil chemistry of upland forests adjacent to the Balbina Hydroelectric Reservoir, Amazonas State, Brazil. We randomized 20 sampling units in upland forests located on the banks of streams adjacent to the hydropower plant. Each sampling unit consisted of two paired forests: one artificial "flooded forest" near the stream and an unflooded "control forest." We performed soil chemical analyses to determine the pH and total organic C, N, Al3+, and nutrient levels (P, Ca, Mg, and K). In the short term, flooding caused soil acidification, C loss, and increased soil nutrient availability, but this effect did not occur in the long term. In the long term, soil acidity decreased, C loss occurred, and available N cumulatively decreased because of annual flooding after the impoundment of the reservoir. These cumulative N losses, associated with high C emissions, may alter the regional climate and contribute to global climate change. [ABSTRACT FROM AUTHOR]

The Amazonian biome is important not only for South America but also for the entire planet, providing essential environmental services. The state of Rondônia ranks third in deforestation rates in the Brazilian Legal Amazon (BLA) political division. This study aims to evaluate the land use/land cover (LULC) changes over the past ten years (2009–2019), as well as, to predict the LULC in the next 10 years, using TerrSet 18.3 software, in the state of Rondônia, Brazil. The machine learning algorithms within the Google Earth Engine cloud-based platform employed a Random Forest classifier in image classifications. The Markov-CA deep learning algorithm predicted future LULC changes by comparing scenarios of one and three transitions. The results showed a reduction in forested areas of about 15.7% between 2009 and 2019 in the Rondônia state. According to the predictive model, by 2030, around 30% of the remaining forests will be logged, most likely converted into occupied areas. The results reinforce the importance of measures and policies integrated with investments in research and satellite monitoring to reduce deforestation in the Brazilian Amazon and ensure the continuity of the Amazonian role in halting climate change. [ABSTRACT FROM AUTHOR]

In Brazil, as in the world, the mining sector is expanding steadily. Currently, the sector accounts for 11.5% of Brazil's GDP, and the country is the world's fifth-largest producer of mining products. The environmental impacts of mining and other activities that compete for land use need to be evaluated. The objective of this work was to assess vegetation recomposition in an area where bauxite extraction occurred, using analysis of a vegetation index calculated from satellite images. The method was applied at a bauxite mine in Paragominas, Pará, Brazil. The evaluations covered the steps of opening the area, mining operations, and replanting, considering three types of replanting: natural regeneration, traditional planting, and nucleation, for the period between 2013 and 2019, using 2006 as the base situation for the secondary forest. The results showed that the replanting method directly influences the vegetation index according to satellite images. Several factors affected the values obtained, such as operational factors and topsoil used. The natural regeneration method was found to produce the best results. [ABSTRACT FROM AUTHOR]

In the last 30 years, the growth of the agriculture and livestock industries in the Cerrado biome has caused severe changes in land use and land cover (LULC), and areas previously occupied by native vegetation are changing to agricultural monocultures (e.g., soybean or corn) and/or pastures. Thus, the objective of this study was to analyze the LULC changes for the years 1986, 1999, 2007, and 2016 based on Landsat time series and object-based image analysis (OBIA) for the Prata River Basin. Twelve LULC classes were mapped: riparian forest, cerrado, swampy grasslands, wetlands, semideciduous forest, pasture, agriculture, fallow agricultural land, barren land, eucalyptus, water bodies, and burnt area. The classifications presented results with an overall accuracy of more than 93% and a kappa coefficient of 0.92. In 2007, the pasture class had the highest increase in area (48.5%), with a total area of 118.32 km2 of Cerrado biome vegetation converted to pasture, and the classes banhado, riparian forest, swampy grasslands, and cerrado had the greatest reductions in area (41.58%, 29.67%, 25.44%, and 21.63%, respectively). More precisely, the wetlands class underwent the greatest decrease under the advancement of pasture in the studied period (− 36.2%). These changes are due to factors favorable to agropastoral practices, such as a flat relief and soil with good agricultural suitability. [ABSTRACT FROM AUTHOR]

This paper presents a dataset of yearly land use and land cover classification maps for Mato Grosso State, Brazil, from 2001 to 2017. Mato Grosso is one of the world's fast moving agricultural frontiers. To ensure multi-year compatibility, the work uses MODIS sensor analysis-ready products and an innovative method that applies machine learning techniques to classify satellite image time series. The maps provide information about crop and pasture expansion over natural vegetation, as well as spatially explicit estimates of increases in agricultural productivity and trade-offs between crop and pasture expansion. Therefore, the dataset provides new and relevant information to understand the impact of environmental policies on the expansion of tropical agriculture in Brazil. Using such results, researchers can make informed assessments of the interplay between production and protection within Amazon, Cerrado, and Pantanal biomes. Measurement(s) land • land use Technology Type(s) computational modeling technique Factor Type(s) year • geographic location • land use and cover class Sample Characteristic - Environment land Sample Characteristic - Location Mato Grosso State Machine-accessible metadata file describing the reported data: 10.6084/m9.figshare.11440461 [ABSTRACT FROM AUTHOR]

Changes to land use generate imbalances in the natural dynamics of aquatic ecosystems. These changes can vary according to the specific characteristics of each environment and due to seasonal factors, reinforcing the importance of studies in this area in different regions of the globe. Thus, the aim of this study was to analyze the effects of land use change on the rivers and streams of the Cachoeira River Basin in the Northeast of Brazil. Samples were collected bi-monthly at 16 points along the basin over 1 year and analyzed for physical and chemical parameters (temperature, pH, conductivity, and percentage saturation of dissolved oxygen), inorganic nutrients (NO3−, NO2−, NH4+/NH3, PO43−, SiO4) and dissolved major ions (Ca2+, K+, Mg2+, Na+, HCO3−). The highest concentrations of NO3−, NO2−, NH4+/NH3, and PO43− occurred at the points with the highest percentage of urban areas and population density. The major ions Ca2+, K+, Mg2+, Na+, and HCO3− were positively correlated with the percentage of pasture coverage; however, the high concentrations of these ions and the strong correlation between them revealed that other factors besides land use, such as soil cover, geological formation, and water deficit, may be jointly contributing to increases in their concentrations. Thus, the results show that urbanization represents the type of land use with the greatest negative effect on water quality since it alters the concentrations of inorganic nutrients dissolved in the Cachoeira River Basin. [ABSTRACT FROM AUTHOR]

It is necessary to understand the importance of landscapes that comprise the environment across a broad range of time and space and that each part of these landscapes responds to changes in environmental factors and land use. This study employs a multiscale modeling approach in the Rio Doce State Park (PERD), located in Minas Gerais, Brazil, based on a previous study on land use change in this region over the last 30 years (1985–2015), with an aim of predicting possible scenarios for the next 15 years (2015–2030). The results indicate that the municipalities and buffer zones within the PERD will suffer from increased human disturbance in all four land use types present in the region (Urban, Agriculture, Pasture, and Forestry). Correspondingly, areas of natural environment (Forest and Water) will shrink due to an increase in forest fragmentation, causing the loss of permanent ecological reserves, thereby endangering the biodiversity of these areas. Cooperation between the local community and private companies is therefore necessary to improve regional environmental conservation, encourage advanced sustainable development, and improve the quality of life for residents within each municipality near the State Park. [ABSTRACT FROM AUTHOR]

The Brazilian Cerrado area is in rapid decline because of the expansion of modern agriculture. In this study, we used extensive field data and a 30-year chronosequence of Landsat images (1980-2010) to assess the effects of time since conversion of Cerrado into agriculture upon soil chemical attributes and soybean/corn yield in the Alto do Rio Verde watershed. We determined the rates of vegetation conversion into agriculture, the agricultural land use time since conversion, and the temporal changes in topsoil (0-20 cm soil depth) and subsurface (20-40 cm) chemical attributes of the soils. In addition, we investigated possible associations between fertilization/over-fertilization and land use history detected from the satellites. The results showed that 61.8% of the native vegetation in the Alto do Rio Verde watershed was already converted into agriculture with 31% of soils being used in agriculture for more than 30 years. While other fertilizers in cultivated soils (e.g., Ca, Mg, and P) have been compensated over time by soil management practices to keep crop yield high, large reductions in C (38%) and N (29%) were observed in old cultivated areas. Furthermore, soybean and cornfields having more than 10 years of farming presented higher values of P and Mg than the ideal levels necessary for plant development. Therefore, increased risks of over-fertilization of the soils and environmental contamination with these macronutrients were associated with soybean and cornfields having more than 10 years of farming, especially those with more than 30 years of agricultural land use. [ABSTRACT FROM AUTHOR]

Biodiesel is an alternative to tackle global warming, especially for reducing greenhouse gases (GHG) emissions when replacing fossil fuels. However, it can compete for land with food production. Brazil is a global player on soybeans farming and most of the biodiesel produced in the country comes from it. This work proposes a new approach to evaluate its impact, associating land use change (LUC) analysis with life cycle assessment (LCA) in a representative Brazilian soybeans farming zone. LUC assessment used Landsat satellite imagery analysis from the years 1993 and 2013, and intergovernmental panel on climate change (IPCC) guidelines to estimate GHG emissions. LCA was based on field data collection processed with SimaPro. Results show that the increment on annual GHG emissions per hectare, derived from the apportioning total emissions for the period studied, was 50.16 kg CO eq ha y. From this increment, 97.1 % come from LUC, being the largest share from converting pastures to soybeans farming (81.2 % of the total emissions). However, in the area, a large share of converted pastures are degraded, acting as source of emissions, not as sink as considered by IPCC. At the same time, practices like no-tillage make soybeans a carbon sink. Therefore, results could change if alternative approaches were to be adopted, being a challenge for future work. Therefore, when considering biodiesel from soybeans, a close regard to local land use dynamics is essential to evaluate impacts. Besides, promoting more efficient use of land already cleared with the goal to avoid deforestation can turn biodiesel into a sustainable renewable energy source. [ABSTRACT FROM AUTHOR]

We studied the tree-regeneration patterns in three distinct agricultural settlements in the Eastern Amazon to test the influence of land-use mosaics. The following questions are addressed: are the floristic structure and composition of regenerating trees affected by the various land-use types applied in the agricultural settlements? Do tree-regeneration patterns respond similarly to distinct land-use mosaics? Is there a relationship between tree regeneration and soil characteristics among the land-use types? The regeneration was inventoried at 45 sampling points in each settlement. At each sampling point, fourteen soil variables were analyzed. Nine different land-use types were considered. The floristic structure and composition of the settlements showed differences in the density of individuals and species and high species heterogeneity among the land-use types. The maximum Jaccard similarity coefficient found between land-use types was only 29 %. Shade-tolerant species were the most diverse functional group in most land-use types, including pasture and annual crops, ranging from 91 % of the number of species in the conserved and exploited forests of Travessão 338-S to 53 % in the invaded pastures of Maçaranduba. The land-use types influenced significantly the floristic structure and composition of regenerating trees in two agricultural settlements, but not in third the settlement, which had greater forest cover. This finding demonstrates that the composition of each land-use mosaic, established by different management approaches, affects regeneration patterns. Tree regeneration was related to soil characteristics in all mosaics. Preparation of the area by burning was most likely the determining factor in the differences in soil characteristics between forests and agricultural areas. [ABSTRACT FROM AUTHOR]

Predictive models for chlorophyll- a concentration are the most common ecological tools for water-quality management. However, the interactions among factors driving eutrophication processes remain poorly understood. In addition to nutrient concentrations, other variables such as, for instance, hydrology, land use and biotic interactions may also be included as explanatory variables. Here, we compared a set of a priori models (which included local, morphological, and landscape variables) with respect to their power to predict chlorophyll- a concentration in 21 reservoirs of central Brazil. The best model, selected according to the Akaike information criterion, explained 67.7% of the variation in chlorophyll- a concentration, and indicated a positive relationship with total phosphorus concentration (the main predictor in our model) and depth. Turbidity was negatively correlated with chlorophyll- a concentration. Contrary to recent studies indicating the importance of landscape predictors, our results suggested a preponderance of local factors in determining chlorophyll- a concentration, and that the control of phosphorus sources in tropical reservoirs is as important as it is in temperate ecosystems. We also detected a substantial uncertainty regarding the best model, suggesting that further studies should focus on explicitly modeling the variation in the strength of the relationships between chlorophyll- a and explanatory variables. [ABSTRACT FROM AUTHOR]

Background: Brazilian Amazon forests contain a large stock of carbon that could be released into the atmosphere as a result of land use and cover change. To quantify the carbon stocks, Brazil has forest inventory plots from different sources, but they are unstandardized and not always available to the scientific community. Considering the Brazilian Amazon extension, the use of remote sensing, combined with forest inventory plots, is one of the best options to estimate forest aboveground biomass (AGB). Nevertheless, the combination of limited forest inventory data and different remote sensing products has resulted in significant differences in the spatial distribution of AGB estimates. This study evaluates the spatial coverage of AGB data (forest inventory plots, AGB maps and remote sensing products) in undisturbed forests in the Brazilian Amazon. Additionally, we analyze the interconnection between these data and AGB stakeholders producing the information. Specifically, we provide the first benchmark of the existing field plots in terms of their size, frequency, and spatial distribution. Results: We synthesized the coverage of forest inventory plots, AGB maps and airborne light detection and ranging (LiDAR) transects of the Brazilian Amazon. Although several extensive forest inventories have been implemented, these AGB data cover a small fraction of this region (e.g., central Amazon remains largely uncovered). Although the use of new technology such as airborne LiDAR cover a significant extension of AGB surveys, these data and forest plots represent only 1% of the entire forest area of the Brazilian Amazon. Conclusions: Considering that several institutions involved in forest inventories of the Brazilian Amazon have different goals, protocols, and time frames for forest surveys, forest inventory data of the Brazilian Amazon remain unstandardized. Research funding agencies have a very important role in establishing a clear sharing policy to make data free and open as well as in harmonizing the collection procedure. Nevertheless, the use of old and new forest inventory plots combined with airborne LiDAR data and satellite images will likely reduce the uncertainty of the AGB distribution of the Brazilian Amazon. [ABSTRACT FROM AUTHOR]

A sediment core was sampled in an urban lake in southern Brazil, and the presence of 27 trace elements was assessed. The geochronology showed that the core corresponds to the period from 1914 to 2012. Accumulation of metals and the level of pollution was measured by the geoaccumulation index (Igeo) and enrichment factor (EF). According to Igeo and EF, the lake showed a high concentration of Ag, Se, Na, Au, S, Ca, Mg, Ba, Sb, Bi, and Sr with 5 ≤ EF ≤ 45 and Igeo class = 2–6. The EF to Au = 45 and Ag = 40. In contrast, Fe, Al, As, Cr, Ga, La, Sc, and Th do not represent pollution (Igeo ≤ 0 and EF ≤ 1.6). A principal component analysis and Spearman correlation showed a first group composed of Ca, Mg, P, Ba, Sr, Na, K, Ag, Bi, Au, Mo, sand, silt, and total organic carbon with positive correlation ≥ 0.70 and > 0.95 to Sr, Ag, sand, and silt. These were negatively correlated ≥− 0.70 with Fe. The second group: Fe, La, Ga, Ti, V, Cr, As, Al, Th from lithogenic source. Prediction models for the concentration for Mg, Na, P, Sr, Fe, Ga, and total organic carbon to years 2020–2050 were obtained with R2 > 0.65. In the anthropogenic source analyses, a watershed land use map indicates multiple uses of the land, with 53% urban area, 14.6% agriculture, and 14.5% forest. [ABSTRACT FROM AUTHOR]