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Abstract: Linked Open Science is an approach to solve challenges of an executable paper. It is a combination of four “silver bullets”: 1) publication of scientific data, metadata, results, and provenance information using Linked Data principles, 2) open source and web-based environments for executing, validating and exploring research, 3) Cloud Computing for effcient and distributed computing, and 4) Creative Commons for the legal infrastructure. We will use a realistic scientific research setting related to research on deforestation of the Brazilian Amazon rainforest to provide scenarios to illustrate the application of Linked Open Science. [Copyright &y& Elsevier]

The Amazon forest has the highest biodiversity on Earth. However, information on Amazonian vertebrate diversity is still deficient and scattered across the published, peer‐reviewed, and gray literature and in unpublished raw data. Camera traps are an effective non‐invasive method of surveying vertebrates, applicable to different scales of time and space. In this study, we organized and standardized camera trap records from different Amazon regions to compile the most extensive data set of inventories of mammal, bird, and reptile species ever assembled for the area. The complete data set comprises 154,123 records of 317 species (185 birds, 119 mammals, and 13 reptiles) gathered from surveys from the Amazonian portion of eight countries (Brazil, Bolivia, Colombia, Ecuador, French Guiana, Peru, Suriname, and Venezuela). The most frequently recorded species per taxa were: mammals: Cuniculus paca (11,907 records); birds: Pauxi tuberosa (3713 records); and reptiles: Tupinambis teguixin (716 records). The information detailed in this data paper opens up opportunities for new ecological studies at different spatial and temporal scales, allowing for a more accurate evaluation of the effects of habitat loss, fragmentation, climate change, and other human‐mediated defaunation processes in one of the most important and threatened tropical environments in the world. The data set is not copyright restricted; please cite this data paper when using its data in publications and we also request that researchers and educators inform us of how they are using these data. [ABSTRACT FROM AUTHOR]

Podzol-ferralsol soil systems cover great areas in Amazonia and in other equatorial regions, they are an end-member of old equatorial landscape evolution, are frequently associated with kaolin deposits and store and export large amounts of carbon. Their biogeochemistry was usually inferred from soil mineralogy and from spring or river water properties. This paper presents a database for groundwaters sampled in situ in a typical podzol-ferralsol soil catena from the Alto Rio Negro region, Brazil; the sampling periods allowed to sample under high- and low-level water-table conditions. The compositions of the groundwaters percolating the soil system are consistent with the currently observed mineral and organic paragenesis. The acidity and the site density of the dissolved organic matter (DOM) produced and circulating in the podzol white sand horizons are similar to what was observed in acid podzolic temperate zone. The aggressiveness of the white sand groundwater with regard to secondary minerals favours the podzol development at the expense of the ferralsolic or kaolin material. Some DOM is able to percolate in depth through clayey material with concentrations up to 9.7mgCl-1 (4.0 on average). This DOM is characterized by high site densities indicating a large proportion of small carboxylic acids. In the deep kaolin and in the ferralsolic horizons, the Si and Al content of the groundwater is controlled by gibbsite and kaolinite precipitation/dissolution and by quartz dissolution. The mobility of Fe, mainly transported as Fe2+, is sensitive to small variations in EH. The bleaching of the deep kaolin at the upper part of the slopes is favoured by the high content of small carboxylic compounds and by the redox conditions of the solutions issuing from the podzolic horizons. The transfer of Al and Fe result in the precipitation of Al-nodules in slope horizons and of Fe-oxides in the upper downslope horizon. It can be inferred that thick bleached kaolin are likely everywhere presently active giant podzols are close to a slope gradient sufficient to allow deep percolation of groundwater. [ABSTRACT FROM AUTHOR]

The characterization of leaf phenology in tropical forests is of major importance and improves our understanding of earth-atmosphere-climate interactions. The availability of satellite optical data with a high temporal resolution has permitted the identification of unexpected phenological cycles, particularly over the Amazon region. A primary issue in these studies is the relationship between the optical reflectance of pixels of 1 km or more in size and ground information of limited spatial extent. In this paper, we demonstrate that optical data with high to very-high spatial resolution can help bridge this scale gap by providing snapshots of the canopy that allow discernment of the leafphenological stage of trees and the proportions of leaved crowns within the canopy. We also propose applications for broad-scale forest characterization and mapping in West Central Africa over an area of 141 000km² . Eleven years of the Moderate Resolution Imaging Spectroradiometer (MODIS) Enhanced Vegetation Index (EVI) data were averaged over the wet and dry seasons to provide a dataset of optimal radiometric quality at a spatial resolution of 250 m. Sample areas covered at a very-high (GeoEye) and high (SPOT-5) spatial resolution were used to identify forest types and to quantify the proportion of leaved trees in the canopy. The dry season EVI was positively correlated with the proportion of leaved trees in the canopy. This relationship allowed the conversion of EVI into canopy deciduousness at the regional level. On this basis, ecologically important forest types could be mapped, including young secondary, open Marantaceae, Gilbertiodendron dewevrei and swamp forests. We show that in west central African forests, a large share of the variability in canopy reflectance, as captured by the EVI, is due to variation in the proportion of leaved trees in the upper canopy, thereby opening new perspectives for biodiversity and carbon-cycle applications. [ABSTRACT FROM AUTHOR]

Windthrows change forest structure and species composition in Central Amazon forests. However, the effects of widespread tree mortality associated with wind-disturbances on soil properties have not yet been described. In this study, we investigated short-term effects (seven years after disturbance) of a windthrow event on soil carbon stocks and concentrations in a Central Amazon terra firme forest. The soil carbon stock (averaged over a 0-30 cm depth profile) in disturbed plots (61.4 ± 4.18 Mg ha−1, mean ± standard error) was marginally higher (p = 0.009) than that from undisturbed plots (47.7 ± 6.95 Mg ha−1). The soil organic carbon concentration in disturbed plots (2.0 ± 0.08%) was significantly higher (p < 0.001) than that from undisturbed plots (1.36 ± 0.12%). Moreover, soil carbon stocks were positively correlated with soil clay content (r = 0.575 and p = 0.019) and with tree mortality intensity (r = 0.493 and p = 0.045). Our results indicate that large inputs of plant litter associated with large windthrow events cause a short-term increase in soil carbon content, and the degree of increase is related to soil clay content and tree mortality intensity. Higher nutrient availability in soils from large canopy gaps created by wind disturbance may increase vegetation resilience and favor forest recovery. [ABSTRACT FROM AUTHOR]

The nutrient-rich waters of the Amazon River Plume (ARP) support dense blooms of diatom-diazotroph assemblages (DDA) that introduce large quantities of new nitrogen to the planktonic ecosystem and, unlike other nitrogen-fixers, are likely to directly fuel vertical carbon flux. To investigate the factors controlling DDA blooms, we develop a five phytoplankton (cyanobacteria, diatoms, unicellular microbial diazotrophs, DDA, and Trichodesmium), two zooplankton model and embed it within a 1/6° resolution physical model of the tropical and subtropical Atlantic. The model generates realistic DDA blooms in the ARP and also exhibits basin-wide primary production, nitrogen fixation, and grazing rates consistent with observed values. By following ARP water parcels with synthetic Lagrangian drifters released at the river mouth we are able to assess the relative impacts of grazing, nutrient supply, and physical forcing on DDA bloom formation. DDA bloom formation is stimulated in the silica-rich water of the ARP by decreases in grazing pressure when mesozooplankton (which co-occur in high densities with coastal diatom blooms) concentrations decrease. Bloom termination is driven primarily by silica limitation of the DDA. In agreement with in situ data, this net growth niche for DDA exists in a salinity range from ~ 20-34 PSU, although this co-occurrence is coincidental rather than causative. Because net growth rates are relatively modest, bloom formation in ARP water parcels depends critically on the time spent in this ideal habitat, with high DDA biomass only occurring when water parcels spent > 23 days in the optimal habitat niche. [ABSTRACT FROM AUTHOR]

Background: The success of PCR technique depends on many factors, such as high quality DNA pellets obtained from blood samples, good reagents and adequate conditions of amplification. Taking these limitations into account, a retrospective epidemiological study for malaria diagnosis was conducted in a mesoendemic area in the Brazilian Amazon. Methods: A nested PCR protocol with DNA extracted from two blood storage devices obtained from Giemsa-stained thick blood smears and filter-papers was used for malaria diagnosis. The extracted DNA was used as a template to amplify approximately 100 bp species-specific sequences of the small subunit of the ribosomal RNA (18S SSU rRNA) of Plasmodium sp. The prevalence of single and mixed infections was examined in a cross-sectional survey carried out among 369 miners living in the district of Apiacás, Mato Grosso State. The parasitemia levels detected by microscopic examination were compared to the PCR results. Results: DNA samples isolated from blood on filter-paper allowed the detection and identification of Plasmodium in 165 (44.7%) of the 369 individuals evaluated, while only 62 (16.8%) had positive results using DNA obtained from thick smears, a similar rate observed by microscopic examination. The sensitivities of PCR using DNA from blood smears and filter-papers were 65% and 73.0%, respectively. Low parasite infections (below 20 parasites/μL blood) were not detected when thick blood smears were used as a DNA source. Conclusions: Although the blood preserved as thick blood smears provides an alternative and useful tool for malaria molecular diagnosis, its relatively poor performance at low level parasitemias impairs the correct determination of malaria prevalence in epidemiological studies. However, the results obtained in the present study confirm that the use of filter-paper to collect blood is useful for field studies. [ABSTRACT FROM AUTHOR]

The ongoing demand for information on forest productivity has increased the number of permanent monitoring plots across the Amazon. Those plots, however, do not comprise the whole diversity of forest types in the Amazon. The complex effects of soil, climate and hydrology on the productivity of seasonally waterlogged interfluvial wetland forests are still poorly understood. The presented study is the first field-based estimate for tree ages and wood biomass productivity in the vast interfluvial region between the Purus and Madeira rivers. We estimate stand age and wood biomass productivity by a combination of tree-ring data and allometric equations for biomass stocks of eight plots distributed along 600 km in the Purus-Madeira interfluvial area that is crossed by the BR-319 highway. We relate stand age and wood biomass productivity to hydrological and edaphic conditions. Mean productivity and stand age were 5.6±1.1Mgha-1 yr-1 and 102±18 yr, respectively. There is a strong relationship between tree age and diameter, as well as between mean diameter increment and mean wood density within a plot. Regarding the soil hydromorphic properties we find a positive correlation with wood biomass productivity and a negative relationship with stand age. Productivity also shows a positive correlation with the superficial phosphorus concentration. In addition, superficial phosphorus concentration increases with enhanced soil hydromorphic condition. We raise three hypotheses to explain these results: (1) the reduction of iron molecules on the saturated soils with plinthite layers close to the surface releases available phosphorous for the plants; (2) the poor structure of the saturated soils creates an environmental filter selecting tree species of faster growth rates and shorter life spans and (3) plant growth on saturated soil is favored during the dry season, since there should be low restrictions for soil water availability. [ABSTRACT FROM AUTHOR]

This paper explores a multitude of threats to water security in the Peruvian Amazon using the WaterWorld policy support system. WaterWorld is a spatially explicit, physically-based globally-applicable model for baseline and scenario water balance that is particularly well suited to heterogeneous environments with little locally available data (e.g. ungauged basins) and which is delivered through a simple web interface, requiring little local capacity for use. The model is capable of producing a hydrological baseline representing the mean water balance for 1950-2000 and allows for examining impacts of population, climate and land use change as well as land and water management interventions on hydrology. This paper describes the application of WaterWorld to the Peruvian Amazon, an area that is increasingly under pressure from deforestation and water pollution as a result of population growth, rural to urban migration and oil and gas extraction, potentially impacting both water quantity and water quality. By applying single and combined scenarios of: climate change, deforestation around existing and planned roads, population growth and rural-urban migration, mining and oil and gas exploitation, we explore the potential combined impacts of these multiple changes on water resources in the Peruvian Amazon and discuss the likely pathways for adaptation to and mitigation against their worst effects. See Mulligan et al. (2013) for a similar analysis for the entire Amazon Basin. [ABSTRACT FROM AUTHOR]

The Amazon Forest, the largest contiguous tropical forest in the world, stores a significant fraction of the carbon on land. Changes in climate and land use affect total carbon stocks, making it critical to continuously update and revise the best estimates for the region, particularly considering changes in forest dynamics. Forest inventory data cover only a tiny fraction of the Amazon region, and the coverage is not sufficient to ensure reliable data interpolation and validation. This paper presents a new forest above-ground biomass map for the Brazilian Amazon and the associated uncertainty both with a resolution of 250 meters and baseline for the satellite dataset the year of 2016 (i.e., the year of the satellite observation). A significant increase in data availability from forest inventories and remote sensing has enabled progress towards high-resolution biomass estimates. This work uses the largest airborne LiDAR database ever collected in the Amazon, mapping 360,000 km2 through transects distributed in all vegetation categories in the region. The map uses airborne laser scanning (ALS) data calibrated by field forest inventories that are extrapolated to the region using a machine learning approach with inputs from Synthetic Aperture Radar (PALSAR), vegetation indices obtained from the Moderate-Resolution Imaging Spectroradiometer (MODIS) satellite, and precipitation information from the Tropical Rainfall Measuring Mission (TRMM). A total of 174 field inventories geolocated using a Differential Global Positioning System (DGPS) were used to validate the biomass estimations. The experimental design allowed for a comprehensive representation of several vegetation types, producing an above-ground biomass map varying from a maximum value of 518 Mg ha−1, a mean of 174 Mg ha−1, and a standard deviation of 102 Mg ha−1. This unique dataset enabled a better representation of the regional distribution of the forest biomass and structure, providing further studies and critical information for decision-making concerning forest conservation, planning, carbon emissions estimate, and mechanisms for supporting carbon emissions reductions. [ABSTRACT FROM AUTHOR]

Current methods for modelling burnt area in Dynamic Global Vegetation Models involve complex fire spread calculations, which rely on many inputs, including fuel characteristics, wind speed and countless parameters. They are therefore susceptible to large uncertainties through error propagation. Using observed fractal distributions of fire scars in Brazilian Amazonia, we propose an alternative burnt area model for tropical forests, with fire counts as sole input and few parameters. Several parameterizations of two possible distributions are calibrated at multiple spatial resolutions using a satellite-derived burned area map, and compared. The tapered Pareto model most accurately simulates the total area burnt (only 3.5 km2 larger than the recorded 16 387 km²) and its spatial distribution. When tested pan-tropically using MODIS MCD14ML fire counts, the model accurately predicts temporal and spatial fire trends, but produces generally higher estimates than the GFED3.1 burnt area product, suggesting higher pan-tropical carbon emissions from fires than previously estimated. [ABSTRACT FROM AUTHOR]

High-resolution mapping of tropical forest carbon stocks can assist forest management and improve implementation of large-scale carbon retention and enhancement programs. Previous high-resolution approaches have relied on field plot and/or Light Detection and Ranging (LiDAR) samples of aboveground carbon density, which are typically upscaled to larger geographic areas using stratification maps. Such efforts often rely on detailed vegetation maps to stratify the region for sampling, but existing tropical forest maps are often too coarse and field plots too sparse for high resolution carbon assessments. We developed a top-down approach for high-resolution carbon mapping in a 16.5 million ha region (>40 %) of the Colombian Amazon -- a remote landscape seldom documented. We report on three advances for large-scale carbon mapping: (I) employing a universal approach to airborne LiDAR-calibration with limited field data; (ii) quantifying environmental controls over carbon densities; and (iii) developing stratification- and regression-based approaches for scaling up to regions outside of LiDAR coverage. We found that carbon stocks are predicted by a combination of satellite-derived elevation, fractional canopy cover and terrain ruggedness, allowing upscaling of the LiDAR samples to the full 16.5 million ha region. LiDAR-derived carbon mapping samples had 14.6% uncertainty at 1 ha resolution, and regional maps based on stratification and regression approaches had 25.6% and 29.6% uncertainty, respectively, in any given hectare. High-resolution approaches with reported local-scale uncertainties will provide the most confidence for monitoring changes in tropical forest carbon stocks. Improved confidence will allow resource managers and decisionmakers to more rapidly and effectively implement actions that better conserve and utilize forests in tropical regions. [ABSTRACT FROM AUTHOR]

Land use change (LUC) is a main cause of global environmental change, and is an important activity to be studied. Our research aims to examine the current state of evidence on the link between LUC and human health in the Amazon region. We conducted a scoping review of literature in two research databases, resulting in 14 papers for analysis. Our analysis demonstrated a lack of clear definitions for LUC, a wide variety of negative health effects from LUC, the lack of qualitative articles, a lack of studies exploring the potential positive health effects of LUC, and the predominance of studies coming from the Brazilian Amazon. Our study validated the prevailing idea that LUC can lead to negative health consequences, if not managed properly. [ABSTRACT FROM AUTHOR]

Smoke stimulates seed germination of a range of species from ecosystems that may or may not be fire prone. We evaluated the effects of smoke-water on germination of ten tree species of economic value in the Amazon region. Two materials were burnt to produce smoke-water: germination paper and the wood of Cecropia palmata Willd. Seven dilutions of the solutions were tested. Seeds of nine forest trees were germinated under controlled laboratory conditions (25°C±2°C) in the laboratory. Bertholletia excelsa Humb. & Bonpl., was tested in the nursery (approximately 25–36°C) because of its large seeds. Irrespective of the material burned, smoke-water significantly increased seed germination of three species: Cordia goeldiana Hub., Ochroma pyramidale (Cav. ex Lam.) Urb. and Jacaranda copaia (Aubl.) D. Don. and there was a significant inhibitory effect on Swietenia macrophylla King. Germination was accelerated by smoke in J. copaia, B. excelsa and Bellucia grossularioides (L.) Triana. The most pronounced effect was observed in B. excelsa, as the mean germination time of 108d (control) was reduced to 76d with smoke-water made from germination paper (dilution of 1:25) and to 61d with the one from Cecropia wood (dilution of 1:250). For five of the ten species studied, smoke-water either increased or accelerated seed germination, irrespective of the materials used for its production. Seeds with low vigour and prolonged germination time seemed to be more receptive to smoke. [ABSTRACT FROM AUTHOR]

The modification of landscapes surrounding water bodies leads to changes in limnological characteristics and decreased aquatic biodiversity, such as fish and macroinvertebrates. Aquatic insects are sensitive to changes in aquatic ecosystems and quickly respond to those changes. The aim of this paper was to evaluate the relationship between the compositions of aquatic and semi-aquatic Heteroptera with environmental variables along an environmental gradient in streams at the headwaters of the Xingu River, Brazil. We collected samples from 12 streams belonging to the Suiá-Miçú river basin and tributaries of the Xingu River, in September (dry season), 2008. The Suiá-Miçú river is one of the tributaries on the right bank of the Xingu River, and it is located in the ecotone between the Cerrado and the Amazon rainforest in the area characterized as the "arc of deforestation". Insects were sampled in fixed 100 m transections and divided into 20 segments of 5 meters each. To assess the habitat integrity in each stream, the habitat integrity index (HII) was applied. The following environmental variables were measured: electrical conductivity, turbidity, depth, and the normalized difference vegetation index (NDVI). The ordering of species composition was performed with the principal coordinate analysis (PCoA), and the relationship between environmental variables and composition was performed using a Mantel test. Of the 263 individuals collected, distributed in 8 families, there were 20 genera, of these, 12 were from Nepomorpha and 8 from Gerromorpha. The most abundant genera were Limnocoris (n = 121) and Rhagovelia (n = 32). Naucoridae was the most diverse family. Together, the environmental variables explained ~50% of the species distribution (r = 0.49; p = 0.001). These results reinforce the efficacy of aquatic Heteroptera to monitor environmental conditions. Here, in particular, the responses of this group to variations in landscape metrics, environmental integrity, and water variables together demonstrate that it can be useful to indicate the quality of habitat in streams. [ABSTRACT FROM AUTHOR]

Copyright of Revista Espaço do Currículo is the property of Revista Espaco do Curriculo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We present a thorough analysis of the scientific production in climate change and adaptation in Brazil. We conducted a bibliometric and bibliographic review to reveal and discuss how climate change research has been carried out. We compared a broader climate change research dataset with a more specific climate adaptation research dataset, to understand the main differences and convergence points, and how science conducted from a mitigation and adaptation perspective demonstrates potential to confront the climate change challenges and drivers in Brazil. Four main clusters of investigation within climate change were detected: (1) impacts on forest and plant development, (2) land use and ecology, (3) adaptation/governance, and (4) climate/atmospheric studies. Only about 5% of the total studies on climate change address adaptation, for which three main clusters of research were identified: (1) adaptation actions and policies; (2) urban environment, vulnerability, and health and (3) food and coastal impacts. Although there are strong research trends in climate change for the Amazon Forest, there was less evidence of studies concerning climate adaptation for this and other Brazilian biomes, smaller cities, rural and traditional communities, and poorer regions. Our results shed a light on the more commonly chosen research topics, their strongest points and potential gaps and trends. This can contribute to the scientific communication and implementation of climate actions in Brazil, and a better understanding of the climate science knowledge from the perspective of a middle-income country. [ABSTRACT FROM AUTHOR]

In their comments about our paper, the authors remark on two issues regarding our results relating to the MACCS-ATCOR Joint Algorithm (MAJA). The first relates to the sub-optimal performance of this algorithm under the conditions of our tests, while the second corresponds to an error in our interpretation of MAJA's bit mask. To answer the first issue, we acknowledge MAJA's capacity to improve its performance as the number of images increases with time. However, in our paper, we used the images we had available at the time we wrote our paper. Regarding the second issue, we misread the MAJA's bit mask and mistakenly labelled shadows as clouds. We regret our error and here we present the updated tables and images. We corrected our estimation and, consequently, there is an increment in MAJA's accuracy in the detection of clouds and cloud shadows. However, these increments are not enough to change the conclusion of our original paper. [ABSTRACT FROM AUTHOR]

Here we offer a brief introduction to this special issue on argument-encoding systems of the little-known languages of Bolivian Amazonia, a region extremely rich linguistically. After providing some information on the sociolinguistic settings and the history of linguistic research in this area, we focus on the domain of argument-encoding systems in those languages and show how very diverse types of systems are found in languages spoken in very close proximity, including hierarchical/inverse cross-referencing systems, ergative systems, and split-intransitive systems. We also point to a number of typologically and theoretically interesting phenomena found in these languages, such as fluid transitivity. double-object ditransitive constructions, and rare valency-changing derivations such as multiple applicatives and sociative causatives. [ABSTRACT FROM AUTHOR]

The China‐France Oceanography Satellite (CFOSAT) was successfully launched on October 29, 2018, which carries two innovative payloads, that is, the surface waves investigation and monitoring (SWIM) instrument and the rotating fan‐beam scatterometer (RFSCAT). CFOSAT scatterometer (CSCAT) is dedicated to the monitoring of sea surface wind vectors and climate studies, but also for the applications over land and polar regions. CSCAT employs a "rotating fan‐beam" design rather than "pencil‐beam" approach and "fixed fan‐beam" approach adopted by the scatterometers in orbit before. In this paper, the data processing approach of CSCAT is described. The geolocation reference mapping model is employed in CSCAT slice geolocation. In noise processing, CSCAT adopts the method of weighted least squares polynomial surface fitting to conduct noise correction factor estimation adaptively. The attitude cube algorithm used for X integral factor computation is developed to obtain precise backscatter coefficients based on the radar equation. Because of the interdependency of the CSCAT data processing and the hardware configuration and onboard signal processing of the instrument, the instrument module configuration and signal processing design are also analyzed and presented comprehensively. Especially, the influence and compensation of Doppler frequency are introduced. The backscatter coefficient accuracy is estimated on the Amazon forest, and the results show that the backscatter coefficient accuracy of CSCAT on 25 × 25 km grids is less than 0.5 dB except that the near end and far end of the beam are slightly higher. The statistical results show the wind retrieval results meet the CFOSAT mission requirements. Key Points: The data preprocessing principle and algorithm of China‐France Oceanography Satellite (CFOSAT) rotating fan‐beam scatterometer are summarized comprehensivelyThe CFOSAT rotating fan‐beam scatterometer design and signal processing are summarized comprehensivelyThe backscatter coefficient measurement accuracy of CFOSAT are provided [ABSTRACT FROM AUTHOR]

Copyright of RAP: Revista Brasileira de Administração Pública is the property of RAP: Revista Brasileira de Administracao Publica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper proposed and verified an optimal estimation method of satellite attitude deviation in orbit based on the frequency domain features of microwave remote sensing data from the Gaofen-3B (GF-3B) satellite. The Synthetic Aperture Radar (SAR) imaging results of the Amazon forest's strip pattern were obtained at different imaging incident angles of the GF-3B satellite. Then, the inversions of the Doppler center deviation of the SAR signal obtained the corresponding beam pointing errors at different imaging incident angles. Next, a three-degree-of-freedom nonlinear least square fitting model was established between the Doppler center deviation of the SAR signal and satellite attitude deviation. Combined with the measured SAR signals, satellite attitude deviations in different dimensions (pitch, yaw, and roll) were separated and estimated. On this basis, the GF-3B satellite proceeded with an on-orbit attitude correction test. The maximum Doppler center deviation at all imaging incident angles decreased from 400Hz to 46Hz, and the residual beam pointing errors were less than 0.01°. The proposed optimal estimation method can guarantee the on-orbit attitude deviation suppression and image quality improvement of the SAR satellites. • An optimal attitude deviations estimation method of SAR satellites is proposed based on the echo frequency domain features. • The fitting model of attitude deviations is established by combining microwave remote sensing imagery and orbit dynamics. • The proposed method has been used for the GF-3B satellite and verified by in-orbit imaging experiments. [ABSTRACT FROM AUTHOR]

Deforestation has a significant impact on the environment, accelerating global warming and causing irreversible damage to ecosystems. Large-scale deforestation monitoring techniques still mostly rely on statistical approaches and traditional machine learning models applied to multi-spectral, optical satellite imagery and meta-data like land cover maps. However, clouds often obstruct observations of land in optical satellite imagery, especially in the tropics, which limits their effectiveness. Moreover, statistical approaches and traditional machine learning methods may not capture the wide range of underlying distributions in deforestation data due to limited model capacity. To overcome these drawbacks, we apply an attention-based neural network architecture that learns to detect deforestation end-to-end from time series of synthetic aperture radar (SAR) images. Sentinel-1 C-Band SAR data are mostly independent of the weather conditions and our trained neural network model generalizes across a wide range of deforestation patterns of Amazon forests. We curate a new dataset, called BraDD-S1TS, comprising approximately 25,000 image sequences for deforested and unchanged land throughout the Brazilian Amazon. We experimentally evaluate our method on this dataset and compare it to state-of-the-art approaches. We find it outperforms still-in-use methods by 13.7 percentage points in intersection over union (IoU). We make BraDD-S1TS publicly available along with this publication to serve as a novel testbed for comparing different deforestation detection methods in future studies. [ABSTRACT FROM AUTHOR]

Deforestation is a threat to biodiversity and the world's climate. As agriculture and mining areas grow, forest loss becomes unbearable for the environment. Consequently, monitoring deforestation is crucial for decision makers to create polices. The most reliable deforestation data about the Amazon forest is generated by the Brazil's National Institute for Space Research (INPE) through its PRODES project. This effort is labor and time intensive because it depends on visual interpretation from experts. Additionally, frequent Amazon's atmospheric phenomena, such as clouds, difficult image analysis which induces alternative approaches such as time series analysis. One way to increase the number of images of an area consists of using images from different satellites. NASA provides the Harmonized Landsat and Sentinel-2 (HLS) dataset solving spectral dissimilarities of satellite sensors. In this paper, the possibilities of HLS for forest monitoring are explored by applying two deforestation detection methods, Break Detection for Additive Season and Trend (BFAST) monitor and Random Forest, over four different vegetation indices, NDVI, EVI, GEMI and SAVI. The SAVI index used as input for BFAST monitor performed the best in this data setup with 95.23% for deforested pixel, 53.69% for non-deforested pixels. Although the HLS data is described as analysis ready, further pre-processing can enhance the outcome of the analysis. Especially, since the cloud and cirrus cover in the Amazon causes gaps in the dataset, a best pixel method is recommended to create patched images and thus a continuous time series as input for any land cover and land use classification. [ABSTRACT FROM AUTHOR]

Copyright of Topoi: Revista de História is the property of TOPOI: Revista de Historia, Programa de Pos-graduacao em Historia Social da UFRJ and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A traditional feature selection of filters evaluates the importance of a feature by using a particular metric, deducing unstable performances when the dataset changes. In this paper, a new hybrid feature selection (called MFHFS) based on multi-filter weights and multi-feature weights is proposed. Concretely speaking, MFHFS includes the following three stages: Firstly, all samples are normalized and discretized, and the noises and the outliers are removed based on 10-folder cross validation. Secondly, the vector of multi-filter weights and the matrix of multi-feature weights are calculated and used to combine different feature subsets obtained by the optimal filters. Finally, a Q-range based feature relevance calculation method is proposed to measure the relationship of different features and the greedy searching policy is used to filter the redundant features of the temp feature subset to obtain the final feature subset. Experiments are carried out using two typical classifiers of support vector machine and random forest on six datasets (APS, Madelon, CNAE9, Gisette, DrivFace and Amazon). When the measurements of F1macro and F1micro are used, the experimental results show that the proposed method has great improvement on classification accuracy compared to the traditional filters, and it achieves significant improvements on running speed while guaranteeing the classification accuracy compared to typical hybrid feature selections. [ABSTRACT FROM AUTHOR]

An important goal of regional development in the Brazilian Amazon was to enhance social welfare and alleviate dire poverty in other parts of the country by providing land to the poor. Nevertheless, both poverty and landlessness have persisted despite development policies that distributed billions of dollars on highway construction, loans, and outright subsidies. Inequitable land distribution has been held as a prime factor in land conflict across the country. Although episodes of conflict over land are common in Brazilian history, this paper focuses on agrarian issues that arose with the opening of the Amazon frontier in the 1970s. The paper presents a political economy approach that considers the role of hierarchical forces interacting across spatial scales, in creating conditions ripe for land conflict at the local level. The premise is that the Brazilian government, intending to bring about economic and social development, promoted contradictory strategies creating land scarcity. These strategies led to expansion of large ranching operations, creation of conservation units, and demarcation of indigenous reserves, which constrained the pool of land available for small farmer settlement. Empirical analysis employing regression and spatial statistics is used to test the proposed model, advancing previous efforts by applying spatial regression, incorporating improved indicators of conflict and explanatory variables generated by a Geographic Information System (GIS). The findings provide support for some elements of the argument, demonstrating statistically significant relationships between land conflict and land concentration, cattle ranching, and road construction. Finally, a case study analysis of a county in the heart of the land conflict zone is provided, illustrating the interaction of scalar forces, and the articulation of land conflict at the local level. [ABSTRACT FROM AUTHOR]

The paper examines the current relevance of the set of variables reported in the literature as driving deforestation in the Brazilian Amazon. The analysis uses a computable general equilibrium (CGE) model adapted to capture regional economic structures and the environmental processes specific to tropical areas. The paper compares the impact on deforestation in the Brazilian Amazon of changes in real exchange rate; modifications in agricultural tax and support policies, reductions in transportation costs arising from investment in infrastructure in the Amazon, changes in land tenure regimes; and technological change in agriculture affecting productivity and agronomic sustainability. [ABSTRACT FROM AUTHOR]

The Neotropical termite genus Uncitermes Rocha & Cancello, 2012 was known from a single species, U. teevani (Emerson, 1925). In this paper a new species, Uncitermes almeriae sp. n., is described and illustrated from worker and soldier castes, along with observations on the Uncitermes nest. A distribution map with the occurrences of both species is presented. The new species is distinguished from its congener by the presence of short bristles covering the head capsule and frontal tube. [ABSTRACT FROM AUTHOR]

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The Ecosystem Demography model version 2.2 (ED-2.2) is a terrestrial biosphere model that simulates the biophysical, ecological, and biogeochemical dynamics of vertically and horizontally heterogeneous terrestrial ecosystems. In a companion paper , we described how the model solves the energy, water, and carbon cycles, and verified the high degree of conservation of these properties in long-term simulations that include long-term (multi-decadal) vegetation dynamics. Here, we present a detailed assessment of the model's ability to represent multiple processes associated with the biophysical and biogeochemical cycles in Amazon forests. We use multiple measurements from eddy covariance towers, forest inventory plots, and regional remote-sensing products to assess the model's ability to represent biophysical, physiological, and ecological processes at multiple timescales, ranging from subdaily to century long. The ED-2.2 model accurately describes the vertical distribution of light, water fluxes, and the storage of water, energy, and carbon in the canopy air space, the regional distribution of biomass in tropical South America, and the variability of biomass as a function of environmental drivers. In addition, ED-2.2 qualitatively captures several emergent properties of the ecosystem found in observations, specifically observed relationships between aboveground biomass, mortality rates, and wood density; however, the slopes of these relationships were not accurately captured. We also identified several limitations, including the model's tendency to overestimate the magnitude and seasonality of heterotrophic respiration and to overestimate growth rates in a nutrient-poor tropical site. The evaluation presented here highlights the potential of incorporating structural and functional heterogeneity within biomes in Earth system models (ESMs) and to realistically represent their impacts on energy, water, and carbon cycles. We also identify several priorities for further model development. [ABSTRACT FROM AUTHOR]

This paper focuses on transactions of edible goods among the Menkü, an indigenous group of the southern Brazilian Amazon. The distribution cycles of killed game are described as a process of sharing by which the relationships of the giver to those around him are created and redefined. In this case sharing is characterized by the co-presence of donor and recipient. Furthermore sharing is conceived as a process which defines and confirms relations of affinity and alterity. It is argued that for the Menkü sharing is a multilateral process that depends on the complementarity of the sexes and the respective life phases of those involved. Transactions are revealed as an ambivalent process, which on the one hand contributes to the creation of good group morality, while on the other hand implying obligations towards the human and non-human worlds. Based on the notion of the high value of social cohesion, the article focuses on how transactions involving consumable goods are incorporated in an egalitarian community. Unlike monetary transactions non-monetary transactions involving edible goods are revealed as allowing multiple interactions to take place with the encompassing environment of the people, ancestors and spirits of the savannah and the forest. It is argued that the distribution and consumption of the components of a 'complete meal' are considered to express successful interactions between different social spheres as a prerequisite for permanent well-being among the Menkü. [ABSTRACT FROM AUTHOR]

Hydropower has been the leading source of renewable energy across theworld, accounting for up to 71% of this supply as of 2016. This capacity was built up in North America and Europe between 1920 and 1970 when thousands of dams were built. Big dams stopped being built in developed nations, because the best sites for dams were already developed and environmental and social concerns made the costs unacceptable. Nowadays, more dams are being removed in North America and Europe than are being built. The hydropower industry moved to building dams in the developing world and since the 1970s, began to build even larger hydropower dams along the Mekong River Basin, the Amazon River Basin, and the Congo River Basin. The same problems are being repeated: disrupting river ecology, deforestation, losing aquatic and terrestrial biodiversity, releasing substantial greenhouse gases, displacing thousands of people, and altering people's livelihoods plus affecting the food systems, water quality, and agriculture near them. This paper studies the proliferation of large dams in developing countries and the importance of incorporating climate change into considerations of whether to build a dam along with some of the governance and compensation challenges. We also examine the overestimation of benefits and underestimation of costs along with changes that are needed to address the legitimate social and environmental concerns of people living in areas where dams are planned. Finally, we propose innovative solutions that can move hydropower toward sustainable practices together with solar, wind, and other renewable sources. [ABSTRACT FROM AUTHOR]

This paper compares land use patterns of mestizo colonists and indigenous populations in the central Ecuadorian Amazon, based on data from a household survey covering mestizo colonist, Kichwa and Shuar households. As expected, colonists mostly engage in commercial agriculture and cattle ranching, but there are substantial differences in land use patterns between the Shuar and the Kichwa. The Shuar engage in cash cropping and cattle ranching, and on average, devote even more land to agricultural uses than mestizo colonists in this sample. In contrast, the Kichwa engage more in subsistence crop production and less in commercial agriculture. Such different patterns appear related to local conditions, earlier migratory and settlement patterns, and the level of exposure to markets. The implications of this for policy are explored in the conclusions. [ABSTRACT FROM AUTHOR]

The Brazilian Legal Amazon is an extensive territory in which different factors influence the dynamics of forest fires. Currently, the Brazilian government has two tools in the public domain and free of charge, PRODES and BDQueimadas, to monitor and make decisions to combat deforestation and forest fires. This work aimed to evaluate and correlate the forest fire alerts and deforestation in the Amazon Forest in the state of Pará. The analyses were based on carrying out a diagnosis of forest fires and deforestation; the behavior of forest fires and deforestation over the last twenty years; the statistical relationship between deforestation and forest fires and their spatialization. This work identified that Pará is the state in the Legal Amazon with the highest occurrence of forest fires and deforestation. Deforestation in the four-year period Jan/2003-Dec/2006 showed a higher rate compared to the four-year periods Jan/2011-Dec/2018. A high correlation was found between forest fire alerts and increases in deforestation. There is a spatial relationship between cities with greater increases in deforestation and high numbers of fire alerts. In relation to the occurrence of forest fires and deforestation, the south of the state was the most critical region and the north had lower rates. [ABSTRACT FROM AUTHOR]

Indigenous traditional land uses, including hunting, fishing, sacred activities, and land-based education at the Red Sucker Lake First Nation (RSLFN) in Manitoba, Canada, are impacted by mining. The Red Sucker Lake First Nation (RSLFN) people want their territories' land and water to be protected for traditional uses, culture, and ecological integrity. Towards this goal, their Island Lake Tribal Council sought support for an Indigenous-protected and conserved area (IPCA) in their territory, outside of existing mining claims, but without success. The two-eyed seeing approach was adopted in this study. Traditional land use mapping and interviews were undertaken with 21 Indigenous people from the RSLFN, showing that many traditional land uses are concentrated on greenstone belts. The interviews revealed that mining exploration has resulted in large petroleum spills, noise distress, private property destruction, wildlife die-offs, and animal population declines. These issues negatively impact RSLFN's traditional land use practices, ecosystem integrity, and community health. Governments need to partner with Indigenous communities to reach their biodiversity targets, particularly considering northern Canada's peatlands, including those in the RSLFN territory, surpassing Amazon forests for carbon storage. The role of critical minerals in renewable energy and geopolitics has colonial governments undermining Indigenous rights, climate stabilization, and biodiversity to prioritize extractivism. Mining at the RSLFN has environmental impacts from exploration to decommissioning and after, as well as the massive infrastructure required that includes roads, hydro, and massive energy supplies, with a proposed multimedia national Northern Corridor to export RSLFN's resources and other resources to six ports. [ABSTRACT FROM AUTHOR]

This study delves into perceptions of land and forest tenure (in)security among Indigenous and mestizo populations in the Peruvian Amazon. Despite all having collective lands, the selected communities vary in their formalisation processes. This research seeks to enhance comprehension of tenure security perceptions in the Peruvian Amazon by investigating sources of security and insecurity across key tenure components. A combination of descriptive, bivariate, and multivariate analyses is employed, based on fieldwork conducted between July 2015 and December 2017 in 22 Native and Peasant Communities in Loreto and Madre de Dios, utilising 1006 intra-household surveys, 52 in-depth interviews, and 44 focus group discussions. The results reveal similarities and differences in (in)security sources between titled and untitled communities. The study also explores the influence of gender and ethnicity on these perceptions, finding ethnicity-based variation in security perception over the past 20 years (1995–2015). Recognising these differences in perception is critical for assessing the robustness of exercising acquired collective rights. [ABSTRACT FROM AUTHOR]

Strong convective systems characterize the tropical central-southern region of Brazil. These systems provide abundant water supply for agroindustrial activities and pose flood risks to large cities. Here, we present high-frequency (2–10 min ; inter- and intra-event) rainfall isotopic compositions (n = 90 samples) to reveal regional and local atmospheric processes controlling the isotopic variability of convective systems between 2019–2021. Inter-event rainfall weighted-average (δwgd) values were low (δ18Owgd ≤ - 10.0 ‰) due to the higher rainfall along the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model trajectories from the Amazon forest during the summer. In contrast, during autumn and spring seasons HYSPLIT model trajectories from the Atlantic Ocean and southern Brazil exhibited lower rainfall amounts, resulting in high δ18Owgd ≥ - 4.2 ‰. This strong regional δwgd pattern often masks intra-event isotopic variability. Therefore, we analyzed the vertical structure of local rainfall using reflectivity (Z) from microradar data. Variations in Z indicate that microphysical processes as raindrops fall led to changes in δ18O and deuterium excess (d -excess). Our findings establish a novel framework for evaluating the meteorological controls on the isotopic variability of convective precipitation in tropical South America, fill the gap in high-frequency studies in this region, and generate an isotopic dataset for convective model evaluations. [ABSTRACT FROM AUTHOR]

Dynamic ecosystems, such as the Amazon forest, are expected to show critical slowing down behavior, or slower recovery from recurrent small perturbations, as they approach an ecological threshold to a different ecosystem state. Drought occurrences are becoming more prevalent across the Amazon, with known negative effects on forest health and functioning, but their actual role in the critical slowing down patterns still remains elusive. In this study, we evaluate the effect of trends in extreme drought occurrences on temporal autocorrelation (TAC) patterns of satellite-derived indices of vegetation activity, an indicator of slowing down, between 2001 and 2019. Differentiating between extreme drought frequency, intensity, and duration, we investigate their respective effects on the slowing down response. Our results indicate that the intensity of extreme droughts is a more important driver of slowing down than their duration, although their impacts vary across the different Amazon regions. In addition, areas with more variable precipitation are already less ecologically stable and need fewer droughts to induce slowing down. We present findings indicating that most of the Amazon region does not show an increasing trend in TAC. However, the predicted increase in extreme drought intensity and frequency could potentially transition significant portions of this ecosystem into a state with altered functionality. [ABSTRACT FROM AUTHOR]

This paper explores China's role in deforestation in Latin America. Brazil's Amazon region contains vast natural resources including land, timber, minerals and hydroelectric potential. China's strong economy and large demands relative to domestic supplies of these resources mean that China has become Brazil's largest trading partner, primarily for natural resources. The paper examines how China influences deforestation in Brazilian Amazonia in a variety of ways, including through the direct influence of Chinese enterprises through land purchases and other mechanisms. This paper finds that the rapid rise in exports of soy and beef products to China are two of the major drivers of Amazonian deforestation in Brazil. The paper further argues that Chinese purchases of agricultural and forest land and Chinese imports of commodities such as timber and aluminum also cause environmental impacts in Amazonia. Chinese financing and investment in Amazonian infrastructure such as railways and mineral processing facilities have additional impacts. [ABSTRACT FROM AUTHOR]

This paper assesses the uncertainties involved in the projections of seasonal temperature and precipitation changes over South America in the twenty-first century. Climate simulations generated by 24 general circulation models are weighted according to the reliability ensemble averaging (REA) approach. The results show that the REA mean temperature change is slightly smaller over South America compared to the simple ensemble mean. Higher reliability in the temperature projections is found over the La Plata basin, and a larger uncertainty range is located in the Amazon. A temperature increase exceeding 2 °C is found to have a very likely (>90 %) probability of occurrence for the entire South American continent in all seasons, and a more likely than not (>50 %) probability of exceeding 4 °C by the end of this century is found over northwest South America, the Amazon Basin, and Northeast Brazil. For precipitation, the projected changes have the same magnitude as the uncertainty range and are comparable to natural variability. [ABSTRACT FROM AUTHOR]

Biogeochemistry is hosting this special thematic issue devoted to studies of land-water interactions, as part of the Large-scale Biosphere-Atmosphere Experiment in Amazônia (LBA). This compilation of papers covers a broad range of topics with a common theme of coupling land and water processes, across pristine and impacted systems. Findings highlighted that hydrologic flowpaths are clearly important across basin size and structure in determining how water and solutes reach streams. Land-use changes have pronounced impacts on flowpaths, and subsequently, on stream chemistry, from small streams to large rivers. Carbon is produced and transformed across a broad array of fluvial environments and wetlands. Surface waters are not only driven by, but provide feedback to, the atmosphere. [ABSTRACT FROM AUTHOR]

The emergence of sedentism and agriculture in Amazonia continues to sit uncomfortably within accounts of South American pre-Columbian history. This is partially because deep-seated models were formulated when only ceramic evidence was known, partly because newer data continue to defy simple explanations, and partially because many discussions continue to ignore evidence of pre-Columbian anthropogenic landscape transformations. This paper presents the results of recent geoarchaeological research on Amazonian anthropogenic soils. It advances the argument that properties of two different types of soils, terras pretas and terras mulatas, support their interpretation as correlates of, respectively, past settlement areas and fields where spatially-intensive, organic amendment-reliant cultivation took place. This assessment identifies anthropogenic soil formation as a hallmark of the Amazonian Formative and prompts questions about when similar forms of enrichment first appear in the Amazon basin. The paper reviews evidence for embryonic anthrosol formation to highlight its significance for understanding the domestication of a key Amazonian crop: manioc (Manihot esculenta ssp. esculenta). A model for manioc domestication that incorporates anthropogenic soils outlines some scenarios which link the distribution of its two broader varieties-sweet and bitter manioc-with the widespread appearance of Amazonian anthropogenic dark earths during the first millennium AD. [ABSTRACT FROM AUTHOR]

Since the 1970s, migration to the Amazon has led to a growing human presence and resulting dramatic changes in the physical landscape of the Northern Ecuadorian Amazon frontier, including considerable deforestation. Over time, a second demographic phenomenon has emerged with the children of the original migrants leaving settler farms to set out on their own. The vast majority have remained in the Amazon region, some contributing to further changes in land use via rural–rural migration to establish new farms and others to incipient urbanization. This paper uses longitudinal, multi-scale data on settler colonists between 1990 and 1999 to analyze rural–rural and rural–urban migration among second-generation colonists within the region. Following a description of migrants and settlers in terms of their individual, household and community characteristics, a multinomial discrete-time hazard model is used to estimate the determinants of out-migration of the second generation settlers to both urban and rural areas. We find significant differences in the determinants of migration to the two types of destinations in personal characteristics, human capital endowments, stage of farm and household lifecycles, migration networks, and access to community resources and infrastructure. The paper concludes with a discussion of policy implications of migrants’ choice of rural versus urban destinations. [ABSTRACT FROM AUTHOR]

This paper critically reviews reconstructions of cultural development in prehistoric Amazonia and argues for the primacy of regional and interregional exchange in generating the complex distributions of ethno-linguistic identities traced by linguists and archaeologists in the area. This approach requires an explicit abandonment of notions of migrating "peoples" in favor of modern anthropological understandings of ethnicity and ethnogenesis. Further, the paper discusses the significance of such a regional system perspective on Amazonian ethnogenesis for the ongoing debate on the extent of social stratification and agricultural intensification on the floodplains and wet savannas of low-land South America. It concludes that the emergence of Arawakan chiefdoms and ethnic identities in such environments after the first millennium BC signifies the occupation of a niche defined in terms of both ecology and regional exchange but also that it transformed both these kinds of conditions. In these processes, ethnicity, social stratification, economy, and ecology were all recursively intertwined. [ABSTRACT FROM AUTHOR]

This paper critically reviews reconstructions of cultural development in prehistoric Amazonia and argues for the primacy of regional and interregional exchange in generating the complex distributions of ethno-linguistic identities traced by linguists and archaeologists in the area. This approach requires an explicit abandonment of notions of migrating "peoples" in favor of modern anthropological understandings of ethnicity and ethnogenesis. Further, the paper discusses the significance of such a regional system perspective on Amazonian ethnogenesis for the ongoing debate on the extent of social stratification and agricultural intensification on the fioodplains and wet savannas of lowland South America. It concludes that the emergence of Arawakan chiefdoms and ethnic identities in such environments after the first millennium BC signifies the occupation of a niche defined in terms of both ecology and regional exchange but also that it transformed both these kinds of conditions. In these processes, ethnicity, social stratification, economy, and ecology were all recursively intertwined. [ABSTRACT FROM AUTHOR]

The Brazilian Amazon forest and cerrado savanna encompasses a region of enormous ecological, climatic, and land-use variation. Satellite remote sensing is the only tractable means to measure the biophysical attributes of vegetation throughout this region, but coarse-resolution sensors cannot resolve the details of forest structure and land-cover change deemed critical to many land-use, ecological, and conservation-oriented studies. The Carnegie Landsat Analysis System (CLAS) was developed for studies of forest and savanna structural attributes using widely available Landsat Enhanced Thematic Mapper Plus (ETM+) satellite data and advanced methods in automated spectral mixture analysis. The methodology of the CLAS approach is presented along with a study of its sensitivity to atmospheric correction errors. CLAS is then applied to a mosaic of Landsat images spanning the years 1999–2001 as a proof of concept and capability for large-scale, very high resolution mapping of the Amazon and bordering cerrado savanna. A total of 197 images were analyzed for fractional photosynthetic vegetation (PV), nonphotosynthetic vegetation (NPV), and bare substrate covers using a probabilistic spectral mixture model. Results from areas without significant land use, clouds, cloud shadows, and water bodies were compiled by the Brazilian state and vegetation class to understand the baseline structural typology of forests and savannas using this new system. Conversion of the satellite-derived PV data to woody canopy gap fraction was made to highlight major differences by vegetation and ecosystem classes. The results indicate important differences in fractional photosynthetic cover and canopy gap fraction that can now be accounted for in future studies of land-cover change, ecological variability, and biogeochemical processes across the Amazon and bordering cerrado regions of Brazil. [ABSTRACT FROM AUTHOR]

Some of the results from the climate component of the Large Scale Biosphere-Atmosphere Experiment in Amazonia (LBA), which are presented in this Special Issue are summarised. Recent advances in Amazonian climate modelling are also discussed. There is a range of papers which fall into three groups: surface fluxes and boundary layer growth; convection, clouds and rainfall; and climate modelling. The new insight given by this work is discussed and an argument is made for future research to employ a wider approach to Amazonian climate modelling. [ABSTRACT FROM AUTHOR]

This paper investigates the dynamics of logjam-induced floods and alluvial deposition in the Bolivian Amazon and the effects these have on forest disturbance and recovery cycles. It expands on previous work by Gullison et al. (1996) who reported a case of catastrophic floods triggered by logjams in the Chimane Forest in the Bolivian Amazon. No further studies have followed up on this observation and no research has been published on the effects of large wood in tropical lowland rivers. The study is based on the analysis of a time series of Landsat imagery (1984-2016) and field evidence. Results show that logjam-induced floods are a major driver of forest disturbance along the Andean piedmont in the Bolivian Amazon. New logjams form on an almost yearly basis, always further upriver, until an avulsion takes place. Logjam-induced floods are characterized here by the sudden deposition of a thick sand layer and the death of forest in a V-shaped area. The Bolivian Amazon offers a unique opportunity for further research on how large wood affects river behavior in lowland tropical settings and how large and frequent forest disturbance events resulting from river logjams affect forest biodiversity and community successions. [ABSTRACT FROM AUTHOR]

The use of Niche Construction Theory in archaeological research demands that we establish empirically how human-constructed niches acted as legacies that shaped the selection pressures affecting past human populations. One potential approach is to examine whether human demography changed as a result of the continued use of landscapes enduringly transformed by past societies. This paper presents proxies for Amazonian population growth during the late Holocene and discusses their significance within the broader context of landscape legacies resulting from cumulative anthropic environmental alteration during pre-Columbian times. [ABSTRACT FROM AUTHOR]