Bacaba, Pracaxi and Uxi Oils for Therapeutic Purposes: A Scoping Review.

Fruits such as bacaba (Oenocarpus bacaba Mart), pracaxi (Pentaclethra macroloba Kuntze) and uxi (Endopleura uchi (Huber) Cuatrec), from the Amazon rainforest, are potentially interesting for studies of natural products. The current article aims at mapping and characterizing studies on the bacaba, pracaxi and uxi species. This review reports the main bioactive compounds identified in these species and discusses their therapeutic potential. Searches were performed in MEDLINE (Via Pubmed) and Web of Science. Thirty-one studies that described or evaluated the development of formulations aimed at the therapeutic use of the species were included. The findings suggest that species have the potential for the development of pharmaceutical formulations due to their therapeutic properties. However, further studies are required to assess safety and efficacy of these products. Therefore, it is suggested that new research studies propose strategies so that technological development is based on awareness and preservation of the biome.

Mosquitoes (Diptera: Culicidae) of the Amazonian savannas of French Guiana with a description of two new species.

Amazonian savannas are among the most noteworthy landscape components of the coastal plain of French Guiana. Although they cover only 0.22% of the territory, they bring together a large part of the animal and plant diversity of this overseas region of France. This article outlines the results of the first study dedicated to mosquitoes (Diptera: Culicidae) of Amazonian savannas. Samplings were conducted in eight independent savannas evenly distributed along a transect of 170 km on the coastal plain of French Guiana. A total of 50 mosquito species were recorded, which is about 20% of the culicid fauna currently known in French Guiana. Among them, Culex (Melanoconion) organaboensis sp. nov. and Cx. (Mel.) zabanicus sp. nov. are newly described based on both morphological features of the male genitalia and a DNA barcode obtained from type specimens. Diagnostic characters to assist their identification are provided and their placement within the infrasubgeneric classification of the subgenus Melanoconion is discussed.

Seasonal variation and host sex affect bat-bat fly interaction networks in the Amazonian savannahs.

Bats are the second-most diverse group of mammals in the world, and bat flies are their main parasites. However, significant knowledge gaps remain regarding these antagonistic interactions, especially since diverse factors such as seasonality and host sex can affect their network structures. Here, we explore the influence of such factors by comparing species richness and composition of bat flies on host bats, as well as specialization and modularity of bat-bat fly interaction networks between seasons and adult host sexes. We captured bats and collected their ectoparasitic flies at 10 sampling sites in the savannahs of Amapá State, northeastern region of the Brazilian Amazon. Despite female bats being more parasitized and recording greater bat fly species richness in the wet season, neither relationship was statistically significant. The pooled network could be divided into 15 compartments with 54 links, and all subnetworks comprised >12 compartments. The total number of links ranged from 27 to 48 (for the dry and wet seasons, respectively), and female and male subnetworks had 44 and 41 links, respectively. Connectance values were very low for the pooled network and for all subnetworks. Our results revealed higher bat fly species richness and abundance in the wet season, whereas specialization and modularity were higher in the dry season. Moreover, the subnetwork for female bats displayed higher specialization and modularity than the male subnetwork. Therefore, both seasonality and host sex contribute in different ways to bat-bat fly network structure. Future studies should consider these factors when evaluating bat-bat fly interaction networks.

Malaria Risk Drivers in the Brazilian Amazon: Land Use-Land Cover Interactions and Biological Diversity.

Malaria is a prevalent disease in several tropical and subtropical regions, including Brazil, where it remains a significant public health concern. Even though there have been substantial efforts to decrease the number of cases, the reoccurrence of epidemics in regions that have been free of cases for many years presents a significant challenge. Due to the multifaceted factors that influence the spread of malaria, influencing malaria risk factors were analyzed through regional outbreak cluster analysis and spatio-temporal models in the Brazilian Amazon, incorporating climate, land use/cover interactions, species richness, and number of endemic birds and amphibians. Results showed that high amphibian and bird richness and endemism correlated with a reduction in malaria risk. The presence of forest had a risk-increasing effect, but it depended on its juxtaposition with anthropic land uses. Biodiversity and landscape composition, rather than forest formation presence alone, modulated malaria risk in the period. Areas with low endemic species diversity and high human activity, predominantly anthropogenic landscapes, posed high malaria risk. This study underscores the importance of considering the broader ecological context in malaria control efforts.

Tick and flea infestations in captive Tapirus terrestris and Tapirus kabomani (Perissodactyla: Tapiridae) in the Brazilian Amazon.

The present study aimed to identify tick and flea species infesting captive tapirs (Tapirus terrestris and Tapirus kabomani) in the Brazilian Amazon. Ectoparasites were collected from tapirs chemically restrained in Zoo-botanical Parks, breeding facilities, conservationists and, environmental compensation areas in the states of Amapá, Amazonas, and Pará. After collection, the tick and flea specimens were placed in plastic pots containing isopropanol and identified according to dichotomous keys. Ectoparasite infestations were observed in 55% (18/33) tapirs, of which 61% (11/18) were single infestations with ticks or fleas, and 39% (7/18) were mixed infestations with different species of ticks and/or fleas. In total, 227 ticks (15 larvae, 107 nymphs, 38 females and 67 males) and 14 fleas (eight females and six males) were collected, identifying four tick species (Amblyomma cajennense sensu stricto , Amblyomma naponense, Amblyomma oblongoguttatum, and Amblyomma pacae) and three flea species and/or subspecies (Ctenocephalides felis felis, Rhopalopsyllus australis australis, and Tunga penetrans). In conclusion, infestations with Ixodidae ticks and Rhopalopsyllidae, Pulicidae and Tungidae fleas were found in captive tapirs in the Brazilian Amazon, and A. cajennense s.s. was the most frequent species. Additionally, the present study reports new associations between A. pacae and R. a. australis with T. terrestris and between A. cajennense s.s. with T. kabomani.

Proximal and Distal Vagal Indigestion in Buffaloes (Bubalus bubalis) in the Amazon Biome.

This study aims to describe the clinical signs and ultrasonographic and necropsy findings of the first cases of proximal (Buffalo 1) and distal (Buffalo 2) vagal indigestion in two Bubalus bubalis in the Brazilian Amazon biome. The clinical histories of the buffaloes were characterized by progressive weight loss, recurrent tympany, abdominal distention (apple and pear shapes), anorexia, and scant feces. Buffalo 1 was submitted to orogastric intubation, and due to the recurrent tympany, an exploratory laparotomy. Buffalo 2 was submitted to ultrasound examination, and a segment of the pylorus was shown to be adhered to the eventration by ultrasonography. Both animals produced positive results for the atropine test. In the necropsy evaluation, Buffalo 1 was shown to have dilation of the esophagus, rumen, and reticulum; the ruminal contents of animal 1 were olive green and foamy with bubbles within the ingesta. On the other hand, Buffalo 2 was shown to have distention of the forestomach and abomasum; the complex rumen-reticulum and omasum contents were semi-liquid and had a yellowish color. In animal 2, in the eventration region, there was adherence to the pyloric region. The diagnosis of vagal indigestion was based on the history, clinical signs, and ultrasound and necropsy findings, in addition to the results of the atropine test.

Deforestation impacts on dengue incidence in the Brazilian Amazon.

The objective of the study is to perform the spatial analysis of the conditioning factors for the increase in the incidence rate of dengue cases in municipalities located in the Amazon biome, in the period from 2016 to 2021. Three statistical approaches were applied: Moran's index, ordinary least squares regression, and geographically weighted regression. The results revealed that the incidence rates of dengue cases cluster in two areas, both located in the south of the Amazon biome, which is associated with the Arc of Deforestation. The variable deforestation influences the increase in dengue incidence rates revealed by the OLS and GWR model. The adjusted R2 of the GWR model was 0.70, that is, the model explains about 70% of the total case variation of dengue incidence rates in the Amazon biome. The results of the study evidence the need for public policies aimed at the prevention and combat of deforestation in the Amazon region.

Full Exploitation of Peach Palm (Bactris gasipaes Kunth): State of the Art and Perspectives.

The peach palm (Bactris gasipaes Kunth) is a palm tree native to the Amazon region, with plantations expanding to the Brazilian Southwest and South regions. This work is a critical review of historical, botanical, social, environmental, and nutritional aspects of edible and nonedible parts of the plant. In Brazil, the importance of the cultivation of B. gasipaes to produce palm heart has grown considerably, due to its advantages in relation to other palm species, such as precocity, rusticity and tillering. The last one is especially important, as it makes the exploitation of peach palm hearts, contrary to what happens with other palm tree species, a non-predatory practice. Of special interest are the recent efforts aiming at the valorization of the fruit as a source of carotenoids and starch. Further developments indicate that the B. gasipaes lignocellulosic wastes hold great potential for being upcycled into valuable biotechnological products such as prebiotics, enzymes, cellulose nanofibrils and high fiber flours. Clean technologies are protagonists of the recovery processes, ensuring the closure of the product's life cycle in a "green" way. Future research should focus on expanding and making the recovery processes economically viable, which would be of great importance for stimulating the peach palm production chain.

Essential and fixed oils from Amazonian fruits: proprieties and applications.

The Amazon biome is rich in oilseed plant species, which have essential physical-chemical, nutritional and pharmacological properties, in addition to potential economic value for different biotechnological and industrial applications. In the extraction of fixed oils, some Amazon fruit that are oleaginous matrices are acquiring more prominence, such as tucumã (Astrocaryum vulgare), pupunha (Bactris gasipaes), buriti (Mauritia flexuosa), Brazil nut (Bertholletia excelsa), pracaxi (Pentaclethra macroloba), patawa (Oenocarpus bataua), among others. These oilseed fruits have natural antioxidants, essential fatty acids, and good oxidative stability. The essential oils from these oilseed species have antibiotic and anti-inflammatory properties, in addition to the presence of natural antioxidants, such as carotenoids and tocopherols. Thus, Amazonian oilseed species are valuable resources. For these properties to be preserved during fruit processing, the process of extracting the oil is critical. More studies are needed on their properties and applications, seeking to add commercial value, and the optimization of oils and fats processing to obtain quality products. Therefore, this article aims to present Amazonian fruits' potential to obtain fixed and essential oils and possible application in the food industry.

Flora of Ferruginous Outcrops Under Climate Change: A Study in the Cangas of Carajás (Eastern Amazon).

Climate change has impacted biodiversity, affecting species and altering their geographical distribution. Besides understanding the impact in the species, it has been advocated that answering if different traits will be differently impacted could allow refined predictions of how climate change will jeopardize biodiversity. Our aim was to evaluate if climate change will potentially impact plant species differently, considering their traits. We evaluated 608 plant species that occur in the naturally open areas of ferruginous outcrops (namely, cangas) in the National Forest of Carajás (Eastern Amazon). Firstly, we estimated the effects of climate change on each species using species distribution modeling, and analyzed this impact in the set containing all species. Secondly, we classified plant species considering the following traits: (i) pollination syndromes (melittophily, phalaenophily, psychophily, cantharophily, entomophily, ornithophily, chiropterophily, anemophily); (ii) habit (tree, shrub, herb, liana, parasite); and (iii) the main habitat of occurrence (open areas and forests). Thirdly, we investigated if the effects of climate change could be significantly more intense considering all the different traits quoted. Our results showed that most plant species will potentially face reduction of suitable habitats under future climate and the scenarios showed that 42% of them may not find suitable areas in the cangas of Carajás. We found no significant difference within each analyzed trait, considering the potential impact of climate change. The most climatically suitable areas (i.e., areas with high probability of species occurrence in the future) are those in the southwest of the study area. These areas can be considered as priority areas for species protection against climate change.

Deforestation drivers in the Brazilian Amazon: assessing new spatial predictors.

Researches on the deforestation of the Amazon have gained prominence in the last recent years, mainly with the change in the policy regarding the facing of this phenomenon by the Brazilian government. Therefore, an understanding about the causes that pressure the occurrence of deforestation remains relevant and has a leading role in the world. Therefore, the aim of this study is to perform the analysis of the spatial variability of the reasons for the deforestation in the Amazon Biome, in Brazil, (2010-2019). To achieve this goal, 14 variables were selected, the choice and adjustment of the regression model were determined and a diagnosis was carried out in order to verify the most appropriate model. To achieve this purpose, a geographic database was structured in a geographic information system environment. The main results revealed that the adjusted R2 of the Geographically Weighted Regression (GWR) was 0.96, that is, the GWR model explains 96% of the variations in deforestation. Therefore, it was observed a significant gain when using this model. In addition, it was also observed that the average variable of the number of oxen was, among those analyzed, the one that showed the highest correlation with deforestation. Thus, it was found that the livestock sector in southern Amazonia is the main economic agent that pressures large areas of deforestation, since stockfarming is practiced extensively. Finally, it was concluded that the municipalities with the largest areas of deforestation formed a cluster in the southern portion of the Amazon, in the arc of deforestation.

Amazon-derived nutraceuticals: Promises to mitigate chronic inflammatory states and neuroinflammation.

Nutraceuticals have been the focus of numerous research in recent years and accumulating data support their use for promoting some health benefits. Several nutraceuticals have been widely studied as supplements due to their functional properties ameliorating symptoms associated with neurological disorders, such as oxidative stress and chronic inflammatory states. This seems to be the case of some fruits and seeds from the Amazon Biome consumed since the pre-Columbian period that could have potential beneficial impact on the human nervous system. The beneficial activities of these food sources are possibly related to a large number of bioactive molecules including polyphenols, carotenoids, unsaturated fatty acids, vitamins, and trace elements. In this context, this review compiled the research on six Amazonian fruits and seeds species and some of the major nutraceuticals found in their composition, presenting brief mechanisms related to their protagonist action in improving inflammatory responses and neuroinflammation.

Detection of Treponema spp. in bovine digital dermatitis in the Amazon biome, Brazil / Detecção de Treponema spp. em dermatite digital bovina no bioma amazônico, Brasil

Bovine digital dermatitis (BDD) is a polybacterial claw disease that is endemic to dairy cattle kept in loose house systems, and treponemas are the main bacteria implicated in this disease. The objective of this study was to report the occurrence of Treponema spp. in BDD from crossbred dairy cattle (Holstein x Zebu) kept in a pasture in the Brazilian Amazon biome. The diagnostic of BDD was performed by inspecting the distal extremities of cattle during milking in one or more visits comprising 15 farms. In total, it could be inspected 1,847 cows from August 2016 to July 2017, and 25 lesions of BDD were diagnosed. The feet were scored (System M: M0 = no lesion, M1 = ulcer stage <2cm, M2 = ulcer stage >2cm, M3 = healing stage, M4 = chronic stage, M4.1 = chronic stage with ulcer area). Twenty four biopsy samples were taken from feet with BDD and five biopsy samples from feet with no lesions. The histopathology of stained tissues was performed by hematoxylin and eosin and Warthin-Starry method. The samples were also tested by nested PCR for the three previously isolated BDD Treponema phylogroups (T. medium/T. vincentii-like, T. phagedenis-like and T. putidum/T. denticola-like). Spirochetes were observed in 54.2% (13/24) of the lesions, and in 91.7% (22/24) of the samples were detected the DNA of this spirochete belonging to the treponema phylogroups implicated in BDD. In 25% (6/24) of the lesions were detected all the phylogroups. Forty percent (40%, 2/5) of the M0 samples were also positive for the nested Polymerase Chain Reaction (nested-PCR), as 8.3% (2/24) of the lesions were negative in both techniques employed. Treponema putidum/T. denticola-like was the most detected bacterial in all the stages, and active lesions (M2 and M4.1) presented a greater proportion of T. medium/T. vincentii-like and T. phagedenis-like, but no statistical differences were observed (p>0.05). It could be concluded that BDD lesions in crossbred dairy cattle kept to pasture in the Amazon biome were classified as "polytreponemal" infections and the phylogroup T. putidum/T. denticola-like was the most frequent in the lesions.(AU)

Dermatite digital bovina (DDB) é uma enfermidade polibacteriana dos dígitos endêmica em vacas leiteiras criadas em estábulos e as treponemas são as principais bactérias envolvidas. Este estudo teve como objetivo relatar a ocorrência de Treponema spp. em DDB em bovinos leiteiros mestiços (Holandês x Zebu) criados a pasto no bioma amazônico brasileiro. O diagnóstico da DDB foi realizado pela inspeção, em uma ou mais visitas, das extremidades distais das vacas durante a ordenha em 15 propriedades. No total, foram inspecionadas 1.847 vacas de agosto de 2016 a julho de 2017 e diagnosticou-se 25 lesões de DDB. As extremidades distais inspecionadas foram classificadas em escores (M0 = sem lesão, M1 = estágio ulcerado <2cm, M2 = estágio ulcerado >2cm, M3 = estágio em cicatrização, M4 = estágio crônico, M4.1 = estágio crônico com área ulcerada) e realizada 24 biópsias de dígitos com DDB e cinco biópsias de dígitos em estágio M0. Foram realizadas a histopatologia pelas colorações de hematoxilina e eosina e pelo método de Warthin-Starry, e a nested de reação em cadeia de polimerase (nested-PCR) para os três filogrupos de treponemas previamente isolados de DDB (Treponema medium/T. vincentii-like, T. phagedenis-like e T. putidum/T. denticola-like). Espiroquetas foram observadas em 54,2% (13/24) das lesões e em 91,7% (22/24) detectou-se o DNA de, pelo menos, um dos filogrupos de treponemas pesquisados. Em 25% (6/24) das lesões foram detectados o DNA dos três filogrupos. Em 40% (2/5) das amostras em estágio M0 também foram positivas na nested-PCR, assim como 8,3% (2/24) das lesões foram negativas em ambas as técnicas empregadas. T. putidum/T. denticola-like foi o filogrupo mais detectado em todos os estágios e lesões ativas (M2 e M4.1) apresentaram uma maior proporção para Treponema medium/T. vincentii-like e T. phagedenis-like, mas não se obteve diferença estatística na ocorrência dos filogrupos entre os estágios das lesões (P>0,05). Conclui-se que lesões de DDB em rebanhos leiteiros mestiços criados a pasto no bioma amazônico brasileiro são "politreponemais" e o filogrupo T. putidum/T. denticola-like é o mais frequente nas lesões.(AU)

Fruit-based drink sensory, physicochemical, and antioxidant properties in the Amazon region: Murici (Byrsonima crassifolia (L.) Kunth and verbascifolia (L.) DC) and tapereba (Spondia mombin).

Increased fruit consumption due its protective effect on the organism is accompanied by the development of the processing industry of these products. The aim of this work was to optimize fruit pulp-based beverage formulations from the murici and tapereba Amazon region, taking into account their sensory acceptance and antioxidant activity. Total soluble solid content, reducing sugar content, titratable acidity contents, pH, and ascorbic acid content were determined in pulps and formulations. The total content phenolic compounds and antioxidant activity were also evaluated. A 22 factorial experiment was formulated to optimize ingredients for the production of murici and tapereba fruit drinks. The murici pulp had higher acidity and higher ascorbic acid content. The analysis of phenolic compounds and antioxidant activity presented higher quantity in tapereba pulp. Tapereba-based beverages had better acceptance by the evaluated criteria. Fruit-based beverages murici and tapereba are a well-accepted product and have important nutritional characteristics.

The role of protected and deforested areas in the hydrological processes of Itacaiúnas River Basin, eastern Amazonia.

To protect indigenous land and avoid the spread of deforestation in the Amazon, state and federal Brazilian agencies recognized several protected areas since the 1990s. However, the importance of these protected areas in the water cycle and the hydrologic connection with surrounding landscapes is little analyzed. In this study, we evaluated the role of preserved and deforested areas in the water balance in the Itacaiúnas River Basin using the MGB hydrological model. We estimated the impacts of land cover changes on evapotranspiration and discharge for four scenarios: Preserved (1984 land cover), Recent (2013 land cover, with 50% deforestation), Hypothetical deforestation of protected areas (70% deforestation) and complete deforestation of protected areas (79% deforestation). We showed that deforestation of the remaining preserved area could be responsible for a decrease of 23% (3.5 km³/year) in water transfer to the atmosphere by evapotranspiration. Furthermore, we showed that each 15% of deforestation occurring between the Preserved and Recent scenarios increased the average discharges by 5.4% (40 m³/s). Additionally, past land cover changes in the headwaters of the Itacaiúnas River Basin caused statistically significant changes in discharges inside the protected areas. This insight is considered important due to the association between increases in discharges and water quality issues. The results suggest that headwater areas of secondary drainages that run into the forested domains should be prioritized for reforestation programs. Likewise, the reforestation of nonprotected areas could be responsible for restoring ecosystem services, including hydrological functions, biodiversity and water quality.

First record of the chemical composition of essential oil of Piper bellidifolium, Piper durilignum, Piper acutilimbum and Piper consanguineum from the Brazilian Amazon forest / Primeiro registro da composição química de óleos essenciais de Piper bellidifolium, Piper durilignum, Piper acutilimbum e Piperconsanguineumda Floresta Amazônica no Brasil

Piper bellidifolium, Piper durilignum, Piper acutilimbum and Piper consanguineum are bushes that occur in the Amazon and are morphologically similar. With the aim of analyzing the chemical profile of the volatile constituents of these species, essential oils from the leaves were obtained through steam distillation and analyzed using gas chromatography-flame ionization detection (GC-FID) and gas chromatograph coupled to a mass spectrometer (GC-MS). The chemical analysis enabled the identification of 95 compounds representing 96.3 ± 0.6% of the P. bellidifolium oil, 95.5 ± 0.71% of the P. durilignum oil, 98.0 ± 1.0% of the P. acutilimbum oil and 96.1 ± 2.1% of the P. consanguineum oil. Although sesquiterpenes were the predominant chemical class in the oils of the four species, qualitative and quantitative differences were found in their chemical composition. The major constituents were (E)-nerolidol (20.3 ± 0.4%) in the P. bellidifolium oil, germacrene D (11.1 ± 0.3%) in the P. durilignum oil, and -eudesmol in both the P. consanguineum (18.6 ± 0.5%) and P. acutilimbum (7.5 ± 0.4%) oils. Despite their morphological similarity, a principal component analysis (PCA) of the GC-MS data clearly separated the four species according to the chemical profile of the essential oil extracted from their leaves.

Piper bellidifolium, Piper durilignum, Piper acutilimbum e Piper consanguineum são arbustos que ocorrem na Amazônia e são morfologicamente similares. Com o intuito de analisar o perfil químico dos constituintes voláteis dessas espécies, óleos essenciais das folhas foram obtidos por hidrodestilação e analisados por cromatografia gasosa - detector por ionização de chama (CG-FID) e cromatografia gasosa acoplada a espectrometria de massa (CG-EM). A análise química permitiu identificar 95 compostos, representando 96.3 ± 0.6% do óleo de P. bellidifolium; 95.5 ± 0.71% de P. durilignum; 98.0 ± 1.0% de P. acutilimbum e 96.1 ± 2.1% de P. consanguineum. Apesar dos óleos das quatro espécies terem sesquiterpeno como classe química predominante, diferenças qualitativas e quantitativas em sua composição química foram observadas. Os principais componentes encontrados foram: (E)-nerolidol (20.3 ± 0.4%) em P. bellidifolium; germacreno D (11.1 ± 0.3%) em P. durilignum; e -eudesmol nos óleos de P. consanguineum (18.6 ± 0.5%) e P. acutilimbum (7.5 ± 0.4%). Apesar da similaridade morfológica entre as espécies, uma análise de componentes principais (PCA) dos dados de CG-EM claramente separou as quatro espécies quanto ao perfil químico do óleo essencial extríado de suas folhas.

Analysis of soybean cropland expansion in the southern Brazilian Amazon and its relation to economic drivers / Análise da expansão do cultivo da soja no sul da Amazônia brasileira utilizando imagens de satélite e sua relação com forçantes econômicas

ABSTRACT The agricultural dynamics of soybean expansion have long been recognized as a major driver of excessive land cover change on the southwestern border of the Brazilian Amazon. The hypothesis that the soybean market exerts an influence on land use was investigated by the association between economic indicators and soybean crop dynamics in the state of Mato Grosso (western Brazil). We integrated a historical series of satellite data of soybean cropland expansion and the two main economic variables (selling prices and production costs) for soybean in Mato Grosso. We focused on the relation between profit (the difference between the average soybean price and production costs) and land-use transition to soybean from 2001 to 2013. The spatially explicit analysis showed that the overall accuracy between the resulting first-time use and the most recent soybean crop area in 2013 was 96.75%, with a Kappa index of 0.63. However, dissimilar values found between Omission and Commission indicators suggest that most of the expanded areas prior to 2013 (5.57 million ha) were under a high dynamical range of land uses. Although there is no direct relation between either the deforestation rate or expansion trends (first-time-use rate) and profit, the results strongly suggest (R2=0.81) that profit exerts a direct and non-negligible influence on the evolution of consolidated land use for soybean in Mato Grosso State.

RESUMO A dinâmica agrícola relacionada à expansão da soja tem sido reconhecida como um dos principais fatores da excessiva conversão da cobertura do solo no Estado de Mato Grosso, no sudoeste da Amazônia brasileira. A hipótese de que o mercado de soja exerce influência no uso do solo, foi investigada pela associação de indicadores econômicos com a dinâmica da cultura de soja no Mato Grosso. Integramos séries históricas de dados de satélite para expansão da área de cultivo de soja e de suas duas principais variáveis ​​econômicas associadas (preço de venda e custo de produção). Enfocamos a relação entre lucro (a diferença entre as médias do preço da soja e do custo de produção) e a conversão do uso do solo para soja de 2001 a 2013. A análise espacial explícita revelou que a precisão global na comparação entre o mapa resultante de first-time-use de cultivo de soja em 2013 foi de 96,75%, com índice Kappa de 0,63. Entretanto, a divergência obtida entre os indicadores de erro por comissão e omissão, sugerem que a maior parte da expansão da soja ocorrida antes de 2013 (5,57 milhões de ha) esteve sob influência de uma intensa dinâmica de uso do solo. Embora seja claro não haver relação direta entre a taxa de desmatamento ou tendências de expansão (taxa de uso pela primeira vez) e o lucro, os resultados sugerem fortemente (R2=0,81) que o lucro exerce influência direta e não-negligenciável na evolução do uso do solo consolidado com soja no estado de Mato Grosso.

Carbon dioxide emissions from Tucuruí reservoir (Amazon biome): New findings based on three-dimensional ecological model simulations.

We used a three-dimensional model to assess the dynamics of diffusive carbon dioxide flux (F(CO2)) from a hydroelectric reservoir located at Amazon rainforest. Our results showed that for the studied periods (2013 summer/wet and winter/dry seasons) the surface averaged F(CO2) presented similar behaviors, with regular emissions peaks. The mean daily surface averaged F(CO2) showed no significant difference between the seasons (p>0.01), with values around -1338mg Cm-2day-1 (summer/wet) and -1395mg Cm-2day-1 (winter/dry). At diel scale, the F(CO2) was large during the night and morning and low during the afternoon in both seasons. Regarding its spatial distribution, the F(CO2) showed to be more heterogeneous during the summer/wet than during the winter/dry season. The highest F(CO2) were observed at transition zone (-300mg Cm-2h-1) during summer and at littoral zone (-55mg Cm-2h-1) during the winter. The total CO2 emitted by the reservoir along 2013 year was estimated to be 1.1Tg C year-1. By extrapolating our results we found that the total carbon emitted by all Amazonian reservoirs can be around 7Tg C year-1, which is 22% lower than the previous published estimate. This significant difference should not be neglected in the carbon inventories since the carbon emission is a key factor when comparing the environmental impacts of different sources of electricity generation and can influences decision makers in the selection of the more appropriate source of electricity and, in case of hydroelectricity, the geographical position of the reservoirs.