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Less than half of the original two million km2 of the Brazilian Savanna natural vegetation, called the Cerrado Biome, remains standing. Given its climate and socio-biodiversity importance, more effective public policies are needed to protect the remaining natural areas. In this paper, we present the methodology and results of the DETER Cerrado, an early warning deforestation system within the Cerrado region. The findings support that DETER is effective in detecting a wider range of deforestation patch sizes, from the larger patches, heavily associated with agricultural expansion, to the smaller areas (>1 ha <10 ha). Nevertheless, 80% of the deforestation is concentrated in the 10-km radius zone from the DETER Alerts. This area was later detected by the Cerrado Deforestation Monitoring Project (PRODES), the system that accounts for the annual deforestation rate assessment, which highlights the capability of the DETER system to provide support to the surveillance of deforestation in the Cerrado. [ABSTRACT FROM AUTHOR]

Agricultural intensification is often seen as an appropriate approach to meet the growing demand for agricultural products. In regions affected by seasonal or chronic water scarcity, closing the yield gap depends on irrigation. Brazil is the second-largest wheat importer of the world and irrigated wheat has high yield potential in Brazil, especially in tropical and sub-tropical regions of the country. The crop coefficient (Kc) is still a practical and simple way of quantifying crop irrigation requirements. In this paper, we provided Kc values based on a robust experimental dataset across different wheat-producing regions in Brazil. Four experiments were conducted in three sites [season 2017 in Piracicaba, State of São Paulo (Southeast region); season 2012 Maringá, State of Paraná (Southern region); and seasons 2016 and 2017 Rondonópolis, State of Mato Grosso) (Midwest region)] using lysimeters and the Bowen ratio energy balance method for crop evapotranspiration measurements. Our data showed that Kc values varied among the regions analyzed. For the Midwest region, Kc values ranged from 0.88 to 1.36; the Southeastern region from 0.81 to 1.15, and the Southern region from 0.67 to 1.01. Considering values suggested by FAO, those for arid climates should be used in the Midwest region, sub-humid values for the Southeast, and humid values in the Southern. Differently, that was observed for other crops, our database showed wheat Kc values being stable disregarding the ETo range, which might be related to relatively lower ETo during the winter. [ABSTRACT FROM AUTHOR]

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Tropical wetlands are amongst the most biodiverse ecosystems on Earth and have immense socioecological value. However, tropical wetlands are considered exploitable resources and continue to be drained and converted to other "productive" uses. It is therefore urgent to identify and understand the interactions between various drivers of change triggering degradation of such wetlands. In the present study, we systematically reviewed and analyzed the existing literature on wetlands in two tropical countries namely India and Brazil with special reference to inland wetlands, and proposed a conceptual model illustrating the intricate linkages of such wetlands with different drivers of change. We also developed the Nature Futures' Framework to depict the diverse values of inland wetlands contributing to human wellbeing in the two tropical countries. Findings revealed similar drivers of change triggering the degradation of Indian and Brazilian wetlands. These include changes in climate & land use, population growth, poor land governance due to weak policies, besides other anthropogenic activities such as deforestation, and overexploitation of wetland resources. Among these, land-use change such as agriculture intensification and infrastructure development were the major direct drivers; whereas, institutional and governance factors such as the absence of concrete policy measures were the major indirect drivers threatening the inland wetlands in India and Brazil. Results also revealed some contrasting drivers of change such as illegal human settlements, and land grabbing by the brick industry for Indian wetlands; while, gold mining and intensification of bovine systems for Brazilian wetlands. Our paper also provides an insight into the status of wetland conservation in India and Brazil. We recommend the promotion of community-based conservation practices while adopting sustainable livelihood strategies by the local people for the conservation and wise use of inland wetlands in India and Brazil. The arguments raised in the paper have the potential to assist the stakeholders and/or decision-makers towards implementing sustainable management strategies for inland wetlands in the two countries, and tropical wetlands in general. [ABSTRACT FROM AUTHOR]

Copyright of Sustainability in Debate / Sustentabilidade em Debate is the property of University of Brasilia, Center for Sustainable Development 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.)

Due to its low share of energy-related emissions, energy systems models have overlooked the implications of technological transition in the agricultural sector and its interaction in the wider energy system. This paper explores the role of agriculture intensification by using a novel agricultural-based energy systems model. The aim is to explore the future role of Brazil's agriculture and its dynamics with other energy sectors under two carbon constraint scenarios. The main focus has been to study resource competition between sugarcane and natural gas at a country level. Results show that in order to meet the future food and bioenergy demand, the agricultural sector would start intensifying by 2030, improving productivity at the expense of higher energy demand, however, land-related emissions would be minimised due to freed-up pasture land and reduction in deforestation rates. Additionally, the development of balanced bioenergy and natural gas markets may help limit the sugarcane expansion rates, preserving up to 12.6 million hectares of forest land, with significant emissions benefits. [ABSTRACT FROM AUTHOR]

The Brazilian Cerrado is recognized as one of the most threatened biomes in the world, as the region has experienced a striking change from natural Cerrado vegetation to intense cash crop production. This paper reviews the history of land conversion in the Cerrado and the development of soil properties and water resources under past and ongoing land use. We compared soil and water quality parameters from different land uses considering 80 soil and 18 water studies conducted in different regions across the Cerrado to provide quantitative evidence of soil and water alterations from land use change. Following the conversion of native Cerrado, significant effects on soil pH, bulk density and available P and K for croplands and less-pronounced effects on pastures were evident. Soil total N did not differ between land uses because most of the sites classified as croplands were nitrogen-fixing soybeans, which are not artificially fertilized with N. In contrast, water quality studies showed nitrogen enrichment in agricultural catchments, indicating fertilizer impacts and potential susceptibility to eutrophication. Regardless of the land use, P is widely absent because of the high-fixing capacities of deeply weathered soils and the filtering capacity of riparian vegetation. Pesticides, however, were consistently detected throughout the entire aquatic system. In several case studies, extremely high-peak concentrations exceeded Brazilian and European Union (EU) water quality limits, which were potentially accompanied by serious health implications. Land use intensification is likely to continue, particularly in regions where less annual rainfall and severe droughts are projected in the northeastern and western Cerrado. Thus, the leaching risk and displacement of agrochemicals are expected to increase, particularly because the current legislation has caused a reduction in riparian vegetation. We conclude that land use intensification is likely to seriously limit the Cerrado's future regarding both agricultural productivity and ecosystem stability. Because only limited data are available, we recommend further field studies to understand the interaction between terrestrial and aquatic systems. This study may serve as a valuable database for integrated modelling to investigate the impact of land use and climate change on soil and water resources and to test and develop mitigation measures for the Cerrado. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

• Deforestation-induced rainfall changes negatively impact soybean and maize yields in Brazil. • Soybean and maize yields could have been 6.6 % and 9.9 % higher per year if rainfall patterns hadn't been altered by deforestation. • Agricultural efficiency improvements insufficient to counteract rainfall-changes effects on yields. • Study underscores the vital role of forest preservation for agricultural resilience and food security. • Forests' critical role in regulating the water cycle highlighted in the face of climate change. Whereas the global demand for food, fiber and energy is increasing, the capacity of ecosystems services to sustain agricultural production is being compromised worldwide. Brazil is a global food supplier that has benefitted from agricultural intensification in the past decades. At the same time, expansion of cropland has led to deforestation that, in turn, is increasingly affecting rainfall patterns thereby influencing crop yields. This study examines how loss in forest cover has impacted agricultural yields through change in rainfall. To do so, we use modelled data on changes in rainfall patterns due to deforestation as input to a crop model. We assess yield changes within the soybean-maize double cropping system, the country's most relevant agricultural system, in five states within the Amazon and Cerrado biomes. Findings revealed that soybean and maize yields would have been respectively 6.6 % and 9.9 % higher per year in the last decade if rainfall patterns hadn't been altered by deforestation from 1982 onwards. Although agricultural efficiency improved between 2011 and 2020, it was insufficient to offset the negative effect of altered rainfall on yields. Our paper reveals the link between deforestation and crop yields, emphasizing the need to preserve forest cover for agricultural resilience and food security. It reinforces the critical role of forests in regulating the water cycle, particularly in the face of climate change-induced warmer and drier conditions that can impact agricultural production and other human activities. [ABSTRACT FROM AUTHOR]

Over the last several decades, Brazil has become both the world's leading soy producer and the world's leading consumer of hazardous pesticides. Despite identified links between pesticide exposure and carcinogenesis, there has been little populationlevel research on the effects of pesticide intensification on broader human health in Brazil. We estimate the relationship between expanded soy production--and related community exposure to pesticides--on childhood cancer incidence using 15 y of data on disease mortality. We find a statistically significant increase in pediatric leukemia following expanded local soy production, but timely access to treatment mitigates this relationship. We show that pesticide exposure likely occurs via water supply penetration. Our findings represent only the tip of the iceberg for substantial health externalities of high-input crop production and land use change. Our results are of particular interest in developing contexts with demand for intensified food production systems and underscore the need for stronger regulation of pesticides and increased public health attention to exposure in the broader community. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Applied Ecology is the property of Wiley-Blackwell 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.)

Tropical deforestation in Brazil is a major source of greenhouse gas emissions that contribute to climate change. Brazil has taken several steps to reduce emissions associated with deforestation including the development of policies to promote and reward cattle ranching intensification. Intensification practices are hypothesized to reduce the conversion of tropical forests while simultaneously increasing the productivity of ranching on current pasture lands. This paper assesses the impact of intensification on the demand for productive land. A theoretical model of land use, which considers the degree of intensification in the estimation of the derived demand for pasture, is tested with data from small-scale landowners who operate dairy farms and calving operations in the greater Ouro Preto do Oeste region of Rondônia. Results suggest different trajectories for beef and dairy production. The intensification of cattle production exhibits a nonlinear relationship with the demand for productive land: first as farms become more intensive the demand for newly cleared land increases, but then decreases with further intensification. The results are different for dairy intensification, which is found to be correlated with reduced deforestation. Findings suggest that the reliance on policies that promote intensification can be a risky way of achieving climate change objectives. [ABSTRACT FROM AUTHOR]

Landsat imagery offers the most extended continuous land surface observation at 30 m spatial resolution and is widely used in land change studies. On the other hand, the recent developments on big data, such as cloud computing, give new opportunities for carrying out satellite-based continuous land cover monitoring including land use/cover change and more subtle changes as forest degradation, agriculture intensification and vegetation phenological patterns alterations. However, in the range 0–10 ∘ south latitude, especially in the summer and autumn, there is a high rainfall and high clouds presence. We hypothesise that it will be challenging to characterise vegetation phenology in regions where the number of valid (cloud-free) remotely-sensed observation is low or when the observations are unevenly distributed over the year. This paper aims to evaluate whether there is sufficient availability of Landsat 7 and 8 images over Brazil to support the analysis of phenodynamics of vegetation. We used Google Earth Engine to assess Landsat data availability during the last decades over the Brazilian territory. The valid observations (excluding clouds and shadow areas) from Landsat 4/5/7/8 during the period 1984–2017 were determined at pixel level. The results show a lower intensity of Landsat observations in the northern and northeastern parts of Brazil compared to the southern region, mainly due to clouds' presence. Taking advantage of the overlapping areas between satellite paths where the number of observations is larger, we modelled the loss of information caused by a lower number of valid (cloud free) observations. We showed that, in the deciduous woody formations of the Caatinga dominium, the scarcity of valid observations has an adverse effect on indices' performance aimed at describing vegetation phenology. However, the combination of Landsat data with satellite constellation such as Sentinel will likely permit to overcome many of these limitations. [ABSTRACT FROM AUTHOR]

Cattle ranching in Brazil is a key driver of deforestation and greenhouse gas (GHG) emissions. The Brazilian government plans to reduce national GHG emissions by at least 36%, partly by reducing emissions in the livestock sector through strategies such as intensification, pasture improvement, and rotational grazing. In response, sustainability programs promoting these practices have begun operation. Though studies have previously investigated aspects of GHG emissions and sequestration in improved pastures, they have not linked improvements with programmatic interventions. We surveyed 40 cattle ranchers located in the Brazilian Amazon biome to investigate how GHG emissions differed between farms participating in livestock sustainability programs with intensified production and farms not participating in these programs. We found that participating farms produced 8.3 kg of CO 2 e/kg of carcass weight (CW) less than did non-participating farms, which represents 19% fewer emissions. Farms that had participated in a sustainability program for at least two years showed larger differences in emissions: 19.0 kg of CO 2 e/kg CW less for program farms compared with their counterparts, or 35.8% fewer emissions. Key drivers of the total CO 2 e/kg CW in all farms were enteric fermentation and manure management. This paper provides farm-level data supporting intensification as a possible strategy to reduce emissions per kilogram of beef produced, and suggests that future research efforts should focus on long-term impacts of intensification and expand metrics for success beyond GHG calculations. [ABSTRACT FROM AUTHOR]

The current development model of the agricultural sector in Brazil has considerable potential to cause negative environmental impacts, including the pollution of aquatic ecosystems, as it may contribute to the intensification of erosive processes on deforested soils, to the leaching of eroded materials, and to the consequent siltation of waterbodies with soil particles containing environmental pollutants. We aimed at assessing the occurrence of several pesticide residues in aquatic ecosystems located near large soybean crops of the Santarém region, in the eastern Brazilian Amazon. By adopting a methodological approach combining analytical and environmental chemistry, 10 groundwater samples, 18 surface water, and 15 drainage bottom sediment samples, all collected in streams from the study region, were analyzed. The study included a distributed sampling procedure covering an area of approximately 20 km2, and the potential risks of the studied pollutants and their implications for the region were likewise examined and critically discussed. Results indicate that active ingredients such as the herbicides atrazine and metolachlor were detected in the waters, as well as organochlorine insecticides such as DDTs and endosulfan. The spatialization of the resulting pesticide concentrations in water suggests that the contamination would not be punctual but would rather come from various point sources. As for the sediments, glyphosate and DDT contamination was likewise pervasive. Our findings suggest the need of elucidating the sediment and water polluting effects of large-scale soybean crops in the Amazonian rainforest. [ABSTRACT FROM AUTHOR]

In Brazil, bioelectricity generation from sugarcane bagasse and black liquor is regarded as a sustainable electricity supply option. However, questions regarding land use, investment decisions, and demand for paper, ethanol and sugar make its future role uncertain. The aim of this paper is to present a novel modelling framework based on a soft-link between a multi-sectoral Brazilian integrated assessment model (MUSE-Brazil) and an electricity portfolio optimisation model (EPOM). The proposed framework is capable of dynamically simulating sectoral electricity demand, regional bioenergy production under land use constraints and optimal power sector technological shares in each of the electricity subsystems. Considering Brazil under a 2 °C carbon budget, two scenarios based on economic attractiveness of producing second-generation ethanol have been investigated. Under the scenario where second-generation ethanol is not produced, outputs indicate that by 2050, Brazil would increase sugarcane and wood production by 68% and 49% respectively without causing direct or indirect deforestation. Agriculture intensification is evidenced as an alternative for reducing land use disruptions. Bioelectricity share is projected to remain around 9–10%. However, if second generation ethanol becomes cost-effective, thus limiting bagasse availability, the share of bioelectricity production would decrease to approximately 7.7%, with natural gas-fired plants playing a stronger role in the future power system expansion, causing an increase on electricity sector emissions. • A novel framework considering energy systems and portfolio optimisation is proposed. • Two different carbon constrained bioelectricity scenarios in Brazil are investigated. • Power system emissions could represent between 13.3% and 14.5% of the carbon budget. • Controlling deforestation in the Amazon is fundamental to reach mitigation targets. • Bioelectricity potential is considerably reduced when 2G ethanol is produced. [ABSTRACT FROM AUTHOR]

Natural landscapes are facing rapid transformation in many parts of the world, but the consequences of such changes for insects are poorly known. We evaluated how the conversion of the savannas and forests from Brazil´s Cerrado into lands devoted to intensive agriculture, livestock, or plantation forestry affects euglossine bees. We determined the effects of land-use change on the species richness of euglossines, and functional traits related to the body size and wing fluctuating asymmetry (FA) of a habitat generalist species. Few species were recorded in the anthropogenic land uses and most presented lower abundances in the converted than in the native habitats. The exception was Eulaema nigrita, whose average abundance in cattle pastures and in soy fields did not differ from that observed in the native habitats. However, El. nigrita males collected in pastures or in soy fields were significantly smaller than those from savannas and forests, whereas those from eucalypt tree plantations were smaller than those from savanna. Furthermore, El. nigrita males from the tree plantations had higher levels of FA in wing shape than those from native forests. Implications for conservation: Our results showed that land-use change in the Cerrado biodiversity hotspot causes the impoverishment and homogenization of the Euglossini fauna. Furthermore, we found evidence that the converted habitats present more stressful conditions for the larval development of some species. This indicates that the conservation of euglossine populations in human- modified Cerrado landscapes depends largely on the presence of protected areas, including those within rural private land as required by Brazil´s Native Vegetation Protection Law. [ABSTRACT FROM AUTHOR]

By combining crop, livestock and/or forestry activities in the same area, integrated systems (IS) can increase organic matter content in the soil – which favors biomass production and allows for higher livestock stocking rates in pasturelands. The implementation of IS is therefore seen as a promising strategy for sustainable agricultural intensification in Brazil, particularly in Mato Grosso state (MT). However, despite the benefits associated with IS and incentives offered by the federal government to stimulate their dissemination, little is known about these systems or the challenges to implement them, and only a limited number of farmers have adopted IS so far. This paper presents a comprehensive assessment of all IS identified in Mato Grosso by 2012/13, which were mapped and described in terms of their main technical and non-technical features. These findings were combined with farm survey data set to provide a detailed account of the various technologies currently being disseminated, their individual diffusion levels and potential adoption constraints. Results generated through qualitative and quantitative research methods give an overview of IS’ state of the art, reveal farmer perception of such technology and offer insights into the prospects for low-carbon agriculture in the region. The study’s major findings are that IS are present in more than 40 of the 141 municipalities of MT, and the vast majority (89%) involve only crop and livestock. Farmers have adopted three different crop–livestock configurations, depending on their production strategy. Cultural aspects play a major role in farmer decisions to adopt IS, credit provision has not been relevant for IS adoption, and a broader dissemination of IS may occur as land transitions continue. [ABSTRACT FROM AUTHOR]

Due to different combinations of agriculture, livestock and forestry managed by rotation, succession and intercropping practices, integrated agriculture production systems such as integrated crop–livestock systems (iCL) constitute a very complex target and a challenge for automatic mapping of cropping practices based on remote sensing data. The overall objective of this study was to develop a classification strategy for the annual mapping of integrated Crop–Livestock systems (iCL) at a regional scale. This strategy was designed and tested in the six agro-climatic regions of Mato Grosso, the largest Brazilian soybean producer state, using MODIS satellite time-series images acquired between 2012 and 2019, ground data with heterogeneous distribution in space and time and a Random Forest classifier. The results showed that: 1. the use of unbalanced training samples with a class composition close to the real one was the right classifier training strategy; 2. the use of a single training database (pooling samples from different years and regions) to classify each region and year individually proved to be robust enough to provide similar classification accuracies in comparison to those based on the use of a database acquired for each region and for each year. The final hierarchical classification overall accuracy was 0.89 for Level 1, the cropping pattern level (single and double crops DC); 0.84 for Level 2, the DC category level (integrated system iCL soy-pasture/brachiaria, soy-cotton and soy-cereal); 0.77 for Level 3, the iCL level (iCL1 soy-pasture and iCL2 soy-pasture mixed with corn). The F-scores for DC, iCL and iCL1 cropping systems presented high accuracy (0.89, 0.85 and 0.84), while iCL2 was more difficult to classify (0.63). This approach will next be applied across the entire Brazilian soybean corridor, leading to an operational tool for monitoring the adoption of sustainable intensification practices recognized by Brazil's Agriculture Low Carbon Plan (ABC PLAN). [ABSTRACT FROM AUTHOR]

Background: Cutaneous leishmaniasis (CL) is an endemic disease in Brazil that is highly prevalent in the northern region of the country. Although there is a continuous and growing number of cases registered in the state of Roraima, there is limited information regarding the species of Leishmania that affect the human population. In this study, we aimed to characterize which Leishmania species cause human disease in those presenting with cutaneous leishmaniasis in endemic areas of the State of Roraima. Methods: We conducted a prospective surveillance study between 2016 to 2018 in health centers located in the State of Roraima, Brazil. Participants with clinical suspicion of CL were enrolled and provided lesion samples for parasitological detection by microscopy. A subset of the samples was tested by polymerase chain reaction and sequencing of the internal transcribed spacer 1 (ITS-1 PCR) for molecular species identification. Results: A total of 262 participants were enrolled in this study. Of those, 129 (49.27%) were positive by parasitological examination. Most positive subjects (81.58%) were male, and most cases presented a single lesion (80.26%). ITS-1 PCR and sequencing on a subset of 76 samples allowed us to detect nine different species of Leishmania: L. (V.) braziliensis, L (V.) panamensis, L. (V.) guyanensis, L. (V.) naiffi, L. (V.) shawi, L.(V.) utingensis, L. (V.) lindenbergi, L. (L.) amazonensis and L. (L.) mexicana. Conclusions: Our study provides the first assessment of circulating species of Leishmania in the State of Roraima, Brazil, and shows the high diversity in this region. This study opens the path for further research on the transmission of leishmaniasis in the northernmost Brazilian State including vector and reservoir surveillance as well as for intensification of investigation and control activities against CL in the region. [ABSTRACT FROM AUTHOR]

The Nationally Determined Contributions (NDCs) to the Paris Agreement (PA) submitted so far do not put the world on track to meet the targets of the Agreement and by 2020 countries should ratchet up ambition in the new round of NDCs. Brazil's NDC to the PA received mixed reviews and has been rated as "medium" ambition. We use the Brazil Land Use and Energy System (BLUES) model to explore low-emission scenarios for Brazil for the 2010–2050 period that cost-effectively raise ambition to levels consistent with PA targets. Our results reinforce the fundamental role of the agriculture, forest, and land use (AFOLU) sectors and explore inter-sectoral linkages to power generation and transportation. We identify transportation as a prime candidate for decarbonization, leveraging Brazil's already low-carbon electricity production and its high bioenergy production. Results indicate the most important mitigation measures are electrification of the light-duty vehicle (LDV) fleet for passenger transportation, biodiesel and biokerosene production via Fischer-Tropsch synthesis from lignocellulosic feedstock, and intensification of agricultural production. The use of carbon capture and storage (CCS) as well as netzero deforestation make significant contributions. We identify opportunities for Brazil, but synergies and trade-offs across sectors should be minded when designing climate policies. [ABSTRACT FROM AUTHOR]

Non-random oviposition preference by target pest species on Bt and non-Bt refuge plants may increase the proportion of the population under selection pressure, reducing the value of the refuge strategy for resistance management. Here, we tested the oviposition preference for Bt over non-Bt plants and the damage-avoiding oviposition behavior of moths of the fall armyworm (FAW), Spodoptera frugiperda, a worldwide pest species with three reported cases of field-evolved resistance to Bt maize. In the greenhouse, choice assays indicated no oviposition preference for Cry1F Bt maize over its non-Bt isoline whatever intact or injured by FAW larvae. In a field experiment in a region of intensive agriculture in Brazil, the number of egg masses and FAW larvae was recorded on seven Bt maize varieties and two non-Bt maize varieties during vegetative and reproductive growth stages. There was only a weak oviposition preference by FAW moths for less damaged plants in the V10 stage. When using Cry1A.105 + Cry2Ab Bt maize and 50% refuge in a field experiment in another region in Southeastern Brazil, the number of egg masses on Bt and non-Bt plants also indicated no oviposition preference by the moths. Consistently, these results indicate that FAW moths do not distinguish Bt and non-Bt plants for oviposition and that conspecific larval damage has minor interference in the oviposition choice. Therefore, there seems to be random egg-laying preference of FAW moths in Bt maize fields, an oviposition behavior typical of generalist moth species and unlikely to be associated with the rapid selection of Bt-toxin-resistant FAWs. [ABSTRACT FROM AUTHOR]

Agricultural activities can affect the delivery of nutrients to streams, riparian canopy cover, and the capacity of aquatic systems to process nutrients and sediments. There are few measures of nutrient uptake and metabolism from tropical or subtropical streams in general, and even fewer from tropical regions of South America. We examined ammonium (NH4+) and soluble reactive phosphorus (SRP) retention in streams in Brazil and Argentina. We selected 12 streams with relatively little or extensive agricultural activity and conducted whole‐stream nutrient additions and measurements of gross primary production and ecosystem respiration. We used multiple linear regression to determine potential drivers of nutrient uptake metrics across the streams. Nutrient concentrations and retention differed significantly between land use categories. Both NH4+ and SRP concentrations were higher in the agricultural sites (means of 161 and 495 μg l–1, respectively), whereas metabolic rates were slower and transient storage was smaller. Our analysis indicated that agriculture increased ambient uptake lengths and decreased uptake velocities. The regression models revealed that ambient SRP had a positive effect on NH4+ uptake and vice versa, suggesting strong stoichiometric controls. Drivers for nutrient uptake in streams with low‐intensity agriculture also included canopy cover, temperature, and ecosystem respiration rates. Nutrient assimilation in agricultural sites was influenced by a higher number of variables (gross primary production for SRP, discharge, and transient storage for both nutrients). Our results indicate agricultural activity changes both the magnitude of in‐stream nutrient uptake and the mechanisms that control its variation, with important implications for South American streams under agricultural intensification. [ABSTRACT FROM AUTHOR]

The vampire bat (Desmodus rotundus) plays a crucial role in the maintenance and transmission of the rabies virus to humans and livestock, impacting public health and economic production. Its importance lies not only in its capacity to transmit the virus but also in its ability to adapt to anthropic changes, as expressed in its wide geographic distribution in Latin America. Deforestation, livestock intensification, and other human activities have reduced the abundance of its wild prey but have also provided new and abundant shelter and foraging resources for the vampire bats. We used radiotelemetry to evaluate relations between topography, feeding site choice, and foraging behavior in southeastern Brazil, where three occupied D. rotundus roosts, out of 11 possible, were systematically monitored throughout a 1-year period once every 2 months. Sixty-two vampire bats were captured; biometric data were collected and 44 radiotransmitters were installed in adult individuals, producing telemetry data that were recorded in VHF receptors installed in the farms. Elevation of the roosts was related to the farms attacked by the vampire bats. Understanding the use of the environment and resources by vampire bats is critical to improving rabies control aiming at the reduction of disease impacts. From the perspective of the official veterinary service, telemetry would be ineffective as a rabies surveillance system due to the costs and limitations of the available technology. However, livestock rabies control measures would be greatly improved if ecological characteristics of the vampire bat were considered. [ABSTRACT FROM AUTHOR]

Agricultural expansion and intensification is occurring in seasonally dry regions of Central America, while droughts are intensifying due to increasing water demand and climatic change. Empirical measurements of water consumption of major crops in this region are scarce but crucial to assess agricultural water use dynamics in the light of increasing regional water conflicts. We empirically quantify total crop water use (CWU) and water footprints (WFs) of rainfed upland rice (wet season) and groundwater‐irrigated melons (dry season) grown sequentially as a double cropping system, one of the major cropping systems in the seasonally dry province of Guanacaste in northwestern Costa Rica. Data for this study cover 2 years and were measured with a state‐of‐the‐art eddy covariance water and carbon flux station. Upland rice only consumed green water (CWUgreen = 383 L/m2), while melons only consumed blue water (CWUblue = 177 L/m2). Irrigation was found to be 1.5 times larger than the actual melon water consumption, with better irrigation efficiencies than reported for melon farms in Brazil but slightly inferior to farms in Spain. Melon WFblue was 79 m3/t, a much lower value than global and regional estimates reported but similar to values reported for melons produced in Brazil or Spain. Upland rice WFgreen (681 m3/t) was reported for the first time and was proven to be much lower than flood irrigated‐rice WFblue‐green. Our results demonstrated lower overall water demand for upland rice‐melon double crop compared to the two other major monocultures of the region (flood‐irrigated rice and irrigated sugar cane). Plain Language Summary: Agricultural intensification is occurring in seasonally dry tropical areas. At the same time, droughts are becoming more severe due to climate change in many tropical regions. Empirical measurements of water usage in agriculture and water use efficiency are scarce in the tropics but are critical to achieving sustainable water management and resilient agricultural systems. We instrumented a production farm in the seasonally dry Guanacaste province of Costa Rica to measure agricultural water use for a regionally widespread double cropping system composed of irrigated melons and rainfed rice grown sequentially during the dry and wet seasons, respectively. For rice, 681 m3 of rainwater was used per ton of yield, which is much less water than the water used to produce rice in flooded fields. Seventy‐nine cubic meters of irrigated water was used per ton of melons, which is similar to values reported for melons produced in Brazil or Spain. Irrigation of melons was found to be 1.5 times larger than crop water consumption during the dry season, and irrigation efficiencies were similar to Brazilian melon farms but slightly inferior to Spanish farms. We showed that the studied system used considerably less water than did two principal monocultures in the region (irrigated rice and irrigated sugar cane). This cropping system seems a competitive option for the Central American wet‐dry tropics in terms of water use. Key Points: Water footprints of upland rice and irrigated melons empirically derived from eddy covariance were provided for the first timeMelon irrigation was 1.5 times larger than actual crop water consumption, posing a potential risk for seasonal water depletionOverall upland rice‐melon double cropping system showed a considerably lower water demand than did the other major monocultures in the region [ABSTRACT FROM AUTHOR]

Copyright of Annals of the American Association of Geographers is the property of Taylor & Francis Ltd 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.)