130 research outputs found

    Land-use in Amazonia and the Cerrado of Brazil: State of Knowledge and GIS Database

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    We have assembled datasets to strengthen the LargeScale Biosphere Atmosphere Experiment in Amazonia (LBA). These datasets can now be accessed through the Woods Hole Research Center homepage (www.whrc.org), and will soon be linked to the Pre-LBA homepages of the Brazilian Space Research Institute's Center for Weather and Climate Prediction (Instituto de Pesquisas Espaciais, Centro de Previsao de Tempo e Estudos Climaticos, INPE/CPTEC) and through the Oak Ridge National Laboratory, Distributed Active Archive Center (ORNL/DMC). Some of the datasets that we are making available involved new field research and/or the digitization of data available in Brazilian government agencies. For example, during the grant period we conducted interviews at 1,100 sawmills across Amazonia to determine their production of sawn timber, and their harvest intensities. These data provide the basis for the first quantitative assessment of the area of forest affected each year by selective logging (Nepstad et al, submitted to Nature). We digitized the locations of all of the rural households in the State of Para that have been mapped by the Brazilian malaria combat agency (SUCAM). We also mapped and digitized areas of deforestation in the state of Tocantins, which is comprised largely of savanna (cerrado), an ecosystem that has been routinely excluded from deforestation mapping exercises

    Human impacts on soil carbon dynamics of deep-rooted Amazonian forests and effect of land use change on the carbon cycle in Amazon soils

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    The main objective of these NASA-funded projects is to improve our understanding of land-use impacts on soil carbon dynamics in the Amazon Basin. Soil contains approximately one half of tropical forest carbon stocks, yet the fate of this carbon following forest impoverishment is poorly studied. Our mechanistics approach draws on numerous techniques for measuring soil carbon outputs, inputs, and turnover time in the soils of adjacent forest and pasture ecosystems at our research site in Paragominas, state of Para, Brazil. We are scaling up from this site-specific work by analyzing Basin-wide patterns in rooting depth and rainfall seasonality, the two factors that we believe should explain much of the variation in tropical soil carbons dynamics. In this report, we summarize ongoing measurements at our Paragominas study site, progress in employing new field data to understand soil C dynamics, and some surprising results from our regional, scale-up work

    09-05 "The Environmental Impacts of Soybean Expansion and Infrastructure Development in Brazil’s Amazon Basin"

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    For decades, the development of transportation infrastructure in the Brazilian Amazon has been the government’s main social and economic development policy in the region. Reductions in transportation costs have not only opened the agricultural frontier to cattle ranching and logging but have also caused more than two-thirds of Amazonian deforestation. Currently, soybean cultivation is a new economic force demanding improvements to roads in the region. Profitable soybean crops have spread over the Mato Grosso’s cerrados and now head toward the core of the Amazon rain forest. One of the main constraints for soy expansion into the Amazon has been the poor condition of roads. In this study, we analyze the effect Amazon transportation infrastructure programs have on soybean expansion by lowering transport costs. The analysis is based on spatial estimates of transportation costs for the soybean sector, first using current road networks and then projecting changes based on the paving of the Cuiabá-Santarém road. Our results indicate that paving the Cuiabá-Santarém road would reduce transportation costs by an average of 10pertonforfarmerslocatedinthenorthernpartofMatoGrosso,byallowingproducerstoreroutesoybeanshipmentstotheSantareˊmport.Pavingtheroadalsowouldexpandtheareawheregrowingsoybeansiseconomicallyfeasiblebyabout70percent,from120,000to205,000km2.MostofthisnewareawouldbelocatedinthestateofParaˊandiscoveredlargelybyforests.ACostBenefitanalysisoftheroadprojectindicatesthattheinvestmentsininfrastructurewouldgeneratemorethan10 per ton for farmers located in the northern part of Mato Grosso, by allowing producers to reroute soybean shipments to the Santarém port. Paving the road also would expand the area where growing soybeans is economically feasible by about 70 percent, from 120,000 to 205,000 km2. Most of this new area would be located in the state of Pará and is covered largely by forests. A Cost-Benefit analysis of the road project indicates that the investments in infrastructure would generate more than 180 million for soybean farmers over a period of twenty years. These benefits, however, ignore the project’s environmental impacts. If the destruction of ecological services and products provided by the existing forests is accounted for, then the Cuiabá-Santarém investment would generate a net loss of between 762millionand762 million and 1.9 billion. This result shows the importance of including the value of the natural capital in feasibility studies of infrastructure projects to reflect their real benefits to society as a whole.

    Interactions among Amazon land use, forests and climate: prospects for a near-term forest tipping point

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    Some model experiments predict a large-scale substitution of Amazon forest by savannah-like vegetation by the end of the twenty-first century. Expanding global demands for biofuels and grains, positive feedbacks in the Amazon forest fire regime and drought may drive a faster process of forest degradation that could lead to a near-term forest dieback. Rising worldwide demands for biofuel and meat are creating powerful new incentives for agro-industrial expansion into Amazon forest regions. Forest fires, drought and logging increase susceptibility to further burning while deforestation and smoke can inhibit rainfall, exacerbating fire risk. If sea surface temperature anomalies (such as El Niño episodes) and associated Amazon droughts of the last decade continue into the future, approximately 55% of the forests of the Amazon will be cleared, logged, damaged by drought or burned over the next 20 years, emitting 15–26 Pg of carbon to the atmosphere. Several important trends could prevent a near-term dieback. As fire-sensitive investments accumulate in the landscape, property holders use less fire and invest more in fire control. Commodity markets are demanding higher environmental performance from farmers and cattle ranchers. Protected areas have been established in the pathway of expanding agricultural frontiers. Finally, emerging carbon market incentives for reductions in deforestation could support these trends

    Completing below-ground carbon budgets for pastures, recovering forests, and mature forests of Amazonia

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    The objective of this grant was to complete below-ground carbon budgets for pastures and forest soils in the Amazon. Profiles of radon and carbon dioxide were used to estimate depth distribution of CO2 production in soil. This information is necessary for determining the importance of deep roots as sources of carbon inputs. Samples were collected for measuring root biomass from new research sites at Santana de Araguaia and Trombetas. Soil gases will be analyzed for CO2 and (14)CO2, and soil organic matter will be analyzed for C-14. Estimates of soil texture from the RADAMBRASIL database were merged with climate data to calculate soil water extraction by forest canopies during the dry season. In addition, a preliminary map of areas where deep roots are needed for deep soil water was produced. A list of manuscripts and papers prepared during the reporting periods is given

    Impactos ecológicos do manejo comunitário de recursos naturais em comunidades ribeirinhas de várzea e terra firme na região de Tefé, AM

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    The theoretical bases of conservationism and preservation are discussed in this research, based on a field study carried out in the region of Tefé, the Middle Solimões. Twelve communities located in “Varzea” and “Terra Firme” ecosystems were studied, of which six communities have adopted a model of natural resourcemanagement, focusing on management of lakes and the other six have never participated in processes of management. The data of “Terra Firme” communities with and without management, not different from “Varzea” communities without management, in relation to perceptions of impact. The use of managed resources allowed greater control of them by the users. The model of management adopted was more appropriate to the communities in “Varzea” than in the communities of “Terra Firme”, according to the own characteristics of ecosystems.As bases teóricas do conservacionismo e do preservacionismo são discutidas neste trabalho de pesquisa, baseadas em um estudo de campo desenvolvido na região de Tefé, no Médio Solimões. Foram estudadas 12 comunidades localizadas em ecossistemas de várzea e terra firme, das quais 6 adotaram um modelo de manejo de recursos naturais, com enfoque em manejo de lagos e as outras 6 nunca participaram de processos de manejo. As percepções dos comunitários em relação aos impactos do manejo sobre o ecossistema também foram analisadas. A percepção de benefício em relação ao manejo foi fundamental para o incentivo à conservação. O modelo de manejo adotado foi mais adequado às comunidades de várzea do que para as comunidades de terra firme, em função das próprias características dos ecossistemas de Macapá e a várzea da Amazônia peruana

    Eo-1 Hyperion Measures Canopy Drought Stress In Amazonia

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    The central, south and southeast portions of the Amazon Basin experience a period of decreased cloud cover and precipitation from June through November. There are likely important effects of seasonal and interannual rainfall variation on forest leaf area index, canopy water stress, productivity and regional carbon cycling in the Amazon. While both ground and spaceborne studies of precipitation continue to improve, there has been almost no progress made in observing forest canopy responses to rainfall variability in the humid tropics. This shortfall stems from the large stature of the vegetation and great spatial extent of tropical forests, both of which strongly impede field studies of forest responses to water availability. Those few studies employing satellite measures of canopy responses to seasonal and interannual drought (e.g., Bohlman et al. 1998, Asner et al. 2000) have been limited by the spectral resolution and sampling available from Landsat and AVHRR sensors. We report on a study combining the first landscape-level, managed drought experiment in Amazon tropical forest with the first spaceborne imaging spectrometer observations of this experimental area. Using extensive field data on rainfall inputs, soil water content, and both leaf and canopy responses, we test the hypothesis that spectroscopic signatures unique to hyperspectral observations can be used to quantify relative differences in canopy stress resulting from water availability

    Drought effects on litterfall, wood production and belowground carbon cycling in an Amazon forest: results of a throughfall reduction experiment

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    The Amazon Basin experiences severe droughts that may become more common in the future. Little is known of the effects of such droughts on Amazon forest productivity and carbon allocation. We tested the prediction that severe drought decreases litterfall and wood production but potentially has multiple cancelling effects on belowground production within a 7-year partial throughfall exclusion experiment. We simulated an approximately 35–41% reduction in effective rainfall from 2000 through 2004 in a 1 ha plot and compared forest response with a similar control plot. Wood production was the most sensitive component of above-ground net primary productivity (ANPP) to drought, declining by 13% the first year and up to 62% thereafter. Litterfall declined only in the third year of drought, with a maximum difference of 23% below the control plot. Soil CO2 efflux and its 14C signature showed no significant treatment response, suggesting similar amounts and sources of belowground production. ANPP was similar between plots in 2000 and declined to a low of 41% below the control plot during the subsequent treatment years, rebounding to only a 10% difference during the first post-treatment year. Live aboveground carbon declined by 32.5 Mg ha−1 through the effects of drought on ANPP and tree mortality. Results of this unreplicated, long-term, large-scale ecosystem manipulation experiment demonstrate that multi-year severe drought can substantially reduce Amazon forest carbon stocks

    Embryonic exposure to produced water can cause cardiac toxicity and deformations in Atlantic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) larvae

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    Regular discharges of produced water from the oil and gas industry represents the largest direct discharge of effluent into the marine environment worldwide. Organic compound classes typically reported in produced water include saturated hydrocarbons, monoaromatic and polyaromatic hydrocarbons (MAHs, PAHs) as well as oxygenated compounds, such as phenols, acids and ketones. This forms a cocktail of known and suspect toxicants, but limited knowledge is yet available on the sub-lethal toxicity of produced water to cold-water marine fish species. In the present work, we conducted a 4-day exposure of embryos of Atlantic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) to produced water extracts equivalent to 1:50, 1:500 and 1:5000 times dilutions of raw effluent. No significant reduction in survival or hatching success was observed, however, for cod, hatching was initiated earlier for exposed embryos in a concentration-dependent manner. During recovery, significantly reduced embryonic heart rate was observed for both species. After hatch, larvae subjected to embryonic exposure to produced water extracts were smaller, and displayed signs of cardiotoxicity, jaw and craniofacial deformations. In order to improve risk assessment and regulation of produced water discharges, it is important to identify which produced water components contribute to these effects.acceptedVersio

    Indigenous Lands, Protected Areas, and Slowing Climate Change

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    Recent climate talks in Copenhagen reaffirmed the crucial role of reducing emissions from deforestation and degradation (REDD). Creating and strengthening indigenous lands and other protected areas represents an effective, practical, and immediate REDD strategy that addresses both biodiversity and climate crises at once
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