158 research outputs found
Manejo de la biodiversidad en los ecosistemas agrícolas
El “Manejo de la Biodiversidad en los Ecosistemas Agrícolas” mira cómo los agricultores manejan, mantienen, y se benefician de la biodiversidad en los sistemas de producción agrícola. El volumen incluye las más recientes investigaciones y desarrollos en el mantenimiento de la diversidad local en los niveles de la genética de las especies y de los ecosistemas. Los capítulos se tratan de la evaluación de la biodiversidad ecosistémica en la producción agrícola, ganadera, acuático y los diversidades asociados (tales como los polinizadores y los microorganismos del suelo); los praticas de gestión que influyen la diversidad; el papel potencial de la diversidad para la reducción de las presiones de plagas y enfermedades; y los estudios actuales que ejemplifican el valor potencial nutricional, ecosistémica, y financiera de esta diversidad en virtud de las cambiantes condiciones económicas y ambientales. El volumen contiene perspectivas que combinan el pensamiento de los scientificos sociales y biológicas
Gestion de la biodiversité dans les écosystèmes agricoles
La biodiversité dans les écosystèmes agricoles nous fournit la nourriture ainsi que les moyens de la produire. Les différentes variétés de plantes et d’animaux qui nous servent de nourriture sont des éléments indéniables de la biodiversité agricole. Moins visibles, mais tout aussi importants, sont les myriades d'organismes du sol, les pollinisateurs, et les ennemis naturels tels que les épidémies et les maladies, essentiellement utiles à la régulation qui renforce la production agricole. Ce livre examine ces différents aspects de la biodiversité agricole. Un certain nombre de chapitres examinent les ressourcesgénétiques des cultures et les ressources génétiques animales. Les autres chapitres portent sur la biodiversité aquatique, la diversité des pollinisateurs, et la biodiversité des sols. Trois chapitres traitent les différents aspects de la relation entre la diversité et la gestion des épidémies et des maladies. Les chapitres 12 et 13 concernent les agriculteurs et leur gestion de la diversité dans un contexte plus large en matière de complexité spatiale et de changements environnementaux et économiques. Le chapitre 14 se penche sur la contribution de la diversité au régime alimentaire, à la nutrition et à la santé humaine. Les chapitres 15 à 17 analysent la valeur des ressources génétiques et des services écologiques apportée par la biodi- versité dans les écosystèmes agricoles
Nut production in Bertholletia excelsa across a logged forest mosaic: implications for multiple forest use
Although many examples of multiple-use forest management may be found in tropical smallholder systems, few studies provide empirical support for the integration of selective timber harvesting with non-timber forest product (NTFP) extraction. Brazil nut (Bertholletia excelsa, Lecythidaceae) is one of the world’s most economically-important NTFP species extracted almost entirely from natural forests across the Amazon Basin. An obligate out-crosser, Brazil nut flowers are pollinated by large-bodied bees, a process resulting in a hard round fruit that takes up to 14 months to mature. As many smallholders turn to the financial security provided by timber, Brazil nut fruits are increasingly being harvested in logged forests. We tested the influence of tree and stand-level covariates (distance to nearest cut stump and local logging intensity) on total nut production at the individual tree level in five recently logged Brazil nut concessions covering about 4000 ha of forest in Madre de Dios, Peru. Our field team accompanied Brazil nut harvesters during the traditional harvest period (January-April 2012 and January-April 2013) in order to collect data on fruit production. Three hundred and ninety-nine (approximately 80%) of the 499 trees included in this study were at least 100 m from the nearest cut stump, suggesting that concessionaires avoid logging near adult Brazil nut trees. Yet even for those trees on the edge of logging gaps, distance to nearest cut stump and local logging intensity did not have a statistically significant influence on Brazil nut production at the applied logging intensities (typically 1–2 timber trees removed per ha). In one concession where at least 4 trees ha-1 were removed, however, the logging intensity covariate resulted in a marginally significant (0.09) P value, highlighting a potential risk for a drop in nut production at higher intensities. While we do not suggest that logging activities should be completely avoided in Brazil nut rich forests, when a buffer zone cannot be observed, low logging intensities should be implemented. The sustainability of this integrated management system will ultimately depend on a complex series of socioeconomic and ecological interactions. Yet we submit that our study provides an important initial step in understanding the compatibility of timber harvesting with a high value NTFP, potentially allowing for diversification of forest use strategies in Amazonian Perù
North Tropical Atlantic influence on western Amazon fire season variability
The prevailing wet climate in the western Amazon is not favorable to the natural occurrence of fires. Nevertheless, the current process of clearing of humid forests for agriculture and cattle ranching has increased the vulnerability of the region to the spread of fires. Using meteorological stations precipitation and the Moderate Resolution Spectroradiometer (MODIS) Active-Fires (AF) during 2000-2009, we show that fire anomalies vary closely with July-August-September (JAS) precipitation variability as measured by the Standardized Precipitation Index (SPI). The precipitation variability is, in turn, greatly determined by sea surface temperature (SST) anomalies in the North Tropical Atlantic (NTA). We develop a linear regression model to relate local fire activity to an index of the NTA-SST. By using seasonal forecasts of SST from a coupled model, we are able to predict anomalous JAS fire activity as early as April. We applied the method to predict the severe 2010 JAS season, which indicated strongly positive seasonal fire anomalies within the 95% prediction confidence intervals in most western Amazon. The spatial distribution of predicted SPI was also in accordance with observed precipitation anomalies. This three months lead time precipitation and fire prediction product in the western Amazon could help local decision makers to establish an early warning systems or other appropriate course of action before the fire season begins
A shared perspective on managing Amazonian sustainable-use reserves in an era of megafires.
Unprecedented forest fires are affecting large swathes of what were once fire‐free Amazonian forests, including extensive areas of community‐managed reserves. This shared overview of experiences of practitioners and researchers examines ways in which these reserves can be supported to reduce the risk of forest fires. We highlight six considerations that are key to fire reduction: inclusive management and community leadership, adapting to demographic and cultural changes, identifying examples of good practice, socially just alternative livelihoods, forecasting and planning and bridging scientific research and innovation. Policy implications. The escalating fire problem in Amazonia and elsewhere means we urgently need to learn from past experiences. Co‐developed ecological and social research can support novel approaches to reserve management, but achieving this will require sustained investment and ongoing dialogue between communities, managers, researchers and the government
Epidemiology of envenomations by terrestrial venomous animals in Brazil based on case reporting: from obvious facts to contingencies
Monitoring the spatio-temporal dynamics of swidden agriculture and fallow vegetation recovery using Landsat imagery in northern Laos
Contributions of the old urban homegardens for food production and consumption in Rio Claro, Southeastern Brazil
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