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71.
The recent rise in Brazilian soybean production has generated concern among the environmental community and some authors that natural tropical environments of the Amazon Basin are being converted to soybean fields. Proponents of soybean production counter that soybeans represent a viable agricultural commodity for the region; environmental concern is unwarranted, because new soybean fields are replacing already deforested or otherwise transformed lands. Both arguments have been made without comprehensive study and measure of land-use/land-cover (LULC) in areas undergoing expansion of soybean production. This case study, conducted in the municipality of Vilhena, Rond?nia, Brazil, in the southwestern Amazon Basin, uses remote sensing to evaluate the LULC accompanying this municipality's large growth in soybean production from 1996 to 2001. Forests are being converted for soybean production, but most of the production increase appears attributable to slight expansion of already existing fields, conversion of already deforested land, and higher yields. 相似文献
72.
A routing procedure is introduced which accounts for the loss of a conservative solute tracer from preferred paths during macropore flow. Water flow is treated as a series of kinematic waves from which the tracer is lost due to mixing previously stored soil water, and an expression for solute loss is added to a previously developed model. The model parameters are estimated through experiments at three different input rates applied to a column of a macroporous forest soil.The results of seven experimental runs indicate that solute losses are consistently highest at the early stages of infiltration and drainage flow. An empirical relationship is proposed which links the frequency distribution of the flow parameter with that for solute loss from the preferred path during transient water flow and solute transport. 相似文献
73.
Distribution of endocrine disruptors in the Llobregat River basin (Catalonia, NE Spain) 总被引:9,自引:0,他引:9
The Llobregat basin is a Mediterranean fluvial system with major agricultural, urban and industrial impacts. We combined chemical quantification by liquid chromatography–mass spectrometry with electrospray interface (LC-ESI-MS) and the recombinant yeast assay (RYA) assays to estimate the loads of endocrine disrupting compounds (EDCs) along the basin. Chemical analysis revealed maximum concentrations (at μg l−1 level) of alkylphenols at the lower course of the Llobregat River, which correlated with high levels of estrogenic activity detected by RYA. Analysis by RYA and LC-ESI-MS of influent and effluent waters from four sewage treatment plants (STP) discharging into the basin showed the removal of 80–95% of EDCs by STP treatment. Chemical analysis data and RYA data showed a quasi-linear correlation, demonstrating the complementariness of both methods. Our data suggest that the concentrations of the analysed compounds were enough to explain the total estrogenicity of water and STP samples from the Llobregat basin. 相似文献
74.
Thomas Fellmann Peter Witzke Franz Weiss Benjamin Van Doorslaer Dusan Drabik Ingo Huck Guna Salputra Torbjörn Jansson Adrian Leip 《Mitigation and Adaptation Strategies for Global Change》2018,23(3):451-468
Taking the European Union (EU) as a case study, we simulate the application of non-uniform national mitigation targets to achieve a sectoral reduction in agricultural non-carbon dioxide (CO2) greenhouse gas (GHG) emissions. Scenario results show substantial impacts on EU agricultural production, in particular, the livestock sector. Significant increases in imports and decreases in exports result in rather moderate domestic consumption impacts but induce production increases in non-EU countries that are associated with considerable emission leakage effects. The results underline four major challenges for the general integration of agriculture into national and global climate change mitigation policy frameworks and strategies, as they strengthen requests for (1) a targeted but flexible implementation of mitigation obligations at national and global level and (2) the need for a wider consideration of technological mitigation options. The results also indicate that a globally effective reduction in agricultural emissions requires (3) multilateral commitments for agriculture to limit emission leakage and may have to (4) consider options that tackle the reduction in GHG emissions from the consumption side. 相似文献
75.
Cryptocurrencies have the potential to revolutionize the exchange of information and money through blockchain and distributed ledger technologies. Despite the promise of such underlying technologies, their reliance upon distributed consensus processes to approve software updates raises the potential for governance failures to destabilize a given cryptocurrency. These governance failures, known as ‘hard forks,’ can separate a cryptocurrency into two rival camps. Where such events can destabilize a given cryptocurrency’s value, and instill distrust in the capacity of a cryptocurrency to survive as a reliable vehicle of exchange, it is imperative for the cryptocurrency community to improve their governance processes and limit the potential for hard forks to occur. While the distributed nature of cryptocurrency governance makes any traditional governing process unlikely to succeed, anticipatory approaches that establish thresholds and metrics to determine when software reform is necessary may help alleviate the governance failures presented by many hard forks. 相似文献
76.
Amireeta K. Rawlani Benjamin K. Sovacool 《Mitigation and Adaptation Strategies for Global Change》2011,16(8):845-863
This article explores the drivers, benefits, and challenges to climate change adaptation in Bangladesh. It specifically investigates
the “Community Based Adaptation to Climate Change through Coastal Afforestation Program,” a 5-year $5 million adaptation scheme
being funded and implemented in part by the Government of Bangladesh, United Nations Development Program, and Global Environment
Facility. The article explores how the CBACC-CA builds various types of adaptive capacity in Bangladesh and the extent its
design and implementation offers lessons for other adaptation programs around the world. The first part of the study begins
by describing its research methods consisting of research interviews, site visits, and a literature review. It then summarizes
six primary sectors vulnerable to climate change in Bangladesh: water resources and coastal zones, infrastructure and human
settlements, agriculture and food security, forestry and biodiversity, fisheries, and human health. The article next describes
the genesis and background behind the CBACC-CA, with an emphasis on components that promote capacity development, demonstration
projects, risk reduction, and knowledge management. The article concludes that technology by itself is only a partial component
of successful adaptation efforts, and that multiple and integrated adaptation measures that cut across sectors and social,
institutional, and infrastructural dimensions are needed to truly build resilience and effectiveness. 相似文献
77.
Chien?Pham VanEmail author Benjamin?de Brye Eric?Deleersnijder A.?J.?F.?Hoitink Maximiliano?Sassi Benoit?Spinewine Hidayat?Hidayat Sandra?Soares-Fraz?o 《Environmental Fluid Mechanics》2016,16(3):603-633
Large rivers often present a river–lake–delta system, with a wide range of temporal and spatial scales of the flow due to the combined effects of human activities and various natural factors, e.g., river discharge, tides, climatic variability, droughts, floods. Numerical models that allow for simulating the flow in these river–lake–delta systems are essential to study them and predict their evolution under the impact of various forcings. This is because they provide information that cannot be easily measured with sufficient temporal and spatial detail. In this study, we combine one-dimensional sectional-averaged (1D) and two-dimensional depth-averaged (2D) models, in the framework of the finite element model SLIM, to simulate the flow in the Mahakam river–lake–delta system (Indonesia). The 1D model representing the Mahakam River and four tributaries is coupled to the 2D unstructured mesh model implemented on the Mahakam Delta, the adjacent Makassar Strait, and three lakes in the central part of the river catchment. Using observations of water elevation at five stations, the bottom friction for river and tributaries, lakes, delta, and adjacent coastal zone is calibrated. Next, the model is validated using another period of observations of water elevation, flow velocity, and water discharge at various stations. Several criteria are implemented to assess the quality of the simulations, and a good agreement between simulations and observations is achieved in both calibration and validation stages. Different aspects of the flow, i.e., the division of water at two bifurcations in the delta, the effects of the lakes on the flow in the lower part of the system, the area of tidal propagation, are also quantified and discussed. 相似文献
78.
Benjamin D. Charlton Ronald R. Swaisgood Zhang Zhihe Rebecca J. Snyder 《Behavioral ecology and sociobiology》2012,66(6):969-974
Although androgen-dependant traits are predicted to signal overall male quality, no study has examined the response of a nonhuman animal to variation in a known acoustic cue to male androgen levels (steroid hormones that are key drivers of male sexual behaviour). Here, we use a single-speaker approach to present male and female giant pandas with re-synthesised male bleats representing callers with high and low androgen levels. Our results revealed that male and female giant pandas had significantly greater-looking responses, spent more time pacing, and were faster to respond to playbacks of bleats simulating high androgen males. When we analysed the sexes separately, a slightly different response pattern was revealed: whereas males and females still had significantly greater-looking responses and were faster to respond to bleats simulating high androgen males, only male giant pandas tended to spend more time pacing. These findings suggest that vocal cues to male androgen levels are functionally relevant to male and female giant pandas during the breeding season, and constitute the first demonstration that a nonhuman animal could be using a vocal signal to assess male hormonal state. We go on to discuss the ecological relevance of signalling androgen levels in this species’ sexual communication and the possible application of our results to conservation breeding. 相似文献
79.
David W. Clow Harrison Forrester Benjamin Miller Heidi Roop James O. Sickman Hodon Ryu Jorge Santo Domingo 《Environmental management》2013,52(6):1400-1414
During 2010–2011, a study was conducted in Sequoia and Kings Canyon National Parks (SEKI) to evaluate the influence of pack animals (stock) and backpackers on water quality in wilderness lakes and streams. The study had three main components: (1) a synoptic survey of water quality in wilderness areas of the parks, (2) paired water quality sampling above and below several areas with differing types and amounts of visitor use, and (3) intensive monitoring at six sites to document temporal variations in water quality. Data from the synoptic water quality survey indicated that wilderness lakes and streams are dilute and have low nutrient and Escherichia coli concentrations. The synoptic survey sites were categorized as minimal use, backpacker-use, or mixed use (stock and backpackers), depending on the most prevalent type of use upstream from the sampling locations. Sites with mixed use tended to have higher concentrations of most constituents (including E. coli) than those categorized as minimal-use (P ≤ 0.05); concentrations at backpacker-use sites were intermediate. Data from paired-site sampling indicated that E. coli, total coliform, and particulate phosphorus concentrations were greater in streams downstream from mixed-use areas than upstream from those areas (P ≤ 0.05). Paired-site data also indicated few statistically significant differences in nutrient, E. coli, or total coliform concentrations in streams upstream and downstream from backpacker-use areas. The intensive-monitoring data indicated that nutrient and E. coli concentrations normally were low, except during storms, when notable increases in concentrations of E. coli, nutrients, dissolved organic carbon, and turbidity occurred. In summary, results from this study indicate that water quality in SEKI wilderness generally is good, except during storms; and visitor use appears to have a small, but statistically significant influence on stream water quality. 相似文献
80.
The biochemical response of wild sticklebacks collected in Autumn 2005 at seven stations in the North of France was studied using a set of complementary biomarkers. Here, data on biotransformation of xenobiotics, oxidative stress exposure and damages, neurotoxicity and endocrine disruption are provided. All the sites are characterized by a specific response pattern that allows distinguishing sampling locations. Moreover, these responses are in accordance with data on existing environmental pressures and the chemical analysis of metals performed in surface water. The assessment of individual responses is completed by fish population disturbance monitoring. Based on these measurements, the investigated sites are characterized by different levels of disturbance. This study argues for a multi-parametric approach of aquatic ecosystem contamination based on association between chemical, biochemical and ecological endpoints and provides a testimony of the usefulness of stickleback for this purpose. 相似文献