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91.
Ecosystem services (ES), such as biological control, pollination, soil formation, nutrient cycling in agriculture are vital for the sustainable supply of food and fibre. The current trends of decline in the ability of agricultural ecosystems to provide ES pose great threat to food security worldwide. This paper discusses the concept of ES and identifies ES associated with agriculture. It discusses the economic and ecological benefits of these ES on farmland in general and its linkages with organic agriculture. The provision of ES on farmland may help to motivate the redesign of small-scale farms using new eco-technologies based on novel and sound ecological knowledge. This has potential to meet the food demand of growing population without damaging human health and the environment. 相似文献
92.
Asbjørn Aaheim Bård Romstad Håkon Sælen 《Mitigation and Adaptation Strategies for Global Change》2010,15(7):763-778
This paper describes how relatively detailed knowledge about probabilities of natural hazards can be used to make decisions
to develop areas and control the risk within hazard zones. The assessment serves two purposes. First, it shows how information
can support decisions. Second, decision criteria put leads on what information is required. This is helpful to identify unavailable
information. We show by an example from a land-slide prone area in Norway how a relatively reliable estimate of the probability
of slides ends up in a rather uncertain estimate of the risk. Uncertainty about the risk represented by natural hazards imply
great challenges to the development of adaptation policies to meet climate change, but they are required. We develop a simplified
criterion for optimal adaptation, and estimate the added social value required to defend development in hazard prone areas
instead of developing a risk-free alternative. The value is estimated between 0 and 0.40 Euros per Euro invested in the case
area, depending on type of slide, category of asset and other costs that occur in the wake of slides. 相似文献
93.
Vulnerability is a term frequently used to describe the potential threat to rural communities posed by climate variability and change. Despite growing use of the term, analytical measures of vulnerability that are useful for prioritising and evaluating policy responses are yet to evolve. Demand for research capable of prioritising adaptation responses has evolved rapidly with an increasing awareness of climate change and its potential impacts on rural communities. Research into the climate-related vulnerability of Australian rural communities is only just beginning to emerge. Current research is dominated by hazard/impact modelling, drawing on a heritage of managing the risks posed by seasonal climate variability. There is a natural tendency to use the same risk management approach to understand the emergent nature of vulnerability. In this paper, we explore the consequences for policy advice of imperfectly examining vulnerability through the lens of an impact/hazard modelling approach to risk management. In a second paper in this series, we show how hazard/impact modelling can be complemented with more holistic measures of adaptive capacity to provide quantitative insights into the vulnerability of Australian rural communities to climate variability and change. 相似文献
94.
Jay S. Gregg Steven J. Smith 《Mitigation and Adaptation Strategies for Global Change》2010,15(3):241-262
As co-products, agricultural and forestry residues represent a potential low cost, low carbon, source for bioenergy. A method
is developed for estimating the maximum sustainable amount of energy potentially available from agricultural and forestry
residues by converting crop production statistics into associated residue, while allocating some of this resource to remain
on the field to mitigate erosion and maintain soil nutrients. Currently, we estimate that the world produces residue biomass
that could be sustainably harvested and converted into nearly 50 EJ yr−1 of energy. The top three countries where this resource is estimated to be most abundant are currently net energy importers:
China, the United States (US), and India. The global potential from residue biomass is estimated to increase to approximately
50–100 EJ yr−1 by mid- to late- century, depending on physical assumptions such as of future crop yields and the amount of residue sustainably
harvestable. The future market for biomass residues was simulated using the Object-Oriented Energy, Climate, and Technology
Systems Mini Climate Assessment Model (ObjECTS MiniCAM). Utilization of residue biomass as an energy source is projected for the next century under different climate
policy scenarios. Total global use of residue biomass is estimated to be 20–100 EJ yr−1 by mid- to late- century, depending on the presence of a climate policy and the economics of harvesting, aggregating, and
transporting residue. Much of this potential is in developing regions of the world, including China, Latin America, Southeast
Asia, and India. 相似文献
95.
96.
Hepatitis A virus (HAV) is currently recognized as an important human food borne pathogen, and it is one of the most resistant
enteric RNA viruses, is highly infectious, and may lead to widespread outbreaks. The aim of this study was to optimize the
methods to detect HAV from artificially contaminated food. To this end, strawberry and lettuce were experimentally contaminated
with HAV suspension containing 6 × 106 copies/ml. After contamination, HAV persistence and washing procedure were evaluated at 0, 1, 3, 7, and 9 days of storage.
Five elution buffers (PBS (pH 7.4)/0.1% Tween80; 50 mM glycine/3% (wt/vol) beef extract (pH 9.5); PBS (pH 7, 4); 25 mM glycine/0.1
Tween80; and 1 M sodium bicarbonate) were used to elute the virus, and qualitative and quantitative PCR were used for HAV
detection. HAV was detected by qualitative and quantitative PCR using any of the five elution buffers, but PBS was the most
effective. Even after washing, HAV was detected up to 9 days after contamination by quantitative PCR. Quantitative PCR was
more sensitive than qualitative PCR since samples containing viral load lower than 1.4 × 103 copies/ml could not be detected by qualitative PCR. Quantitative PCR can be used for rapid detection of food borne viruses
and will help in the monitoring and control of food borne disease. 相似文献
97.
Contamination of aquatic ecosystems with heavy metals has been receiving increased worldwide attention due to their harmful e ects
on human health and other organisms in the environment. Most of the studies dealing with toxic e ects of metals deal with single
metal species, while the aquatic organisms are typically exposed to mixtures of metals. Hence, in order to provide data supporting
the usefulness of freshwater fish as indicators of heavy metal pollution, it has been proposed in the present study to investigate the
bioaccumulation and depuration of chromium in the selected organs of freshwater fingerlings Cirrhinus mrigala, individually and in
binary solutions with nickel. The results show that the kidney is a target organ for chromium accumulation, which implies that it is also
the “critical” organ for toxic symptoms. The results further show that accumulation of nickel in all the tissues of C. mrigala is higher
than that of chromium. In addition, the metal accumulations of the binary mixtures of chromium and nickel are substantially higher
than those of the individual metals, indicating synergistic interactions between the two metals. Theoretically the simplest explanation
for an additive joint action of toxicants in a mixture is that they act in a qualitatively similar way. The observed data suggest that C.
mrigala could be suitable monitoring organisms to study the bioavailability of water-bound metals in freshwater habitats. 相似文献
98.
Caroline S. Chaboo Michael S. Engel Maria Lourdes Chamorro-Lacayo 《Die Naturwissenschaften》2009,96(9):1121-1126
Complex ethological adaptations and intraspecific interactions leave few fossil traces. We document three Dominican (20 million
years old [myo]) and Baltic (45 myo) amber fossils that exhibit firm evidence of highly integrated interactions between mothers
and offspring in the diverse camptosomate lineage of beetles (Chrysomelidae, leaf beetles). As in contemporary species, these
hard cases were initially constructed by mothers, then inherited and retained by offspring, which then elaborate this protective
domicile with an unusual but economical building material, their feces. The three fossils are classified in the Subfamily
Cryptocephalinae; two are classified in the tribe Chlamisini based on morphological evidence—the flattened head lacking a
sharp keel and long legs with simple recurved untoothed claws. These diagnostic features are not clearly visible in the third
specimen to permit more refined identification. These fossils provide more precise paleontological dating of tribal nodes
within the cryptocephaline radiation of leaf beetles. These fossils are the first and earliest evidence of mother–offspring
interaction, building behavior, and fecal recycling in Camptosomata beetles and of inheritance of architectural structures
in beetles. 相似文献
99.
Marek K. Jarecki Timothy B. Parkin Alvarus S.K. Chan Thomas C. Kaspar Thomas B. Moorman Jeremy W. Singer Brian J. Kerr Jerry L. Hatfield Raymond Jones 《Agriculture, ecosystems & environment》2009,134(1-2):29-35
Agriculture contributes 40–60% of the total annual N2O emissions to the atmosphere. Development of management practices to reduce these emissions would have a significant impact on greenhouse gas levels. Non-leguminous cover crops are efficient scavengers of residual soil NO3, thereby reducing leaching losses. However, the effect of a grass cover crop on N2O emissions from soil receiving liquid swine manure has not been evaluated. This study investigated: (i) the temporal patterns of N2O emissions following addition of swine manure slurry in a laboratory setting under fluctuating soil moisture regimes; (ii) assessed the potential of a rye (Secale cereale L.) cover crop to decrease N2O emissions under these conditions; and (iii) quantified field N2O emissions in response to either spring applied urea ammonium nitrate (UAN) or different rates of fall-applied liquid swine manure, in the presence or absence of a rye/oat winter cover crop. Laboratory experiments investigating cover crop effects N2O emissions were performed in a controlled environment chamber programmed for a 14 h light period, 18 °C day temperature, and 15 °C night temperature. Treatments with or without a living rye cover crop were treated with either: (i) no manure; (ii) a phosphorus-based manure application rate (low manure): or (iii) a nitrogen-based manure application rate (high manure). We observed a significant reduction in N2O emissions in the presence of the rye cover crop. Field experiments were performed on a fine-loamy soil in Central Iowa from October 12, 2005 to October 2, 2006. We observed no significant effect of the cover crop on cumulative N2O emissions in the field. The primary factor influencing N2O emission was N application rate, regardless of form or timing. The response of N2O emission to N additions was non-linear, with progressively more N2O emitted with increasing N application. These results indicate that while cover crops have the potential to reduce N2O emissions, N application rate may be the overriding factor. 相似文献
100.
European scale application of atmospheric reactive nitrogen measurements in a low-cost approach to infer dry deposition fluxes 总被引:1,自引:0,他引:1
Y.S. Tang I. Simmons N. van Dijk C. Di Marco E. Nemitz U. Dmmgen K. Gilke V. Djuricic S. Vidic Z. Gliha D. Borovecki M. Mitosinkova J.E. Hanssen T.H. Uggerud M.J. Sanz P. Sanz J.V. Chorda C.R. Flechard Y. Fauvel M. Ferm C. Perrino M.A. Sutton 《Agriculture, ecosystems & environment》2009,133(3-4):183
A European scale network was established in 2006 as part of the NitroEurope Integrated Project to infer reactive nitrogen (Nr) dry deposition fluxes, based on low-cost sampling of gaseous and aerosol species and inferential modelling. The network provides monthly measurements of NH3, NH4+, HNO3 and NO3−, as well as SO2, SO42−, HCl, Cl− and base cations at 58 sites. Measurements are made with an established low-cost denuder methodology (DELTA) as a basis to: (1) examine temporal trends and spatial patterns across Europe, (2) improve and calibrate inferential modelling techniques to estimate exchange of Nr species, (3) provide best estimates of atmospheric dry N deposition, and (4) permit an analysis of net GHG exchange in relation to atmospheric and agricultural N inputs at the European scale. Responsibility for measurements is shared among seven European laboratories. An inter-comparison of the DELTA implementation by 6 laboratories at 4 test sites (Montelibretti, Italy; Braunschweig, Germany; Paterna, Spain and Auchencorth, UK) from July to October 2006 provided training for the laboratories and showed that good agreement was achieved in different climatic conditions (87% of laboratory site-means within 20% of the inter-laboratory median). Results obtained from the first year of measurements show substantial spatial variability in atmospheric Nr concentrations, illustrating the major local (NH3) and regional (HNO3, NO3−, and NH4+) differences in Nr concentrations. These results provide the basis to develop future estimates of site-based Nr dry deposition fluxes across Europe, and highlight the role of NH3, largely of agricultural origin, which was the largest single constituent and will dominate dry Nr fluxes at most sites. 相似文献