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11.
The sustainable intensification of agriculture   总被引:1,自引:0,他引:1  
Agricultural development is currently facing unprecedented challenges. With 800 million people already having insufficient access to food, population growth estimates project an even bleaker situation in the future. The article summarizes the major schools of thought regarding how to face the dilemma, and advocates sustainable intensification of agriculture, relying on integrated use of a wide range of technologies to manage pests, nutrients, soil and water. Local knowledge and adaptive methods are stressed rather than comprehensive packages of externally-supplied technologies. The article shows how regenerative, low-input agriculture, founded on full farmer participation in all stages of development and extension, can be highly productive. It is stressed that policy must not prescribe specific, concretely defined technologies or practices, as this would restrict future farmer options. Farmers and communities should be allowed and encouraged to adapt to changing conditions; what needs to be sustainable are local processes of innovation and adaptation.
The article highlights environmental and economic benefits resulting from sustainable intensification practices, for farmers as well as communities and nations with examples are taken from Africa, Asia and Latin America.
Despite the increasing success of sustainable agriculture, it is clear that the challenge remains to 'scale up' the process from small 'islands of success' to fundamental reform of both policies and policy formulation processes.  相似文献   
12.

Environmental and ecological degradation can be monitored by biological indicators such as plants, yet little research has been done using subterranean organisms such as collembola, especially in cities. Collembola, a soil fauna group, can be used to assess soil quality and to decipher assembly rules of soil organisms in cities. Here, we review 75 articles on soil collembola in an urban context. We found that soil properties and landscape characteristics influenced soil communities. There is a need for more connectivity between green urban spaces to allow the dispersion of collembola. Little information is available on the assembly of collembola communities, on biotic interactions and on dynamics of colonisation.

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13.
The value of accumulated ecological knowledge, termed ecoliteracy, is vital to both human and ecosystem health. Maintenance of this knowledge is essential for continued support of local conservation efforts and the capacity of communities to self- or co-manage their local resources sustainably. Most previous studies have been qualitative and small scale, documenting ecoliteracy in geographically isolated locations. In this study, we take a different approach, focusing on (1) the primary factors affecting individual levels of ecoliteracy, (2) whether these factors shift with economic development, and (3) if different knowledge protection strategies are required for the future. We compared non-resource-dependent communities in the United Kingdom with resource-dependent communities in India and Indonesia (n=1250 interviews). We found that UK residents with the highest levels of ecoliteracy visited the countryside frequently, lived and grew up in rural areas, and acquired their knowledge from informal word-of-mouth sources, such as parents and friends, rather than television and schooling. The ecoliteracy of resource-dependent community members, however, varied with wealth status and gender. The least wealthy families depended most on local resources for their livelihoods and had the highest levels of ecoliteracy. Gender roles affected both the level and content of an individual's ecoliteracy. The importance of reciprocal oral transfer of this knowledge in addition to direct experience to the maintenance of ecoliteracy was apparent at all sites. Lessons learned may contribute to new local resource management strategies for combined ecoliteracy conservation. Without novel policies, local community management capacity is likely to be depleted in the future.  相似文献   
14.
The San Francisco Bay Region of the California Regional Water Quality Control Board (SFB CRWQCB) and the San Francisco District of the US Army Corps of Engineers (US ACOE) are looking for an expeditious means to determine whether regulated wetland projects produce ecologically valuable systems and remain in compliance with their permits (i.e. fulfill their legal requirements) until project completion. A study was therefore undertaken in which 20 compensatory wetland mitigation projects in the San Francisco Bay Region were reviewed and assessed for both permit compliance and habitat function, and this was done using a rapid assessment method adapted for this purpose. Thus, in addition to determining compliance and function, a further goal of this study was to test the efficacy of the assessment method, which, if useful, could be applied not only to mitigation projects, but also to restoration projects and natural wetland systems. Survey results suggest that most projects permitted 5 or more years ago are in compliance with their permit conditions and are realizing their intended habitat functions. The larger restoration sites or those situated between existing wetland sites tend to be more successful and offer more benefits to wildlife than the smaller isolated ones. These results are consistent with regulatory experience suggesting that economies of scale could be realized both with (1) large scale regional wetland restoration sites, through which efforts are combined to control invasive species and share costs, and (2) coordinated efforts by regulatory agencies to track project information and to monitor the increasing number and size of mitigation and restoration sites. In regard to the assessment methods, we find that their value lies in providing a consistent protocol for evaluations, but that the ultimate assessment will rely heavily on professional judgment, regulatory experience, and the garnering of pre-assessment information.  相似文献   
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At Cape Vera, Devon Island (Nunavut, Canada), a colony of northern fulmars (Fulmarus glacialis) concentrates and releases contaminants through their guano to the environment. We determined whether persistent organic pollutants (POPs) from seabirds were transferred to coastal food webs. Snow buntings (Plectrophenax nivalis) were the most contaminated species, with ∑PCB and ∑DDT (mean: 168, 106 ng/g ww) concentrations surpassing environmental guidelines for protecting wildlife. When examined collectively, PCB congeners and DDT in jewel lichen (Xanthoria elegans) were lower in samples taken farther from the seabird colony, and increased with increasing δ15N values. However, only concentrations of p’p-DDE:∑DDT and PCB-95 were significantly correlated inversely with distance from the seabird cliffs. Linkages between marine-derived POPs and their concentrations in terrestrial mammals were less clear. Our study provides novel contaminant data for these species and supports biovector transport as a source of organic contaminants to certain components of the terrestrial food web.  相似文献   
18.
There are close to 8500 major protected areas, covering some 5% of the world's land area. Many countries have more than 10% of their area set aside for conservation purposes. But this increase in designated conservation has been accompanied by a strong ideology that people are bad for natural resources. Policies and practice have, therefore, both encouraged exclusion and discouraged local participation. As a result, social conflicts have grown in and around protected areas, and conservation goals themselves have been threatened. Conservation science itself needs rethinking. It has been dominated by the positivist and rationalist paradigm, in which professionals assume they know best and so can analyse and influence natural resources in the ways they desire. But if natural resources are to be conserved, then the skills, knowledge and needs of local people will have to be built upon. This will require radical reversals in current professional thinking and practice .  相似文献   
19.
In this paper, interactions or co-movement between the CER and EUA futures prices are examined in order to shed light on the dependency between the European Union Emissions Trading Scheme (EU ETS) and the clean development mechanism (MDP). Our analysis uses the wavelet method to model the correlation between CER and EUA in the time-frequency domain. It highlights the impact of different investors (according to their investment horizons) on the co-movement between the CER and EUA prices, and therefore, the behavior of individual investors as speculators, arbitrageurs, and hedgers on European allowance and CDM credits cumulatively. In this vein, we analyze according to the frequency intervals, price convergence, identification of potential factors that could explain a difference in futures prices, and structural changes in the EUA and CER prices. The application is made using daily EUA’s and CER’s prices data.  相似文献   
20.

The fate of six human-use drugs was assessed and predicted in mesocosms designed to mimic shallow constructed wetlands during the onset of fall and senescence. Mesocosms were monitored for 28 days after the addition of carbamazepine, clofibric acid, fluoxetine and naproxen (nominal initial concentrations of 5 μg/L each), sulfamethoxazole, and sulfapyridine (nominal initial concentrations of 150 μg/L each), with and without phosphorous (P) addition at 1.6 mg/L. We hypothesized that addition of P would stimulate primary productivity and enhance removal of pharmaceuticals from the water column. Carbamazepine, clofibric acid, fluoxetine, and naproxen had half-lives of 8.7, 11, 1.5, and 2.5, and 8.6, 11.0, 1.4, and 2.5 days in treatments with and without P amendment, respectively. Sulfamethoxazole and sulfapyridine had half-lives of 17 and 4.9 days in mesocosms with P amendment and 17 and 4.7 days without amendment. A concurrent pulse of P with pharmaceuticals did not significantly enhance the removal of these compounds. Predicted half-lives from modeling efforts were consistent with observed values, with photolysis the greatest contributor to chemical attenuation.

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