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851.
The multi-disciplinary evaluation of a national agri-environment scheme   总被引:8,自引:0,他引:8  
With an increasing amount of public funds being spent on agri-environmental schemes effective methods have to be developed to evaluate them. As many schemes have multiple objectives there is a need for a multi-disciplinary approach to any evaluation. A method was developed to assess the degree to which ecological, landscape, historical and access objectives for the Countryside Stewardship Scheme (CSS) in England have been met. The method used a sample of 484 agreements for which data were collected from surveys, a desk study and an interview with the agreement holder. These data were then evaluated by an expert team of an ecologist, landscape architect, landscape historian, and a social scientist specializing in rural affairs. The team were subsequently brought together with a Chair to discuss their findings for each agreement, allocating scores for each of five criteria: agreement negotiation; appropriateness, environmental effectiveness, compliance and side effects. The additionality that each agreement was likely to provide was also assessed. The results of this process suggest that in the majority of cases the CSS agreements should maintain or enhance the environment in terms of ecology, landscape, and landscape history and increase public enjoyment of the countryside. Thirty-six percent of agreements showed high additionality and 38% medium additionality which demonstrates that the CSS is likely to provide a benefit to society. Agreement negotiation, predicted environmental effectiveness and predicted compliance all improved significantly over the period 1996-98. Recommendations made from this project have been implemented by the Government department to improve the CSS. The multi-disciplinary method was successful and, with further development, could be used for assessment of any agri-environment scheme, or potentially any conservation project or broader 'rural development' scheme encompassing environmental, economic and social objectives. A key to success is the need for the criteria to be tailored for the project concerned and clearly established at the beginning.  相似文献   
852.
The psychological reactions of 211 women undergoing prenatal diagnosis (PND) with amniocentesis (group A, n = 122) or chorionic villus biopsy (group V, n = 90) were exmained by questionnaires and interviews. The distress experienced while waiting for the test, during the test procedure, and while waiting for the result was reported by the women, both in questionnaires and in interviews. In the questionnaires, no difference between the two diagnostic methods was observed. In the interviews, however, the women undergoing amniocentesis appeared significantly more distressed by the procedure. In group A 97 per cent and in group V 100 per cent wished a method which, like chorionic villus biopsy, could be used in the first weeks of pregnancy. The risk of miscarriage was, as described in other studies, regarded as a serious threat by the pregnant women.  相似文献   
853.
Changes in the survival parameters of the red fox were analyzed at different phases of the population cycle. It was found that the survival rate in all age classes, including newborns, drastically increased at the phase of population growth. The relationship between the general mortality rate and population size was determined. A hypothesis concerning the mechanism of these changes in the general mortality rate is suggested.  相似文献   
854.
A symbiotic relationship between a damselfish (Stegastes fasciolatus) and 2 surgeonfishes (Acanthurus lineatus and A. leucosternon) is described. The damselfish, which is about 1/10 the size of the surgeonfishes, is concentrated in, and appears to prefer to be in, the feeding areas of the surgeonfishes. There is an average of one adult damselfish per adult surgeonfish feeding area. All 3 species defend their feeding areas against conspecifics and various other fishes that have similar diets, but there are few aggressive interactions between the cohabitants. Most of the interspecific defense of cohabited areas is provided by the surgeonfishes. The cohabitant species eat the same types of benthic microalgae, but only the damselfish eats microcrustaceans. It appears that the net cost to a surgeonfish of having a damselfish in its feeding area is very low because (1) biomass density of the damselfish is low, (2) it uses some food that the surgeonfishes do not use, and (3) it makes a small contribution to the defense of shared feeding areas. Even if there is a cost to the surgeonfish, the small size of the damselfish would allow it to take shelter from the surgeonfish, thus making it too costly for the surgeonfish to exclude it. Such cohabitation relationships, which may be quite common among reef fishes, represent a means by which the coexistence of species that use the same limiting resources is achieved.  相似文献   
855.
856.
TSP samples, collected at two stations in the area of Thessaloniki during the period July 1987‐June 1988, were analysed for heavy metals (Fe, Pb, Zn, Cu, Mn, Cr, Co, Ni and V). Flame and flameless atomic absorption spectrophotometry was used for metal determinations. Metals determined were characterized with respect to their origin from natural or man‐made emission sources. Source identification was attempted by relation of metal concentrations to wind direction, and interelement correlations.

Results obtained showed that Pb, Zn and Cu are emitted from man‐made sources (traffic, domestic heating, industry), V, Ni and Co are derived partially from natural and man‐made sources, while Cr is mainly soil‐derived.  相似文献   
857.
The effects of two exogenous factors, ground fires and industrial air pollution, on natural regeneration of Scots pine (Pinus sylvestris L.) cenopopulations have been studied in the Transural region. It has been found that an increased level of air pollution leads to a decrease in the abundance and occurrence frequency of pine undergrowth; as the intensity of ground fire increases, these parameters of the postfire generation of undergrowth increase as well, especially in background areas. As shown by two-way ANOVA, either of these factors and their interaction have a significant effect on the density of pine undergrowth, with this effect being stronger in the case of ground fires.  相似文献   
858.
The reestablisment of autochthonous plant species is an essential strategy for recovering degraded areas under semiarid conditions. A field experiment was carried out to assess the short-term effect of two reafforestation methods involving mycorrhizal inoculation and compost addition on soil quality parameters and Rhamnus lycioides seedling growth. The nutrient content (NPK) and enzymatic activities (dehydrogenase, urease, protease-BAA, acid phosphatase and β-glucosidase) increased and bulk density decreased in the rhizosphere soil with the organic amendment. Biomass C of rhizosphere soil increased by at least 240% with respect to the control soil after mycorrhizal inoculation and the combination of compost addition + mycorrhizal inoculation. Both mycorrhizal inoculation and composted organic residue addition increased R. lycioides seedling growth in the same proportion. In the short term, we conclude that the application of both reafforestation methods not only enhances the establishment of R. lycioides seedlings, but also improves soil quality.  相似文献   
859.
A marginal abatement cost curve (MACC) traces out the relationship between the quantity of pollution abated and the marginal cost of abating each additional unit. In the context of air quality management, MACCs are typically developed by sorting control technologies by their relative cost-effectiveness. Other potentially important abatement measures such as renewable electricity, energy efficiency, and fuel switching (RE/EE/FS) are often not incorporated into MACCs, as it is difficult to quantify their costs and abatement potential. In this paper, a U.S. energy system model is used to develop a MACC for nitrogen oxides (NOx) that incorporates both traditional controls and these additional measures. The MACC is decomposed by sector, and the relative cost-effectiveness of RE/EE/FS and traditional controls are compared. RE/EE/FS are shown to have the potential to increase emission reductions beyond what is possible when applying traditional controls alone. Furthermore, a portion of RE/EE/FS appear to be cost-competitive with traditional controls.

Implications: Renewable electricity, energy efficiency, and fuel switching can be cost-competitive with traditional air pollutant controls for abating air pollutant emissions. The application of renewable electricity, energy efficiency, and fuel switching is also shown to have the potential to increase emission reductions beyond what is possible when applying traditional controls alone.  相似文献   

860.
Radionuclide, radiogenic lead isotope and trace metal analyses on fine-grained sediment cores collected along 160 km of the upper and tidal Hudson River were used to examine temporal trends of contaminant loadings and to develop radiogenic lead isotopes both as a stratigraphic tool and as tracers for resolving decadal particle transport fluxes. Very large inputs of Cd, Sb, Pb, and Cr are evident in the sediment record, potentially from a single manufacturing facility. The total range in radiogenic lead isotope ratios observed in well-dated cores collected about 24 km downstream of the plant is large (e.g., maximum difference in 206Pb/207Pb is 10%), characterized by four major shifts occurring in the 1950s, 1960s, 1970s and 1980s. The upper Hudson signals in Cd and radiogenic lead isotopes were still evident in sediments collected 160 km downstream in the tidal Hudson. The large magnitude and abrupt shifts in radiogenic lead isotope ratios as a function of depth provide sensitive temporal constraints that complement information derived from radionuclide analyses to significantly improve the precision of dating assignments. Application of a simple dilution model to data from paired cores suggests much larger sediment inputs in one section of the river than previously reported, suggesting particle influxes to the Hudson have been underestimated.  相似文献   
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