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1.
Managing diffuse water pollution from agricultural land continues to be one of the more intractable challenges for environmental policy. The advent of the Water Framework Directive places the onus on EU member states to identify reasons why water bodies fail or are at risk of failure to meet good ecological status. In such cases, programmes of measures are to be enacted to mitigate the causes at least cost. Failing this, users may ultimately be faced with the full costs of pollution. This paper considers the scope for measures that address nitrogen and phosphorus pollution at source. Specifically the paper relates the diffuse pollution problem to the extent of over application of nitrogen and phosphorus. Data envelopment analysis applied to English cereal and dairy farmers, provides an indication of resource use and evidence of over application. This inefficiency provides a potential basis for either a least cost abatement approach using effective information and advice, or alternatively a pollution charge.  相似文献   

2.
The New South Wales Government recently introduced the Native Vegetation Conservation Act to protect the native grassland and woodland of the state. The Act protects biodiversity by preventing farmers from clearing such vegetation on their properties but, as a consequence, reduces farm incomes and land values. An economic model of the relationship between land value and percentage of farm in native vegetation is integrated with an ecological model of the relationship between species lost and percentage of the farms in native vegetation. The integrated framework is applied to estimate the opportunity costs of the Act for one important agricultural area of the state, the northern part of the Brigalow Belt South Bio-Region. If all the vegetation were protected, the reduction in land value would be at least 14.3%, which is an opportunity cost of at least 148.5 dollars m for the area. Both the benefits and costs of biodiversity protection must be accounted for, so risk simulations are then combined with benefit-cost analysis to compare the benefits of biodiversity protection to these costs.  相似文献   

3.
A land suitability study was carried out by applying a multiple-criteria technique to 12 different vegetation types in Mexico's Tamaulipas state to help select potentially suitable sites for hazardous waste treatment plants. Species richness, spatial distribution, and uniqueness were selected as the criteria for estimating a vegetation type's suitability. Using the analytical hierarchy process, we ranked and mapped vegetation types, then compared the results with rankings of the same vegetation types based only on their number of endemic species. The suitabilities of the various vegetation types were ordered in more or less the same way by both methods, except in two cases for which the results were very different. The method proved to be a useful tool despite the availability of only partial (mostly qualitative) information; under such circumstances, expert experience can be incorporated in the evaluation process to a limited degree. The technique described in this paper has a high potential to aid decisions when many opinions and options must be considered simultaneously.  相似文献   

4.
Improved techniques for measuring and monitoring the state of biodiversity are required for reporting on national obligations to international and regional conservation institutions. Measuring the extent of grazing-related degradation in semi-arid ecosystems has proved difficult. Here we present an accurate and cost-effective method for doing this, and apply it in a South African semi-arid region that forms part of a globally significant biodiversity hotspot. We grouped structurally and functionally similar vegetation units, which were expert-mapped at the 1:50,000 scale, into four habitat types, and developed habitat-specific degradation models. We quantified degradation into three categories, using differences between dry and wet season values of the Normalized Difference Vegetation Index (NDVI) for the three succulent karoo habitats, and the difference between maximum and mean NDVI values for the subtropical thicket habitat. Field evaluation revealed an accuracy of 86%. Overall, degradation was high: 24% of the study area was modeled as severely degraded, and only 9% as intact. Levels of degradation were highest for bottomland habitats that were most exposed to grazing impacts. In sharp contrast to our methods, a widely used, broad-scale and snapshot assessment of land cover in South Africa was only 33% accurate, and it considerably underestimated the extent of severely degraded habitat in the study area. While our approach requires a multidisciplinary team, and in particular expert knowledge on the characteristics and spatial delimitation of vegetation types, it is repeatable, rapid, and relatively inexpensive. Consequently, it holds great promise for monitoring and evaluation programs in semi-arid ecosystems, in Africa, and beyond.  相似文献   

5.
Spatial and temporal variations in vegetation are examined in relation to land tenure, population increase, and rainfall variation in a part of Peddie district, Eastern Cape. Sequential aerial photographs between 1938 and 1988 are analyzed to determine trends in vegetation and population change in three different land-tenure units. The areal extent at each date of four distinct vegetation categories is determined using PC ARC/INFO GIS. Long-term annual rainfall trends for the area are analyzed and juxtaposed with vegetation changes. Extensive ground-truthing exercises are carried out to verify the present condition of vegetation condition in terms of cover and species composition. Differences in land-tenure systems are discerned as the dominant factor controlling variations in vegetation degradation. The study also reveals that neither population changes nor rainfall variations can explain the observed trends in vegetation degradation. Earlier injudicious land-use practices, sustained since the turn of the last century, may provide plausible explanations for the trends and present status of vegetation degradation in the area.  相似文献   

6.
The Chinese government has recently been attaching increasing importance to the application of effective legal tools to tackle land degradation (LD) issues. Based on the concept of sustainable development, China began developing and reaping the benefits of environmental and natural resources legislation including LD control regulations in the 1990s. In the past three years, some central‐western provinces in China have been implementing a “ People's Republic of China/Global Environment Facility (PRC/GEF ) Partnership on LD Control of Dryland Ecosystems”, which is based on an integrated ecosystem management (IEM) approach. IEM is designed to achieve a balanced, scientific and participatory approach to natural resources management, which creates the potential to improve the quality of Chinese environmental law and policy procedures. The paper studies the existing Chinese national laws and regulations pertinent to LD control within 9 areas covering land, desertification, soil erosion, grassland, forest, water, agriculture, wild animals and plants, and environment protection in detail, against IEM principles and basic legal elements. The main objective is to identify problems and provide feasible solutions and recommendations for the improvement of the existing laws and regulations. The authors conclude that the development of an improved national legislative framework is essential if LD control is to be successfully achieved. The paper is partly based on Component 1 — Improving Policies, Laws and Regulations for Land Degradation Control under PRC/GEF Partnership on Land Degradation in Dryland Ecosystems (TA 4357).  相似文献   

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