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A major obstacle to the conservation and management of semi-natural grassland (SNG) is the general lack of consistent and precise maps showing the extent and quality of this habitat type. SNG is related to, and influenced by, agricultural land use. Both intensive land use as well as a lack of extensive land use can reduce the extent and quality of SNG. For Denmark, this paper demonstrates how parcel-specific land-use data can be applied to detect localities with spatial convergences and conflicts between SNG and agricultural land use. Based on their respective influence on SNG, land use is aggregated into five major classes and spatially overlaid with existing nationally registered SNG. Results show that almost 11 % of all SNG is mapped either on cropped land or on rotational grassland, indicating a conflict between mapped SNG and land use. Thirty percent of SNG is mapped outside any agricultural land use, pointing to a lack of management. Fifty nine percent of SNG is mapped either on land receiving payments for grazing/mowing or on other land under extensive management, indicating a convergence between SNG and land use. Finally, 30 % of land receiving payments for grazing/mowing and 62 % of other land under extensive management does not contain any semi-natural habitat. Potential, as yet unmapped, SNG might exist in these localities. Based on these results it is argued that the application of parcel-specific land-use data could significantly improve monitoring of SNG.  相似文献   

3.
Given the importance of anthropogenic determinants in forest ecosystems within Europe, the objective of this paper is to link the evidence arising from biological models to socio-economic determinants, where the expected returns of forest investments represent the main driver. A micro-economic area allocation module is therefore coupled with an inventory-based forest dynamics module and a partial-equilibrium market module in a national-level forest sector model for France (FFSM++). Running long-term scenarios (until 2100), we show the implication of an active management policy on forest composition: when the most profitable option drives forest investments, coniferous forests are generally preferred over broadleaved ones. This result is, however, reappraised when the risk aversion of forest owners is explicitly considered in the model, given the higher risk associated with the former. We further show the strong stability of forest ecosystems that, due to the very long cycles, undergoes very small variations in volume stocks, even in scenarios where the initial forest regeneration is strongly influenced.  相似文献   

4.
The authors have developed the Activity Accounting Technique for predicting far field noise levels due to operation of specific set of mining machinery. The technique is based on the breaking down of the mining operations into a number of activities and establishing their duration and average location. By estimating the noise levels due to these activities, the overall noise field near a surface mine can be predicted. Experiments were undertaken at a quarry to validate the model developed based on this technique. Results of these experiments are discussed in this paper. The Activity Accounting Technique has the scope of elaborate application for prediction of environmental noise near mining sites. In a system where the activities involved and their duration can be estimated one can develop a noise quality prediction model based on near field spectrum of the sound pressure levels due to the activities. However, this method will be more useful if an acoustic database can be evolved for all the possible activities for different alternative equipment system.  相似文献   

5.
Over the past decade, the cause of nature preservation in Singapore had gained momentum through the efforts of the various non-governmental organisations. Tussles over disputed nature areas such as the Lower Peirce Forest, Marina South, Senoko, etc., had also garnered a great deal of publicity in the mass media. Many arguments for nature conservation were given by conservationists --- from the economic to the ecological --- without considering carefully their local relevance and impact. This paper provides an outline of a value orientation for nature preservation in Singapore --- taking into account the local context in terms of the economic, cultural, social and ecological conditions existing in this country. The major values usually associated with nature conservation are reviewed and prioritised in terms of local relevance and impact. The strategic thrust of the value orientation advocated is, in the final analysis, anthropocentric rather than non--anthropocentric in perspective.  相似文献   

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In this article, we are concerned with the general problem of choosing from a set of taxa T a subset S to protect in order to try to contribute to halting biodiversity loss as efficiently as possible given limited resources. The protection of a taxon decreases its extinction probability, and the impact of protecting the taxa of S is measured by the resulting expected phylogenetic diversity (ePD) of the set T. The primary challenge posed by this approach lies in determining the extinction probability of a taxon (protected or unprotected). To deal with this difficulty, the uncertainty about the extinction probabilities can be described through a set of possible scenarios, each corresponding to different extinction probability values for each taxon. We show how to determine an “optimal robust set” of taxa to protect, defined as the set of taxa that minimizes the maximum “regret,” i.e., the maximum relative gap, over all the scenarios, between (1) the ePD of T obtained by protecting the taxa of this set and (2) the ePD of T which would be produced by protecting the subset of taxa optimal for the considered scenario. In our experimental conditions covering 100 cases, this gap is almost always less than 1%. Consequently, the ePD of T obtained by protecting the taxa of the optimal robust set is not far from the maximum ePD of T that could have been obtained if we had known the true scenario. In other words, a way of escaping (in large part, at least) from the uncertainty related to the extinction probabilities of the taxa consists of choosing to protect those belonging to the optimal robust set. We also compare the optimal robust set to other relevant subsets of T.  相似文献   

7.
根据《测量不确定度评定与评定表示指南》(JJF 1059-1999)建立了石墨炉原子吸收光谱法测定全血中铅不确定度的数学模型,分析了测试过程中不确定度的来源,并对各不确定度分量进行量化。本次测量的合成相对不确定度值为0.047 3,其中最大的分量是样品消化前处理重复测定引入的,其不确定度分量值为0.04。本次全血中铅测定结果为(130.7±12.4)μg/L,k=2,即测定结果置信水平为95%。  相似文献   

8.
X射线荧光光谱法测定土壤样品中铅的不确定度评定   总被引:4,自引:1,他引:4  
用实例对X射线荧光光谱法测定土壤样品中铅的不确定度进行了评定.测量结果的不确定度由仪器综合稳定性、制样、标准物质、回归工作曲线、重复测量等所引入的不确定度分量组成.在对各个不确定度分量进行量化的基础上,通过合成得到测量结果的标准不确定度,再乘以95%置信概率下的扩展因子2,得到测量结果的扩展不确定度.  相似文献   

9.
通过对空气湿度与总悬浮颗粒物之间关系的分析,得出平衡修正系数,提高了总悬浮颗粒物测定结果的准确性和时效性。  相似文献   

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以陕西省3个典型区域的3条高速公路为例,在构建高速公路水土保持生态服务功能价值评价体系并确定各评价指标计算方法的基础上,全面分析了高速公路水土保持的生态服务功能价值。旨在相互交流的基础上,为后期同类工程水土保持投资预算设计和资金管理使用提供理论依据。  相似文献   

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