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31.
The use of plants to decontaminate soils polluted by heavy metals has received considerable attention in recent years as a low-cost technique. Poplars (Populus spp.) can accumulate relatively high levels of certain metals, and have the added advantage of producing biomass that can be used for energy production. A short rotation coppice culture with 13 poplar clones was established on a former waste disposal site, which was moderately polluted with heavy metals. Total content of metals in leaves, wood and bark were determined in August and October/November. Significant clonal differences in accumulation were found for most metals, although clones with the highest concentration of all metals were not found. Cadmium, zinc and aluminium were most efficiently taken up. The lowest concentration was found in wood; the highest concentrations were generally found in senescing leaves, making removal and treatment of fallen leaves necessary.  相似文献   
32.
The present study aims at assessing the life span of populations of the orchid L. loeselii during successional in dune slacks on the Wadden Sea islands. An inventory of Liparis loeselii populations was carried out on 6 islands, while the population structure was assessed in more detail on the island of Texel. The occurrence of the orchid was related to soil factors and hydrological conditions. Groundwater levels were measured in a dune area with natural dune slack formation. The groundwater composition was analyses and the freshwater lenses were modelled. Various scenarios were investigated, including sea level rise and sand nourishment. The window of opportunity for L. loeselii to colonize a new slack is relatively narrow. Under favorable management, the population can survive c. 20 years. Soil pH was positively correlated with the occurrence of L. loeselii populations, while a high organic matter content was negatively correlated. Sites with large populations of L. loeselii, were situated in young dune slacks, that functioned as flow-through lakes and has top soilsinfluenced by anoxic calcareous groundwater. Modelling showed that the freshwater lens would decrease due to sea level rise, while artificial sand nourishment could counteract this effect. The populations of the Hors area on Texel, the Netherlands, can survive for several decades due to continuous formation of new slacks. Discharge of calcareous groundwater is essential to keep the pH on a high level. The hydrological systems that supply dune slack with groundwater are relatively small and are vulnerable for changes in sea level rise.  相似文献   
33.
Efforts to assess forest ecosystem carbon stocks, biodiversity, and fire hazards have spurred the need for comprehensive assessments of forest ecosystem dead wood (DW) components around the world. Currently, information regarding the prevalence, status, and methods of DW inventories occurring in the world’s forested landscapes is scattered. The goal of this study is to describe the status, DW components measured, sample methods employed, and DW component thresholds used by national forest inventories that currently inventory DW around the world. Study results indicate that most countries do not inventory forest DW. Globally, we estimate that about 13% of countries inventory DW using a diversity of sample methods and DW component definitions. A common feature among DW inventories was that most countries had only just begun DW inventories and employ very low sample intensities. There are major hurdles to harmonizing national forest inventories of DW: differences in population definitions, lack of clarity on sample protocols/estimation procedures, and sparse availability of inventory data/reports. Increasing database/estimation flexibility, developing common dimensional thresholds of DW components, publishing inventory procedures/protocols, releasing inventory data/reports to international peer review, and increasing communication (e.g., workshops) among countries inventorying DW are suggestions forwarded by this study to increase DW inventory harmonization.  相似文献   
34.
自2008年10月以来,全球金融危机持续升级,公司面临的质量和良好的公司治理方面的压力在继续增加。为了挖掘风险管理的内涵,来自IGH的Pieter Strydom博士将对一系列管理准则进行研究.分析确定出到底是什么样的人员、公司和政府更加善于管理风险。当然导致组织命运不同的原因很复杂,本次Pieter Strydom博士首先从人的因素开始分析。  相似文献   
35.
We conducted a study to assess to what extent current ecolabels contain standards that stimulate conservation and sustainable use of on-farm biodiversity of agricultural landscapes (agrobiodiversity). First, we developed an agrobiodiversity management yardstick to assess and compare the labeling schemes of ecolabels for arable farming. Key characteristics of the yardstick are the five levels linking the abstract notion of agrobiodiversity management to concrete measures on a farm and its foundation upon expert judgment regarding the effect of farming practices on agrobiodiversity. Several environmental themes, among them agrobiodiversity management, are regulated through the standards of labeling schemes of ecolabels. With the aid of this yardstick, the labeling schemes were scrutinized and the number, average efficacy, and compulsory nature of relevant standards was determined for 10 categories of farm management. The results show that all examined ecolabels contain at least some standards that stimulate conservation and sustainable use of agrobiodiversity, but there are large differences between the labels. We consider the results of the five ecolabels to be insufficient to warrant their usefulness as a governance strategy that the Dutch government could refer to and depend on as part of a national agrobiodiversity policy to stimulate agrobiodiversity.  相似文献   
36.
Via a historical reconstruction, this paper primarily demonstrates how the societal debate on genetically modified organisms (GMOs) gradually extended in terms of actors involved and concerns reflected. It is argued that the implementation of recombinant DNA technology out of the laboratory and into civil society entailed a “complex of concerns.” In this complex, distinctions between environmental, agricultural, socio-economic, and ethical issues proved to be blurred. This fueled the confusion between the wider debate on genetic modification and the risk assessment of transgenic crops in the European Union. In this paper, the lasting skeptical and/or ambivalent attitude of Europeans towards agro-food biotechnology is interpreted as signaling an ongoing social request – and even a quest – for an evaluation of biotechnology with Sense and Sensibility. In this (re)quest, a broader-than-scientific dimension is sought for that allows addressing the GMO debate in a more “sensible” way, whilst making “sense” of the different stances taken in it. Here, the restyling of the European regulatory frame on transgenic agro-food products and of science communication models are discussed and taken to be indicative of the (re)quest to move from a merely scientific evaluation and risk-based policy towards a socially more robust evaluation that takes the “non-scientific” concerns at stake in the GMO debate seriously.  相似文献   
37.

The continuously growing global demands on a finite land resource will require better strategic policies and management of trade-offs to avoid conflicts between different land-use sectors. Visions of the future can support strategic planning by stimulating dialogue, building a consensus on shared priorities and providing long-term targets. We present a novel approach to elicit stakeholder visions of future desired land use, which was applied with a broad range of experts to develop cross-sectoral visions in Europe. The approach is based on (i) combination of software tools and facilitation techniques to stimulate engagement and creativity; (ii) methodical selection of stakeholders; (iii) use of land attributes to deconstruct the multifaceted sectoral visions into land-use changes that can be clustered into few cross-sectoral visions, and (iv) a rigorous iterative process. Three cross-sectoral visions of sustainable land use in Europe in 2040 emerged from applying the approach in participatory workshops involving experts in nature conservation, recreation, agriculture, forestry, settlements, energy, and water. The three visions—Best Land in Europe, Regional Connected and Local Multifunctional—shared a wish to achieve a land use that is sustainable through multifunctionality, resource use efficiency, controlled urban growth, rural renewal and widespread nature. However, they differ on the scale at which land services are provided—EU-wide, regional or local—reflecting the land-sparing versus land-sharing debate. We discuss the usefulness of the approach, as well as the challenges posed and solutions offered by the visions to support strategic land-use planning.

  相似文献   
38.
Truck tyres can cause significant environmental pressure through the life cycle. The main aim of this paper is investigate to what extent international policy measures on foreign trade, international recycling and harmonisation of legislation can contribute in effectively reducing environmental pressure caused in the truck tyre life cycle. A two-region simulation model, representing Western and Eastern Europe, is developed that integrates the complete life cycle, incorporates environmental impacts in its economic analysis, is technically dynamic by accounting for learning-by-doing effects, and allows for variations in trade of new and old truck tyres. In this study the economic, environmental and social effectiveness of harmonisation and trade measures in the European life cycle for truck tyre is tested. Several conclusions can be drawn from the model simulations. First, the environmental effects caused by the trade of used tyres from Western to Eastern Europe are of limited impact on the overall environmental damage caused by truck tyres. The consumption stage is by far the main contributor to environmental damage. Within the marginal analysis of trade, harmonisation of disposal fees illustrated to generate very limited positive results. The private and external costs in the solid waste management (SWM) stage are too limited to have a notable impact on the overall configuration of the European tyre life cycle. The introduction of strict laws on tread depth in Eastern Europe has a much stronger impact on material flows than the harmonisation scenario. This suggests that domestic policy measures should be the primarily focus on interventions in this stage of the life cycle, for instance, by improving the management of tyre pressure. Because trade of used tyres has little impact on the consumption stage, this issue should not get priority in European environmental programs.  相似文献   
39.
Harvesting nontimber forest products (NTFPs) is a major economic activity in tropical forests. As many NTFPs are overexploited, sustainability analyses are required to set harvest guidelines. Here we introduce and apply a new approach to evaluating sustainability, which combines prospective (elasticity) and retrospective (Life Table Response Experiments [LTRE]) demographic analyses of matrix population models. We relate the elasticity of vital rates (representing their importance for population growth rate, lamda) to their contribution to harvest-induced change in lamda ("LTRE contribution"). When high-elasticity vital rates have a low LTRE contribution, exploitation is potentially sustainable as negative effects for population growth are buffered. If the reverse is found, there is little scope for sustainability because crucial vital rates are affected. Our approach is less sensitive to chance fluctuations than the commonly used sustainability criterion of lamda = 1.0, as it does not depend on the absolute value of lamda. We applied this analysis to Geonoma deversa, a clustered forest understory palm. We studied three experimentally defoliated and control populations in a Bolivian rainforest during two years. Cutting all leaves of large ramets did not change mortality but strongly affected growth and reproduction. In spite of severe changes in some vital rates, population growth rate was not significantly reduced after defoliation. A literature review revealed that six other understory palms species responded very similarly to defoliation. The combination of LTRE contributions and elasticity analyses showed that low-elasticity vital rates were mainly responsible for the defoliation-induced change in lamda for Geonoma deversa. For two other understory palms (Astrocaryum mexicanum and Chamaedorea radicalis) new demographic analyses yielded very similar results. For Geonoma, the LTRE contribution-elasticity relation strongly changed when we mimicked harvest damage. Adding 5% mortality to defoliated palms caused stronger change in lamda, mainly due to changes in a high-elasticity vital rate (survival). Therefore, harvest practices that involve stem killing are clearly unsustainable. Our results show that commercial leaf cutting in Geonoma deversa is potentially sustainable, and that this is likely the case for understory palms in general. Our approach to evaluating harvest sustainability can be applied to other NTFPs.  相似文献   
40.
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