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21.
科尔沁沙地及其周围地区土地利用变化的情景分析   总被引:19,自引:0,他引:19  
根据科尔沁沙地及其周围地区过去15年(1985~2000年)土地利用的时空动态变化、2000年的土地利用格局以及2010年的土地利用规划数据,构建了模拟研究地区土地利用变化的CLUE-S模型。在该模型的支持下,论文分别对研究地区未来10年(2000~2010年)土地利用变化格局的马尔柯夫情景和规划情景进行了模拟,然后,通过2000年土地利用现状图与2010年情景模拟图的叠加,分析了在以上两种情景下土地利用变化的共同之处及差异。研究结果对完善科尔沁沙地及其周围地区土地利用变化的动态管理具有重要意义。  相似文献   
22.
Understanding patterns, dynamics, and drivers of land use is crucial for improving our ability to cope with sustainability challenges. The human appropriation of net primary production (HANPP) framework provides a set of integrated socio-ecological indicators that quantify how land use alters energy flows in ecosystems via land conversions and biomass harvest. Thus, HANPP enables researchers to systematically and consistently assess the outcome of changes in land cover and land-use intensity across spatio-temporal scales. Yet, fine-scale HANPP assessments are so far missing, an information important to address site-specific ecological implications of land use. Here, we provide such an assessment for Europe at a 1-km scale for the years 1990, 2000, and 2006. The assessment was based on a consistent land-use/biomass flow dataset derived from statistical data, remote sensing maps, and a dynamic global vegetation model. We find that HANPP in Europe amounted to ~43 % of potential productivity, well above the global average of ~25 %, with little variation in the European average since 1990. HANPP was highest in Central Europe and lower in Northern and Southern Europe. At the regional level, distinct changes in land-use intensity were observed, most importantly the decline of cropland areas and yields following the breakdown of socialism in Eastern Europe and the subsequent recovery after 2000, or strong dynamics related to storm events that resulted in massive salvage loggings. In sum, however, these local dynamics cancelled each other out at the aggregate level. We conclude that this finding warrants further research into aspects of the scale-dependency of dynamics and stability of land use.  相似文献   
23.
The European livestock sector has changed rapidly in the recent past and further changes are expected in the near future due to reforms in the European Common Agricultural Policy (CAP), increasing environmental concerns and changing consumer awareness. We developed a multi-scale modeling approach for exploring spatial and temporal dynamics of livestock distribution by accounting for drivers at different spatial scales. Such approach can provide a basis for environmental impact assessments of livestock farming at broad spatial scales. Assessment of change in both quantity and location was made for six livestock types. Four contrasting scenarios were applied ranging from globalization to regionalization, as well as from low regulation levels and dominance of market forces towards a higher degree of governmental regulation. National level livestock numbers as calculated by a macro-economic model were spatially distributed at the landscape scale according to the scenario assumptions considering biophysical, socio-economic, and political forces. Results indicate for most of the old European Union (EU) member countries a decrease in livestock numbers. In the new EU member countries sheep, goats and pigs are expected to decline while beef cattle and poultry are expected to grow. Livestock densities are expected to increase both within and outside current livestock hotspot regions in absence of environmental legislations. Environmental pressure as result of high livestock densities may, however, also remain in regulated scenarios where environmental policies are implemented and income support remains stable over time due to path dependencies in the livestock sector. But contrary to the non-regulated scenario it is less likely that new areas with high risk of negative environmental impacts due to livestock farming will develop.  相似文献   
24.
Rapid deforestation has occurred in northern Thailand over the last few decades and it is expected to continue. The government has implemented conservation policies aimed at maintaining forest cover of 50% or more and promoting agribusiness, forestry, and tourism development in the region. The goal of this paper was to analyze the likely effects of various directions of development on the region. Specific objectives were (1) to forecast land-use change and land-use patterns across the region based on three scenarios, (2) to analyze the consequences for biodiversity, and (3) to identify areas most susceptible to future deforestation and high biodiversity loss. The study combined a dynamic land-use change model (Dyna-CLUE) with a model for biodiversity assessment (GLOBIO3). The Dyna-CLUE model was used to determine the spatial patterns of land-use change for the three scenarios. The methodology developed for the Global Biodiversity Assessment Model framework (GLOBIO 3) was used to estimate biodiversity intactness expressed as the remaining relative mean species abundance (MSA) of the original species relative to their abundance in the primary vegetation. The results revealed that forest cover in 2050 would mainly persist in the west and upper north of the region, which is rugged and not easily accessible. In contrast, the highest deforestation was expected to occur in the lower north. MSA values decreased from 0.52 in 2002 to 0.45, 0.46, and 0.48, respectively, for the three scenarios in 2050. In addition, the estimated area with a high threat to biodiversity (an MSA decrease >0.5) derived from the simulated land-use maps in 2050 was approximately 2.8% of the region for the trend scenario. In contrast, the high-threat areas covered 1.6 and 0.3% of the region for the integrated-management and conservation-oriented scenarios, respectively. Based on the model outcomes, conservation measures were recommended to minimize the impacts of deforestation on biodiversity. The model results indicated that only establishing a fixed percentage of forest was not efficient in conserving biodiversity. Measures aimed at the conservation of locations with high biodiversity values, limited fragmentation, and careful consideration of road expansion in pristine forest areas may be more efficient to achieve biodiversity conservation.  相似文献   
25.
This paper presents an assessment of the potential impact of the EUs biofuel directive on European land use and biodiversity. In a spatially explicit analysis, it is determined which ecologically valuable land use types are likely to be directly replaced by biofuel crops. In addition, it is determined which land use types may be indirectly replaced by biofuel crops through competition over land between biofuel and food crops. Four scenarios of land use change are analyzed for the period 2000–2030 while for each scenario two policy variants are analyzed respectively with and without implementation of the biofuel directive. The results indicate that the area of semi natural vegetation, forest and High Nature Value farmland directly replaced by biofuel crops is small in all scenarios and differs little between policy variants. The direct effects of the directive on European land use and biodiversity therefore are relatively minor. The indirect effects of the directive on European land use and biodiversity are much larger than its direct effects. The area semi natural vegetation is found to be 3–8% smaller in policy variants with the directive as compared to policy variants without the directive. In contrast, little difference is found between the policy variants with respect to the forest area. The results of this study show that the expected indirect effects of the directive on biodiversity are much greater than its direct effects. This suggests that indirect effects need to be taken explicitly into account in assessing the environmental effects of biofuel crop cultivation and designing sustainable pathways for implementing biofuel policies.  相似文献   
26.
This experiment compares the short and long time element accumulation behaviour of transplants of Flavoparmelia caperata lichen thalli and total deposition in an atmospheric polluted area. It was found that lichens exposed for a short time behaved differently from lichens in cumulative exposition suggesting the presence of acclimatization behaviour. The lichen transplant elemental content does not unequivocally represent the average or cumulative environmental availability of the exposure period. Reflection characteristics depend on the element and the lichen physiological conditions. Good correlations between lichen elemental contents and total deposition were obtained when a physiological lichen parameter was introduced in a mathematical model, suggesting that metabolically mediated accumulation is important.  相似文献   
27.
Effect of land cover data on nitrous oxide inventory in fen meadows   总被引:1,自引:0,他引:1  
Landscape representations based on land cover databases differ significantly from the real landscape. Using a land cover database with high uncertainty as input for emission inventory analyses can cause propagation of systematic and random errors. The objective of this study was to analyze how different land cover representations introduce systematic errors into the results of regional N2O emission inventories. Surface areas of grassland, ditches, and ditch banks were estimated for two polders in the Dutch fen meadow landscape using five land cover representations: four commonly used databases and a detailed field map, which most closely resembles the real landscape. These estimated surface areas were scaled up to the Dutch western fen meadow landscape. Based on the estimated surface areas agricultural N2O emissions were estimated using different inventory techniques. All four common databases overestimated the grassland area when compared to the field map. This caused a considerable overestimation of agricultural N2O emissions, ranging from 9% for more detailed databases to 11% for the coarsest database. The effect of poor land cover representation was larger for an inventory method based on a process model than for inventory methods based on simple emission factors. Although the effect of errors in land cover representations may be small compared to the effect of uncertainties in emission factors, these effects are systematic (i.e., cause bias) and do not cancel out by spatial upscaling. Moreover, bias in land cover representations can be quantified or reduced by careful selection of the land cover database.  相似文献   
28.
29.
Archetypical patterns and trajectories of land systems in Europe   总被引:1,自引:0,他引:1  
Regional Environmental Change - Assessments of land-system change have dominantly focused on conversions among broad land-use categories, whereas intensity changes within these categories have...  相似文献   
30.
In Cyprus all couples carrying α0-thalassaemia mutations are detected in the course of the thalassaemia carrier screening program and prenatal diagnosis is offered to all of them. Prenatal diagnosis for α-thalassaemia is routinely done by two independent molecular methods. With the first method, the mutations of the parents are directly determined by gap-PCR and then the chorionic villus sample (CVS) is examined for the presence of these mutations. With the other method, a (CA)n repeat polymorphic site located between the ψα1- and α2-globin genes is used for determining the presence or absence of the normal and mutant alleles. In the period from 1995 to 1999, molecular analysis of 46 couples in which haematological data were consistent with deletion of two α-globin genes in both partners indicated that only 13 of them were actually at risk for haemoglobin (Hb) Bart's hydrops fetalis and prenatal diagnosis was provided in 16 pregnancies. The molecular diagnosis was possible in all cases with the use of both gap-PCR and (CA)n repeat polymorphisms analysis. No misdiagnosed cases for α-thalassaemia have been reported to date. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   
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