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991.
Ecological impacts of arable intensification in Europe 总被引:33,自引:0,他引:33
Stoate C Boatman ND Borralho RJ Carvalho CR de Snoo GR Eden P 《Journal of environmental management》2001,63(4):337-365
Although arable landscapes have a long history, environmental problems have accelerated in recent decades. The effects of these changes are usually externalized, being greater for society as a whole than for the farms on which they operate, and incentives to correct them are therefore largely lacking. Arable landscapes are valued by society beyond the farming community, but increased mechanization and farm size, simplification of crop rotations, and loss of non-crop features, have led to a reduction in landscape diversity. Low intensity arable systems have evolved a characteristic and diverse fauna and flora, but development of high input, simplified arable systems has been associated with a decline in biodiversity. Arable intensification has resulted in loss of non-crop habitats and simplification of plant and animal communities within crops, with consequent disruption to food chains and declines in many farmland species. Abandonment of arable management has also led to the replacement of such wildlife with more common and widespread species. Soils have deteriorated as a result of erosion, compaction, loss of organic matter and contamination with pesticides, and in some areas, heavy metals. Impacts on water are closely related to those on soils as nutrient and pesticide pollution of water results from surface runoff and subsurface flow, often associated with soil particles, which themselves have economic and ecological impacts. Nitrates and some pesticides also enter groundwater following leaching from arable land. Greatest impacts are associated with simplified, high input arable systems. Intensification of arable farming has been associated with pollution of air by pesticides, NO2 and CO2, while the loss of soil organic matter has reduced the system's capacity for carbon sequestration. International trade contributes to global climate change through long distance transport of arable inputs and products. The EU Rural Development Regulation (1257/99) provides an opportunity to implement measures for alleviating ecological impacts of arable management through a combination of cross-compliance and agri-environment schemes. To alleviate the problems described in this paper, such measures should take account of opportunities for public/private partnerships and should integrate social, cultural, economic and ecological objectives for multifunctional land use. 相似文献
992.
We use spatial data representing transportation networks, elevation, stand height, and recreation use to construct and compare
models of recreation use patterns and visibility in a forest. The recreation use pattern model depicts use frequencies along
travel corridors. The visibility model quantifies visibility for all forest areas. We find that the models provide different
but complementary types of information. Forest managers who are involved in scheduling harvest operations and want to address
the visual concerns of forest visitors may benefit most from the visibility model. Managers who wish to know more about travel
patterns or to reroute forest visitors affected by operations may benefit from the use pattern model. A combination of the
two models has the highest potential for providing planning assistance in multiple-use forests. Both models may be able to
enhance visual resource management (VRM) systems already in use by providing spatially explicit recreation use and visibility
data. 相似文献
993.
The literature guides environmental planning and, specifically, how to use ecological rehabilitation projects to achieve long-term
planning goals and landscape-scale environmental sustainability. There is, however, a perceived gap between principles in
the literature and the use of them by practitioners involved in smaller-scale ecological rehabilitation projects. Using interviews
with practitioners involved in 11 projects within the Regional Municipality of Waterloo, Ontario, Canada, we tested whether
practitioners used five principles for effective planning and implementation of ecological rehabilitation that we derived
from the literature. These five principles were: establishing political and ecological context, using ecologically appropriate
objectives and practices, using comparative multidisciplinary and cross-scale approaches, using adaptive planning and implementation,
and establishing good communication within and external to projects. Few projects followed all five principles, and practitioners
indicated that they used three more project-specific principles: obtaining political/social support, promoting projects and
changing attitudes about projects, and securing sufficient and persistent funding to maintain a project's life. While the
literature emphasizes that ecological rehabilitation is only effective if projects are coordinated on a watershed basis, most
practitioners focused solely on the goals of their specific project. The gap between literature and practice may arise because
most practitioners are new to the field of ecological rehabilitation and still are focused on the methods involved. Time pressures
force practitioners to obviate the literature and get projects started quickly, lest support evaporate. Complicating these
difficulties is decreased support from federal and provincial governments for large-scale environmental planning. It is unclear
whether ecological rehabilitation projects in Waterloo Region (at least) will ever become effective at promoting landscape-scale
ecological goals or remain smaller-scale stop-gaps. 相似文献
994.
Büchert A Cederberg T Dyke P Fiedler H Fürst P Hanberg A Hosseinpour J Hutzinger O Kuenen JG Malisch R Needham LL Olie K Päpke O Rivera Aranda J Thanner G Umlauf G Vartiainen T van Holst C 《Environmental science and pollution research international》2001,8(2):84-88
Dioxin and PCB monitoring programs for food and feeding stuff in most countries of the world, including many European Countries are currently inadequate. Better control of food production lines and food processing procedures is needed to minimize entry of dioxin to the food chain and will help to avoid dioxin contamination accidents. This would also improve the ability to trace back a possible contamination to its source. European guidelines for monitoring programs should be established to ensure comparable and meaningful results. These guidelines should define the minimum requirements for the design of monitoring programs, analytical methods, and quality assurance. Though data from Northern Europe shows that the general population exposure to dioxin and PCB has decreased during the last ten years these compounds continue to be a risk of accidental contamination of the food chain. The most prominent recent example is the Belgian dioxin contamination of feeding stuff in 1999. The Belgian dioxin contamination was not detected due to dioxin monitoring programs but by their direct biological effects seen in animals. Four other cases of dioxin contamination have been detected in Europe since 1997 due to local monitoring programs. One of them (citrus pulp pellets 1998) was in a much larger scale than the Belgian dioxin contamination. The general population's exposure to dioxins and PCBs is still in the same range (1-4 pg WHO-TEQ/kg body weight and day) as the recently revised WHO tolerable daily intake (TDI). There is concern that short-term high level exposure to dioxins, furans, and PCB may cause biological effects on the human fetal development and further research is required. Further actions to control sources building on considerable advances already made in many countries may need to be supplemented by measures to prevent direct contamination of feeding stuff or food to reduce general population exposure further. 相似文献
995.
Annually since 1989, biannually since 1994, the environs (approximately 50 km2) of the Swiss nuclear facilities are surveyed (by helicopters) flying the same survey lines. The equipment and the data processing software used for these surveys were built and developed at the Institute of Geophysics, ETH Zurich. For mapping of man-made radiation at or around nuclear facility sites a pixel representation and the MMGC (man-made gross count) ratio is used. So far no artificial radioactivity that could not be explained by the Chernobyl event (1986) or by earlier nuclear weapon tests was detected outside the fenced sites of the nuclear facilities. 相似文献
996.
We have studied a phosphate rock plant which produces dicalcium phosphate (DCP), used as a source of calcium and phosphorus for domestic animals. A by-product in the manufacturing process is calcium chloride which is used in the oil industry, the food industry and as road-salt. The objectives of our study were to describe the fluxes of radionuclides from the 238U decay series and to estimate the radiation doses to workers at the plant. The radionuclides in the phosphate rock were found to be in secular radioactive equilibrium with 238U, with an average activity concentration of 837 Bq kg-1. Separation and concentration processes were observed at different stages in the plant. Most of the 226Ra was found in the calcium chloride, while the major part of the 238U, about 950 Bq kg-1, was found in the dicalcium phosphate. The annual occupational effective dose to the workers was found to be below the 1 mSv limit recommended by ICRP (1991a) for the public. This study has shown a good example of an important non-nuclear industry with a high input of natural radionuclides with several conceivable pathways to man. 相似文献
997.
998.
Effect of pH on the sorption of uranium in soils 总被引:5,自引:0,他引:5
This work was undertaken to study the influence of soil type and chemical composition on uranium sorption ratios (SR in 1 kg-1) in order to reduce the uncertainty associated with this parameter in risk assessment models. Thirteen soil samples were collected from three different locations in France under different geological conditions. Clay content varied from 7.0 to 50.0%, pH ranged from 5.5 to 8.8 and organic matter content from 1.0 to 4.6%. Soils were incubated at room temperature in polyethylene packets for 28 days in the presence of 1 mg U kg-1 soil. Sorption ratio values varied from 0.9 to 3198 for all soils with no significant effect of soil texture or of organic matter. However, soil pH was highly linearly correlated with (log SR) as a probable consequence of the existence of different uranium complexes as a function of soil pH. The sorption behaviour differences between UO2(2+) and UO2(2+)-carbonate complexes are so great that any other effect of soil properties on U sorption is hidden. Thus, soil pH should be the focus variable for reduction of the uncertainty associated with the soil Kd value used in environmental risk assessments, even for reducing the uncertainty in site-specific Kd values. 相似文献
999.
Rizzio E Bergamaschi L Valcuvia MG Profumo A Gallorini M 《Environment international》2001,26(7-8):543-549
Lichens as biomonitors and neutron activation analysis as analytical technique have been employed to study the distribution of trace elements (TE) in a mountain region of north Italy (Biella) characterized by settlements of wool industry. Samples of airborne particulate matter collected onto filters, different species of lichens and samples of soils have been analyzed for the calculation of the enrichment factors (EFs) of more than 25 TE. By comparison of the corresponding EFs, the most suitable lichen species (Parmelia caperata) was selected as specific TE biomonitor of the area investigated. Samples of this lichen were collected and analyzed for the evaluation of the TE distribution in four different locations. The results obtained from the analysis of the lichens gave information about the predominant direction of pollutants transportation, while those related to the concentrations found in the air particulate allowed the evaluation of the degree of the local TE atmospheric pollution. 相似文献
1000.
The formation and transformation of live and dead phytomass in agrocenoses with a complex horizontal structure are described. These processes are demonstrated to be specific and to be determined by differences in the horizontal structure. Only agrocenoses of a mosaic structure (with square parcels) have optimal conditions for these processes. 相似文献