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Summary Prespa National Park is situated at the northwestern corner of Greece bordering Yugoslavia and Albania and covers 25,690 ha of which 8,114 ha are lake. The remaining area is forest, rangeland and arable land in the vicinity of twelve villages. The objectives of the park authority are to preserve the wetland with its special fauna of rare bird species, its flora, the geomorphological formations of the lake and the natural environment. The nucleus of the park is comprised by Lake Mikri Prespa and the surrounding wetland. It is in this wetland that an exceptional assemblage of rare and endangered species breed. However, the park is recently undergoing rapid development of its agroecosystems in terms both of higher subsidiary energy inputs, notably irrigation, and of acreage, i.e. of substituting some of the wetland for cropland. The objective of this study was to assess the potential environmental hazards from practicing agriculture in the park and to propose measures of abatement. Assessment was based on field surveys, administration documents and interviews. Cropland is not intensively used at present. Two thirds is covered by winter cereals and the remaining by other row crops (beans and potatoes). There are no deciduous orchards. Practices are carried out without regard for environmental conservation. Farmers' attitudes towards the wildlife range from indifference to hostility because they attribute the lag in their economic development to the past restrictions imposed by the National Park Administration. The main environmental consequences from the ongoing agricultural development in Prespa are assessed to be a dramatic increase of nonpoint agricultural pollution of the lake, with phosphorus and pesticides as the primary pollutants. Moreover, accidents in the use of pesticides may lead to immediate deterioration of the nucleus wildlife habitats. Since irrigated agroecosystems are there to stay and grow in subsidiary energy, measures are needed to prevent harmful consequences. Such measures are the alleviation of the land ownership problem, adoption of cultural practices to limit soil erosion, rational use of chemical fertilizers and pesticides and education of farmers. It is concluded that the internationally invaluable natural ecosystems of the park are definitely threatened by the development of the irrigated agroecosystems. The measures proposed will limit this threat and at the same time will help to perpetuate the productivity of the agroecosystems themselves.Mrs. M. D. Pyrovetsi is a lecturer in the Department of Biology and Professor P. A. Gerakis is Head of the Department of Agriculture; both are within the Aristotle University of Thessaloniki, Greece.  相似文献   
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Agricultural activities in the agroecosystems neighbouring wetland ecosystems are considered a major threat to the latter in all Mediterranean countries. This threat was investigated in thirteen internationally important wetland sites (Ramsar sites) of Greece. The effects of ten activities commonly practised in the surrounding agroecosystems on four wetland functions and four wetland values were evaluated. The functions were: nutrient removal/transformation, sediment/toxicant retention, flood flow alteration, and ground water discharge. The values were: biodiversity, fishing, hunting, and recreation. It was found that the Adamus' Wetland Evaluation Technique is useful even in the little studied Ramsar sites of Greece. Irrigation is the most decisive activity negatively influencing all functions and values, followed by cropland expansion and overgrazing. Coastal lagoons are the least affected by agricultural activities. It is concluded that in Greece the sustainability of wetland ecosystems depends to a significant degree on the sustainability of agroecosystems. The reverse is also true because wetlands provide irrigation water, crop pollinators, some frost protection, and predators of crop pests. The two ecosystem types are functionally closely linked. Therefore, a national policy for the sustainable development of the soil, water, and genetic resources of Greece must integratively consider both these ecosystems types.  相似文献   
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In the present study, an investigation of the mineralogy and morphology, the heavy metal content and the health risk of urban road dusts from the second largest city of Greece was conducted. For this reason road dust samples from selected sites within the city core area were collected. No differences were observed in the mineralogy of road dusts coming from different sampling sites, and they were mainly consisted of quartz and calcite, while an elevated amorphous content was detected. Morphologically road dusts presented Ca-rich, Fe-rich and silicates particles with various shapes and sizes. The mean concentrations of Cd, Cr, Cu, Mn, Ni, Pb and Zn in road dust were 1.76, 104.9, 662.3, 336.4, 89.43, 209 and 452.8 μg g?1, respectively. A series of spatial distribution patterns revealed that the hotspot areas were tended to associate with major road junctions and regions with high traffic. Combination of pollution indexes and statistical analyses (correlation analysis, cluster analysis and principal component analysis) revealed that road dusts have a severe influence by anthropogenic activities. In attempt to identify the source of metals through geostatistical and multivariate statistical analyses, it was concluded as follows: Cr, Cu, Fe and Zn mainly originated from tire/break wear and vehicle abrasions, while Cd, Mn and Pb were mainly related to fuel/oil leakage from automobiles along with oil lubricants and vehicle abrasion. Hazard quotient values for children based on total metal concentrations for the road dust ingestion route were lower than safe level (=1). However, the fact that the Hazard Index value for Pb (0.459) which is a particularly toxic metal, was close to safe level, renders essential further investigation in order to provide more reliable characterizations of potential health risks.  相似文献   
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