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81.
Fragmentation of Landscape as a Cause for Genetic Subdivision in Bank Voles   总被引:11,自引:0,他引:11  
Abstract: We studied the barrier effects of various roadways on the genetic subdivision of bank vole (Clethrionomys glareolus) populations. Allele frequencies, genetic variability, and genetic distances of natural populations were calculated based on polymorphism of seven microsatellite markers. We compared bank vole populations in control areas without such barriers with animals from both sides of a country road, a railway, and a highway. Using F and R statistics, we demonstrated significant population subdivision in bank vole populations separated by the highway, but not in populations on either side of the other roadways or in the control area. Correlations between geographic and genetic distances were revealed by an extended method based on a Mantel analysis. This allowed us to measure genetic barrier effects and express them as additional geographic distances. For instance, statistically significant differences in allele frequencies in all seven loci examined existed among populations in southern Germany and Switzerland, which are separated by the Rhine River and Lake Constance. The real geographic distance between bank vole populations in Konstanz and those in Lengwil, Switzerland, was 6 km. According to this analysis the genetic barrier effect of the Rhine could be defined as an additional distance of 7.7 km. This study shows for the first time that not only old geographic barriers but also more recent fragmentation of landscape by, for example, highways has an important effect on gene flow and the genetic substructuring of populations, which should be considered in future environmental impact assessments.  相似文献   
82.
83.
Starting from an ecological perspective of urban-industrial areas, environmental accounting is used to analyse and to evaluate which environmental impacts are the result of communal activities (e.g. the results of different kinds of water supply systems). Therefore, the anthropogenic fluxes, the changing quality of areas as well as the processes between the environmental fields are taken into account. The approach is based on methodical elements of te Life Cycle Analysis and the Environmental Impact Assessment. Looking at the ‘urban systems’ within the communal activities, ‘ecological modelling’ gives us a new and fuller picture of the spatial and temporal character of urban metabolism. The approach supports the perception of cumulative effects and the postponement of environmental problems and opens new horizons for process-oriented environmental planning within the community. Greater efficiency and a decrease in costs can be arrived at by leaving ‘end of the pipe’ strategies; opportunities for a better planning process and measures for different individuals and organisations can be drawn up. A data base which acts as a ‘support system’ implements the computer-aided approach to environmental accounting.  相似文献   
84.
85.
Drei neue Nickelenzyme aus anaeroben Bakterien   总被引:2,自引:0,他引:2  
Until recently nickel was not considered to be an element of biological importance. Nutritional studies have shown, however, that many eucaryotic and procaryotic organisms are dependent on the transition metal for growth. Four enzymes are presently known to contain nickel: urease from plants and from bacteria; methyl CoM reductase from methanogenic bacteria; all “uptake” hydrogenases investigated so far; and carbon monoxide dehydrogenase from anaerobic bacteria. The prosthetic group of the methyl CoM reductase has been identified as a nickel tetrapyrrole, the structure of which has been elucidated.  相似文献   
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Three state of the art traffic–emission–dispersion models dealing with particulate matter have been tested and validated over the Bologna metropolitan area with 2001 data and a future scenario has been developed in order to estimate expected PM concentrations in 2010. The modelling system is composed by a traffic model (VISUM) evaluating vehicle fluxes as a function of mobility demand and road network in the area, an emission model (Trefic) estimating pollutants emitted in atmosphere as a function of vehicle fluxes amount and composition and of environmental conditions and a dispersion model (ADMS) evaluating PM concentrations on the area, given the meteorological variables. The three models compose a cascade sequence and results of the previous one feed the next one. PM concentrations computed by the model suite for the town of Bologna, in northern Italy, for the reference period (January 2001) have been compared with air quality stations measurements suggesting the modelling system being especially suitable for evaluating traffic induced PM. Qualitative and quantitative changes in the circulating vehicle fleet have been supposed in order to obtain a realistic scenario for year 2010. Forecasted concentrations have been then compared with limits fixed by current EU legislation for particulate matter.  相似文献   
88.
In the frame of an active monitoring study at the Serra do Mar near the industrial pool of Cubatão, Brazil,Hemerocallis was tested for its suitability as bioindicator of airborne fluoride pollution. In a screening experiment with various cultivars comparison of susceptibility, correlation of visible injury and foliar fluoride concentration as well as comparison with exposure ofGladiolus gave best results for theHemerocallis cultivar ‘Red Moon’. When exposed simultaneously foliar fluoride accumulation ofHemerocallis showed a highly significant linear correlation with fluoride content ofLolium multiflorum, the ‘standardized grass culture’ andGladiolus, well-known bioindicator species for fluoride impact. With respect to the extent of foliar injuryHemerocallis was less sensitive thanGladiolus, in terms of accumulation capacity it ranged betweenLolium andGladiolus. In general, the results of the biomonitoring study proved that the Atlantic Forest vegetation in a valley downwind from the Cubatão fertilizer industries is still suffering from severe fluoride pollution.  相似文献   
89.
Ecological Footprint Analysis (EFA) is an environmental accounting system, in physical unit, able to quantify the total amount of ecosystem resources required by a region or by a production process. This methodology is both scientifically robust and widely diffused for territorial and productive analysis. The application of EFA to agricultural systems are still uncommon and examples in the fruit sector rare.In this work a detailed application of EFA to an experimental trial in a commercial nectarine orchard in Piedmont (Italy) is presented. The field trial is focused on the evaluation of agronomical benefit of various kinds of swine manure for fertilizing orchards. Four productive systems were established from 2008: liquid slurry (LS), covered slurry (CS), solid fraction (SF), mineral nutrition (MN). All the environmental impacts of the four systems were quantified both directly on field and with extrapolations from farmer knowledge. As previous studies suggested, we considered not only the one-year field operations, but also the whole lifetime of the orchard. The environmental costs of each system are presented and related to each other on the basis of their relative footprint value.Results highlight almost the same ecological footprint for the three manure fertilized systems (LS, CS and SF) with average of 0.96 gha t−1) and the highest ecological footprint can be found in the MN system (1.14 gha t−1). Interesting remarks can be done comparing the contributions to the ecological footprint of the field operations related to fertilization in the four systems. In the manure fertilized systems the fertilizer contribution goes from 0.9% to 1.2% of the total ecological footprint; but in the MN system the fertilizer contribution is 6.6% of the total ecological footprint. Results support the hypothesis that internal recycle and connections among different systems increasingly resulted in high system benefit and sustainability.  相似文献   
90.
Fatty acid analysis was used to study the trophic ecology of 10 demersal fish species in the South Georgia region. Principal component analysis grouped the species into three general clusters, revealing resource partitioning between species. Two groups were characterised by large proportions of either monounsaturated or polyunsaturated fatty acids, separating species according to their predominant feeding habitat. The third group showed fatty acid signatures overlapping with either or both of the previous two groups, suggesting a more opportunistic feeding behaviour for these species. Intraspecific comparisons furthermore revealed dietary variability with size, year and geographical location in several species. Mackerel icefish (Champsocephalus gunnari) in particular showed inter-annual differences in muscle lipid concentrations closely linked to prey availability with low lipid contents found in years of low krill (Euphausia superba) abundance. Despite the intraspecific differences the majority of species could be easily distinguished from each other, which indicates the utility of this method in the dietary analysis of higher predators.  相似文献   
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