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1.
Concentrations of Cd, Cu, Cr, Ni, Zn, Fe and metallothioneins (MTs) were measured in the gonads of Paracentrotus lividus from Amvrakikos gulf (Ionian Sea, Greece). Three natural populations were selected; two of them, growing inside the gulf (Agios Thomas and Koronisia), presented higher density and smaller body size than the population living in a coastal area just outside the gulf (Mytikas). Metal and MT levels were not elevated, with the exception of Zn, showing high values related to the reproduction stage of the sea urchins. Significant geographical variations were recorded in the concentrations of Cu, Zn, Cd, Cr and MTs. The highest mean and maximum values of Cu, Zn and MTs were recorded in Agios Thomas while Cd and Cr were higher in Mytikas population. Copper, Zn, Fe and MT concentrations were negatively correlated to the sea urchin body size, while a positive concentration-size relationship was observed for Cd. Although all studied populations grow in a low metal level marine environment, urchins with smaller body size living in a food limited marine environment showed higher gonadosomatic index, metal concentrations and MT levels in their gonads (Agios Thomas and Koronisia) than larger specimens growing in a food unlimited area (Mytikas).  相似文献   

2.
平顶山地区景观格局动态特征及驱动力分析   总被引:1,自引:0,他引:1  
以平顶山地区为研究对象,利用平顶山地区1992年Landsat-TM影像和2006年中巴资源卫星遥感影像,运用景观生态学原理,借助遥感和GIS技术,选取景观多样性、景观优势度、景观均匀度、景观破碎度等指标指数进行分析,揭示平顶山地区近14 a来城市景观格局演变及其驱动力。研究结果表明:交通用地、工矿及居民点和耕地用地显著增加,林地、水域显著减少;除工矿及居民点外,该地区各类型斑块数量均有增加,其中林地增加最为显著;交通用地、工矿及居民点的破碎度降低,水域、林地、耕地的景观类型破碎度增高;耕地的分维数、形状指数呈下降趋势,而林地的分维数和形状指数呈上升趋势;平顶山地区景观多样性和均匀度都呈下降趋势,而优势度和破碎度增加;景观格局变化受人为因素影响较大,人口增加、经济发展、城镇化和工业发展是平顶山地区景观格局演变的主要驱动力。  相似文献   

3.
Available water quality indices have some limitations such as incorporating a limited number of water quality variables and providing deterministic outputs. This paper presents a hybrid probabilistic water quality index by utilizing fuzzy inference systems (FIS), Bayesian networks (BNs), and probabilistic neural networks (PNNs). The outputs of two traditional water quality indices, namely the indices proposed by the National Sanitation Foundation and the Canadian Council of Ministers of the Environment, are selected as inputs of the FIS. The FIS is trained based on the opinions of several water quality experts. Then the trained FIS is used in a Monte Carlo analysis to provide the required input-output data for training both the BN and PNN. The trained BN and PNN can be used for probabilistic water quality assessment using water quality monitoring data. The efficiency and applicability of the proposed methodology is evaluated using water quality data obtained from water quality monitoring system of the Jajrood River in Iran.  相似文献   

4.
5.
The impact of climate change on enteric infection has been a concern in recent years. This study aims to project disability burdens of bacillary dysentery (BD) associated with increasing temperature in different climatic zones in China. Years Lost due to Disabilities (YLDs) were used as the measure of burden of bacillary dysentery in this study. A temperate city in northern China and a subtropical city in southern China were selected as the study areas. The quantitative relationship between temperature and the number of cases in each city was base on the regression models developed in our previous studies. YLDs for bacillary dysentery in 2000 were used as the baseline data. Projection of YLDs for bacillary dysentery in 2020 and 2050 under future temperature scenarios were conducted. Demographic changes over the next 20 to 50 years in study cities were considered in the projections. Under the temperature scenarios alone, the YLDs for bacillary dysentery may increase by up to 80% by 2020 and 174% by 2050 in the temperate city and up to 75% increase in the YLDs by 2020 and a 147% increase by 2050 in the tropical city. Considering potential changes in both temperature and population size and structure, if other factors remain constant, compared with the YLDs observed in 2000, the YLDs for bacillary dysentery may double by 2020 and triple by 2050 in both the temperate and subtropical cities in China. The temperature-related health burden of enteric infection in China may greatly increase in the future if there is no effective intervention. Relevant public health strategies should be developed at an earlier stage to prevent and reduce the impact of infectious disease associated with climate change.  相似文献   

6.
In this research, we study on the distribution of several elements in bed sediments of Anzali wetland. Anzali, one of the most important international wetlands, is located on the southern coast of the Caspian Sea in Iran. This wetland receives discharges of domestic, agricultural, and industrial wastewater, which affect the distribution of elements. Our contribution in this study is threefold. First, we measured the total concentration of metals as well as their chemical partitioning and bioavailability in the sediments. Second, we calculated anthropogenic portions of metals in the sediment of this area. The results reveal anthropogenic portion of metals as Mo > Mn > Cd > As > Zn > Hg > Co > Sn > Cu > V > Ag > Ni > Pb > Fe > Cr > Al, respectively. We evaluated the intensity of pollution by using an enrichment factor, the geo-accumulation index and the pollution index. All these indices do not take into consideration the bioavailability of the elements. As our third and most important contribution, we introduced a new formula that takes into account the bioavailability of different elements. In comparison with aforementioned pollution indices, our newly introduced pollution index has a higher Pearson correlation with anthropogenic portion of metals. This high-correlation coefficient shows that our proposed pollution index is an effective indicator for determining the level of pollution, while other indices preserve their own merits.  相似文献   

7.
This is the second part of the study on sensitivity analysis of the technique for order preference by similarity to ideal solution (TOPSIS) method in water quality assessment. In the present study, the sensitivity of the TOPSIS method to the index input data was investigated. The sensitivity was first theoretically analyzed under two major assumptions. One assumption was that one index or more of the samples were perturbed with the same ratio while other indices kept unchanged. The other one was that all indices of a given sample were changed simultaneously with the same ratio, while the indices of other samples were unchanged. Furthermore, a case study under assumption 2 was also carried out in this paper. When the same indices of different water samples are changed simultaneously with the same variation ratio, the final water quality assessment results will not be influenced at all. When the input data of all indices of a given sample are perturbed with the same variation ratio, the assessment values of all samples will be influenced theoretically. However, the case study shows that only the perturbed sample is sensitive to the variation, and a simple linear equation representing the relation between the closeness coefficient (CC) values of the perturbed sample and variation ratios can be derived under the assumption 2. This linear equation can be used for determining the sample orders under various variation ratios.  相似文献   

8.
生物多样性是环境监测环境保护的重要内容之一,在众多的生物多样性指数中,包含分类学信息的指数具有明显的特点和优势。近20年来,在海洋、淡水、陆地等生境中开展了许多分类学多样性指数相关的应用研究。一些分类学多样性指数能够在一定程度上灵敏地反映出环境退化和污染,在环境监测能力和历史资料对比等方面优于传统多样性指数。在使用分类学差异性指数区分人类干扰和自然变化时结论不一,分类学多样性指数的应用受到一些因素的影响,例如生物类群选择、生境、水深、纬度等是产生分歧的因素。扩大研究范围,明确应用范围可有效发挥分类学差异性指数在环境保护和评价中的作用。  相似文献   

9.
The tourism sector in Europe faces important challenges which it must deal with to promote its future development. In this context, the European Commission considers that two key issues must be addressed. On the one hand, a better base of socio-economic knowledge about tourism and its relationship with the environment is needed, and, on the other hand, it is necessary to improve the image of European areas as quality sustainable tourism destinations. In this paper we present analytical tools that cover these needs. Specifically, we define a system of sustainable tourism indicators and we obtain a composite indicator incorporating weights quantified using a panel of experts. Employing the values of this global indicator as a basis, we define a Sustainable Tourism Country-Brand Ranking which assesses the perception of each country-brand depending on its degree of sustainability, and a system of sustainable tourism labels which reward the management carried out.  相似文献   

10.
This study examines defoliation and discoloration findings collected throughout the Italian Level I network between 1997 and 2000. Prior to this period no Quality Assurance procedures had been implemented, so that earlier findings cannot be considered reliable. The aim of the study is to compare differentindices used in reporting findings, in order to determine the full potential and limitations of each. In international surveys,findings are normally expressed in terms of individual trees presenting a defoliation level greater than 2 %; this criterion,however, has been challenged since it is not based on scientificevidence. By analysing the distribution of defoliation values(grouped in 5% classes) relating to the main species (Fagus sylvatica, Quercus pubescens, Quercus cerris, Picea abies), the study examines the behaviour of statistical indices such as the median, the mode and the mean. Instead of using the traditional 25% threshold to determine the part of the population with the highest defoliation values, a procedureis suggested whereby a different threshold can be determined foreach species. It is established based on the 90° percentile of cumulative defoliation values recorded over the four-year period. Each index used to report findings possessesits own information potential, and the findings may at times appear contradictory. The use of a combined defoliation and discoloration index (Ilce = Lacking Crown Equivalent Index) is also proposed, but the results obtained do not differin substance from the results relating to defoliation alone. Thefunctional limitations of this index are due mainly to the way the data are collected: for this reason suggestions are made onhow to improve the procedure in future surveys.  相似文献   

11.
The disruption of the endocrine systems of gastropod molluscs and consequential physiological changes (imposex and intersex) are used as biomarkers for environmental contamination by tributyltin compounds. The first international laboratory performance study on the determination of imposex and intersex in neogastropod molluscs, Nucella lapillus and Littorina littorea has been undertaken by the QUASIMEME (Quality Assurance of Information for Marine Environmental Monitoring in Europe) project. Samples of live gastropods were distributed and participants were asked to record shell height and sex, together with penis length and vas deferens sequence stage (VDS) in Nucella or the intersex stage (IS) and prostate length in Littorina. Calculations were made of vas deferens sequence index (VDSI) and the relative penis size index (RPSI) in Nucella and of intersex stage index (ISI) and the average female prostate length (FPrL) in Littorina. Thirteen (87%) of the 15 participating laboratories returned data. The remaining two laboratories asked to participate in later exercises. For Nucella, seven laboratories reported sex ratios significantly different from the reference laboratory data. Differences in penis length measurements between laboratories were largely random, although there were indications of systematic errors affecting the data from three laboratories. Seven laboratories reported satisfactory data (Z-score magnitude of Z < 2) for VDSI. The inclusion of a high proportion of sub-adults in the Nucella samples may have made separation of the sexes more difficult than in mature adults. The sub-adults will have had smaller pene than mature adults in the same population, and therefore any errors (random or systematic) in the measurement of penis length or observation of reproductive organs would have a potentially greater impact on the final reported values of the summary imposex indices. The Littorina sample did not show a high degree of intersex (ISI = 0.41). The laboratories could determine the sex of Littorina reliably and only one laboratory reported data significantly different from the reference laboratory. All except two laboratories reported satisfactory data for ISI.  相似文献   

12.
目前,环境资源问题已经对我国建设"和谐社会"构成了严重挑战,如何选取合适的评价指标体系和构建生态评价模型对生态系统进行准确的评价是困难的,也是十分必要的.从生态系统的平衡、波动、干扰及阈值等基本特点出发,构建了区域生态质量评价指标体系包括生产能力指数、服务功能的稳定度指数和人口压力指数三大指标.  相似文献   

13.
通过调研20世纪90年代以来国外主流水生态评价项目中采用的生境指标,统计了14个类型生境指标的使用频率,并针对不同的河流类型,筛选出物理形态特征、河岸带状况、生境组成、生境复杂性、人类干扰和水质状况等6个类型的11项评价指标,推荐作为长江流域河流生境评价指标.随后,利用层次分析法对国外水生生物评价指标进行了统计分析,并...  相似文献   

14.
以重庆市某工业园区表层土壤为研究对象,探讨了土壤重金属在不同季节的污染特征,利用污染指数法、健康风险模型和主成分/绝对主成分得分受体模型进行风险评价和源分析。结果表明:不同季节土壤样品间各重金属含量差异显著。35.5%的样品中汞含量超出土壤污染风险筛选值,其他元素未超标。与土壤背景值相比,各元素表现出不同程度的富集,汞超标约110~1300倍。内梅罗指数显示土壤整体和汞元素处于轻度污染及以下,其他元素为安全。潜在生态危害指数显示,土壤整体和汞属于极强污染,镉属于轻微~强污染,其他元素为轻微污染。土壤重金属总致癌风险为2.6×10-7~1.0×10-5,总非致癌风险熵均小于1,砷存在致癌风险,主要通过经口摄入暴露。秋季中,汞、六价铬、铅、镍、砷和铜来自工业源,镉主要来源于自然成因。春季中,镉和铅来自交通、冶金和燃煤等排放,镍、砷和铜源于冶炼和金属表面处理等排放,汞主要来自化工生产和燃料燃烧。交通运输、工业生产和燃料燃烧等污染的排放是土壤重金属的主要来源,今后应加强园区内汞、砷和镉的源头减排和治理。  相似文献   

15.
Abstact More and more lands worldwide are being cultivated for food production while forests are disappearing at an unprecedented rate. This paper aims to make a long-term forecast on land uses worldwide and provide the publics, researchers, and government officials with a clear profile for land uses in the future. Data of land uses since 1961 were used to fit historical trajectories and make the forecast. The results show that trajectories of land areas can be well fitted with univariate linear regressions. The forecasts of land uses during the coming 25 years were given in detail.Areas of agricultural land, arable land, and permanent pasture land worldwide would increase by 6.6%, 7.2%, and 6.3% respectively in the year 2030 as compared to the current areas. Permanent crops land area all over the world is forecasted to increase 0.64% by 2030. By the year 2030 the areas of forests and woodland, nonarable and nonpermanent land worldwide would decrease by 2.4% and 0.9% against the current areas. All other land area in the world would dramatically decline by 6.4% by the year 2030.Overall the land area related to agriculture would tend to decrease in developed countries, industrialized countries, Europe, and North and Central America. The agriculture related land area would considerably increase in developing countries, least developed countries, low-income countries, Asia, Africa, South America, etc.Developing countries hold larger total land area than developed countries. Dramatic and continuous growth in agricultural land area of developing countries would largely contribute to the expected growth of world agricultural land area in the coming years. Population explosion, food shortage and poverty in the world, especially in developing countries, together caused the excessive cultivation of land for agricultural uses in the past years. Increasing agricultural land area exacerbates the climate changes and degradation of environment. How to limit the growth of human population is a key problem for reducing agricultural land expansion. Development and use of high-yielding and high-quality crop and animal varieties, diversification of human food sources, and technical and financial assistance to developing countries from developed countries, should also be implemented and strengthened in the future in order to slow down or even reverse the increase trend of agricultural land area. Sustainable agriculture is the effective way to stabilize the agricultural land area without food shortage. Through various techniques and measures, sustainable agriculture may meet the food production goals with minimum environmental risk. Public awareness and interest in sustainable agriculture will help realize and ease the increasing stress from agricultural land expansion.  相似文献   

16.
Wildlife conservationists design monitoring programs to assess population dynamics, project future population states, and evaluate the impacts of management actions on populations. Because agency mandates and conservation laws call for monitoring data to elicit management responses, it is imperative to design programs that match the administrative scale for which management decisions are made. We describe a program to monitor population trends in American beaver (Castor canadensis) on the US Department of Agriculture, Black Hills National Forest (BHNF) in southwestern South Dakota and northeastern Wyoming, USA. Beaver have been designated as a management indicator species on the BHNF because of their association with riparian and aquatic habitats and its status as a keystone species. We designed our program to monitor the density of beaver food caches (abundance) within sampling units with beaver and the proportion of sampling units with beavers present at the scale of a national forest. We designated watersheds as sampling units in a stratified random sampling design that we developed based on habitat modeling results. Habitat modeling indicated that the most suitable beaver habitat was near perennial water, near aspen (Populus tremuloides) and willow (Salix spp.), and in low gradient streams at lower elevations. Results from the initial monitoring period in October 2007 allowed us to assess costs and logistical considerations, validate our habitat model, and conduct power analyses to assess whether our sampling design could detect the level of declines in beaver stated in the monitoring objectives. Beaver food caches were located in 20 of 52 sampled watersheds. Monitoring 20 to 25 watersheds with beaver should provide sufficient power to detect 15–40% declines in the beaver food cache index as well as a twofold decline in the odds of beaver being present in watersheds. Indices of abundance, such as the beaver food cache index, provide a practical measure of population status to conduct long-term monitoring across broad landscapes such as national forests.  相似文献   

17.
基于生态宜居和以人为本双重理念,选取区域绿度、区域热度、区域蓝度、区域亮度、区域透明度和区域起伏度等6个指标,利用主成分分析法构建基于遥感的区域人居环境指数(RHEI)。以福建省为例,分季度测算其RHEI,揭示区域人居环境的时空差异。结果表明:福建省RHEI随着季节变化逐渐降低,呈现东南低西北高、沿海岸线向内陆上升的空间分布格局。通过比较各指标的回归模型系数,发现区域蓝度对区域人居环境的影响最大,区域透明度的影响最小。由年度均值回归模型预测,未来每增加0.166单位的区域蓝度或减少0.278单位的区域热度,能提升0.1单位的人居环境质量。  相似文献   

18.
Measuring hydrocarbons from aircraft represents one way to infer biogenic emissions at the surface. The focus of this paper is to show that complementary remote sensing information can be provided by optical measurements of a vegetation index, which is readily measured with high temporal coverage using reflectance data. We examine the similarities between the vegetation index and in situ measurements of the chemicals isoprene, methacrolein, and alpha-pinene to estimate whether the temporal behavior of the in situ measurements of these chemicals could be better understood by the addition of the vegetation index. Data were compared for flights conducted around Houston in August and September 2000. The three independent sets of chemical measurements examined correspond reasonably well with the vegetation index curves for the majority of flight days. While low values of the vegetation index always correspond to low values of the in situ chemical measurements, high values of the index correspond to both high and low values of the chemical measurements. In this sense it represents an upper limit when compared with in situ data (assuming the calibration constant is adequately chosen). This result suggests that while the vegetation index cannot represent a purely predictive quantity for the in situ measurements, it represents a complementary measurement that can be useful in understanding comparisons of various in situ observations, particularly when these observations occur with relatively low temporal frequency. In situ isoprene measurements and the vegetation index were also compared to an isoprene emission inventory to provide additional insight on broad issues relating to the use of vegetation indices in emission database development.  相似文献   

19.
Statistical methods and a Geographic Information System (GIS) were used to investigate potential indicators of ground water vulnerability to agricultural chemical contamination in a representative area of the Mississippi River alluvial aquifer. A total of 47 wells were sampled for analysis of nitrate, phosphorus, potassium, and 13 pesticides commonly-used in the area. Ten soil and hydrogeologic variables and five ground water vulnerability indices were examined to explain the variations of chemical concentrations. The results showed that no individual soil or hydrogeologic variables or their linear combinations could explain more than 25% of the variation of the chemical concentrations. A quadratic response surface model with the values of confining unit thickness, slope, soil permeability, depth to ground water, and recharge rate accounted for 62% of the variation of nitrate, 43% of P, and 83% of K, suggesting that the interactions among soil and hydrogeologic variables were significant. Observed trends of decreasing nitrate and P concentrations with increasing well depth and/or depth to ground water seemed to correlate with carbonate equilibrium in the aquifer and more reduced environment with depth. In view of uncertainties involved, it was recognized that the limitations associated with input data resolution used in GIS and the formulation of leaching indices limited their use for predicting ground water vulnerability. Misuse of pesticides could be another factor that would complicate the relationships between pesticide concentrations and the vulnerability indices.  相似文献   

20.
How to assess the potential habitat integrating landscape dynamics and population research, and how to reintroduce animals to potential habitats in environments highly human disturbed are still questions to be answered in conservation biology. According to behavioral research on Elaphurus davidians, we have developed a suitability index and a risk index to evaluate the potential habitats for the deer. With these indices, we conducted two transect assessments to evaluate the gradient change of the target region. Then, taking rivers as border lines, we tabulated the forest areas, high grassland area and total area and then compared the forest and high grassland area in each subregion. Furthermore, we computed the land use transfer matrix for the whole Yancheng coast during 1987-2000. We also computed human modified index (HMI) in six subregions. Lastly with a geographical information system support we obtained the spatial distribution of the indices and evaluation of the whole potential habitats from a neighborhood analysis. The transect assessment showed that the suitability of the coastal area was higher than that of the inland area for the deer, while the southern area was higher than the northern. Landscape metrics and HMI analysis showed that different landscape patterns and different anthropogenic disturbance existed within the region, and the increasing human disturbance was the key factor causing the pattern dynamics. The evaluation of potential habitats showed that there was an estimated carrying capacity of no more than 10,000 for David's deer reintroduction into the natural area. Also the reintroduction strategy was discussed. This integrated approach linked the population research and the landscape metrics, and the dataset with different scale; thus, it is an approach likely to be useful for the protection of other large animal in a landscape highly disturbed by humans.  相似文献   

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