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1.
As part of a harmonised assessment of urban soils (), we investigated the variability of metal content in soils from Aveiro (Portugal) and Glasgow (UK). Samples were collected from parks and other public open spaces in each city. Metal content (Al, Ca, Cr, Cu, Fe, Mn, Ni, Pb and Zn) and basic soil parameters (texture, CEC, pH, organic matter) were determined and data investigated using principal component analysis (PCA). The two cities differ in absolute levels of metal content reflecting industrial and historical development. Factors identified by PCA included anthropogenic (Cu, Pb, Zn), soil properties and geology, which explain variability when data were assessed based on metal content, soil properties and land use. This study highlights the contribution from geological background even in strongly urbanised environments.  相似文献   

2.
Until the last decade, protecting the environment was seen as a factor contributing to human well-being, and conservation of natural ecosystems was considered to be one of the most important factors of environmental protection. Numerous studies have dealt with the benefits of natural ecosystems and in recent years even more so with ecosystem services, as well as interactions of ecosystem services with each other and with the urban and peri-urban environment. This paper suggests an approach to the spatial unity of the Florina region using basic ecosystem services identified by land use. The aim was, first, to describe the spatial distribution of basic ecosystem services and their interactions and, second, to investigate whether they form important statistical correlations with the basic features of the prefecture. A 1 km × 1 km analysis of 10 ecosystem services covering the surface of the prefecture was carried out.  相似文献   

3.
丙烯酰胺广泛应用于工业生产,是一种潜在的环境污染物。本文从丙烯酰胺的检测方法和健康危害2个方面总结了目前的研究进展。检测方法上,以高效液相色谱-质谱串联法(HPLC-MS/MS)最为常用,一些新技术也逐渐应用到分析中。健康危害方面,丙烯酰胺可引起实验生物的神经、生殖、遗传和发育等毒性和潜在致癌性。其毒性机理为:直接损坏神经元;使活性氧(ROS)积累导致氧化损伤;诱发基因位点突变,或与DNA形成加合物而致其损伤等。鉴于目前研究存在的问题,对以后的工作进行了展望:加强监管与治理工作,保护生态环境和人类健康;深入开展丙烯酰胺对生物体的毒性效应研究;加强我国环境中丙烯酰胺的跟踪监测工作;建立一种快捷的生物测试系统来评估水体(尤其是海洋环境)中丙烯酰胺的毒性风险。  相似文献   

4.
Cattle treatment with antiparasitic drugs is associated with an important risk exposure for dung beetles. Previous studies demonstrated the impact of some avermectin and pyrethroid compounds on several species such as Onthophagus gazella and Neomyia cornicina. However, little information is available regarding the elimination of these compounds in faeces 8 days after a pour-on administration in dairy cows. The present study, utilising a dairy cow model with cypermethrin treatment, demonstrated that concentrations in dry faeces can reach levels of 5?mg?kg?1 between the first and fourth day after treatment and were present up to 3 months after a single dose of administration at a concentration around 10?µg?kg?1. Faecal samples were purified with three successive columns (silica gel, anion exchange phase, and basic alumina) and analysed by GC-MS. The limit of quantification of this method was 0.5?µg?kg?1. The high sensitivity of the method permitted one to see that the risk exposure of cypermethrin to dung beetles is longer than what was noted in the literature. According to other studies, repeated treatment with such agents may lead to the local extinction of dung beetles. Even if the impact of pyrethroid largely depends on the conditions of the ecosystem where the treated cattle are living, adverse effects of these agents may still occur.  相似文献   

5.
水产养殖对水生生态系统中汞甲基化影响研究进展   总被引:3,自引:0,他引:3  
水产养殖造成的水体富营养化不仅导致有机质增加,而且致使很多水体理化参数发生变化,包括水中溶解氧下降、沉积物中有机质和硫酸盐、硫化氢的增加、pH值的下降、生物和微生物群落的破坏等.然而,目前国内外在这方面的研究极少,水产养殖对水体汞甲基化的影响尚不清楚,对其进行深入的研究,并提出合理利用和开发水资源的科学建议具有重要的现实意义.  相似文献   

6.
This study illustrates the use of modern statistical procedures for better wildlife management by addressing three key issues: determination of abundance, modeling of animal distributions and variability of diversity in space and time. Prior information in Markov Chain Monte Carlo (MCMC) methods is used to improve estimates of abundance. Measures of autocorrelation are included when modeling distributions of animal counts, and a diversity index to indicate species abundance and richness for large herbivores is developed. Data from the Masai Mara ecosystem in Kenya are used to develop and demonstrate these procedures. The new abundance estimates are up to 35% more accurate than those obtained by existing methods. Significant temporal changes in spatial patterns are found from a space-time analysis of elephant counts over a 20-year period, with strong interactions over 5 km and 6 months space and time separations, respectively. The new diversity index is sensitive to both high abundance and species richness and is also able to capture year to year variation. It indicates an overall marginal decrease in diversity for large herbivores in the Mara ecosystem. The space-time analyses and diversity index can easily be computed thereby providing tools for rapid decision making.  相似文献   

7.
Human activities have become so extensive that all ecosystems on the planet have been altered to some extent. The fate of humankind will be determined by how sustainable ecosystems and the renewable resources in them are managed. The implication of this is obvious: humanity must live within nature's carrying capacity. In recent years, humans have recognised that growth of the economy depends on natural capital, and it is important that we now recognise that we are part of an international ecological economics community, so as to better integrate the economy and ecology. However, there are few successful examples of this. The aim of this paper is to show a method for integrated analysis between economic growth and natural carrying capacity by linking the concepts of ecological footprint and valuation of ecosystem services. When applied to China for the period 1987–2003, the empirical evidence suggests that the size of the Chinese economy surpassed the carrying capacity in 1992. Perhaps, we should abandon our high-growth predilection and initiate a transition to a steady-state economy.  相似文献   

8.
桉树人工林间种山毛豆,增加了凋落物量和养分归还量,改善了营养元素的生物小循环。在一个轮伐期内山毛豆归还土壤养分的数量如下:氮528.37kg/hm^2,磷28.06kg/hm^2,钾66.20kg/hm^2,钙184.96kg/hm^2,镁57.21kg/hm^2;而同期刚果W5桉归还土壤养分的数量为:氮85.98kg/hm^2,磷3.94kg/hm^2,钾11.80kg/hm^2,钙36.98kg/hm^2,镁18.30kg/hm^2。由于间种山毛豆增加了生态系统的养分收入,减少了水土流失的养分支出,系统的各种养分出现了盈余的状况。  相似文献   

9.
Fishing mortality and primary production (or proxy for) were used to drive the dynamics of fish assemblages in 9 trophodynamic models of contrasting marine ecosystems. Historical trends in abundance were reconstructed by fitting model predictions to observations from stock assessments and fisheries independent survey data. The model fitting exercise derives values for otherwise unknown parameters that specify the relative strength of trophic interactions and, in some instances, a time series anomaly for changes in primary production. We measured how much better or worse were model predictions when bottom-up forcing by primary production were added to top-down forcing by fishing. Searching for cross system patterns, the relative contribution of fishing and changes in primary production, mediated through trophic interactions, are evaluated for the ecosystems as a whole and for selected similar species in different ecosystems. The analysis provides a simple qualitative way to explain which forcing factors have most influence on modeled dynamics. Both fishing and primary production forcing were required to obtain the best model fits to data. Fishing effects more strongly influenced 6 of 9 of the ecosystems, but primary production was more often found to be the main factor influencing the selected pelagic and demersal fish stock trends. Examination of sensitivity to ecological and model parameters suggests that the results are the product of complex food-web interactions rather than simple deterministic responses of the models.  相似文献   

10.
本文在对我国10多个省(自治区)2o多个自然保护区的实际调查和全国资料的统计分析基础上,从我国自然保护区的管理体制、管理机构建设、资源的保护与适度开发利用、科学研究与宣传教育等方面,全面分析了我国自然保护区有效管理的现状,总结了取得的成绩和存在的问题,并针对存在的主要问题,提出了相应的对策与建议。  相似文献   

11.
土壤中的铝及其植物效应的研究进展   总被引:18,自引:0,他引:18  
应小芳  刘鹏  徐根娣 《生态环境》2003,12(2):237-239
概述了铝的性质,土壤中铝的存在形式、铝的流失、铝毒与酸雨的关系,植物对铝的吸收,铝在植物体内的分布以及植物对铝毒胁迫的反应,为进一步开展铝及其植物效应的研究提供了信息。  相似文献   

12.
青檀天然群落土壤成分及其对青檀生长的影响   总被引:1,自引:0,他引:1  
汪殿蓓  李建华  陈玉兰  刘仁阳 《生态环境》2010,19(10):2318-2324
对湖北省三潭风景区青檀(Pteroceltis tatarinowii)天然群落土壤主要元素进行测定,并通过因子相关分析,探讨了土壤成分与青檀生长指标之间的相关性,研究结果可为青檀野生资源的保护和合理利用提供科学依据。结果表明,土壤水溶性Ca2+、Mg2+平均质量分数为3.598和0.176 g·kg-1,速效钾、全氮、有效磷的平均质量分数分别是133.324 mg·kg-1、4.413 g·kg-1和3.569 mg·kg-1,有机质平均质量分数为3.295%。土壤水溶性Ca2+与青檀生长指标之间无显著相关关系;土壤可溶性Mg2+与乔木、灌木的丛生植株数量呈显著正相关,当Mg2+浓度处于0.191~0.221 g·kg-1之间时,青檀的丛生植株数量大;全氮与青檀乔木平均高度、平均胸径呈极显著正相关,与单生植株数量呈显著负相关;有效磷与乔木平均高度和胸径呈显著正相关;速效钾与乔木丛生植株数量及乔木总数量呈显著正相关;有机质灌木冠幅呈显著正相关。按土壤成分可将青檀群落聚成3类,3个聚类组的土壤水溶性Mg2+、全氮(TN)、速效钾(TK)、有效磷(TP)、有机质以及青檀乔木植株总数量存在着显著差异。  相似文献   

13.
桉树人工林间种山毛豆对提高土壤肥力和促进林木生长有极其显著的作用。间种5年后,林地表层土壤有机质和全量养分N、P、K的质量分数,分别为18.21kg/hm^2、0.85kg/hm^2、0.43kg/hm^2、1.30kg/hm^2,而对照林地分别为13.70kg/hm^2、0.56kghm^2、0.34kg/hm^2、1.10kg/hm^2;林地土壤有效养分含量显著提高;土壤结构和土壤水分物理性质显著改善;桉树生长量显著增加,刚果W5桉平均株高增长16%,平均胸径增长22%,单位面积的木材蓄积量增加59%。  相似文献   

14.
Several models have been proposed to understand how so many species can coexist in ecosystems. Despite evidence showing that natural habitats are often patchy and fragmented, these models rarely take into account environmental spatial structure. In this study we investigated the influence of spatial structure in habitat and disturbance regime upon species’ traits and species’ coexistence in a metacommunity. We used a population-based model to simulate competing species in spatially explicit landscapes. The species traits we focused on were dispersal ability, competitiveness, reproductive investment and survival rate. Communities were characterized by their species richness and by the four life-history traits averaged over all the surviving species. Our results show that spatial structure and disturbance have a strong influence on the equilibrium life-history traits within a metacommunity. In the absence of disturbance, spatially structured landscapes favour species investing more in reproduction, but less in dispersal and survival. However, this influence is strongly dependent on the disturbance rate, pointing to an important interaction between spatial structure and disturbance. This interaction also plays a role in species coexistence. While spatial structure tends to reduce diversity in the absence of disturbance, the tendency is reversed when disturbance occurs. In conclusion, the spatial structure of communities is an important determinant of their diversity and characteristic traits. These traits are likely to influence important ecological properties such as resistance to invasion or response to climate change, which in turn will determine the fate of ecosystems facing the current global ecological crisis.  相似文献   

15.
李海燕  李明怡  崔爽 《环境化学》2013,(6):1056-1061
通过实验室模拟研究了进水流速对雨水管道中沉积物-水界面间磷释放规律的影响,得出不同流速条件下沉积物-水界面磷交换的平衡时间,拟合出上覆水磷的平均浓度和沉积物中磷最大累积释放量与流速的关系曲线,并采用连续函数计算方法通过现场采样和实验分析进行不同流速下雨水管道沉积物-水界面磷交换速率的研究,最后根据实验得出的交换速率值,以一条雨水管线为例估算了不同进水流速下沉积物中磷释放总量.结果表明,流速的增大会促进沉积物中磷的释放,且上覆水总磷平均浓度及磷释放最大量随流速的增大而呈指数式增长,对应的指数方程分别为y=1.2194e0.5983x和y=0.436e0.7928x.在实验工况下,流速为0.3、0.5、0.7、0.9和1.1 m.s-1对应的磷平均释放速率分别为0.62、1.04、2.51、2.85和4.09 mg.m-.2min-1;对应的磷释放总量的估算值分别为3410.00、5720.00、27610.00、31350.00和61861.25 mg.  相似文献   

16.
Periphyton samples from Water Conservation Areas, Big Cypress National Preserve, and Everglades National Park in south Florida were analyzed for concentrations of total mercury, methylmercury, nitrogen, phosphorus, organic carbon, and inorganic carbon. Concentrations of total mercury in periphyton decrease slightly along a gradient from north‐to‐south. Both total mercury and methylmercury are positively correlated with organic carbon, nitrogen and phosphorus in periphyton. In horizontal sections of periphyton mats, total mercury concentrations tend to be largest at the tops and bottoms of the mats. Methylmercury concentrations tend to be the largest near the bottom of mats. These localized elevated concentrations of methylmercury suggest that there are “hot spots”; of methylmercury in periphyton.  相似文献   

17.
森林保护对减缓全球变暖有着重要意义。不同森林生态系统由于其所处地理位置不同,气候、土壤、物种构成差异很大,因此其碳汇功能也各不相同,油松是中国北方重要的森林类型之一,为了摸清贺兰山自然保护区森林碳储量,本文通过实地调查取样和室内实验测定的方法,于2011—2012年期间对宁夏贺兰山自然保护区油松林碳储量进行了取样测定,估算了其碳储量。结果表明:油松单株平均含碳率为51.91%,高于国内其他地区的阔叶树种及灌木的含碳率;经估算贺兰山油松林总有机碳储量为13.39kg.m^-2,其中立木碳储量为2.98kg.m^-2,地被层有机碳碳储量为0.86kg·m^-2,土壤层有机碳储量为9.55kg.m^-2,土壤碳储量占林分碳储量的70%以上,是油松林有机碳的主要储存库。总体来看,针叶林的固碳能力要高于阔叶林,在营造固碳林时应优先考虑针叶树种。从分布格局来看,东经105.80°~106.15°,北纬38.36°~39.00°,海拔2000~2400m的区域是油松林的主要分布区域,也是贺兰山森林有机碳的主要分布区,该区域是保护区碳平衡研究和碳汇管理应该关注的重点区域。  相似文献   

18.
Both solitary and primitively social nests of the facultatively social carpenter bee Xylocopa pubescens can be found throughout most of the breeding season. In social nests there is reproductive division of labour between a dominant forager and a guarding female. Two types of guarding females can be discerned: the young pre-reproductive guards, and older, formerly reproductive guards. The latter type of guard is found when, after a take-over of reproductive dominance either by a nestmate (mostly a daughter) or an intruder, the defeated female stays in the nest instead of leaving to try and found or usurp another nest. She is then manipulated into the role of a guard. The dominant female profits from the presence of the guard since she protects the nest against pollen robbery by conspecifics (Hogendoorn and Velthuis 1993). We have studied why superseded females might prefer to remain as a guard, rather than try their luck somewhere else. The hypotheses investigated pertain to (1) the difficulty for the defeated female of finding a new nest and of restarting reproductive activities due to (a) ecological constraints (nest and pollen shortage) and (b) the effect of age and wear on the defeated female; (2) the effects of guarding in terms of inclusive fitness. We found that superseded females remained as guards significantly more often when a nestmate (not necessarily close kin) took over reproductive dominance than when an intruder did so. Other factors associated with the decision of the defeated female to stay or leave were her age and the number of her own young still present after the supersedure. The probability of finding or constructing a new nest was lower for old than for young females. After finding a nest, old females produced less brood than young foundresses. As a result of these two factors old superseded females gained, in terms of inclusive fitness, by staying as guards, whereas young females profited from leaving the nest. We interpret these results as an indication that guarding behaviour has evolved due to kin selection. However, kin discrimination apparently did not occur. Therefore we conclude that in this species kin selection is not, in the proximate frame of reference, based on kin recognition and preference for helping kin. Correspondence to: K. Hogendoorn  相似文献   

19.
为了解重金属污染对海洋鱼类热休克蛋白(HSPs)基因表达的影响,将褐菖鲉(Sebastiscus marmoratus)分别暴露于1.6、8、40、200、500μg·L~(-1)Cd、Pb溶液中,用环介导等温扩增技术(loop-mediated isothermal amplification,LAM P)定量检测褐菖鲉肝脏HSP60、HSP70、HSP90、HSC70 mRNA表达量。结果表明:Pb仅在40μg·L-1时显著抑制HSP60、HSP90、HSC70 mRNA表达量,8μg·L~(-1)时即可显著抑制HSP70 m RNA表达量,并在40μg·L~(-1)时达到最小值;Cd对HSP60、HSP90、HSC70的诱导不明显,但能显著诱导HSP70,并在500μg·L~(-1)时达到最大值。相比之下,褐菖鲉肝HSP70基因对重金属Cd、Pb污染较为敏感,有潜力成为监测海洋重金属污染的预警分子。  相似文献   

20.
For policy decisions with respect to CO2-mitigation measures in the agricultural sector, national and regional estimations of the efficiency of such measures are required. The conversion of ploughed cropland to zero-tillage is discussed as an option to reduce CO2 emissions and promises at the same time effective soil and water conservation. Based on the upscaling of simulation results with the soil and land resources information system SLISYS-BW, estimations of CO2-mitigation rates in relation to crop rotations and soil type have been made for the state of Baden-Württemberg (Germany). The results indicate considerable differences in the CO2-mitigation rates between crop rotations ranging from 0.48 to 0.03 Mg C ha−1 a−1 for winter cereals–spring cereals–rape rotations and winter cereals–spring cereals–corn silage rotations, respectively. The efficiency of the crop rotations is strongly related to the total carbon input and in particular the amount of crop residues. Among the considered soil types, highest CO2-mitigation rates are associated with Cumulic Anthrosols (0.62 Mg C ha−1 a−1) and the lowest with Gleysols (−0.01 Mg C ha−1 a−1). An agricultural extensification scenario with conventional plowing but conversion of the presently applied intensive crop rotations to a clover–clover–winter cereals rotation indicated a CO2-mitigation potential of 466 Gg C a−1. However, the present high market prices for cereals and increasing demand for energy production from biomass encourages an intensification of the agricultural production and an excessive removal of biomass which in future will seriously reduce the potential for carbon sequestration on cropland.  相似文献   

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