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1.
我国东部七省生态系统对酸沉降的相对敏感性   总被引:16,自引:0,他引:16  
讨论了影响亚热带生态系统对酸沉隆敏感怀的生态因子,提出了敏感性等级划分的指标体系,根据大量资料编制了我国东部7省1市生态系统对酸沉隆相对敏感性分区图。结果表明,在研究区域内生态系统的敏感性有相当大的差别,极敏感区和敏感区面积占全区总面积的1/3以上。主要分布在福建、浙江、江西3省。  相似文献   

2.
我国对大气酸沉降的研究起自70年代末.以酸雨研究占主导地位。我国酸雨现象区域性、发展性强,在地理上以南方酸性土壤地区为主,在成分上以硫酸盐型酸雨为主;无论是酸度还是频率,酸雨都是极严重的生态环境问题。酸沉降已对农、林生态系统生产产生了严重的破坏效应,但其累积性的环境化学反馈却未引起人们的足够重视。我国酸雨地区以强酸性富铝土壤为主,对大气酸沉降有较大的敏感性。应用β指标还表明,酸沉降可使南方主要土壤因酸化而在30—60年内降低pH一个单位。近年来对酸沉降诱发的土壤酸化研究以模拟降水的土柱试验为主,从pH下降、盐基淋出、Al及重金属移动等方面来提示出酸沉降可能对土壤产生的化学影响。但作为过程化学研究,其案例监测研究的报道尚很少。对于南方严重的酸雨现象,应加强实地动态监测和过程分析,注重Al化学及其对环境的反馈,将酸沉降对生态系统的破坏提高到生态毒理机制上。  相似文献   

3.
温州红壤的酸沉降临界负荷研究   总被引:5,自引:0,他引:5  
安俊岭  黄美元 《环境化学》1998,17(2):136-142
本文简要介绍了以碱总量守恒为基础建立的兼能描述钙质与非钙质土壤长期酸化过程的动态模型(LTSAM),并利用该模型讨论了温州红壤的酸沉降临界负荷。结果表明,以硫沉降即酸沉降的硫沉降非酸沉降两观点分别来确定红壤的临界负荷,其值依次为3.91与1.84g·m^-2·a^-1,后者仅是前者的47%,差异显著应加以区别。  相似文献   

4.
酸沉降对森林植物影响过程和机理   总被引:4,自引:0,他引:4  
文章丰要包括如下几方而的内容:(1)概述了酸沉降作用下森林衰退的状况及其相关工作的开展情况;(2)总结了酸沉降对森林植物的影响过程和机理;(3)阐述了酸沉降对森林植物影响研究的模型和临界酸负荷值的确定;(4)探讨了存在的问题和未来值得研究的方向。指山未来的研究方向主要是:酸沉降对森林生态系统的影响机理和森林生态系统对酸沉降的反馈机制;酸沉降对非优势种、稀有种及低等植物的影响;酸沉降与其它环境因子对森林植物的共同影响;酸沉降的监控和预测,建立适合我斟实际情况的研究模型;将常规分析手段和分子生物学技术相结合,加强抗性植物和指示植物的筛选工作;加强受损森林植被的恢复和重建工作;开展酸沉降对森林植被的格局动态及森林演替动态变化研究。  相似文献   

5.
随着经济飞速发展与能源消耗快速攀升,中国已成为全球酸沉降最严重的地区之一.酸沉降能够引起地表植被破坏、土壤酸化等一系列的环境问题,在全球范围受到普遍关注.作为全球最重要的生态系统之一,森林生态系统受到酸沉降的深刻影响.本文通过分析国内外已发表的相关文章,综述酸沉降对森林生态系统碳循环关键过程的影响及可能的机理.(1)对植物光合作用的影响:酸沉降通过改变叶绿素含量、气孔导度及酶活性等影响叶片光合作用,而且叶片光合功能受损程度与酸沉降强度和类型有关;(2)对林木生长的影响:酸沉降通过改变叶片结构和诱导土壤酸化影响林木生长,通常酸沉降会抑制林木生长,但会因酸沉降强度和类型有所差异;(3)对凋落物分解的影响:酸沉降通过改变土壤酶活性、微生物群落结构等对不同森林类型凋落物分解产生影响,其影响程度和方向与土壤的酸缓冲能力和酸沉降类型有关;(4)对土壤呼吸(Rs)的影响:酸沉降对Rs的影响受到根系生物量、微生物、酶活性及温度等多种因素共同作用,Rs的不同组分对酸沉降的响应机制不同;(5)对土壤有机碳(SOC)的影响:通常情况下,酸沉降抑制水溶性有机碳(DOC)的溶解,降低微生物活性及生物量从而有利于SOC的积累与稳定.通过探讨森林生态系统碳动态对酸沉降响应的不确定性因素,建议今后加强以下几方面研究:(1)干湿酸沉降比较;(2)酸沉降对树干呼吸、地下碳分配等其他关键生态过程的影响;(3)酸沉降与其他全球变化因子的耦合;(4)酸沉降对森林生态系统碳循环的长期影响.(图1表2参87)  相似文献   

6.
植物对酸沉降的净化缓冲作用研究综述   总被引:1,自引:0,他引:1  
从植物对SO2的吸收作用、森林冠层对湿沉降的缓冲作用以及森林枯枝落叶层对酸沉降的吸收缓冲作用3个方面介绍了国内外在植物对酸沉降的净化缓冲作用方面的研究成果。  相似文献   

7.
植物对酸沉降的净化缓冲作用研究综述   总被引:9,自引:0,他引:9  
从植物对SO2的吸收作用、森林冠层对湿沉降的缓冲作用以及森林枯枝落叶层对酸沉降的吸收缓冲作用3个方面介绍了国内外在植物对酸沉降的净化缓冲作用方面的研究成果。  相似文献   

8.
土壤污染物来源及前沿问题   总被引:29,自引:7,他引:29  
人类活动对土壤系统的影响日趋严重。土壤污染物主要来自污染的大气沉降,废水和污水灌溉,工业废渣和城市垃圾,以及农药施用等。土壤污染对环境和人体健康造成极大的危害。文章通过计算得出了大气汞沉降和酸沉降在中国的累积沉降量,并通过调查分析中国各项污染物来源的最新资料,详细论述了各主要污染因素对土壤系统的影响。文章阐述了污染物在土壤系统中主要的物理化学行为,主要包括污染物在土壤生态系统中的吸附、迁移和扩散、酸沉降对土壤系统的影响等三个方面。最后回顾了该领域的研究现状和主要的前沿问题,并对进一步的深入研究提出了建议。  相似文献   

9.
我国农业对全球变暖的敏感性和脆弱性   总被引:6,自引:0,他引:6  
未来40~60年内,人类活动将增大CO_2、CH_4、CFC_3和N_2O等温室气体的排放,从而导致全球平均气温升高1~3℃。本文从我国农业和气候变化的趋势入手,分析了时全球变暖影响的敏感区和脆弱区,提出了适应对策并估算新增的投资和效益。  相似文献   

10.
周静  崔键  王国强  马友华  关静 《生态环境》2007,16(6):1714-1718
大气湿沉降作为农田生态系统养分的重要来源却一直没有得到足够的重视。文章通过常规农作条件,采用自动降雨收集器结合田间实验方法,重点研究了红壤旱地牧草马唐(Digitaria ischaemum)和蔬菜冬萝卜(Raphanus sativus)连作期间大气湿沉降氮素特征,估算了湿沉降向该生态系统输入的氮量,讨论了其对该生态系统氮素平衡的贡献。结果发现,该研究区域不同月份大气湿沉降T-N平均质量浓度为3.91mg·L-1,其中NH4 -N、NO3--N的分别为1.21、0.61mg·L-1;试验期间,湿沉降输入马唐-冬萝卜连作系统的T-N为34.34kg·hm-2,其中冬萝卜生长期最多,占67.88%,湿沉降T-N对该系统氮素输入、输出、盈余的贡献分别为12.97%、17.65%、48.90%。湿沉降T-N对马唐生态系统氮素输入、输出、盈余的贡献分别为6.45%、16.54%、10.57%;对冬萝卜生态系统氮素输入、输出的贡献分别为24.86%和18.23%。红壤旱地普遍具有"酸瘦黏板"的特点,氮素作为一种重要的生命物质和作物营养的必需元素,对作物产量和人民生活质量的提高具有重要的意义。研究结果表明,湿沉降对农田生态系统的影响不容忽视。  相似文献   

11.
Human pressure has been exponentially growing during recent decades in coastal areas, which have led to drastic losses of biodiversity in coastal ecosystems. The current conservation status of many coastal plant species is directly related to a lack of environmental criteria in the urban planning of coastal areas over recent decades. This study aimed to evaluate the evolution, over the last 9 years, of the conservation status of various populations of the endangered plant Glaucium flavum, exploring the extent to which human pressure and different management strategies practiced in the coastal areas where the populations are established have affected the conservation status of the species. The populations analysed have evolved in a different manner over the last 9 years, as have their threat factors, and a relationship was evident between their conservation status and the evolution of these different threat factors. Our results indicate that an appropriate planning of local management actions, such as the installation of walkways or the successful eradication of invasive species, may be determinant factors for successful conservation of the coastal vegetation. The presence of species that are sensitive to slight changes in the ecosystem, and the main factors that govern the plant performance of these species, must be given full consideration in decision-making processes of coastal planning and management.  相似文献   

12.
卡马西平在污水和水环境中广泛存在,且对水生生态系统安全构成风险,因此成为目前研究较多的药品之一。以北京清河再生水厂为例,研究"超滤—臭氧氧化—氯消毒"处理工艺中卡马西平的去除特性,并针对臭氧氧化和氯消毒工艺建立模拟卡马西平去除过程的机理模型。同时,利用美国环境保护署ECOTOX数据库,获取卡马西平对北京市水生生物物种的毒性数据,并基于毒性数据建立物种敏感度分布(species sensitivity distribution,SSD)模型,评价再生水厂出水补给地表水体时卡马西平产生的生态风险。臭氧氧化和氯消毒模型对卡马西平、总有机碳、氨氮等指标的模拟误差总体低于20%,模型的灵敏参数均可以被较好地识别,且其不确定性显著下降。对比7种SSD模型发现,对数正态分布和对数Logistic分布模型较好地拟合了北京市6个物种的卡马西平毒性数据,二者预测得到的总体生态风险期望值分别为7.4%和8.5%。  相似文献   

13.
The high incidence of hunting activity and forest fires in different ecosystems (particularly in Mediterranean ecosystems) requires a model, which allows for the comprehensive management of hunting resources and estimating the potential damage caused by this type of disturbance. This paper proposes a model for evaluating the socio-economic effects of forest fires on hunting. Its cornerstone lies in evaluating hunting resource availability for each ecosystem within its territorial mosaic. Each game management unit (GMU) is identified by vegetation structure and habitat type. It presents a novel approach in which the economic value of each game management unit is linked to potential forest fire damages. The effect a forest fire has on an entire ecosystem depends on the intensity of its flames. A sample study was undertaken in the province of Huelva in Andalusia (southern Spain). The socio-economic hunting vulnerability of the province of Huelva was 45,188,000€. The results obtained confirmed the need for an economic appraisal of non-forest products in the forest and other woodland areas. Geographic Information System increases the flexibility and simplicity of our methodology which permits immediate extrapolation to other agroforestry territories.  相似文献   

14.
15.
Conservation planners need reliable information on spatial patterns of biodiversity. However, existing data sets are skewed because some ecosystems, taxa, and locations are underrepresented. We determined how many articles have been published in recent decades on the biodiversity of different countries and their constituent provinces. We searched the Web of Science catalogues Science Citation Index (SCI) and Social Science Citation Index (SSCI) for biodiversity-related articles published from 1993 to 2016 that included country and province names. We combined data on research publication frequency with other provincial-scale factors hypothesized to affect the likelihood of research activity (i.e., economic development, human presence, infrastructure, and remoteness). Areas that appeared understudied relative to the biodiversity expected based on site climate likely have been inaccessible to researchers for reasons, notably armed conflict. Geographic publication bias is of most concern in the most remote areas of sub-Saharan Africa and South America. Our provincial-scale model may help compensate for publication biases in conservation planning by revealing the spatial extent of research needs and the low cost of redoing this analysis annually.  相似文献   

16.
Every action in a conservation plan has a different level of effect and consequently contributes differentially to conservation. We examined how several community-based, marine, management actions differed in their contribution to national-level conservation goals in Fiji. We held a workshop with experts on local fauna and flora and local marine management actions to translate conservation goals developed by the national government into ecosystem-specific quantitative objectives and to estimate the relative effectiveness of Fiji's community-based management actions in achieving these objectives. The national conservation objectives were to effectively manage 30% of the nation's fringing reefs, nonfringing reefs, mangroves, and intertidal ecosystems (30% objective) and 10% of other benthic ecosystems (10% objective). The experts evaluated the contribution of the various management actions toward national objectives. Scores ranged from 0 (ineffective) to 1 (maximum effectiveness) and included the following management actions: permanent closures (i.e., all extractive use of resources prohibited indefinitely) (score of 1); conditional closures harvested once per year or less as dictated by a management plan (0.50-0.95); conditional closures harvested without predetermined frequency or duration (0.10-0.85); other management actions, such as regulations on gear and species harvested (0.15-0.50). Through 3 gap analyses, we assessed whether the conservation objectives in Fiji had been achieved. Each analysis was based on a different assumption: (1) all parts of locally managed marine areas (including closures and other management) conserve species and ecosystems effectively; (2) closures conserve species and ecosystems, whereas areas outside closures, open to varying levels of resource extraction, do not; and (3) actions that allow different levels of resource extraction vary in their ability to conserve species and ecosystems. Under assumption 1, Fiji's national conservation objectives were exceeded in all marine ecosystems; under assumption 2, none of Fiji's conservation objectives were met; and under assumption 3, on the basis of the scores assigned by experts, Fiji achieved the 10% but not the 30% objectives for ecosystems. Understanding the relative contribution of management actions to achieving conservation objectives is critical in the assessment of conservation achievements at the national level, where multiple management actions will be needed to achieve national conservation objectives.  相似文献   

17.
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   

18.
Living organisms and ecosystems have been shown to be sensitive to very weak signals originating very far away. The dynamics governing these phenomena is discussed in the framework of Quantum Field Theory. This phenomenon gives an indication on the dynamics responsible for the exchange of information in ecosystems. The peculiar role of coherent water is stressed. It is shown that energy is able to travel in a coherent medium in form of solitons, without any losses.  相似文献   

19.
基于自然灾害的北京幅综合生态风险评价   总被引:2,自引:0,他引:2  
徐丽芬  许学工  卢亚灵  颜磊  马禄义 《生态环境》2010,19(11):2607-2612
经过20多年的发展,风险源评价从单一风险源扩展到多风险源,风险受体从单一受体发展到多受体,评价尺度也从种群、生态系统扩展到区域和景观水平。但总体说来,对多风险源、多过程的多个生态系统层次的风险评价尚不成熟。运用数字高程模型、干燥度分布图、植被指数、人口密度以及8种自然灾害风险源频率分布图、土地利用图、植被类型图、陆地生态系统生态资产分布图等数据,基于ArcGIS 9.2平台,综合考虑生态的脆弱性,风险源的发生频率,受体的暴露水平、危害程度等,对多风险源、多个生态系统综合的北京幅生态风险进行评价。旨在对区域综合生态风险评价方法进行探讨。评价结果显示:(1)高风险区主要为本区环渤海湾沿岸,包括天津市,河北唐山、沧州,山东滨州、东营、潍坊等沿海地带;以及本图幅西部、北部的太行山地,包括河北省、北京市及图幅西部的山西、河南部分地区;(2)较低生态风险区所占比例较高,达42.55%,可见降低生态风险有很大的潜力;(3)高强度的人类开发,尤其是在滨海地区围海造陆,将会导致沿海地区生态风险更高。  相似文献   

20.
As apex predators disappear worldwide, there is escalating evidence of their importance in maintaining the integrity and diversity of the ecosystems they inhabit. The largest extant marsupial carnivore, the Tasmanian devil (Sarcophilus harrisii) is threatened with extinction from a transmissible cancer, devil facial tumor disease (DFTD). The disease, first observed in 1996, has led to apparent population declines in excess of 95% in some areas and has spread to more than 80% of their range. We analyzed a long‐term Tasmania‐wide data set derived from wildlife spotlighting surveys to assess the effects of DFTD‐induced devil decline on populations of other mammals and to examine the relative strength of top–down and bottom–up control of mesopredators between 2 regions with different environmental conditions. Collection of the data began >10 years before DFTD was first observed. A decrease in devil populations was immediate across diseased regions following DFTD arrival, and there has been no indication of population recovery. Feral cats (Felis catus) increased in areas where the disease was present the longest, and feral cat occurrence was significantly and negatively associated with devils. The smallest mesopredator, the eastern quoll (Dasyurus viverrinus), declined rapidly following DFTD arrival. This result suggests the species was indirectly protected by devils through the suppression of larger predators. Rainfall deficiency was also a significant predictor of their decline. Environmental variables determined the relative importance of top–down control in the population regulation of mesopredators. In landscapes of low rainfall and relatively higher proportions of agriculture and human settlement, top–down forces were dampened and bottom–up forces had the most effect on mesopredators. For herbivore prey species, there was evidence of population differences after DFTD arrival, but undetected environmental factors had greater effects. The unique opportunity to assess population changes over extensive temporal and spatial scales following apex predator loss further demonstrated their role in structuring ecosystems and of productivity in determining the strength of top–down control. Cascadas Tróficas Después de la Declinación Inducida por Enfermedad de un Depredador Apical, el Demonio de Tasmania  相似文献   

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