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901.
Elevated levels of copper and zinc in sediment have been shown to adversely affect estuarine infauna. We investigated the additivity of the combined effects of copper and zinc on infaunal recolonisation through a manipulative field experiment in Orewa estuary, New Zealand, using defaunated sediment discs treated with these metals. The nature of their combined effects varied among infaunal taxa and the particular variables being examined. Additive effects were detected for species richness, for the mean log abundances of the polychaetes Prionospio sp. and Scoloplos cylindrifer and for the multivariate response of the community as a whole. Antagonistic effects were detected for the mean log abundances of total infauna and the polychaete Heteromastus sp. Characterising the potentially interactive nature of the combined effects of multiple heavy metals is essential in order to build predictive models of future environmental impacts of metal accumulation in estuarine sediments.  相似文献   
902.
汉江流域位于黄土高原南侧,属中国南北气候的过渡区域,其重矿物组成对区域沉积物物质来源与演化研究具有重要意义。运用强磁选、重液分离法等技术手段将汉江上游谷地黄土沉积物中的重矿物提取出来,在双目显微镜和偏光显微镜下测定其含量和特征。结果表明:(1)汉江黄土重矿物有22种,其中角闪石、磁铁矿、钛铁矿等矿物为优势矿物,占重矿物总量的60%以上;稳定矿物约占重矿物总量的47.95%,是汉江黄土最主要的矿物组合。(2)典型黄土和古土壤中重矿物种类相同,但含量有一定差异,马兰黄土(L1)相较古土壤(S0)不稳定矿物含量较高,稳定矿物含量较低;(3)汉江黄土与北侧黄土高原黄土相比重矿物种类相似,稳定性组合分布一致,但汉江黄土稳定性矿物含量较高,不稳定性矿物含量较低。这些特征说明:(1)汉江上游地区古土壤和黄土物质来源一致,古土壤S0在物质组成上继承了黄土,是黄土高度风化的产物;(2)汉江谷地黄土和黄土高原风成黄土两者的物源区一致,但汉江地区黄土受到较黄土高原地区强的风化成壤作用。  相似文献   
903.
A Typology of Collaboration Efforts in Environmental Management   总被引:4,自引:1,他引:3  
Collaboration involves stakeholders and the public in a process of consensus building to address some of the most difficult environmental management problems facing society today. Collaborative groups vary widely, ranging from small watershed councils to regional ecosystem collaboratives to groups addressing large-scale policy issues. While these collaboratives all match the common principles of collaboration, a closer examination reveals many differences. Using institutional theories about levels of decision making provides a way of classifying collaboratives along a spectrum from action level to organizational level to policy level. This typology is applied to thirty-six collaboration case studies in Australia and the United States that were investigated over a series of years through interviews, observation, document analysis, and surveys. The application reveals different tendencies among the case types in terms of population, size, problem significance, institutional setting, and focus of activities. The typology also reveals functional differences in the types of stakeholders involved, the management arrangements for implementation, and the approaches to implementing change. This typology can help practitioners better understand the challenges and appropriate types of collaborations for different settings. It helps highlight differences in the role of government and decentralization of power. It distinguishes the different theoretical foundations for different types of collaboratives. Finally, it elucidates the different evaluation approaches for different types of collaboratives.  相似文献   
904.
The article considers the impact of introducing government co-management policy in the form of Joint Forest Management (JFM) in an area with a five-decade-old self-organized community forest management system in Orissa, India. We ask a question that appears not to have been previously examined: What happens when JFM replaces an already existing community forest management arrangement? Our comparison of the JFM arrangement with the self-organized community forest management regime (pre- and post-2002 in a selected village) provides three conclusions: (1) The level of villager participation in forest management has declined, along with the erosion of the bundle of common rights held by them; (2) multiple institutional linkages between the village and outside agencies, and reciprocal relations with neighboring villages have been abandoned in favor of a close relationship with the Forestry Department; and (3) the administration of the forestry resource has become politicized. We conclude that the “one-size-fits-all” approach of the JFM, with its pre-packaged objectives and its narrow scope of forest management, is likely to limit experimentation, learning, and institutional innovation that characterizes community forest management.  相似文献   
905.
The present study was designed to reveal whether long-term consumption of bitter apricot seeds causes changes in lipid profile and other risk factors for cardiovascular diseases. The study group consisted of 12 healthy adult volunteers (5 females and 7 males). The average age of women was 41.60 ± 11.28 years and the average age of men was 36.71 ± 13.70 years. Volunteers consumed 60 mg kg?1 of body weight of bitter apricot seeds divided into 8–12 doses daily for 12 weeks. Volunteers were recruited from the general population of Slovak Republic. After 12 weeks, mean body weight of the participants increased from 77.34 to 78.22 kg (P > 0.05). The average total cholesterol levels decreased from 4.86 mmol L?1 at the beginning of the study to 4.44 mmol L?1 at the end of the study (P < 0.05). We did not observe any significant increase in high-density cholesterol (from 1.55 to 1.60 mmol L?1). The average low-density cholesterol levels decreased from 2.93 mmol L?1 at the beginning of the study to 2.31 mmol L?1 at the end of the study (P < 0.001). Concentration of triglycerides increased significantly over the 12-week intervention period from 0.84 to 1.17 mmol L?1. After the intervention, the high-sensitivity C-reactive protein level decreased from 1.92 to 1.23 mg L?1, but results were non-significant (P > 0.05). Creatine kinase serum levels increased from 2.31 to 2.77 mg L?1 (P > 0.05) over the 12-week intervention period. The results suggest that regular intake of bitter apricot seeds may be considered potentially useful for prevention of cardiovascular diseases.  相似文献   
906.
China produces the largest amount of pork in the world, which emits the largest amount of greenhouse gases (GHGs). This paper calculates GHG emissions from China’s hog production at the provincial level using newly published emission factors. Empirical results show that GHG emissions from China’s hog production mainly respond to the scale intensity. Capital abundance and income contribute positively to GHG emissions from hog production. Pork trade increases GHG emissions from China’s hog production with a significantly direct effect, reduces GHG emissions through indirect technique effects.  相似文献   
907.
利用GC-ECD测定了小白洋淀6个采样点的9种浮水、挺水和沉水植物中4种六六六(hexachlorocyclohexanes,HCHs)异构体的含量,分析了其分布、组成及富集特征。结果表明:1)小白洋淀水生植物中总HCHs含量范围在ND~7.47 ng·g-1(ww),浮水植物中HCHs含量最高,挺水植物各组织含量也有明显差异,根部HCHs含量明显高于茎叶2种组织。2)4种HCHs异构体中,γ-HCH的残留水平要显著高于其他3种异构体。在沉水植物和浮水植物中,均以γ-HCH占绝对比例,相对含量达60%~99%;而在挺水植物中,δ-HCHs占有较高比例,并且主要富集在挺水植物的根部,茎中次之,叶中最少。3)小白洋淀浮水植物和沉水植物HCHs含量与水体中HCHs含量呈显著的正相关关系,而挺水植物荷花、蒲草中HCHs各组分含量与水体中HCHs的相关关系不显著。4)水生植物对水中HCHs的富集系数BCF在8.7~661.2范围;浮水植物的BCF最高,沉水植物次之,挺水植物的茎对水体中HCHs的BCF最低。  相似文献   
908.
美国EPCRA法案对我国推动企业环境信息公开的启示   总被引:2,自引:2,他引:0       下载免费PDF全文
本文围绕美国企业环境信息公开专项法案——EPCRA法案和在该法案要求下建立的、为世界各国所广泛采用的企业环境信息公开核心制度——有毒污染物释放清单制度(TRI),分析总结了发达国家促进企业环境信息公开的立法理念、制度体系、工作机制、技术支持、信息平台等方面的经验,并将其与我国企业环境信息公开专项制度《企业事业单位环境信息公开办法》进行了对比分析,识别了我国企业环境信息公开工作相关基础研究、制度设计、制度执行等方面的不足,且结合我国下一阶段推动环境质量全面改善的工作需求、推动排污许可改革等工作任务,就完善我国企业环境信息公开工作提出了建议。  相似文献   
909.
长江口中华鲟自然保护区及临近水域鱼类种类组成现状   总被引:2,自引:0,他引:2  
为了解长江口中华鲟自然保护区及其临近水域鱼类种类组成的现状,2004~2008年利用底拖网、插网、定置网和刺网等多种网具对该水域的鱼类组成状况进行了较为系统的调查。共调查到鱼类105种,隶属于18目43科86属,鱼类种类组成以鲈形目和鲤形目为主;生态类型中海洋鱼类和淡水鱼类各37种,河口定居性鱼类25种,洄游性鱼类6种;鱼类种类组成处于长江下游至东海的过渡类型,鱼类食性以底栖生物、有机碎屑和浮游动物食性为主,凶猛性鱼类较少。与以往调查资料相比,调查水域鱼类物种数有所减少,一些重要的物种更是濒临绝迹。保护区水域鱼类不仅具有较高的物种多样性、河口代表性、稀有性和很高的科研价值,同时其生态系统也较为脆弱,并已受到严重威胁,保护区的保护工作显得尤为重要.  相似文献   
910.
上海青浦区不同用地类型河流滨岸带生境及植物群落组成   总被引:1,自引:0,他引:1  
按照工业用地、农业用地、交通用地、居住用地、绿地和荒地等6类不同用地类型,于上海青浦区选取河流滨岸带样点48个,研究不同用地类型对滨岸带生境及植物群落组成的影响。研究发现:(1)目前该地区河流滨岸带生境优劣程度为:荒地>绿地>农业用地>交通用地>居住区>工业用地。这主要是由于在不同用地类型下人们对河岸类型、滨岸带几何形态以及原有植被的影响所造成。(2)目前该地区河流滨岸带有植物51科118种,平均丰富度水平绿地最高,工业用地最低。从植物的生活型与来源方面看,6类用地类型下的河流滨岸带植物群落组成存在显著差异。工业用地受人为影响强度较大,外来入侵植物比例高达27.22%;农业用地草本平均数量11.75种,为6类用地类型中最高水平;交通用地与居住用地表现出较大人工引种植物比例,分别为37.77%和49.97%;绿地有相对均衡的乔灌草比例,人工引种植物占所有植物的64.05%;荒地缺乏乔木与灌木类型,自然分布植物比例最高,为69.94%。
  相似文献   
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