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1.
Sedimentary charcoal particles from lakes are commonly used to investigate fire history. Fire-history reconstructions are based on measuring the surface area or counting the number of charcoal fragments in adjacent samples. Recently, the volume of charcoal particles was advised as a more accurate method for quantifying past charcoal production. Large charcoal datasets, used to synthesize global fire history, include these different types of charcoal measurements and implicitly assume that they provide comparable fire-history information. However, no study has demonstrated that this assumption is valid. Here we compare fire-frequency reconstructions based on measurements of charcoal area and number, and estimates of charcoal volume from two lake sediment records from the eastern Canadian boreal forest. Results indicate that the three proxies provide comparable fire-history interpretations when using a locally defined threshold to identify fire events.  相似文献   

2.
This paper analyses how in the aftermath of one of the worst environmental disasters ever to occur in Spain – the Aznalcóllar Disaster – various environmentalist and conservationist groups mobilised migratory birds to bring new insights and the need for new precautions to the controversy elicited by the spill. The case study, thus, revolves around how environmentalists established a “hybrid collective action” to draw attention to unconsidered risks and impacts of the disaster and thereby make the case for open debate. Building upon this, I engage with two different, though interrelated, theoretical debates that contribute to a rethinking of environmental management (EM) as a social and materially situated practice. Drawing on the idea of “tactic” (De Certeau, 1984), I draw attention to the devices, actions and procedures that environmentalists carried out to resist attempts to minimise the spill and to undermine administrations’ assumptions of control, coherence and singularity associated the idea of management. Drawing on Tim Ingold’s latest work (2007, 2008, 2011), I analyse environmentalists’ most successful tactic: the enactment of migratory birds as “lines”. Together with other authors in this special issue, I will use this notion to make an argument against some of the assumptions of the “hybrid ontology”. In contrast to more essentialists and static notions of non-human agency and politics, the idea of line is particularly useful as a way of understanding how nature(s) can be effectuated differently and how this leads to the imagining of new regimes of cohabitation, human and non-human management and intervention.  相似文献   

3.
A study of environmental chloride, deuterium, oxygen-18, and tritium in deep sand profiles (35 m) has been carried out in order to estimate their relative value for measuring average groundwater recharge. The investigation was located at a 0.1-km2 site in Quaternary sands near the northwestern coast of Senegal in a zone of rainfed agriculture. By using a steady-state model for duplicate unsaturated zone chloride profiles, the long-term average recharge at the site was estimated to be 30 mm yr–1 or around 10% of the average precipitation (290 mm). The chloride concentration of adjacent shallow groundwater was relatively uniform and comparable to the unsaturated zone average, while the spatial variability in the depth distribution of Cl in the unsaturated zone was considerable. Stable isotope (deuterium and oxygen-18) data show that there is some isotopic enrichment due to direct evaporation through the soil surface. The degree of heavy isotope enrichment is proportional to the extent of evaporative loss and there is good correspondance with the chloride enrichment. Nevertheless, stable isotopes cannot be used quantitatively to estimate the recharge. The excellent preservation of the peak in thermonuclear tritium in precipitation in the unsaturated zone at depths between 12 and 20 m enables an estimated annual recharge of 24 mm yr–1 in this area to be calculated, using the piston flow model. Agreement therefore between Cl and3H as tools for recharge measurement is reasonable over the site.  相似文献   

4.
Private standards and certification schemes are widely acknowledged as playing an increasingly important role in agri-environmental governance. While much of the existing research concludes that these mechanisms consolidate the global extension of neoliberalism – enhancing the power of corporate actors to the detriment of smaller producers – we argue that this overlooks the complex ways in which standards are used by governments and farmers in the governing of farming practices. Focusing specifically on a process standard – Environmental Management Systems (EMS) – promoted by the Australian government as a way of verifying the ‘clean and green’ status of agricultural exports, we examine how one regional group of producers has sought to use EMS standards in practice. Our analysis of a case study in the state of Victoria appears to confirm that EMS was a successful instrument for the extension of neoliberal governance, reinforcing the production of neoliberal subjectivities and practices amongst farmer participants and enabling the government to compensate for gaps in environmental provision. However, it would be a mistake to interpret the development of this EMS scheme as an example of naïve farmers manipulated by the state. In practice, farmers used the opportunities provided by government funding to undertake actions which expressed their own agri-environmental values and practices. Establishment of an EMS and associated eco-label enabled producers to demonstrate and extend their capacity to act as good environmental stewards. Our research highlights how the local application of environmental standards negotiates and shapes, rather than simply contributes to, neoliberal rule.  相似文献   

5.
Leo Charles Zulu   《Geoforum》2009,40(4):686-699
This article uses insights from theory on the social production of scale and multiple social and natural science methods to interrogate village-scale community-based forest management (CBFM) in southern Malawi, focusing on boundary demarcation, rule formulation and scaling, and dynamics of external facilitation. Examination of political agendas of those who pursued, gained from, or protested particular scalar CBFM arrangements uncovered otherwise hidden scalar politics, whose outcomes impeded more than they advanced CBFM goals. I argue that clarifying the scalar politics and configuration of forest governance arrangements can lead to a more nuanced understanding of CBFM challenges and create new opportunities for addressing them. Containerized, single-level CBFM institutions mismatched interacting social, ecological and institutional scalar configurations and relations, and confounded CBFM. Unequal international-donor/national and national/community scalar relations were as important as intra-community dynamics in explaining performance of CBFM. They constructed CBFM on a shaky foundation that put institutional and personal agendas and short-term goals over long-term socioecological sustainability. The politics of rescaling forest rules from village to (broader) Traditional Authority level alienated them from communities and undermined enforcement. Diverse motivations behind a scale-related strategy that separated usufruct from territorial rights in allocating forests mostly undermined socioecological CBFM goals. While scale is not the key or only explanation of CBFM performance, negotiated scaling offered a proactive way to anticipate scale-related conflicts in particular settings, and for communities to create institutional forms that minimize such conflicts at local or intermediate scale levels. Findings support strong, well-resourced states and caution against donor-driven quick fixes.  相似文献   

6.
The presence of an independently dated marker in an archaeological site offers rare opportunities for assessing the reliability of radiocarbon dates, especially when these are close to the age limit of the technique. Two different pretreatment protocols (routine ABA and more rigorous ABOx-SC) were employed in the chemical preparation of the same charcoal sample from a layer closely associated to the Campanian Ignimbrite tephra at the Russian Palaeolithic site of Kostenki 14 (Markina Gora). The ABA-treated fraction gave an age of ∼33 14C ka BP, comparable to a previous determination from the same layer, whereas the ABOx-SC produced an older age of ∼35 14C ka BP. This is the first radiocarbon determination of an archaeological sample to provide an age consistent with the “calendar” age for the CI tephra marker.  相似文献   

7.
Natural resources, especially the forest provide a means of livelihood to rural communities in most developing countries. Unfortunately these resources are under the threat of disappearing because of high population growth rates and poverty that characterise these communities. Any attempt by development agencies at conserving these resources is tantamount to depriving these rural areas of their survival base. Yet due to its strategic socio-economic and cultural importance, the forest ecosystem needs to be sustained for future generations. This paper examines the various challenges faced by the State and other conservation agencies in natural resource management and the possible options which can be employed in an effort to ensure a sustainable exploitation of the forest in Anglophone Cameroon. It discusses the efforts of these actors, within the framework of the emerging concept of community forestry, local community strengthening and integrated rural development. While highlighting some of the achievements of international NGOs like Bird Life International and World Wide Fund for Nature in the region, the study concludes that the future of sustainable management of forest resources relies on a holistic poverty alleviation approach that takes into consideration the empowerment of these communities. This will ensure that they participate and benefit from the exploitation of the resources in the form of local development. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

8.
Thirteen years since the EU Habitats Directive (1992/43/EEC) became a binding legal agreement, this paper considers the implementation of this important European environmental legislation as it applies to the coastal activities of seaports and harbours. The paper examines the relationship between environmental legislation and ports policy, and seeks to provide a comprehensive assessment of the policy and science that has been developed in relation to protected areas and port management. The paper reports the results of a survey of European port professionals, and their perception of the successes and challenges of the management regimes that have been established, as well as their opinions on how these have influenced the management within ports. The paper also provides a detailed examination of the scientific and technical developments with particular regard to dredging and habitat management in European ports. Key research gaps are identified, including: practical approaches to licensing procedures; lack of baseline information, especially with regard to in-combination effects; the efficacy of techniques for mitigating the impacts of dredging; and greater understanding on how more resilient models for collaborative action can be developed. The paper will be of use to environmental planners, scientists, regulators, conservationists, and port managers, as they consider how to apply science and management to the sustainable development and environmental protection of coastal areas.  相似文献   

9.
David Correia 《Geoforum》2007,38(5):1040-1051
Recent research on environmental conflict in New Mexico has focused on racial and ethnic conflict between environmentalists and Hispanic loggers as a means to explain the trajectory of environmental struggle and the failure of Hispano/environmentalist coalitions opposing Forest Service management policies. This paper seeks to extend this explanation by considering the constraining role of federal legislation, institutional management and commercial resource exploitation that limited opportunities for Hispano/environmental collaborative challenges to federal resource management arrangements. I analyze the foundations of sustained yield forestry on the Carson National Forest in northern New Mexico though a focus on the legal construction of sustained yield policies and the practices of implementing sustained yield on the Vallecitos Federal Sustained Yield Unit, a special timber production sub-unit of the Carson. The paper illustrates how the deployment of sustained yield forestry in New Mexico produced not only conditions of production favorable to commercial timber operators, but also established a complex and contradictory regulatory environment that effectively constrained collaborative efforts between environmentalists and small-scale loggers in their efforts to construct alternative futures for resource management in the region.  相似文献   

10.
11.
The causes of forest cover loss in the hill forests in Bangladesh   总被引:1,自引:0,他引:1  
The Hill Forests in Bangladesh have been depleted and degraded in volume, area, and quantity, thus requiring urgent forest protection by identifying the causes of forest loss. This study seeks to identify the fundamental causes of the shrinking forest cover in the Hill Forests in Bangladesh. The results indicate four sets of causes: (i) indigenous forest dwellers, having their own types of problems; (ii) migrants, who, because of problems in their places of origin, have decided to move to the forests; (iii) the timber industry, which, legal or not, are cutting too many trees; and (iv) the government through its Forest Department which is not able or willing to implement suitable policies to regulate the cutting trees and to prevent illegal cutting. Because it is a time consuming task to mitigate the first and second sets of factors, we recommend to involve forest dwellers in forestry practices as much as possible and taking necessary steps to alleviate the third and fourth sets and thereby reduce the rate of forest depletion. Accordingly, a number of strategies that should be adopted to halt the loss of remaining forest cover are discussed. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

12.
J.A.G. Cooper  J. McKenna 《Geoforum》2008,39(1):294-306
Coastal erosion management is primarily based on economic considerations (cost-benefit analysis). From the perspective of social justice (as a particular expression of the wider concept of human rights), however, several arguments can be advanced regarding public intervention in coastal defence management when private property is threatened by coastal erosion. In this paper we examine these arguments at both the short-term local scale and the long-term large spatial scale and consider the merits of inclusion of a social justice dimension in coastal erosion management. The coast provides a range of resources that benefit society as a whole. Coastal residents and property owners face a direct financial loss from coastal erosion but the general public also stands to incur losses other than purely financial if it there is public intervention for the benefit of these property owners. The arguments for public intervention are strongest at the local and short-term scales but they weaken (and even reverse) at geographically larger and longer time scales. At larger scales, the costs to society increase as intergenerational equity, non-coastal residents, climate and sea level change, and the environment are considered. Because of the intensity of interest involved at the local level, we argue that the necessary hard decisions must be made nationally if a sustainable policy is to be adopted. Social justice considerations provide a potential improvement on the traditional economic cost/benefit-based decision-making process of coastal erosion management but they only contribute to sustainability if viewed at the national level.  相似文献   

13.

辽西地区是研究中国文明起源及早期文明化进程的重要区域。红山文化是辽西地区6.5~5.0 ka B.P. 的新石器时代晚期重要的考古学文化。本研究对辽西地区红山文化时期的魏家窝铺遗址、彩陶坡遗址、兴隆沟遗址第二地点和牛河梁遗址第一地点这4个遗址点中浮选和采集的134份样品中大于2 mm的940块木炭进行鉴定,分别是栎属(Quercus L.)、榆属(Ulmus L.)、朴属(Celtis L.)、李属(Prunus L.)、槭树属(Acer L.)、黄檗属(Phellodendron Rupr.)、椴属(Tilia L.)、梣属(Fraxinus L.)、胡桃属(Juglans L.)、松属(Pinus L.)、柳属(Salix L.)、侧柏属(Platycladus L.)等12种木本植物,以及2种未知的炭化植物遗存。研究表明遗址周围分布着桃、杏、胡桃楸等果树,生长着以栎属为建群种的暖温带落叶阔叶林及榆属、槭树属和朴属等阔叶树;山地上可能分布着由松属、侧柏属和黄檗属、椴属、梣属等组成的温性针阔混交林。利用共存生态因子法进行气候重建的结果表明,当时遗址周围的环境较现今温暖湿润。先民用栎属木材建造房屋、薪柴选用栎属、松属和槭树属木材。通过对牛河梁遗址第一地点出土的木炭推测当时祭祀时可能使用栎属木材。除了遗址中出土的炭化果核,核果类木材的出土,进一步佐证了先民会采集核果类木材的果实、种子作为食物,为探索红山文化时期先民生业方式提供了新视角。本研究为解读红山文化时期的先民对林木资源利用策略,了解当时生态环境与生业模式提供了新资料。

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14.
Groundwater over-exploitation has been on the rise in Jordan. Competing demands have grown in the face of perennial water shortages, a situation which has been exacerbated by drought conditions in the past decade. This paper reports findings of a project in which management options to address over-exploitation were developed for one of Jordans principal aquifer systems, the Amman-Zarqa Basin. Options for addressing the situation were developed through a participatory approach that involved government officials and various public and private sector interest groups. Particular efforts were made to involve well irrigators, who are likely to be heavily impacted by the changes required to reduce groundwater pumping to a sustainable level. With information obtained from a rapid appraisal survey as well as from interviews with farmers, community groups, government officials, and technical experts, an extensive set of options was identified for evaluation. Based on integrated hydrogeologic, social, and economic analysis, five complementary management options were recommended for implementation. These included the establishment of an Irrigation Advisory Service, buying out farm wells, placing firm limits on well abstraction and irrigated crop areas, exchanging treated wastewater for groundwater, and measures to increase the efficiency of municipal and industrial water use. Various combinations and levels of these options were grouped in scenarios, representing possible implementation strategies. The scenarios were designed to assist decision makers, well owners and other stakeholders in moving gradually towards a sustainable abstraction regime. Social and economic aspects of each option and scenario were analyzed and presented to stakeholders, together with a summary of legal, institutional and environmental ramifications. Combining scientific analysis with a participatory approach in the Amman Zarqa Basin groundwater management was devised as a prototype to be used in the management of other groundwater basins in Jordan. This participatory management approach would also be useful in other parts of the world that are experiencing similar groundwater over-exploitation problems.Résumé La surexploitation des eaux souterraines prend de limportance en Jordanie. Les demandes en concurrence ont augmenté face à des déficits permanents deau, situation qui a été exacerbée par la sécheresse de la dernière décennie. Cet article rend compte de laboutissement dun projet dans lequel des options de gestion portant sur la surexploitation ont été développées pour lun des principaux systèmes aquifères de Jordanie, le bassin dAmman Zarqa. Des options pour aborder cette situation ont été développées grâce à une approche participative qui implique des fonctionnaires du gouvernement et des groupes dintérêts variés des secteurs public et privé. Des efforts particuliers ont été faits pour impliquer les irrigants utilisant des puits, qui sont probablement ceux qui ont le plus fort impact sur les changements attendus permettant de remettre le système en équilibre. À partir des informations obtenues de campagnes rapides dévaluation, telles que des réunions de communautés et des entrevues avec des experts techniques du gouvernement, un large jeu doptions a été identifié pour lévaluation. Basées sur une analyse hydrogéologique, sociale et économique, cinq options complémentaires de gestion ont été recommandées pour la réalisation. Ce sont la création dun Service Consultatif dIrrigation, achetant les puits agricoles, fixant des limites fermes aux prélèvements des puits et aux zones irriguées, échangeant les eaux usées traitées avec des eaux souterraines, et la mise en place de mesures pour accroître lefficacité des usages collectifs et industriels. Des combinaisons et des niveaux variés de ces options ont été regroupés en scénarios, présentant les stratégies possibles de mise en uvre. Les scénarios ont été mis au point pour assister les décideurs, les propriétaires de puits et les autres acteurs pour atteindre progressivement un régime de prélèvement durable. Les aspects sociaux et économiques de chaque option et de chaque scénario ont été analysés et présentés aux acteurs, en même temps quun résumé des ramifications légales, institutionnelles et environnementales. En combinant une analyse scientifique à une approche participative du bassin dAmman Zarqa, la gestion des eaux souterraines a été imaginée comme un prototype pouvant être utilisé pour la gestion dautres bassins aquifères de Jordanie. Il peut également être utile à dautres régions du monde qui sont concernées par des problèmes similaires de surexploitation des eaux souterraines.Resumen La sobreexplotación de las aguas subterráneas ha ido en aumento en Jordania, donde las demandas en competición han crecido frente a una escasez perenne de agua, situación que ha sido agravada por el estado de sequía de la última década. Este artículo presenta los hallazgos de un proyecto en el que se han desarrollado opciones de gestión para hacer frente a la sobreexplotación en uno de los principales sistemas acuíferos de Jordania: la cuenca de Ammán-Zarga. Se ha elaborado opciones para afrontar la situación mediante un enfoque participativo que incluye a personal del gobierno y a diversos grupos de interés de los sectores público y privado. En particular, se ha intentado involucrar a los regantes que se sirven de aguas subterráneas, quienes tienen más probabilidad de ser directamente afectados por los cambios requeridos para devolver el sistema a un balance equilibrado. A partir de la información obtenida en rápidas campañas de valoración, así como de encuentros con la comunidad y entrevistas con los expertos técnicos del gobierno, se ha identificado un amplio conjunto de opciones para su evaluación. Basándose en un análisis integrado de los aspectos hidrogeológicos, sociales y económicos, se ha recomendado la implementación de cinco opciones complementarias de gestión: establecimiento de un Servicio Asesor de Riego; adquisición de pozos de granjas; imposición de límites estrictos en las extracciones de pozos y superficies de riego; substitución de las aguas subterráneas con aguas residuales depuradas; y medidas para incrementar la eficiencia de los usos municipales e industriales del agua. Se ha agrupado varias combinaciones y niveles de dichas opciones en escenarios, representando estrategias posibles de implementación. Los escenarios han sido diseñados para ayudar a los gestores en la toma de decisiones, a los propietarios de pozos y a otros agentes para que se vaya consiguiendo de forma gradual un régimen de extracciones sustentable. Se ha analizado los aspectos sociales y económicos de cada opción y de cada escenario, presentándolos a los diversos agentes, además de generar un resumen de ramificaciones legales, institucionales y medioambientales. Se ha concebido la combinación de un análisis científico con un enfoque participativo en la cuenca de Ammán-Zarga como un prototipo de gestión de las aguas subterráneas que puede ser aplicado a la gestión de otras cuencas en Jordania. También sería útil en otros lugares del mundo que estén experimentando problemas similares de sobreexplotación de los recursos hídricos subterráneos.Abbreviations and acronyms AED Academy for Educational Development - ARD Associates in Rural Development - AZB Amman–Zarqa Basin - ECC Economic Consultative Council - GMCC Groundwater Management Consultative Committee - GMF Groundwater Management Fund - GIS Geographic Information System - HDH Hashmiya–Dulayl–Hallabat - IAS Irrigation Advisory Service - JICA Japanese International Cooperation Agency - M&I Municipal and Industrial - MOA Ministry of Agriculture - MWI Ministry of Water and Irrigation - NCARTT National Center for Agricultural Research and Technology Transfer - NGO Non-governmental Organization - O&M Operations and Maintenance - RA Rapid Appraisal - RS Remote Sensing - UFW Unaccounted for Water - USAID United States Agency for International Development - WAJ Water Authority of Jordan - WEPIA Water Education & Public Information Activity - WRPS Water Resource Policy Support  相似文献   

15.
Surface water samples from the Drake mining area show elevated metal concentrations, notably cadmium, iron and zinc. A detailed study of a sphalerite /quartz vein from Strauss Pit and chalcopyrite and pyrite from the Adeline mine and Strauss Pit indicate that micro-scale analyses of ores are necessary for environmental management of mine sites. Analyses show that Cd is elevated, up to 2.1 % by weight, and is associated with sphalerite, replacing Zn, or to a lesser extent replacing Pb within small galena grains. High concentrations of Cu are also associated with the Strauss Pit ore as small chalcopyrite grains along the margins of the sphalerite vein, within the central quartz zone of the vein system, and as replacement rims on sphalerite grains. Chalcopyrite from the Adeline mine area, is by comparison, metal poor, but still contains elevated heavy metal concentrations. Whereas, pyrite and chalcopyrite, from Strauss Pit have variable heavy metal concentrations, with chalcopyrite from within sphalerite veins having higher Cd and Zn concentrations than chalcopyrite distal to the veins. Cadmium and other heavy metals within the ores are mobilised during sulphide weathering and enter the drainage network; precipitation of secondary oxidation minerals act as temporary stores for many heavy metals. The complexity of the mineral and heavy metal associations at Strauss Pit suggest that a detailed knowledge of these associations and distributions within ore bodies, and associated waste rocks, are needed by environmental managers of mine sites because the presence of havy metals may greatly affect the decision making process, and management strategies employed. Received; 14 July 1999 · Accepted: 17 August 1999  相似文献   

16.
The vegetation of the treeline ecotone of the southern declivity of arid High Asia (Hindu Kush, northern areas of Pakistan; Himalaya, northern central Nepal) is dominated by hedgehog-like open dwarf shrublands of thorny cushions. Since climatically sensitive ecotones are always also sensitive to human impact, the question arises whether the current lack of forests is a result of the Subboreal climate decline or of human impact. Due to inadequate knowledge of the pollen flora and of ecological indicator values of the plants, pollen analyses in High Asia have mainly been limited to the regional verification of globally known climatic impulses. However, the role of human impact on regional vegetation patterns has been widely neglected. We postulate that today's open dwarf shrublands replace woodlands and forests. Isolated vigorous juniper trees and successful reforestation appear to confirm our hypothesis. An abrupt decline of Pinus forests before 5700 and 5400 ka cal yr BP can be demonstrated. As the first indicator pollen of human impact appeared at both sites synchronous with the forest pollen decline, we infer human impact to be a more decisive cause for this environment change superimposing the effects of a climatic deterioration. The forests were displaced by open dwarf shrublands.  相似文献   

17.
为了更直观地反映天然林资源保护工程(以下简称“天保工程”)对森林生态系统涵养水源和保育土壤功能产生的影响,体现天保工程所带来的生态效益,依据《森林生态系统服务功能评估规范(GB/T 38582—2020)》,以内蒙古大兴安岭重点国有林管理局的林区为研究对象,对天保工程实施前(1998年)和实施后(2018年)2期森林生态系统涵养水源和保育土壤功能进行量化分析,认为内蒙古大兴安岭重点国有林管理局林区(简称“内蒙古森工林区”)涵养水源价值为950.16亿元(1998年)和1 341.32亿元(2018年),保育土壤的价值为563.49亿元(1998年)和760.11亿元(2018年)。天保工程实施前后,森林生态系统涵养水源功能总价值量排名前3位的林业局依次是根河、莫尔道嘎、乌尔旗汉,保育土壤功能排名前3位的依次是根河、乌尔旗汉、金河。从整体空间分布上分析得出的2期涵养水源和保育土壤功能价值量均呈现中部>北部>南部的趋势。  相似文献   

18.
The world is facing a severe water crisis. According to the UN, by 2025 50% of the world’s population will face water scarcity. In India, where 70% of irrigation and 80% of domestic needs are met with groundwater, demand for this resource is expected to exceed supply by 2020. This has led to recent calls for groundwater governance reforms within India, and specifically within the state of Rajasthan, where no regulation exists today. The success of these reforms hinges on the interaction of the state and its agents with local users and managers of groundwater resources. Underpinning these encounters, though, are tensions between local and state forms of groundwater knowledges. The question analyzed here is in what ways do conflicting environmental knowledges adversely affect the management of overexploited groundwater resources in water-scarce India? To address this question, I examine the coevolution of pre-colonial, colonial, and post-independence groundwater and irrigation knowledges and technologies in Rajasthan, India to expose the ways that they are produced, contested, legitimated, and hybridized. The paper argues the following three claims. First, the relationship between the state and local producers of groundwater knowledge practices is non-linear and porous. For instance, the way that state subjects experience the state is uneven because within and in-between historical moments the state may attempt to assimilate, reorganize, plagiarize, or disparage local knowledge. Second, these attempts produce or exacerbate existing historically rooted tensions between farmers and state groundwater engineers. But in response, farmers often seek out non-state avenues of expertise, such as tubewell drilling firms. This results in the further hybridization of knowledge practices and also in the present-day marginalization of the state. Third, the relationship between farmers and the state is further strained because of a current lack of state visibility in the study area and also because the state continues to “see like a state”. These shifting meanings and power relations around groundwater and irrigation knowledges produce tensions that will undoubtedly negatively impact future groundwater governance strategies.  相似文献   

19.
This paper deals with the morphotectonic evaluation of the Delhi region in northern India to understand its impact on land use and urban development. To accommodate heavy urbanization and population rise (being the capital of India), the area has undergone tremendous environmental degradation resulting from a mismatch between adopted land use and morphotectonic considerations. The geomorphic and drainage signatures of the region have evolved out of interaction of varied geological parameters including neotectonic activities. We have evaluated the changes in the drainage pattern of the Yamuna River in the Delhi region to underline its significance in geomorphic evolution and subsequent land use and/or land suitability. The Yamuna River has shown variations both in channel position and geometry over the last two centuries. The observed migration pattern of the river (shifting of confluences, position and disposition of palaeochannels, etc.,) cannot be attributed to normal river phenomenon and appears to have been effected by neotectonic changes. In addition, some case studies are discussed to underline the significance of geomorphic factors in urban development.  相似文献   

20.
贡嘎山暗针叶林区森林蒸散发特征与模拟   总被引:5,自引:0,他引:5       下载免费PDF全文
通过对贡嘎山森林区的蒸发实验观测,利用修正的Penman-Monteith公式对地面和冷杉林蒸散进行模拟,并与水面实际观测资料进行对比。结果显示:控制该区蒸散的主导因子是太阳有效辐射、大气温度以及植被类型;对裸地、灌草、森林模拟的年内变化过程与水面蒸发的实际观测值趋势一致,分别在4月和9月出现两个明显的蒸发高峰。原始Penman公式可以用于裸露地面和短草地面的蒸发计算,然而对森林蒸散发应采用Penman-Monteith公式模拟,其模拟结果显示,在非生长季节森林蒸散发低于非森林地面,而在森林生长季节的蒸散发比非林地要高,其变化差异在±25%之间。因此修正的Penman-Monteith公式是森林地区水量平衡计算的有效工具。  相似文献   

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