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981.
In northeastern America, thousands of kilometers of utility rights-of-way (ROWs) have to be managed to prevent the establishment of a tall vegetation cover that does not comply with safety and maintenance regulations. Recent decades have seen the emergence of ecologically based vegetation control strategies to reduce environmental impacts as well as maintenance costs. One such strategy is to take advantage of competitive herbaceous covers to limit tree invasion. This approach, however, as well as its fundamental underlying principles, has been little scrutinized. In this article, (1) we present the main ecological concepts supporting the use of a herbaceous cover to limit tree invasion, emphasizing naturally forested ecosystems of northeastern America. They include reported evidence of stable plant communities and an overview of potential underlying mechanisms of inhibition. (2) We then review field applications, specifically testing the ability of seeded herbaceous covers to control tree invasion in ROWs. (3) We discuss unresolved issues relevant to management and research. The available evidence suggests that seeding herbaceous covers in ROWs can help control tree invasion, but many issues still limit broad-scale applications. The various interactions that govern plant community dynamics are far from being fully understood, so selecting species still largely depends on an empirical approach. Patterns of resistance to tree invasion must be investigated over a wide range of spatial, historical, and environmental contexts to determine effective management and seeding practices that will lead to broad-scale applications. We suggest establishing communities rather than single dominant species and using as much as possible native species to limit risks of invasion.Published online 相似文献
982.
983.
984.
REALM (REsource ALlocation Model) is a generalised computer simulation package that models harvesting and bulk distribution of water resources within a water supply system. It is a modeling tool, which can be applied to develop specific water allocation models. Like other water resource simulation software tools, REALM uses mass-balance accounting at nodes, while the movement of water within carriers is subject to capacity constraints. It uses a fast network linear programming algorithm to optimise the water allocation within the network during each simulation time step, in accordance with user-defined operating rules. This paper describes the main features of REALM and provides potential users with an appreciation of its capabilities. In particular, it describes two case studies covering major urban and rural water supply systems. These case studies illustrate REALM's capabilities in the use of stochastically generated data in water supply planning and management, modelling of environmental flows, and assessing security of supply issues. 相似文献
985.
Roberto Schaeffer Alexandre Salem Szklo Fernando Monteiro Cima Giovani Machado 《Natural resources forum》2005,29(4):284-297
This article summarizes the results of the project on indicators for sustainable energy development (ISED) in Brazil. The project's aim was to present energy related economic, social and environmental data to policy makers in a coherent and consistent form, showing interlinkages, time‐series and cross‐sectoral analyses and assess energy policy. Two priority areas assessed by these indicators, regarding the country's energy supply and demand, helped in the identification of a number of energy policy options that focused on specific aspects of the country's energy sector. On the supply side, these options include the development and stimulation of renewable energy, such as small‐scale hydroelectric, wind, solar photovoltaic power and bagasse cogeneration; stimulation of programmes for ethanol use as automotive fuel and sugarcane bagasse cogeneration; and implementation of natural gas‐fired, combined heat and power (CHP) plants. On the demand side, policy options include: the full implementation of the law on efficiency standards for appliances; expansion of utility investment in end‐use energy efficiency; adoption of targets and protocols to reduce energy intensity in the industrial sector; improvement of passenger transport efficiency; and the creation of a fund to improve energy affordability for the poor. 相似文献
986.
Indicators for sustainable energy development in Mexico 总被引:1,自引:0,他引:1
José Antonio Medina-Ross Juan C. Mata-Sandoval Roberto López-Pérez 《Natural resources forum》2005,29(4):308-321
This article presents a summary of a study on the application to the Mexican energy sector of a core set of indicators for sustainable energy development (ISED), developed by the International Atomic Energy Agency (IAEA). The study focused on the elaboration of socio‐economic and environmental indicators related to energy production and use, and was aimed at assessing Mexico's existing energy policies and identifying strategies and possible policies that could bring about improvements in major priority areas: energy intensity, atmospheric emissions, energy import dependency and use of renewables. While positive trends have been observed in relation to energy intensity and atmospheric emissions, Mexico is becoming more dependent on imports of gasoline, natural gas and other high‐value secondary energy sources, while exporting significant amounts of primary fuels, such as crude oil. Also, no significant increase has been observed in the use of renewable sources of energy. Social, economic and environmental policies need to be formulated for the energy sector and related investments (public and private) reinforced so that all economic sectors have access to energy from cleaner and more diverse sources. 相似文献
987.
This article presents an assessment of Russia's energy sector, its current state and planned future direction. The analysis of Russia's energy trends is based on a set of indicators for sustainable energy development (ISED), developed under the leadership of the International Atomic Energy Agency (IAEA). The article discusses Russia's Energy Strategy to 2020, and outlines major developments and challenges of the country's energy system. Russia's energy priorities, captured in the Strategy to 2020, emphasize securing a stable and uninterrupted energy supply; reducing energy intensity and improving energy efficiency; developing the domestic energy resource base; reducing negative environmental impacts; and ensuring affordable energy for the poorer segments of the population. Energy needs and challenges are discussed in relation to the three aspects of sustainability as defined in Agenda 21: economic, social and environmental. Concerns are expressed regarding environmental repercussions of energy development, in particular since Russia's 1998 economic rebound. There are also concerns, despite the economic recovery, that anticipated increases in energy tariffs may exceed the affordability of poorer segments of the population. 相似文献
988.
Fridtjof Unander 《Natural resources forum》2005,29(4):377-391
The International Energy Agency (IEA), together with the International Atomic Energy Agency (IAEA), UN‐DESA, Eurostat and the European Environmental Agency, has recently published a comprehensive joint‐agency overview of energy indicators for sustainable development. The IEA's contribution to this publication is based on the IEA energy indicator approach. This approach has been developed and used by the IEA over a number of years. The indicators advocated by the IEA are relatively disaggregated to allow for meaningful analysis of sustainability issues in the energy sector. Using a decomposition approach helps reveal the causal links between human/economic driving forces, energy use and emissions. This article presents examples of IEA's work with indicators and an overview of the methodology used, including an explanation of the link to sustainable development. It also provides an example of a simplified indicator analysis of India, to illustrate the importance of improved data systems in developing indicators that can provide meaningful policy analysis. 相似文献
989.
Contributing elements toward the development of a sustainable solid waste management system in Tucumán, Argentina, are described. Changes in the working environment for the wastepickers have been instrumental in providing a livable wage and diminished health and environmental risks to the wastepickers and to neighboring residents. Income levels to the wastepickers are now approximately 1.75 times minimum wages in Tucumán and are being driven almost entirely by the recycling of plastics. Educational improvements in Tucumán, which are assisting sustainability of the solid waste system, are being significantly improved by the operation of a pilot scale project, by demonstrating opportunities to government officials and school children. Improved financial sustainability to the solid waste management system is also potentially available from carbon credit trading opportunities, presenting the opportunity for 1.2 times the income available from recycling efforts. 相似文献
990.
淮北市采煤塌陷区的土地复垦 总被引:4,自引:0,他引:4
安徽省淮北市的淮北矿区是我国重要的十大煤炭生产基地之一,现有大小煤矿30余座.长期以来,因采煤而造成的塌陷土地累计达14667hm2,由此引起的地貌变形、房屋倒塌、生态环境恶化等灾害,严重影响了当地工农业生产和人们的生活.因此,加强对采煤塌陷区土地复垦的研究极为重要.在实地考察和有关数据分析的基础上,将淮北矿区因采煤塌陷而被破坏的土地分为四个区,总结出两大土地复垦模式,并对复垦后的土地利用进行适宜性评价. 相似文献