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排序方式: 共有2584条查询结果,搜索用时 15 毫秒
961.
一个城市的适度人口规模既与经济发展水平密切相关,它是由所在地区的资源、环境等因素决定的。秦皇岛市是中国北方极度缺水的城市一,水资源构成了限制城市发展的短板因素。通过调整用水结构和采用节水技术,虽可使城市居民的用水份额适度增加,但总量约束决定了该城市的人口规模要保持在与水资源相适应的限度内。 相似文献
962.
Resource management issues continually change over time in response to coevolving social, economic, and ecological systems.
Under these conditions adaptive management, or “learning by doing,” offers an opportunity for more proactive and collaborative
approaches to resolving environmental problems. In turn, this will require the implementation of learning-based extension
approaches alongside more traditional linear technology transfer approaches within the area of environmental extension. In
this paper the Integrated Systems for Knowledge Management (ISKM) approach is presented to illustrate how such learning-based
approaches can be used to help communities develop, apply, and refine technical information within a larger context of shared
understanding. To outline how this works in practice, we use a case study involving pest management. Particular attention
is paid to the issues that emerge as a result of multiple stakeholder involvement within environmental problem situations.
Finally, the potential role of the Internet in supporting and disseminating the experience gained through ongoing adaptive
management processes is examined. 相似文献
963.
Strange E Galbraith H Bickel S Mills D Beltman D Lipton J 《Environmental management》2002,29(2):290-300
The amount of ecological restoration required to mitigate or compensate for environmental injury or habitat loss is often
based on the goal of achieving ecological equivalence. However, few tools are available for estimating the extent of restoration
required to achieve habitat services equivalent to those that were lost. This paper describes habitat equivalency analysis
(HEA), a habitat-based “service-to-service” approach for determining the amount of restoration needed to compensate for natural
resource losses, and examines issues in its application in the case of salt marsh restoration. The scientific literature indicates
that although structural attributes such as vegetation may recover within a few years, there is often a significant lag in
the development of ecological processes such as nutrient cycling that are necessary for a fully functioning salt marsh. Moreover,
natural variation can make recovery trajectories difficult to define and predict for many habitat services. HEA is an excellent
tool for scaling restoration actions because it reflects this ecological variability and complexity. At the same time, practitioners
must recognize that conclusions about the amount of restoration needed to provide ecological services equivalent to those
that are lost will depend critically on the ecological data and assumptions that are used in the HEA calculation. 相似文献
964.
965.
分析了国内当前危险废物治理工作中普遍存在的问题及原因,对解决这些问题的方法进行了探讨,并对危险废物的管理工作提出了建议,同时结合国内外的成功经验,提出了一些新的思路。 相似文献
966.
通过对甘肃省河西走廊农业自然资源优势的分析,本文讨论了光热资源和水资源潜力的开发利用,提出用高新技术手段建立集约化的半闭路式生态农业生产体系,促进河西走廊农业再上新台阶. 相似文献
967.
Indigenous people and mineral taxation regimes 总被引:1,自引:0,他引:1
Ciaran O'Faircheallaigh 《Resources Policy》1998,24(4):187-198
Indigenous people in a number of major mineral-producing countries have established a substantial and growing capacity to tax mineral resources extracted from their traditional lands. However, almost no analysis has been conducted regarding the conceptual and practical issues involved in designing mineral taxation regimes for use by indigenous people. The general literature on mineral taxation is of limited relevance because basic assumptions it makes regarding the nature of the taxing authority (national or state governments) do not apply to indigenous peoples. This article discusses some key characteristics of indigenous communities as they relate to taxation of mineral resources. Against this background, it identifies a number of approaches to mineral taxation which might be utilized by indigenous groups and which acknowledge the specific constraints and circumstances they face while at the same time recognizing their need to attract and maintain investment on their traditional lands. It also reviews the inter-relationship between indigenous and state or governmental tax regimes. 相似文献
968.
Margot W. Garcia 《Environmental management》1989,13(5):583-592
The National Forest Management Act and National Environmental Policy Act require the use of an interdisciplinary team (ID team) to do integrated resource planning for the National Forests and the concurrent environmental analysis. A survey sent to all National Forest planning officers (82% response) reveals the composition of the ID teams used in integrated resource and land management planning. More than half the National Forests ID teams met NEPA and NFMA compositional requirements. National Forest planners recount their experiences with these ID teams. Despite frustrations with many aspects of the ID teams, the planners strongly support the idea that ID teams are an important part of the land-use planning process and think that their use leads to better National Forest integrated resource plans. 相似文献
969.
Erik R. Hagen K. John. Holmes Julie E. Kiang Roland C. Steiner 《Journal of the American Water Resources Association》2005,41(6):1417-1430
The three largest water utilities in the Washington, D.C., metropolitan area (WMA) rely on the Potomac River and its reservoirs for water supply. These utilities have committed to a periodic review of the system's adequacy to meet future demands. In 1990, 1995, 2000, and again in 2004 (for publication in 2005) the utilities requested that the Interstate Commission on the Potomac River Basin (ICPRB) conduct a 20‐year water demand and resource adequacy study to fulfill this need. The selection of the five‐year interval provides multiple benefits. It allows regular updates and incorporation of recent demographic forecasts, and it increases visibility and understanding of the adequacy of the region's water resources. It also provides adequate time to conduct research on the physical system and to incorporate modifications based on this research into subsequent studies. The studies and lessons learned are presented in this case study of the WMA. The work has been a natural outgrowth of a long history of cooperative water supply planning and management among the main WMA water utilities and ICPRB. 相似文献
970.
捕食性瓢虫是重要的天敌昆虫,有利于害虫的生物防治.为查清西藏林芝地区农田瓢虫资源与种群现状,明确优势种类及种群动态和规律,对林芝不同生态区域的青稞、小麦、油菜3种作物农田开展瓢虫资源调查研究,同时选取固定样地定期进行种群动态分析.结果显示:林芝地区农田瓢虫分为2个亚科4个族10个属,共13种,其中11种为捕食性瓢虫.主要优势瓢虫种类为横斑瓢虫、多异瓢虫、二星瓢虫.其中横斑瓢虫在全部调查样地中均有分布,在农田中总体优势度指数、相对多度为最高.3种优势瓢虫在不同作物中种群动态变化规律存在差异,其中横斑瓢虫虫口密度长期高于其余优势瓢虫,且与蚜虫密度曲线有较为明显的重合现象.横斑瓢虫种群密度峰值主要集中在6月中旬至7月上旬,但在不同作物农田中具体峰值时期存在差异.可见,林芝地区农田不同种类瓢虫之间有较大数量差异,在不同生态区域与作物环境下具有不同的种群特征,但是优势瓢虫种类与种群规律较为明确,可用于农田蚜虫生物防治;结果可为保护当地重要昆虫资源及开展生物防治提供基础数据支撑.(图4表6参23) 相似文献