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91.
Contrary to many studies regarding the efficient use of resources that measure the marginal cost of nature conservation by looking at a specific objective and asks about efficient way to achieve it, this article tries to estimate the (marginal) cost of nature conservation in a more flexible way. Instead of looking at a specific objective and then not being able to compare different objectives, we take an approach that is based on experts’ valuation of increased satisfaction from nature conservation. We trace the marginal cost of conservation from their answers and use official cost statistics. Officials in the Israeli Nature and Parks Authority (NPA) were surveyed to determine the activities required to increase the level of nature conservation in two districts of the NPA as well as nationwide. We determined the costs of these proposed activities, and subsequently were able to calculate the total cost and marginal cost of conservation efforts. When operating on a limited budget, conservation authorities can use these schedules as an additional tool to help determine the efficiency of different proposed activities both on a regional scale and nationwide, and to ensure the sustainability of the resulting conservation. In addition, our results demonstrate the existence of economies of scale in nature conservation, and the benefit of both bottom-up and top-down decision processes in nature conservation.  相似文献   
92.
Security buffers of Department of Defense (DoD) and Department of Energy (DOE) reservations provide long-term habitat protection for many rare and endangered species. The importance of these government-owned reservations as nationally valuable resources has been relatively unrecognized. During the last 50 years, the DOE Oak Ridge Reservation (ORR) has been a relatively protected island in a region of rapidly expanding urbanization and land clearing. Consisting of the Oak Ridge National Environmental Research Park and associated lands surrounding DOE facilities at Oak Ridge Tennessee, the unique nature of the ORR in the surrounding landscape is clearly visible from the air and has been documented using remote sensing data. Although forests dominate much of other regions of eastern Tennessee, this 15,000-ha tract of mostly natural forest habitat is unique in the southern Ridge and Valley physiographic province, which is otherwise widely developed for pasture, marginal cropland, woodlot, and urban uses. Twenty state-listed and federal-candidate plant species are known to be present on the ORR. This richness of species, which are provided protection by state and federal laws, exceeds that of the Great Smoky Mountains National Park on a species area basis and is an index of the value of the ORR both regionally and nationally in conserving biodiversity. With the end of the Cold War, changing DoD and DOE missions combined with increasing development pressure contribute to uncertainty in the future management of security reservations.  相似文献   
93.
Cooperation between the United States Department of Agriculture (USDA) Forest Service and the United States Department of Interior (USDI) National Park Service is most often advocated to protect biological diversity on national forests and parks, but the agencies, so far, have done little to implement the biodiversity mandates of such laws as the Endangered Species Act and the National Forest Management Act. The ideological and political history of the Forest Service and Park Service is explored to determine the roots of interagency conflicts. Several recent models of cooperative reform are also critiqued and found to be insufficient to stimulate better working relationships. To protect biodiversity, cooperation must be framed within conservation biology and must place primary emphasis on ecosystem patterns and processes as well as on individual species. Increased education of agency managers, ecosystem-level research, local and regional public participation, scientific oversight committees, new legislation, and enlightened leadership also play important roles. Ultimately, management policies must be reframed within a context of ecocentric values.  相似文献   
94.
哈尔滨市区绿地对交通噪声衰减效果研究   总被引:1,自引:0,他引:1  
2007年4月6日-5月30日,采用HS-5633型数字声级仪分别对哈尔滨市区六处主要交通干道进行交通噪声测量,同时在干道周围的绿地进行对比测量,并将所得数据进行分析统计。结果表明,绿地(包括各类林地、草坪、隔离带及其不同组合)对交通噪声的衰减可达2dB(A)以上,减噪效果十分明显,减噪数值与绿地宽度和绿地植被组成有密切关系。因此,应对城市中各种类型的绿地及其组成的混合林地种植予以足够、有效的重视,如高大乔木+灌木、常绿树+草坪、乔木+灌木+草坪等配置紧凑的绿地类型,并应加大保护力度。  相似文献   
95.
滨海砂矿是目前全球最大的潜在矿产资源之一。以莫桑比克的滨海砂矿作为研究对象,利用光学显微镜、X射线衍射、扫描电镜、等离子体质谱(ICP-MS)等手段对莫桑比克东部滨海砂矿的矿物组成及特征进行了研究。并用数理统计方法讨论了重砂矿的元素赋存状态及其载体矿物。研究结果表明:(1)砂矿的矿石矿物主要为钛铁矿、金红石和锆石,脉石矿物主要为石英和长石。(2)重砂矿的主要化学组分为Ti和Zr;Hf及REE为次要组分;而主要有害元素组分Th和U,其总体含量低,故重砂矿对采选加工和产品利用均无明显环境危害。(3)重砂矿中元素含量与粒度之间呈一定相关性,显示Zr、Hf、U、Cr、Ta的载体矿物的粒度相对较细;Ti、Fe、V、Nb的载体矿物的粒度相对较粗。  相似文献   
96.
The impacts of climate change on potential rice production in Asia are reviewed in the light of the adaptation to climatic variability and change. Collaborative studies carried out by IRRI and US-EPA reported that using process-based crop simulation models increasing temperature may decrease rice potential yield up to 7.4% per degree increment of temperature. When climate scenarios predicted by GCMs were applied it was demonstrated that rice production in Asia may decline by 3.8% under the climates of the next century. Moreover, changes in rainfall pattern and distribution were also found suggesting the possible shift of agricultural lands in the region. The studies however have not taken the impacts of climatic variability into account, which often produce extreme events like that caused by monsoons and El Niño. Shifts in rice-growing areas are likely to be constrained by land-use changes occurring for other developmental reasons, which may force greater cultivation of marginal lands and further deforestation. This should be taken into account and lead to more integrated assessment, especially in developing countries where land-use change is more a top-down policy rather than farmers' decision. A key question is: To what extent will improving the ability of societies to cope with current climatic variability through changing design of agricultural systems and practices help the same societies cope with the likely changes in climate?  相似文献   
97.
本文基于完全信息的经典双寡头古诺模型,构建不完全信息——不同理性程度的动态三寡头博弈模型,对三个寡头企业作出异质性理性的假设:天真理性、有限理性和适应性预期的理性行为,将传统博弈理论和动力系统的分岔理论相结合,模拟排污权交易市场中的寡头厂商行为,在假设企业是通过在排污权交易市场购买额外的排污权治理污染的条件下,探究产量调整速度、边际治污成本和排污权价格对企业产量决策的影响,对纳什均衡的存在和稳定条件进行分析。数值模拟结果表明,产量调整速度处于一定范围内,系统处于稳定状态,当超过这一范围时,适应性预期厂商的均衡产量只发生了倍周期分岔,而有限理性厂商的均衡产量经由倍周期分岔进入混沌状态;边际治污成本对系统稳定性的影响取决于企业的理性预期,随着边际治污成本的增加,有限理性厂商的产量越稳定,而天真理性和适应性预期的厂商刚好相反,经济系统出现周期分岔甚至混沌,混沌最终稳定在纳什均衡水平,说明边际治污成本越高,市场越不稳定;一个有趣的发现是排污权价格的增大有利于寡头市场产量供给的稳定。系统的奇怪吸引子、最大Lyapunov指数和对初值的敏感依赖性验证了系统处于混沌的事实。由于混沌意味着无序使模型预测变得困难,最后运用延迟反馈控制法使混沌稳定在纳什均衡水平,此时寡头厂商获得最大化利润。这对于稳定排污权市场,防止市场出现无序混沌的情形有一定的现实意义。  相似文献   
98.
矿山废弃地的生态恢复   总被引:27,自引:0,他引:27  
本文通过对矿山废弃地及其恢复情况调查,分析了我国矿山废弃地生态恢复的方向及蕴藏的产业机遇。  相似文献   
99.
氨基化合物是大气气溶胶中一类重要的有机氮化合物,由于其具有吸湿性,且沉降入海后可被海洋浮游生物直接利用,因此,可能在大气化学方面和海洋生态系统中具有重要作用.基于此,本研究利用2007年6月至2008年5月在青岛采集的55个总悬浮颗粒物样品,采用邻苯二甲醛/N-乙酰-L-半胱氨酸柱前衍生高效液相色谱法,分析了其中游离氨基化合物(FAC)的浓度.结果表明,气溶胶中总FAC浓度为0.14~8.33 nmol·m-3,其中,精氨酸、甲胺和丙氨酸的贡献最大.不同季节FAC的组成不同,精氨酸在夏、秋季节对FAC的贡献高于冬、春季节,甲胺的相对贡献则在夏季较低,而冬、春季较高.采样期间气团来源和天气状况的不同会影响气溶胶中FAC的浓度和组成.FAC在受南方陆源影响的气溶胶中浓度最高,北方陆源次之,海洋源气溶胶中的浓度最低,蛋白质类氨基化合物对总FAC的贡献在海洋源气溶胶中最高,在南方陆源气溶胶中最低.雾天和烟霾时气溶胶中FAC的浓度分别为晴天时的2.5倍和1.8倍,沙尘天气时FAC浓度与晴天时基本相当,蛋白质类氨基化合物对总FAC的贡献在晴天和雨后相对较高,在烟霾和雾天时相对较低.  相似文献   
100.
Effective conservation of biological diversity on private lands will require changes in land‐use policy and development practice. Conservation development (CD) is an alternative form of residential development in which homes are built on smaller lots and clustered together and the remainder of the property is permanently protected for conservation purposes. We assessed the degree to which CD is permitted and encouraged by local land‐use regulations in 414 counties in the western United States. Thirty‐two percent of local planning jurisdictions have adopted CD ordinances, mostly within the past 10 years. CD ordinances were adopted in counties with human population densities that were 3.0 times greater and in counties with 2.5 times more land use at urban, suburban, and exurban densities than counties without CD ordinances. Despite strong economic incentives for CD (e.g., density bonuses, which allow for a mean of 66% more homes to be built per subdivision area), several issues may limit the effectiveness of CD for biological diversity conservation. Although most CD ordinances required a greater proportion of the site area be protected than in a typical residential development, just 13% (n = 17) of the ordinances required an ecological site analysis to identify and map features that should be protected. Few CD ordinances provided guidelines regarding the design and configuration of the protected lands, including specifying a minimum size for protected land parcels or encouraging contiguity with other protected lands within or near to the site. Eight percent (n =11) of CD ordinances encouraged consultation with a biological expert or compliance with a conservation plan. We recommend that conservation scientists help to improve the effectiveness of CD by educating planning staff and government officials regarding biological diversity conservation, volunteering for their local planning boards, or consulting on development reviews. Guías e Incentivos para el Desarrollo de la Conservación en Regulaciones de Uso Local de Suelos  相似文献   
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