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991.
本文综述了生态系统多样性在生物多样性保护中的意义及5个中心研究问题,即生物群落或生态系统关键种、生物多样性关键地区、生态系统多样性的持续性、受害生态系统的恢复生态学、生态系统多样性保护对策及保护途径。文章还分析和讨论当前国际上有关生态系统多样性保护的对策和实践。  相似文献   
992.
Abstract:  Ongoing loss of biodiversity requires identifying large-scale conservation priorities, but the detailed information on the distribution of species required for this purpose is often missing. We present a systematic reserve selection for 1223 African mammals and amphibians in which habitat suitability models are used as estimates of the area occupied by species. In the framework of the World Conservation Union (IUCN) Global Amphibian Assessment and IUCN Global Mammal Assessment, we collected the geographic range (extent of occurrence) and habitat preferences for each species. We used the latter to build species-specific habitat suitability models inside geographic ranges, and for 181 species we verified the models by comparing suitability levels to presence-absence data collected in the field. We then used the suitable areas as estimators of the area of occupancy and compared the results of systematic reserve selection based on geographic ranges to those based on estimated areas of occupancy. Our results showed that the reserve system would need a 30-100% expansion to achieve minimal conservation targets, concentrated in the tropics, where species richness reaches a maximum. Comparative analyses revealed that using geographic ranges, which overestimate the area occupied by species, underestimates the total amount of area that needs to be conserved. The area selected for conservation doubled when we used the estimated area of occupancy in place of the geographic ranges. This happened because the suitable areas potentially occupied by each species overlapped less than their geographic ranges. As a result, any given protected area contained fewer species than predicted by the analysis of ranges. Because species are more specialized than our estimates of distribution based on extent of occurrence suggest, we propose that this is a general effect in systematic conservation planning.  相似文献   
993.
Abstract:  The World Conservation Union (IUCN) has developed guidelines that enable the assessment of extinction risk at a regional scale. We used these guidelines to assess the extinction risk of birds in the United Kingdom for comparison with an existing assessment of conservation status. Sixty-four species were categorized as regionally threatened, of which 12 were critically endangered. The categorizations of the 223 species assessed agreed broadly with those from the existing U.K. system, which considers more than extinction risk, thus giving a more complete assessment of conservation status. There was, however, a tendency for the IUCN process to give higher risk status to edge-of-range species (some of which are relatively recent colonists considered of comparatively low conservation concern) and low status to those that have declined substantially but remain common (such as many farmland birds, the focus of considerable conservation effort in the United Kingdom). The final red list depended heavily on the subjective decisions made during the assessment process. An alternative interpretation of the guidelines could have resulted in as many as 19 or as few as 6 species being listed as critically endangered. We recommend the revision of the IUCN guidelines to reduce this subjectivity, in particular with respect to the effect of extralimital populations on the likelihood of regional extinction, and hence the potential for variation in the manner of application between regional red-list assessors. Preventing extinction does not have to be the principal driving force behind conservation action at a regional scale if the continuance of a species is safeguarded in other regions.  相似文献   
994.
根据国际《湿地公约》中的湿地定义,分析了长江中下游湿地面临的主要生态问题,提出了加强长江中下游湿地生态保护、促进经济与社会可持续发展的对策和建议。  相似文献   
995.
济南市南部山区保泉生态工程建设   总被引:1,自引:0,他引:1  
魏斌  韩凌 《环境与开发》1998,13(2):12-14
通过对济南市南部山区地下水补给区范围的自然,社会,经济状况调查,分析区内水文地质及地下水的运移规律和“三水”转化规律,从生态建设规模,树种选择,投资预算等方面提出保泉的生态工程建议,并科学估算生态工程措施实施后对保泉的贡献。  相似文献   
996.
本文对燃煤掺烧固硫中的节能问题进行了探讨.试验表明:掺烧适量的钙基固硫剂,不但能提高灰渣熔点,改善结焦性能,强化燃烧,而且可以使总发热量有所提高.因此,掺烧固硫具有节能效果.  相似文献   
997.
Guidelines for Systematic Review in Conservation and Environmental Management   总被引:10,自引:0,他引:10  
Abstract:  An increasing number of applied disciplines are utilizing evidence-based frameworks to review and disseminate the effectiveness of management and policy interventions. The rationale is that increased accessibility of the best available evidence will provide a more efficient and less biased platform for decision making. We argue that there are significant benefits for conservation in using such a framework, but the scientific community needs to undertake and disseminate more systematic reviews before the full benefit can be realized. We devised a set of guidelines for undertaking formalized systematic review, based on a health services model. The guideline stages include planning and conducting a review, including protocol formation, search strategy, data inclusion, data extraction, and analysis. Review dissemination is addressed in terms of current developments and future plans for a Web-based open-access library. By the use of case studies we highlight critical modifications to guidelines for protocol formulation, data-quality assessment, data extraction, and data synthesis for conservation and environmental management. Ecological data presented significant but soluble challenges for the systematic review process, particularly in terms of the quantity, accessibility, and diverse quality of available data. In the field of conservation and environmental management there needs to be further engagement of scientists and practitioners to develop and take ownership of an evidence-based framework.  相似文献   
998.
南京市郊区基本农田保护区土壤重金属污染调查   总被引:5,自引:0,他引:5       下载免费PDF全文
为调查基本农田保护区土壤环境中重金属污染状况,江苏省农业环境监测站于1999年和2001年分别对南京市郊区基本农田土壤环境质量进行了监测,共计布设监测点14个,监项目为镉,铅,砷,汞,铬和pH,结果表明,1999年土壤样品的重金属检出率为97.1%,超标率为5.7%,2001年重金属检出率为100%,超标率为1.4%,1999年土壤样品中超标的重金属元素是镉,超标率为28.6%,2001年超标元素是汞,超标率为7.1%,1999年土壤综合污染指数为1.08,污染等级及污染水平均属轻污染;2001年土壤综合污染指数为0.76,污染等级为警戒线,污染水平达到尚清洁。  相似文献   
999.
Landscape fragmentation and habitat loss are significant threats to the conservation of biological diversity. Creating and restoring corridors between isolated habitat patches can help mitigate or reverse the impacts of fragmentation. It is important that restoration and protection efforts be undertaken in the most efficient and effective way possible because conservation budgets are often severely limited. We address the question of where restoration should take place to efficiently reconnect habitat with a landscape-spanning corridor. Building upon findings in percolation theory, we develop a shortest-path optimization methodology for assessing the minimum amount of restoration needed to establish such corridors. This methodology is applied to large numbers of simulated fragmented landscapes to generate mean and variance statistics for the amount of restoration needed. The results provide new information about the expected level of resources needed to realize different corridor configurations under different degrees of fragmentation and different characterizations of habitat connectivity (“neighbor rules”). These results are expected to be of interest to conservation planners and managers in the allocation of conservation resources to restoration projects.  相似文献   
1000.
The efficacy of simultaneously advancing two distinct conceptual designs (referred to here as fixed-site and non-fixed-site) for species conservation and protection is addressed. In the literature, numerous models can be found that typically stem from a particular design, but rarely are comparisons made between approaches. This paper presents a more integrated optimization framework that models landowner behavior and species viabilities at a landscape scale. Regional demand for resource extraction is used as the economic driver, a variant of simulated annealing is used to solve the model under different species protection approaches, and a detailed species population simulator is utilized to measure biological responses. When directly comparing the outcomes of different species protection strategies from a case study in Oregon (USA), it was found that neither approach was universally superior in terms of financial value or degree of protection for two late seral forest dependent species.  相似文献   
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