首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   10篇
  免费   0篇
环保管理   2篇
基础理论   6篇
灾害及防治   2篇
  2014年   1篇
  2013年   1篇
  2007年   1篇
  2005年   1篇
  2004年   1篇
  1995年   1篇
  1991年   1篇
  1988年   1篇
  1981年   2篇
排序方式: 共有10条查询结果,搜索用时 15 毫秒
1
1.
Biological Consequences of Ecosystem Fragmentation: A Review   总被引:48,自引:0,他引:48  
Abstract. Abstrack Resemcb on fragmented ecosystems bas focused mostly on the biogeograpbic consequences of the creation of habitat "islands" of diffrent size and bas provided little of practical value to managers Hom, ecosystem fragmentation causes large changes in thepbysfcal environment as well as biogeograpbic changes Fragmentation generally msults in a landscape that consists of remnant areas of native vegetation surrounded by a mdrlx of agricultural or other developed land As a mul fluxes of radiation, momentum (i.e., wind), water, and nutrients clcross the landscape are altered significantly. These in turn can haw important influences on the biota witbin remnant are- especially at or near the edge between the remnant and the surrounding matrix The isolatfon of remnant areas by clearing also bas important consequences for the biota These consequences vary with the time since isolatioq distance from other remnants, and degree of connectivity with other remnants The influences of pbysical and biogeographic changes are modified by the size, shape, and pition in the landscape of individual remnanQ witb larger remnants being less aduwsely affected by the jhapaentation process dynamics of remnant areas me predominantly driven by factors aris ing in tbe smunding krndscu Management of, and research on, fiagmented ecosystems sbould be directed at understanding and controlling tbese external influences as much as at tbe biota of tbe remnants themselves Tbere is a strong need to develop an integrated appmach to landsea management tbatplaces conservation merues in tbe context of tbe owrall landscape  相似文献   
2.
Abstract:  We integrated genetics and demography into population modeling in the context of species restorations, in which both the origin of released individuals and the management strategy may influence the success of introduction. Through an explicit individual-based simulation approach, we investigated the effects of the age of released individuals by exploring the relative merits of releasing juveniles or adults to establish populations. We included the effect of genetic variability responsible for inbreeding depression and mutational meltdown. Our general analysis uncovered an interaction between the age of founders and the extent of intrapopulation fitness variability, which substantially influenced the efficiency of selection in populations founded by juveniles and had subsequent positive consequences for long-term persistence compared with the case in which adults were released. We then applied the model to the case of the reintroduction of the Griffon Vulture ( Gyps fulvus fulvus ) to southern France, for which post-release data were available. The demographic aspects of this reintroduction were already analyzed and published, suggesting that it is more efficient to release adults than juveniles, despite an observed reduction of demographic parameters following the release of adults. In that context, the inclusion of genetic considerations qualitatively changes the conclusion, predicting reduced long-term extinction risk if juveniles rather than adults are released.  相似文献   
3.
The Role of the Zairian Health Services in the Rwandan Refugee Crisis   总被引:2,自引:0,他引:2  
In July 1994, a stream of Rwandan refugees entered the southern part of North Kivu Region, Zaire. The public health consequences of this crisis for the host population and health services have not been analysed up to now. The lack of human and financial resources did not prevent Zairian health structures and personnel from taking care of the many refugees settled outside the camps, following their arrival. The public health consequences of the crisis for the local population should be considered an integral part of the disaster.  相似文献   
4.
Abstract:  We assessed the extinction risks of Malagasy amphibians by evaluating their distribution, occurrence in protected areas, population trends, habitat quality, and prevalence in commercial trade. We estimated and mapped the distribution of each of the 220 described Malagasy species and applied, for the first time, the IUCN Red List categories and criteria to all species described at the time of the assessment. Nine species were categorized as critically endangered, 21 as endangered, and 25 as vulnerable. The most threatened species occur on the High Plateau and/or have been subjected to overcollection for the pet trade, but restricted extent of occurrence and ongoing habitat destruction were identified as the most important factors influencing extinction threats. The two areas with the majority of threatened species were the northern Tsaratanana-Marojejy-Masoala highlands and the southeastern Anosy Mountains. The current system of protected areas includes 82% of the threatened amphibian species. Of the critically endangered species, 6 did not occur in any protected area. For conservation of these species we recommend the creation of a reserve for the species of the Mantella aurantiaca group, the inclusion of two Scaphiophryne species in the Convention on the International Trade in Endangered Species Appendix II, and the suspension of commercial collecting for Mantella cowani . Field surveys during the last 15 years reveal no pervasive extinction of Malagasy amphibians resulting from disease or other agents, as has been reported in some other areas of the world.  相似文献   
5.
Biodiversity offsets are intended to achieve no net loss of biodiversity due to economic and human development. A variety of biodiversity components are addressed by offset policies. It is required that loss of protected species due to development be offset under the EU Habitats and Birds Directives in Europe. We call this type of offset a species‐equality offset because the offset pertains to the same species affected by the development project. Whether species equality can be achieved by offset design is unknown. We addressed this gap by reviewing derogation files (i.e., specific files that describe mitigation measures to ensure no net loss under the EU Habitats and Birds Directives) from 85 development projects in France (2009–2010). We collected information on type of effect (reversible vs. irreversible) and characteristics of affected and offset sites (i.e., types of species, total area). We analyzed how the type of effect and the affected‐site characteristics influenced the occurrence of offset measures. The proportion of species targeted by offset measures (i.e., offset species) increased with the irreversibility of the effect of development and the conservation status of the species affected by development (i.e., affected species). Not all effects on endangered species (International Union for Conservation of Nature Red List) were offset; on average, 82% of affected species would be offset. Twenty‐six percent of species of least concern were offset species. Thirty‐five percent of development projects considered all affected species in their offset measures. Species richness was much lower in offset sites than in developed sites even after offset proposals. For developed areas where species richness was relatively high before development, species richness at offset sites was 5–10 times lower. The species‐equality principle appears to have been applied only partially in offset policies, as in the EU directives. We suggest the application of this principle through offsets is highly important for the long‐term conservation of biodiversity in Europe. Compensaciones y Conservación de las Especies de las Directivas de Hábitats y Aves de la UE  相似文献   
6.
7.
In Europe, bromadiolone, an anticoagulant rodenticide authorized for plant protection, may be applied intensively in fields to control rodents. The high level of poisoning of wildlife that follows such treatments over large areas has been frequently reported. In France, bromadiolone has been used to control water voles (Arvicola terrestris) since the 1980s. Both regulation and practices of rodent control have evolved during the last 15 years to restrict the quantity of poisoned bait used by farmers. This has led to a drastic reduction of the number of cases of poisoned wildlife reported by the French surveillance network SAGIR. During the autumn and winter 2011, favorable weather conditions and high vole densities led to the staging of several hundreds of Red Kites (Milvus milvus) in the Puy‐de‐Dôme department (central France). At the same time, intensive treatments with bromadiolone were performed in this area. Although no misuse has been mentioned by the authorities following controls, 28 Red Kites and 16 Common Buzzards (Buteo buteo) were found dead during surveys in November and December 2011. For all these birds, poisoning by bromadiolone as the main cause of death was either confirmed or highly suspected. Other observations suggest a possible impact of bromadiolone on the breeding population of Red Kites in this area during the spring 2011. French regulation of vole control for plant protection is currently under revision, and we believe this event calls for more sustainable management of rodent outbreaks. Based on large‐scale experiments undertaken in eastern France, we propose that direct control of voles at low density (with trapping or limited chemical treatments) and mechanical destruction of vole tunnels, mole control, landscape management, and predator fostering be included in future regulation because such practices could help resolve conservation and agricultural issues. Envenenamiento No Intencional de Fauna Silvestre y Propuestas para un Manejo Sustentable de Roedores.  相似文献   
8.
Functional Homogenization Effect of Urbanization on Bird Communities   总被引:5,自引:0,他引:5  
Abstract:  We studied the community richness and dynamics of birds in landscapes recently affected by urbanization to test the prediction that biotic communities living in degraded landscapes are increasingly composed of generalist species. We analyzed bird communities in 657 plots monitored by the French Breeding Bird Survey from 2001 to 2005, accounting for the probability of species detection and spatial autocorrelation. We used an independent land-cover program to assess urbanization intensity in each FBBS plot, from 1992 to 2002. We found that urbanization induced community homogenization and that populations of specialist species became increasingly unstable with increasing urbanization of the landscape. Our results emphasize that urbanization has a substantial impact on the spatial component of communities and highlight the destabilizing effect of urbanization on communities over time. These results illustrate that urbanization may be a strong driving force in functional community composition and that measuring community homogenization is a powerful tool in the assessment of the effects of landscape changes and thus aides sustainable urban planning.  相似文献   
9.
Developing countries are now in a position to choose between further commitments to petroleum and development of sustainable solar resources. Many solar options are ready and some are already economically competitive, particularly for use in rural areas where most people in developing countries reside. Third World countries are becoming cautious about imitating industrial nations, and in some cases, are beginning to map out unique strategies based on their indigenous cultures and resources. Transitions to solar technologies will not be made without difficulty, however, as baseline data on energy needs and on availability of renewable forms of energy only marginally exist. This paper presents information on the potential and current status of a range of solar technologies. The United States Solar Energy Research Institute (SERI) is advancing a number of technologies that will have direct impact on life in developing countries; but in addition has established a programme to deal specifically with the use of renewable energy resources in developing countries. Technical development, planning, information compilation, and institution building are fundamental parts of the effort. As a research institute, SERI, in particular, wants to ensure that adequate attention is given to the technical problems associated with the use of renewables in developing countries. Too often, these problems are not recognized as being worthy of scientific attention resulting in the design and installation of less than optimal equipment. The limited resources available require optimal allocation and intelligent application. In addition, SERI manages bilateral assistance programmes with developing countries under the auspices of the US Department of Energy and the US Agency for International Development. Les pays en développement ont maintenant la possibilité de choisir entre un système basé sur le pétrole ou la mise en valeur des ressources solaires potentielles. Plusieurs systèmes de récupération de l'énergie solaire sont utilisables et quelques-uns sont déjà économiquement compétitifs, particulièrement dans les régions rurales où se rencontre la majeure partie de la population des pays en développement. Les pays du Tiers Monde exercent de plus en plus une certaine prudence à imiter les pays industriels et, dans certains cas, commencent à formuler des stratégies basées uniquement sur leurs ressources et cultures propres. Cependant, le passage à l'énergie solaire ne se fera pas sans difficulté étant donné que les données de base sur les besoins énergétiques et sur la disponibilité des formes renouvelables d'énergie sont marginales. Cet article donne des informations sur le potentiel et l'état actuel de toute une gamme de technologies solaires. L'Institut de recherche d'énergie solaire (IRES) des Etats-Unis est en train de promouvoir un certain nombre de technologies qui auront une portée directe sur le mode de vie dans les pays en développement. II a aussi élaboré un programme spécial concernant l'utilisation des ressources énergétiques renouvelables dans les pays en développement. Le développement technique, la planification, le rassemblement de l'information et la mise en place d'institutions représentent des composantes fondamentales de cet effort. En tant qu'institut de recherche, IRES en particulier voudrait s'assurer que les problèmes techniques concernant l'utilisation des énergies renouvelables dans les pays en développement soient étudiés sérieusement. Trop souvent ces problèmes ne sont pas reconnus comme méritant une étude scientifique ce qui entraîne la conception et la construction d'un équipement qui n'est pas le meilleur. Les ressources disponibles étant limitées, elles requièrent une répartition optimale ainsi qu'une utilisation intelligente. De plus, IRES dirige des programmes d'assistance bilatérale avec les pays en développement sous les auspices du Département de l'énergie et de l'Agence pour le développement international des Etats-Unis. Los países en desarrollo están ahora en la posibilidad de escoger entre una mayor dependencia del petróleo y el desarrollo de energía solar. Muchas alternativas de uso de energía solar están disponibles y algunas son economicamente competitivas, especialmente en las zonas rurales donde reside la mayor parte de la población de los países en desarrollo. Los países del tercer mundo están mas cautos en imitar los países industrializados, y en algunos casos, están empezando a establecer estrategias basadas en su cultura autóctona y sus recursos. Sin embargo la transición a la tecnología solar no va a ser fácil puesto que la información básica sobre las necesidades de energía y la disponibilidad de recursos renovables es muy escasa. Este artículo examina el potencial y la situación actual de las tecnologías de aplicación de energía solar. En los Estados Unidos, el Instituto de Investigación de Energía Solar (IIES) esta proponiendo ciertas tecnologías que tendrán impacto directo sobre la vida en los países en desarrollo, adicionalmente ha establecido un programa para tratar especificamente el uso de recursos renovables de energía en países en desarrollo. Desarrollo técnico, planificación, procesamiento de información y organización de instituciones son partes fundamentales de este esfuerzo. EL IIES quiere asegurar que se dé adecuada atención a los problemas técnicos relacionados con el uso de recursos renovables en los países en desarrollo. A menudo estos problemas se consideran como no importantes para ser objeto de investigación científica y como resultado se diseñan e instalan equipos que no son óptimos. Sin embargo los recursos limitados requieren que se hagan asignaciones óptimas de recursos y aplicaciones inteligentes. Además, el IIES administra programas de asistencia bilateral con los países en desarrollo bajo los auspicios del Departamento de Energía y la Agencia para el Desarrollo Internacional de los Estados Unidos de América.  相似文献   
10.
Food security problems should be seen as "normal" in and endemic to subsistence agricultural groups in semi-arid zones of developing countries. Natural, popular response mechanisms exist that address these problems when they are at "normal" levels. All response mechanisms in developing countries can be expected to be swamped in times of a major food emergency. During major crises international relief assistance will continue to play a crucial role. Attempts at imposing centralized, institutional social security systems that address the normal "pockets of need" syndrome will be extremely expensive, not self-sustaining, and prone to failure. In that these efforts may undermine natural response mechanisms and draw scarce resources away from more logical, decentralized relief agencies these efforts may prove dangerously counter-productive.  相似文献   
1
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号