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21.
African Inland Fisheries: Experiences with Co-Management and Policies of Decentralization 总被引:1,自引:1,他引:0
Roger Lewins Malloum Ousman Baba Emma Belal Steve Donda Abbagana Mamane Lamine 《社会与自然资源》2014,27(4):405-420
Most countries in Africa have promoted some form of decentralized fisheries management either as discrete co-management projects or as a component of broader decentralization processes that cut across other sectors. These initiatives were shaped by an international policy narrative that emphasises participation in decision making and development. A review of fisheries decentralization experiences in Cameroon, Niger, Nigeria, and Malawi reveals marked differences in purpose, strategy, and performance. In general, co-management projects are limited by their ability to scale up new practice and to maintain viable and representative management institutions. In other cases, the decentralization process is not well supported politically or locally or does not articulate with fisheries policy. Experiences of decentralization in other sectors provide useful lessons. Acknowledging the informal institutional environment or realpolitikof fisheries and the rural economy could provide opportunities to better manage and review the process of decentralization. 相似文献
22.
Drought risk assessment using remote sensing and GIS techniques 总被引:1,自引:0,他引:1
Abdel-Aziz Belal Hassan R. El-Ramady Elsayed S. Mohamed Ahmed M. Saleh 《Arabian Journal of Geosciences》2014,7(1):35-53
Beginning with a discussion of drought definitions, this review paper attempts to provide a review of fundamental concepts of drought, classification of droughts, drought indices, and the role of remote sensing and geographic information systems for drought evaluation. Owing to the rise in water demand and looming climate change, recent years have witnessed much focus on global drought scenarios. As a natural hazard, drought is best characterized by multiple climatological and hydrological parameters. An understanding of the relationships between these two sets of parameters is necessary to develop measures for mitigating the impacts of droughts. Droughts are recognized as an environmental disaster and have attracted the attention of environmentalists, ecologists, hydrologists, meteorologists, geologists, and agricultural scientists. Temperatures; high winds; low relative humidity; and timing and characteristics of rains, including distribution of rainy days during crop growing seasons, intensity, and duration of rain, and onset and termination, play a significant role in the occurrence of droughts. In contrast to aridity, which is a permanent feature of climate and is restricted to low rainfall areas, a drought is a temporary aberration. Often, there is confusion between a heat wave and a drought, and the distinction is emphasized between heat wave and drought, noting that a typical time scale associated with a heat wave is on the order of a week, while a drought may persist for months or even years. The combination of a heat wave and a drought has dire socio-economic consequences. Drought risk is a product of a region’s exposure to the natural hazard and its vulnerability to extended periods of water shortage. If nations and regions are to make progress in reducing the serious consequences of drought, they must improve their understanding of the hazard and the factors that influence vulnerability. It is critical for drought-prone regions to better understand their drought climatology (i.e., the probability of drought at different levels of intensity and duration) and establish comprehensive and integrated drought information system that incorporates climate, soil, and water supply factors such as precipitation, temperature, soil moisture, snow pack, reservoir and lake levels, ground water levels, and stream flow. All drought-prone nations should develop national drought policies and preparedness plans that place emphasis on risk management rather than following the traditional approach of crisis management, where the emphasis is on reactive, emergency response measures. Crisis management decreases self-reliance and increases dependence on government and donors. 相似文献
23.
Assessment of land degradation east of the Nile Delta, Egypt using remote sensing and GIS techniques 总被引:1,自引:0,他引:1
Land degradation is one of the most common issues in the eastern part of the Nile Delta area that threatens the ongoing agricultural activities and prohibits further reclamation expansions. The different degradation types and the associated risk assessment of some soils types of western Suez Canal region during the period from 1997 to 2010 is discussed. The assessment of the different degradation degrees in the investigated area has been carried out through integrating remote sensing, GIS and GLASOD approaches. Results revealed that the salinization, alkalization, soil compaction and water logging are the main types of land degradation in the area. The main causative factors of human induced land degradation types are; over irrigation, human intervention in natural drainage, improper time use of heavy machinery and the absence of conservation measurements. Low and moderately clay flats, gypsifferous flats, have high to very high risk in both salinization sodication and physical degradation. Values such as EC, ESP, and ground water level reach 104.0 dS/m, 176? % and 60 cm, respectively. These results will be of great help and be basic sources for the planners and decision makers in sustainable planning. The spatial land degradation model was developed based on integration between remote sensing data, geographic information system, soil characteristics and DEM. 相似文献