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591.
592.
Land Cover and Use Changes in Relation to the Institutional Framework and Tenure of Land and Resources in Eastern Tanzania Miombo Woodlands 总被引:3,自引:0,他引:3
E.?J.?Luoga E.?T.?F.?WitkowskiEmail author K.?Balkwill 《Environment, Development and Sustainability》2005,7(1):71-93
In Tanzania, well-defined land tenure and resource protection apply in forest reserves which account for 30% of forested land, while the remaining 70% (mostly miombo woodlands) are village and general lands with very limited protection. The aim of this study was to determine local peoples ownership rights, knowledge and institutional capacity for sustainable management of resources in forest reserves and general lands. Data were collected using participatory rural appraisal, structured and semi-structured interviews, as well as aerial photographs and landsat images. In general lands, woodlands declined by 50% between 1964 and 1996, bushlands and croplands increased by 599%, and settlements and homegardens increased by 277%. These land use and vegetation structure changes are attributed to harvesting for charcoal production and shifting cultivation. The continued decline in aerial woodland cover in the general lands suggests that common property regimes do not function in the area. Local institutional capacities are weak in enforcing control mechanisms to check the overuse of resources, which tends to approximate open access conditions. The issues of land tenure and village empowerment are not only institutional, but also political in nature. Government institutions should provide and motivate for an enabling environment, including acknowledgement of traditional knowledge, well-defined property rights and operational village by-laws. In order to ensure equity and sustainable development of natural resources, the paradigm shift in management is important whereby communal goods are to be managed for the benefit of the local society. 相似文献
593.
本文基于钢筋混凝土结构理论及锈蚀钢筋混凝土构件的力学性能的变化规律,建立了钢筋混凝土构件残余承载力的计算模型,并通过实验验证了计算模型的有效性.模型的物理概念明确、简单实用,可供现役混凝土结构的耐久性评估及维修决策参考. 相似文献
594.
根据沂沭河流域的水文特征和水质状况,建立了沂沭河流域河流水环境容量数学模型和计算方法,依据该流域水环境功能区划,计算出流域内各水功能区和各河流的环境容量及最大允许排污量,从而为沂沭河流域实施水污染物总量控制和南水北调东线工程山东段水质达标提供基础数据。 相似文献
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596.
Larry Dale 《Resources Policy》1984,10(3):153-162
The loss of foreign mineral supplies may affect domestic supply and price. To investigate the assumption that prices, a simple mine investment model that relates mine capacity to deposit attributes is used. A test of the model to see how well it approximates industry investment practice illustrates its accuracy. The model suggests that price changes can substantially affect the optimal capacity of planned or existing mines as well as the mineral supply in the USA. 相似文献
597.
区域生态承载力与可持续发展 总被引:35,自引:1,他引:34
李金海 《中国人口.资源与环境》2001,11(3):76-78
本文探讨了生态承载力的概念和估测的方法,分析了大陆典型生态系统净第一性生产力的背景值,研究了确定自然系统最优生态承载力的依据,在此基础上,提出了提高区域生态承载力,实现区域可持续发展基本对策。 相似文献
598.
中国适宜人口分布研究——从人口的相对分布看各省区可持续性 总被引:18,自引:2,他引:16
本文分析了中国人口分布现状与水资源、海拔高度、地表起伏指数和多种社会经济因素之间的关系,建立了综合的适宜人口分布模型,计算了中国各省的理论人口密度发布,并对模型进行检验。 相似文献
599.
Petter Næss Martin J. H. Mogridge and Synnøve Lyssand Sandberg 《Natural resources forum》2001,25(2):147-155
The transport policy currently followed in many European cities seems to be a combination of investments in public transport in order to increase, or at least maintain, its market share, and road building in order to keep up with expected traffic growth. Apparently, there is a prevalent belief among policy makers that increased road capacity in urban areas does not in itself cause any growth in car traffic worth mentioning. Such a belief neglects the simple economic theory of supply and demand, as well as more specific theories about the dynamics of traffic under congested conditions. An empirical study of commuting patterns in two transport corridors in Oslo, Norway, shows that a considerable proportion of commuters are sensitive to changes in the speed of the respective modes of transportation. The mode chosen depends to a large extent on the ratio of door-to-door travel times by car and transit. Freer flowing traffic in the road network will induce a higher proportion of commuters to travel by car. Conversely, faster public transport will reduce the proportion of car commuters, but the effects of such improvements will be offset if road capacity is simultaneously increased. In addition to the relative speeds of car and transit, the parking conditions at the workplace are of great importance to the choice of transport mode. 相似文献
600.