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991.
毛竹林生态系统动态经济阈值 总被引:2,自引:0,他引:2
运用经济阈值(ET)的研究方法建立了毛竹林生态系统经济阈值模型。探讨了毛竹林生态系统一元和二元复合动态经济阈值,研究结果表明:对于不同的毛竹林分,林分立竹度(N)越大,其经济阈值(ET)也随之增大,对于同一毛竹林分来说,经济阈值随着笋的平均价格(Ps),贴现率(δ),笋的平均单重(Ws),每年挖去笋增量的比例(k)和经营时间(t)特等因子的增大而增大,而随着竹材的平均价格(PB),成竹率(R)的增大而减少,此外,还进一步分析了毛竹林经济阈值与Ps,PB两个主要影响因子之间的复合动态变化关系。结果表明PB对毛竹林经济阈值的影响较Ps大,并编制了毛竹林生态系统二元复合动态经济阈值一览表。从而为实现毛竹林的丰产经营提供方便与指导。 相似文献
992.
This article presents the results of a methodology based on an extensive sociological fieldwork in three different sites settled along a gradient of aridity in Nigerien Sahel. This fieldwork led to build a set of rules for the behaviour of individuals in non-pastoralist villages. We implemented these rules into an agent-based model simulating three village archetypes. Each archetype includes biophysical, economical, social agricultural and livestock modules. Results from simulations with no social transition processes show that villages specialize themselves into different economic activities according to natural resource specificities: A decreasing intensification gradient is observed from the most favoured site, with more local productions and good ecological indicators, to the less-favoured site, with a growing proportion of the population wealth coming from migration remittances and “off-shore” livestock. Two family transition processes were implemented, following field observations and literature-based hypotheses: family organizations evolve between a patriarchal mode and a non-cooperative mode following tensions due to income redistribution. Family inheritance systems evolve from a “customary” one-heir mode to a “local Muslim” mode in which all males inherits land. This evolution depends on family tensions due to land availability. Once introducing these processes, the population of each site differentiates itself into specialized groups according to size, assets and social status. Meanwhile, the group proportions and specializations strongly vary according to the sites but they are all characterized by the emergence of individualistic family types and the increase of the village populations’ robustness. 相似文献
993.
Jung Wan Lee 《国际发展与全球生态学杂志》2016,23(3):221-232
This paper integrates tourism, economic growth, and environmental issues in a multivariate format. Unlike recent research on this topic, a panel data of selected sample nations of sub-Saharan Africa is adopted by using cointegration and panel regression models. The current research discovers both long-run equilibrium and short-run dynamics between economic growth, tourism, energy use, and carbon emissions in sub-Saharan Africa. Furthermore, tourism and energy use show a highly significant direct impact on economic growth. In addition, tourism, energy use, and economic growth yield a highly significant positive effect on carbon emissions. Dissecting the region into oil producers and non-oil producers further suggests that the economic growth of sub-Saharan Africa has been accomplished by strong growth in tourism and energy use. However, there is highly significant evidence that in oil producing countries, CO2 emissions are directly affected by energy use and economic growth and not by tourism. For non-oil producing countries, tourism and energy use but not economic growth incur a highly significant positive impact on carbon emissions. 相似文献
994.
论水资源格局与可持续发展 总被引:8,自引:0,他引:8
孟庆民 《中国人口.资源与环境》1999,9(2):26-30
以可持续发展理论为指导,分析了我国水资源自然格局及利用格局的现状与问题,提出了作为可持续发展重要支撑的水资源,其可持续利用的根本途径是建立可持续发展的水资源格局,即流域经济系统格局,并实现流域基础上的区域竞争与协作一体化 相似文献
995.
文章在综述国内外学者对环境库兹涅茨曲线研究的基础上,选取河南省1997年-2011年的经济与环境数据,建立了计量模型,分析了经济增长与多个环境指标之间的关系。实证研究表明,河南省经济增长与环境状况之间尚未呈倒“U”曲线特征,工业“三废”处于倒“U”型的上升阶段,工业COD和工业SO2分别呈现倒“N”型和“N”型的波浪形状。河南省总体环境压力依然较大,对河南省环境保护工作提出了政策建议。 相似文献
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999.
乐山市诱发地震的社会影响及对策 总被引:3,自引:0,他引:3
本文简述了健为县罗城镇的注水采盐诱发地震和沙湾区铜街子水库蓄水诱发地震的影响及对策。 相似文献
1000.
The decline in sea cucumber fisheries that serve the Asian dried seafood market has prompted an increase in global sea cucumber
aquaculture. The tropical sandfish (Holothuria scabra) has, in this context, been reared and produced with mixed success. In the Western Indian Ocean, villagers often participate
in the export fishery for sea cucumbers as a source of income. However, with a growing concern of depleted stocks introduction
of hatcheries to farm sandfish as a community livelihood and to replenish wild stocks is being promoted. This review identifies
and discusses a number of aspects that constitute constraints or implications with regard to development of sandfish farming
in the region. The conclusion is that for sandfish farming to live up to its expectations the possible impacts need to be
further studied, and that improved evaluation of ongoing projects is required. In the interim, a precautionary approach toward
new enterprise activities is suggested. 相似文献