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881.
882.
王克林 《中国地理科学(英文版)》1998,(3)
I.INTRODUCTIONItisgeneralyacceptedthatthedegradationofrenewableresourcesandfragileenvironmentsindevelopingcountriesisbecomin... 相似文献
883.
J. Henry Owusu 《The Professional geographer》1998,50(4):418-436
Since the early 1980s, most Sub-Saharan African countries have resorted to structural adjustment programs to reform their ailing economies. Adjustment, however, may provide a convenient means for governments of the adjusting economies and international capital to meet their current economic and political interests, usually by sacrificing the physical environment, with huge environmental costs for the adjusting country. This paper uses Ghana's forestry sector, which has been characterized by a dramatic increase in woodexports since adjustment, to demonstrate a direct link between adjustment and environmental destruction. Ghana's dramatic increase in wood exports, involving a rapid and extensive deforestation, results from the government's need to meet its increasing external debt service obligations, and is exacerbated by the series of massive local currency devaluation required under adjustment “to get prices right.” The systematic reduction in government revenue from devaluation to amortize the increasing debts, keeps the government and indebted wood processing firms on a treadmill of export-based extraction/deforestation. 相似文献
884.
MICHAEL WILLIAMS 《Geographical review》1998,88(2):275-300
ABSTRACT. The first half of the twentieth century marked both an end to confidence in human control of the earth and a prelude to the contemporary era of intense environmental concern after 1950. This conspectus of the environmental history/historical geography of the transitional years between 1900 and 1950 focuses on rising concerns over resource supplies and exploitation, particularly land settlement, timber supplies, soil erosion, and river-basin control. Conservation and the pervasiveness of ecological thinking and analogy form a strong underlying theme. 相似文献
885.
黑河下游额济纳绿洲环境退化及综合治理* 总被引:64,自引:13,他引:51
黑河下游的额济纳绿洲是内蒙西部阿拉善高原的主要天然绿洲。近半个世纪特别是近10年来,由于不合理人类活动和自然因素的双重作用,黑河下泄水量不断减少,生态环境恶化,严重影响到本地区乃至周围广大地区的持续发展。通过分析生态环境恶化的现状和原因,提出了生态环境的治理必须以水为中心,加快中游地区节水农业的发展步伐,保证下游一定量的供水,并严格控制不合理的人为活动,力争在10~15年内实现生态环境的良性循环。 相似文献
886.
887.
Potential salinity limitations on nitrogen fixation in sediments from Mono Lake, California 总被引:2,自引:0,他引:2
David B. Herbst 《International Journal of Salt Lake Research》1998,7(3):261-274
Mono Lake is a hypersaline alkaline lake in the high altitude Great Basin desert of eastern California. Algal productivity
of the lake is nitrogen-limited, and a contributing source is derived from benthic nitrogen fixation. Lake level and salinity
have fluctuated with natural climatic variations but have also been affected by the diversion of tributary streams. This research
examines the influence of varied salinity and lake level on the potential for benthic nitrogen fixation in Mono Lake. A sediment-surface
microbial mat community was exposed directly, and in acclimated cultures, to a range of Mono Lake salinities under anaerobic
incubations and the activity of nitrogenase assayed by acetylene reduction. Activity was stimulated in light, but also occurred
in darkness. Over an experimental salinity range from 50 to 150 g L−1 TDS, nitrogenase activity was reduced by 90 per cent, with the activity persisting at the highest salinity being attributable
to dark fixation alone. Between a salinity of 50 g L−1, occurring in Mono Lake over 50 years ago, and 100 g L−1, nitrogenase activity was reduced by nearly half. Changes in the area of the littoral zone at varied lake levels also affect
the total amount of potential benthic nitrogen fixation in the lake. An accounting of yearly inputs of nitrogen to Mono Lake
suggests N2-fixation could contribute as much as 76–81 percent of the total. Inhibition of nitrogen fixation rates by increased salinity
could limit the long-term nutrient supply and benthic primary productivity of this ecosystem. 相似文献
888.
利用地理信息技术实现图形数据与属性数据完美的结合,维持图形数据和属性数据的一致,可以使建立在其之上的地籍管理系统使用方便、操作直观、快速准确. 相似文献
889.
土壤水全时空调控的初步探讨 总被引:3,自引:1,他引:2
农业是第一用水大户,有利利用土壤是实现黑龙港地区农业可持续发展的关键,本文分析了黑龙港地区主要作物需水与降水的关系,建立了作物生长条件包气带流动系统的概念,并以此为基础提出了土壤水全时空调控的概念,探讨了土壤水全时空调控的涵义与措施,指出土壤水调控是一系统工程,必须多种措施有机结合,简单介绍了王瞳试验场开展的田间土壤水调控试验成果。 相似文献
890.
B.F. Iyun 《GeoJournal》1998,44(2):129-139
The viewpoint that most health problems are environmentally related has always been promoted by medical geography. In recent
times, concern about environmental degradation has been of high priority for many national and international organizations
as ‘we human beings become a threat to our planet’. There is also a need to specifically focus attention on the impact of
so-called development efforts on the health of women and children, in particular those living in highly marginalized regions
which often contribute substantially to the overall development of their countries.
This paper uses the concept of vulnerability as a departure point from which to map the health risks to children in Igbekun
area of Ondo State, the ‘transgressive muddy’ oil-rich coastal area of Nigeria. The paper attempts to highlight the poor quality
of life and health of children in particular, and how it is becoming much more difficult to practice health intervention programmes,
especially oral rehydration therapy (ORT) in the area.
The Igbekun area is an unhealthy and harsh environment, complicated by the devastating effects of oil drilling in recent years.
The siltation and sedimentation of the creeks and lagoons have serious health dimensions as human faeces float in and around
villages because the ‘bush toilets’ can no longer be reached. The on-going environmental crisis has also deprived women of
their traditional means of livelihood; fishing.
There is a relatively high level of ignorance (compared with other women living in the same local government area (LGA) of
causes of the commonest diseases such as diarrhoea, acute respiratory infection (ARI) and measles. A majority of the women
have never heard of family planning, immunization against diseases and interventions such as ORT. Promotive health care services,
especially those that strive to reduce the high mortality of children have passed the mothers by. It is also becoming impracticable
to promote ORT because of the widespread ‘salty and oily’ water supply in the area.
The greatest concern of the women now is that oil drilling activities have further amplified their stressful conditions especially
their health and that of their children. Unfortunately, their plight is not acknowledged by the Nigerian authorities and the
oil companies are least concerned about alleviating the poor health status of the community, in particular the most vulnerable
groups, children under the age of five.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献