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201.
In projects of community development and natural resource management, local residents collaborate with government and NGOs on decisions about forest management and participate in programs designed to improve livelihoods while sustaining natural resources. This paper uses case studies and survey data in Gansu province of northwest China to explore social, ecological, and economic outcomes of community-based co-management (CBCM). Findings show that CBCM appears to have significantly increased livelihoods for local community residents overall. Forest condition and attitudes about forest conservation were also improved. However, economic benefits were not enjoyed uniformly within the communities because, although CBCM projects are nominally available to all, certain subgroups within communities are less likely to participate. Greater education, being married, and access to information are all strongly correlated with participation and thus the economic benefits of CBCM projects. Women, although they frequently participate in household decisions, are infrequent participants in CBCM projects, perhaps because project design does not meet their needs. Future improvements to CBCM project design should include increased access to information, education, and equitable treatment of diverse stakeholders in the decision-making process. Such improvements would likely lead to improvements in livelihoods as well as more sustainable forest management and conservation. 相似文献
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Sam H. Johnson W. Doral Kemper Max K. Lowdermilk 《Journal of the American Water Resources Association》1979,15(2):473-495
ABSTRACT: Over half of the water delivered from the canal system to the watercourses managed by the farmers is not made available to the farmers' crops in Pakistan. Most of this water loss is due to loss of water through the banks of the watercourses. Lack of maintaining these banks and lack of cleaning the watercourse is a result of inadequate organization of the 10 to 150 farmers who use the watercourse, and a deficiency of knowledge concerning the amount of their water which is being lost. Various methods of watercourse improvement have been evaluated including concrete and masonry linings and simple earthen improvements of the ditches with concrete control structures, junctions, and turnouts. With the cost of labor low in Pakistan, the earthen improvements with concrete structures appear to be the best investment. Farm water management improvement programs have been implemented in most of the provinces which include this type of watercourse improvement, land leveling and advice to the farmers on how and when to irrigate his crops to optimize his production. The rate at which personnel can be trained to help the farmers implement these improved water management practices is limiting the rate of implementation. 相似文献
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Dissolved organic materials released by the freshwater microalgae Scenedesmus acuminatus were fractionated into low- and high-molecular weight materials, which were investigated for their capacity to bind copper. The high-molecular weight material was also investigated for its monosaccharide composition and is further discussed in relation to the copper binding property. S. acuminatus was grown in batch cultures under laboratory controlled conditions and harvested at the beginning of stationary growth phase when exuded organic materials were obtained. Copper-complexing property of the total exuded organic materials and exopolysaccharides before and after freeze-drying was evaluated by complexometric titrations and Scatchard Plot Analysis of the titration data. The results revealed the presence of two copper-complexing ligands in the total exuded material, but only one in the exopolysaccharide. Stronger copper-complexing ligands are associated to low molecular weight compounds (LogK'1=7.3, LogCL1=-5.6; LogK'2=6.3, LogCL2=-5.1), whereas weaker ligands to the high molecular weight fraction (LogK'2=6.4, LogCL2=-5.6). Although freeze-drying the polymeric organic material (exopolysaccharide) may result in conformational changes of the molecule, no effect on copper-complexing properties was detected. Gas chromatography was used to evaluate the monosaccharide composition of the microalgal exopolysaccharide, which detected high content of mannose and 12% of acid monosaccharides. 相似文献
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E. Menzel Max Schmidt R. Bünsow Gottwalt Christian Hirsch 《Die Naturwissenschaften》1962,49(14):335-336
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A Science for Survival: Values and Conservation Biology 总被引:3,自引:0,他引:3
Practice of conservation biology that does not actively and continuously question the values that shape it is self-defeating: Conservation biology is inescapably normative. Advocacy for the preservation of biodiversity is part of the scientific practice of conservation biology. If the editorial policy of or the publications in Conservation Biology direct the discipline toward an "objective, value-free" approach, then they do not educate and transform society but rather narrow the focus to the "object of knowledge" (be this species, gene pools, landscapes, or ecosystems). To pretend that the acquisition of "positive knowledge" alone will avert mass extinctions is misguided. Conservation biologists should reflect on the constitutive values (especially contextual, but also methodological and bias) underlying their research programs and policy recommendations. Such reflection is itself an inherent element of scientific objectivity and takes into account the social nature of scientific knowledge. Without openly acknowledging such a perspective, conservation biology could become merely a subdiscipline of biology, intellectually and functionally sterile and incapable of averting an anthropogenic mass extinction. 相似文献