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891.
SUMMARY In recent years, indigenous tenure over forest lands has emerged as a means to conserve forests while recognizing indigenous rights. There is concern, however, that indigenous reserves may not be an appropriate policy tool for sustained forest conservation. Our research examined how recognition of indigenous common-property rights has controlled agricultural expansion and conserved forests in Bosawas Biosphere Reserve, Nicaragua. We used satellite imagery with empirical data gathered in the field on land-use institutions, population pressures, and land-use practices to compare whether indigenous communities under territorial management or public management are better able to (1) control the ‘fast threat’ of frontier expansion and (2) address the long-term ecological threats posed by indigenous land-use practices and institutional changes in the region. Our findings are that indigenous residents who share common-property rights over their territories are better able to control agricultural expansion than are indigenous residents living on public lands. With respect to the long-term threats to the region, a series of simulations of possible land-use pressures demonstrate that the enforcement of territorial boundaries and further development of indigenous forest management rules will prove crucial in determining land-use capacity and deforestation over the next 50 years. 相似文献
892.
Establishing marine protected areas (MPAs) helps to restore and sustain marine and fishery resources, but in the Philippines only 20% of total MPAs are achieving their management objectives. We conducted a case study of a small MPA in Northern Philippines to understand socio-economic status and livelihoods of the fishermen stakeholders, and examine their attitudes and perceptions on marine resource values and conservation. Using an ordered probit model, we also investigated factors affecting these perceptions. We found a lower fish income ratio in higher income quartiles, a small share of local non-fishery income, and an apparent lack of other livelihood opportunities within the rural economy. The majority of fishermen had positive perceptions of the non-market value of marine resources, agreed with the need for MPAs, and perceived positive potential income benefit from MPAs. Level of education and fishing income were consistent significant positive determinants of these perceptions. Policy implications suggest: involving likely-to-be-displaced reef fishers in the crafting of management plans; conducting intensive research on appropriate and feasible livelihood options, for example, marine culture technologies; and designing explicit strategies to increase the propensity of coastal households to invest in children's education as a strategy for long-term sustainability of resource management. 相似文献
893.
本研究建立气相色谱/质谱来测定电子垃圾拆解区土壤中四溴双酚 A(TBBPA)的方法。该化合物通过超声波辅助萃取,溶剂选择V(丙酮)﹕V(正己烷)=1﹕1或乙酸乙酯;净化柱选择酸化的氟罗里硅土和无水硫酸钠混合物或CleanertC18-SPE进行净化;净化液浓缩后经衍生反应,衍生试剂选用N,O-双(三甲基硅烷基)三氟乙酰胺(BSTFA)和含1%的三甲基氯硅烷(TMCS)。该方法测定电子垃圾拆解区土壤中TBBPA的检出限为(S/N=3)0.1μg·kg^-1加标回收率平均值为92.7%(n=5),重现性RSD为2.52%(n=5);线性范围是20~400μg·kg^-1相关系数0.999。该方法用于调查电子垃圾拆解区土壤中四溴双酚A,范围值为5.17~218.00μg·kg^-1其周围农田土壤中四溴双酚A,范围值为0.312~4.170μg·kg^-1 相似文献
894.
对江汉平原水文地质调查发现,该地区地下水砷含量已远超国家饮用水标准。以沉积物培养的土著细菌混合液为生物材料,以江汉平原高砷含水层沉积物为研究对象,在实验室内模拟地下水系统,研究厌氧环境条件下,不同生物量土著细菌和pH值对沉积物中砷迁移转化的影响,以及土著细菌活动下砷在不同沉积物中的迁移转化。结果表明,不同生物量菌悬液都能促进沉积物中As的释放,增加总As和As(III)的浓度,但150mL处理组,在研究后期,总As和As(III)的浓度呈现减缓趋势;在初始生物量一定的条件下,沉积物中As含量越高,细菌活动下总As相对释出量就越低,而且As(III)占所释出总As的比值就越高,但两个高砷含量沉积物组的差异较小;在初始pH值为5、7和9的培养条件下,细菌都能加速砷的迁移,但pH值为5的处理组(简称pH5处理组)最弱,在前8天,pH9处理组较pH7处理组的低,随后超过pH7处理组。研究表明,土著细菌悬液能加速As从沉积物中释出,并且释出的As以As(III)为主;在耐受的弱碱性环境条件下,细菌对砷的迁移和转化随环境的pH值增加而增强。 相似文献
895.
Qiang WANG Lijuan ZHAO Xuekun FANG Jianhua XU Yifan LI Yehong SHI Jianxin HU 《Frontiers of Environmental Science & Engineering》2013,7(1):10-18
Chlordane (1,2,4,5,6,7,8,8-octachloro-3a,4,7, 7a-tetra-hydro-4,7-methanoindane) is one of organochlorine pesticides (OCPs) which has been listed as one of the persistent organic pollutants (POPs) to be reduced and finally eliminated in the Stockholm Convention on Persistent Organic Pollutants, because of its great persistence, toxicity, bio-accumulation and long-range transport potential. It is critical to create a national chlordane usage inventories for China to compile chlordane emission inventories, which is helpful for carrying out risk assessments and other researches related to chlordane in China. The annual data of chlordane usage was calculated and modified in accordance with the reported annual production of chlordane which was caculated on the basis of the termite distribution, the data of chlordane usage rate and the annual new construction area (NCA).With the help of Geographic Information System, the usage data of this NCA were allocated to a grid system then, with a 1/4° longitude by 1/6° latitude resolution and a size for each grid cell of approximately 25 km by 25 km. Between 1988 and 2008, the total usage of chlordane in China was 2745 t, accounting for approximately 80% of the production in the same period. Zhejiang Province was the largest consumer of chlordane in China, whose usage adds up to 980 t, greatly exceeding other provinces/regions, followed by Jiangsu Province (534 t) and Sichuan Province (428 t). The region with the least usage of chlordane was Beijing. Provinces of Guizhou, Henan and Hebei did not use any chlordane, even though termites had occurred in these provinces. Gridded usage inventories showed that the intensive use of chlordane was concentrated in the southeast part of China, Yangtze River Delta and Pearl River Delta in particular. The satisfaction of the inventories was supported by the consistence between the estimated data of annual usage and the reported annual production of chlordane, and by the consistence between distribution pattern of chlordane’s usage and ambient air concentration. 相似文献
896.
897.
北京山区泥石流灾害保险的风险评判方法研究 总被引:4,自引:0,他引:4
泥石流是北京山区主要的自然灾害,在1989-1999年期间,泥石流灾害造成的经济损失高达3.09亿元.对泥石流灾害保险风险的评判是首先按北京山区各区县的泥石流危险度分区划分风险区,然后对各风险区进行灾害危险性和灾害易损性评判.在危险性评判中,按各风险区的泥石流危险度等级赋予危险度评判指标值.在易损性评判中,选择国内生产总值、固定资产、人口密度和人口自然增长率等4个因素作为评判指标,并分为两个层次进行评判.第一层次是经济易损性与社会易损性评判,第二层次是泥石流灾害易损性评判.最后用泥石流灾害保险风险分析数学模型,计算出各风险区的泥石流灾害保险风险度,并由此绘制了北京山区泥石流灾害保险风险区划图. 相似文献
898.
渤海典型海域表层沉积物正构烷烃特征比较 总被引:2,自引:0,他引:2
对渤海典型海域表层沉积物正构烷烃特征进行比较研究.分别采集葫芦岛市近岸海域(1#)、东营市近岸海域(2#)、营口市近岸海域(3#)9个站点的表层沉积物样品,经索氏提取、柱净化后进行GC-MS分析.结果表明,各站位都表现为双峰型,显示了陆源与海源双重贡献特征,但主导峰各不相同;正构烷烃含量(∑n-alk)均值分别为5.43μg.g-1、2.27μg.g-1、4.30μg.g-1;三海域碳优势指数CPI、奇偶优势指数OEP、姥鲛烷和植烷比值Pr/Ph等特征比值基本相同,指示混合来源及中性偏氧化的沉积环境;C31/C19均值分别为11.19、4.51、6.73,短/长链比值L/H均值分别为0.50、1.48、1.31,类脂物比值TAR均值分别为3.61、1.03、1.19,综合显示葫芦岛市近岸海域正构烷烃来源主要为陆源高等植物,而营口及东营近岸海域沉积物正构烷烃更多来源于内生浮游生物源及石油源,三海域沉积物受人类污染影响程度从高到低分别为2#海域(东营)>3#海域(营口)>1#海域(葫芦岛市),且东营近岸海域沉积物受石油污染特征明显.这些特征都与3个海域周边城市发展与污染输入特征有直接的关系. 相似文献
899.
900.
Hamede R Lachish S Belov K Woods G Kreiss A Pearse AM Lazenby B Jones M McCallum H 《Conservation biology》2012,26(1):124-134
Pathogen-driven declines in animal populations are increasingly regarded as a major conservation issue. The Tasmanian devil (Sarcophilus harrisii) is threatened with extinction by devil facial tumor disease, a unique transmissible cancer. The disease is transmitted through direct transfer of tumor cells, which is possible because the genetic diversity of Tasmanian devils is low, particularly in the major histocompatibility complex genes of the immune system. The far northwest of Tasmania now holds the last remaining disease-free wild devil populations. The recent discovery of unique major histocompatibility complex genotypes in the northwestern region of Tasmania has raised the possibility that some animals may be resilient to the disease. We examined the differences in the epidemiology and population effects of devil facial tumor disease at 3 well-studied affected sites in eastern Tasmania and 1 in western Tasmania (West Pencil Pine). In contrast to the 3 eastern sites, there has been no rapid increase in disease prevalence or evidence of population decline at West Pencil Pine. Moreover, this is the only onsite at which the population age structure has remained unaltered 4 years after the first detection of disease. The most plausible explanations for the substantial differences in population effects and epidemiology of the disease between eastern and western sites are geographic differences in genotypes or phenotypes of devils and functional differences between tumor strains in the 2 regions. We suggest that conservation efforts focus on identifying whether either or both these explanations are correct and then, if resistance alleles exist, to attempt to spread the resistant alleles into affected populations. Such assisted selection has rarely been attempted for the management of wildlife diseases, but it may be widely applicable. 相似文献