The Historical Dynamics of Social–Ecological Traps

Environmental degradation is a typical unintended outcome of collective human behavior. Hardin’s metaphor of the “tragedy of the commons” has become a conceived wisdom that captures the social dynamics leading to environmental degradation. Recently, “traps” has gained currency as an alternative concept to explain the rigidity of social and ecological processes that produce environmental degradation and livelihood impoverishment. The trap metaphor is, however, a great deal more complex compared to Hardin’s insight. This paper takes stock of studies using the trap metaphor. It argues that the concept includes time and history in the analysis, but only as background conditions and not as a factor of causality. From a historical–sociological perspective this is remarkable since social–ecological traps are clearly path-dependent processes, which are causally produced through a conjunction of events. To prove this point the paper conceptualizes social–ecological traps as a process instead of a condition, and systematically compares history and timing in one classic and three recent studies of social–ecological traps. Based on this comparison it concludes that conjunction of social and environmental events contributes profoundly to the production of trap processes. The paper further discusses the implications of this conclusion for policy intervention and outlines how future research might generalize insights from historical–sociological studies of traps.     

新疆北疆地区少数民族贫困县可持续发展水平时空变化解构——以木垒哈萨克自治县为例

可持续发展水平时空解构表明,木垒县可持续发展能力很弱,资源问题成为限制其经济发展、社会发展及环境保护的主要因素。近8年来,木垒县可持续发展水平虽然呈良性上升状态,但其上升主要归功于社会发展因素,经济发展指数、资源指数等对其上升的推动性并不强。仅以提高经济发展水平为目的的掠夺式开发,使得资源匮乏的木垒县因此出现较为严重的资源性环境问题,并制约经济水平的提高。上述分析表明,资源指数成为新疆北疆地区少数民族贫困县可持续发展的基础,少数民族贫困县的贫困现状与其可持续发展能力弱是密切联系的。消除贫困的前提条件是实现可持续发展,因此,提高新疆少数民族贫困县的可持续发展水平这项任务迫切而重要。     

政府减贫行为的动态效应——中国农村减贫问题的SVAR模型实证分析(1990-2008)

脱贫人口返贫率偏高是中国农村贫困问题的一个显著特征.这种客观现实要求我们,应该仔细考察农村贫困发生率、贫困深度和贫困强度对政府干预行为的跨期响应,从而动态地而不是静态地评价政府减贫行为绩效.本文将普惠式的农村农业发展政策与扶贫政策一起纳入减贫分析框架,构建一个结构向量自回归模型(SVAR)模型,以弥补现有文献用多变量时间序列数据通过单方程模型回归分析的局限,从SVAR模型中获得结构冲击响应函数,动态地评价政府行为的减贫效应.实证分析表明,目前的政府行为,无论是普惠式的农村农业发展政策,还是瞄准贫困人口的扶贫政策,对农村贫困的政策干预都没有形成持久的影响,冲击响应衰减很快.为了降低脱贫人口返贫率,政府减贫政策的目标应定位于提升贫困人口的自身发展能力,扩展贫困人口参与经济增长的机会,使经济增长成为他们获取稳定收益的源泉.     

区域高速公路网络构建对可达性空间格局的影响——以安徽沿江地区为实证 

以安徽沿江为实证，采用加权平均旅行时间指标，分析了高速公路网构建对节点区内联系及区外联系可达性格局的影响，并以此为基础，综合分析了节点总体可达性格局的变动；随后对总体可达性的变动幅度及其相对可达性变动格局进行了探讨。结果表明：安徽沿江高速公路网络的构建显著提高了区域整体可达性，且促进了可达性的均衡化；区内联系可达性、区外联系可达性及总体可达性三者格局特征不同，路网构建所形成的影响也各有差别；东部及北部地区可达性变动幅度小于西南部地区；根据可达性系数的变化幅度及方向，可将节点归为相对可达性下降、相对可达性稳定及相对可达性上升3类。     

Managing Watershed Externalities in India: Theory and Practice

Watershed development is the focus of poverty alleviation programs in rural India. Watershed projects aim to solve problems of externalities, but they also create their own externalities, which cause uneven distribution of costs and benefits that undermine project objectives and harm the poor. Numerous approaches exist to internalize externalities, including awareness creation, moral suasion, investment subsidies, regulatory limits and fines, indirect benefits, mergers, and recent innovations like payment for environmental services and cap and trade. These can be judged on several criteria; the best approach would solve the problem cost effectively and help or at least not hurt poor people. Watershed projects in India were examined to identify the approaches taken to internalize watershed externalities. Investment subsidies and indirect employment benefits are the least effective approaches theoretically, but they are the most commonly applied, most likely because they are easy to administer and bring popular short term gains. Some theoretically favorable approaches that have been used elsewhere, such as payment for environmental services, may not work as well in India due to high transaction costs. However, one key innovation that easily could be applied in India is to make investment subsidies contingent on performance. Legal support and property rights reform would be needed for other favorable approaches.     

Sustainable agriculture and eradication of rural poverty in Pakistan

Poverty is rampant in the rural areas of Pakistan, where people are in a state of deprivation with regard to incomes, clothing, housing, healthcare, education, sanitary facilities and human rights. Agriculture generates nearly 20.9 percent of the country's GDP and provides employment for 43.4 percent of its workforce. Most importantly, 65.9 percent of the population living in rural areas is directly or indirectly dependent on agriculture for their livelihood. Rising population, shrinking agricultural land, increasing demand for water resources, widespread land degradation and inadequate infrastructure appear to be major concerns of the agriculture sector in Pakistan. An attempt has been made to examine the population growth–agriculture growth–poverty alleviation linkage. It is argued that agriculture will continue to be one of the most important sectors of Pakistan's economy for years to come. To alleviate poverty, it is suggested that Pakistan enhance the productivity of the agriculture sector through the provision of a series of inputs including provision of easy credit to the small farmer, availability of quality fertilizers and pesticides, tractor and harvester services, improvement in the effectiveness of the vast irrigation system and, finally, farmer education. It is concluded that the high rate of population growth needs to be curbed for increased agricultural productivity to have any significant effect on poverty in rural areas of Pakistan.     

东北林区火烧防火线方法研究

火烧防火线在东北林区应用广泛,是预防森林火灾的重要措施.这项工作由于受天气、可燃物、点火技术等各方面因素影响较大,应用时具有一定的风险性.本文针对火烧防火线过程中,用火条件的选择、点火技术的运用以及用火安全等方面加以分析.     

Factors related to seat belt use among fatally injured teenage drivers

PROBLEM: In the United States, teenage drivers have a higher crash risk and lower observed seat belt use than other age groups. METHOD: Seat belt use was examined for teenage (16-19 years) drivers who were fatally injured in traffic crashes occurring in the United States during the years 1995-2000. Vehicle, driver, and crash factors potentially related to belt use were examined. State differences in belt use rates among fatally injured teenage drivers were related to states' observed belt use rates for all ages and other state-level variables. RESULTS: During 1995-2000, mean belt use was 36% among fatally injured teenage drivers and 23% among fatally injured teenage passengers. One of the strongest predictors of higher belt use for both drivers and passengers was whether the crash occurred in a state with a primary seat belt law. Belt use rates for 1995-2000 for fatally injured teenage drivers ranged from 20% or less in six states to more than 60% in two states. States with the highest use rates were those with strong primary belt use laws and those with high rates of observed belt use for all ages. Lower belt use among fatally injured teenage drivers was associated with increasing age; male drivers; drivers of SUVs, vans, or pickup trucks rather than cars; older vehicles; crashes occurring late at night; crashes occurring on rural roadways; single vehicle crashes; and drivers with BACs of 0.10 or higher. Teenage driver belt use declined as the number of teenage passengers increased, but increased in the presence of at least one passenger 30 years or older. IMPACT ON TRAFFIC SAFETY: It is suggested that to increase teenage belt use, states should enact strong primary belt use laws and mount highly publicized efforts to enforce these laws. Graduated driver licensing systems should incorporate strong provisions that require seat belt use by teenage drivers and passengers.     

A research agenda for increasing safety belt use in the United States

On November 13-14, 2003, a symposium on high-visibility safety belt use enforcement in Raleigh, NC: (a) celebrated the 10th anniversary of North Carolina's Click It or Ticket program; (b) documented current knowledge regarding safety belt use; (c) proposed strategies to increase use further; and (d) discussed research to support these strategies.     

山脊防火林带有效结构的研究

防火林带的防火性能与阻风性能密切相关。本实验采用风洞模拟方法,对通风结构、疏透结构和紧密结构3种防火林带附近的风速进行测定,绘制了3种结构防火林带迎风面的风廊线。结果表明：紧密结构与疏透结构防火林带附近的阻风性能比较好,而通风结构阻风性能最差;但紧密结构防火林带上方的相对风速高达130％,为飞火的产生创造了条件;疏透结构林带上方的最大相对风速只有110％,不具备飞火产生的条件。所以,山脊防火林带的有效结构为疏透结构。