Environmental Variability, Migration, and Rural Livelihoods

描述（由申请人提供）：关于环境变化和可变性如何影响移民决策，从而影响人口再分配，我们所知甚少。这种理解很重要，因为移徙对个人和社区的健康和福祉有影响。此外，鉴于政府间气候变化专门委员会最近发布的报告（IPCC 2007:4）断言气候系统存在“明确的”变化，预计未来区域降水和温度模式将继续发生变化，提高对移民环境维度的理解至关重要。其中许多变化将最严重地影响已经脆弱的地区，包括南非农村地区，我们的研究背景，那里的降水和温度预计会发生变化。在这些农村环境中，生计往往严重依赖当地的自然资源。重要的陆上活动包括可耕地耕作、畜牧业以及自然资源（如薪材、野生草药）的消费和贸易。自然资源还可作为抵御失业和/或死亡等家庭冲击的“缓冲器”。鉴于这种对资源的高度依赖，当地植被覆盖的变化（由于降水/温度模式的变化）具有巨大的影响生计的潜力。就外移而言，生计选择的减少可以成为形成移徙趋势的“推动”因素。利用“农村生计”框架，我们在一个健康和人口监测点阿金库尔健康和人口单位（AHPU）内模拟了外移（2002年和2007年）与当地自然资源的可用性和可变性（2002-2006年）之间的关系。AHPU位于南非东北部的一个贫困农村地区，自1992年以来，每隔12-18个月从21个村庄的12,000多户家庭中收集人口普查数据。此外，它位于陡峭的局部拓扑梯度内，在整个研究环境中提供了植被可用性的实质性变化。我们将测量当地“绿色”的社会经济和遥感数据结合起来，开发了多变量空间信息模型，以检查外移和邻近自然资源的可用性和可变性。除了具体的研究成果外，该项目还被设计为纵向模型开发的基础，利用人口监测设置提供的人口-环境分析优势。实际上，很少有现有的适当数据可以对社会经济和环境进程之间的关联进行建模，而健康和人口监测站点则提供了处理这些复杂关联的独特机会。

DESCRIPTION (provided by applicant): Little is known about the ways in which environmental change and variability shape migration decision-making and, therefore, population redistribution. Such understanding is important because migration has implications for the health and well-being of individuals and communities. In addition, an improved understanding of migration's environmental dimensions is essential given the recently-released report by the Intergovernmental Panel on Climate Change which asserts there are "unequivocal" changes in the climate system (IPCC 2007:4) with future expectations of continued shifts in regional precipitation and temperature patterns. Many of these changes will most severely impact already-vulnerable regions including rural South Africa, our study setting, where precipitation and temperature shifts are anticipated. In these rural settings, livelihoods are often characterized by heavy dependence on local natural resources. Important land-based activities include arable farming, livestock husbandry, and consumption and trade in natural resources (e.g., fuelwood, wild herbs). Natural resources also act as "buffers" against household shocks such as job loss and/or mortality. Given this high level of resource dependence, changes in local vegetation cover (due to shifts in precipitation/temperature patterns) hold tremendous potential to impact livelihoods. As related to outmigration, a decline in livelihood options can act as a "push" factor shaping migration trends. Using a "Rural Livelihoods" framework, we model the association between outmigration (in 2002 and 2007) and the availability and variability of local natural resources (2002-2006) within a health and demographic surveillance site, the Agincourt Health and Population Unit (AHPU). Located in an impoverished rural area in the South Africa's northeast, the AHPU has collected census data at 12-18 month intervals since 1992 from over 12,000 households in 21 villages. In addition, its location within a steep local topological gradient affords substantial variation in vegetation availability across the study setting. We combine socioeconomic and remotely sensed data measuring local "greenness," and develop multivariate spatially-informed models to examine outmigration and the availability and variability of proximate natural resources. In addition to specific research results, this project is designed as a foundation for development of longitudinal models tapping into the analytical strength for population-environment provided by demographic surveillance settings. Indeed, there are few settings with existing, appropriate data for modeling the associations between socioeconomic and environmental processes and health and demographic surveillance sites represent unique opportunities to grapple with these complex associations. PUBLIC HEALTH RELEVANCE: This research will improve understanding of the association between rural livelihoods, especially related to migration decisions, and environmental change in impoverished rural areas of less developed countries. Residents of these regions are especially vulnerable to environmental changes due to high reliance on local natural resources such as fuelwood and wild foods. Migration can be a coping strategy in response to changes in the availability of local natural resources, although relocation has important consequences for health and well-being of migrants and of individuals and communities in receiving areas.