EAGER: Modeling Coupled Herd and Household Dynamics in Pastoral Systems

EAGER：对畜牧系统中的耦合畜群和家庭动态进行建模

• 批准号: 1546061
• 负责人: Mark Moritz
• 金额: $ 3.78万
• 依托单位: Ohio State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-15 至 2017-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1546061&HistoricalAwards=false
• 关键词: EAGER; Modeling; Coupled; Herd; Household

Anthropologists use the term "pastoralism" to refer to economies that depend on raising livestock. Pastoralism has long been viewed as a good strategy for people who live in less productive environments with few natural resources. However, even pastoralists have to be concerned about balancing the number of animals they keep with the pasture available to feed them and the labor available to care for them. Indeed, population models show that livestock populations have the potential to grow exponentially and oustrip the carrying capacity of their environments. But empirical evidence indicates otherwise: in the real world, pastoral livestock populations are relatively stable. The question then is how is this balance achieved? Until now the most popular explanation has been that droughts, diseases, and other disasters keep livestock populations in check. But the research supported by this award will test an alternative explanation: demographic dynamics -- the natural expansion and contraction of family sizes over time -- operating at the herd and household level may constrain the growth of livestock populations regionally. If this is indeed the case, as this interdisciplinary research team proposes, then it has implications for development interventions in pastoral societies. Improving veterinary health and reducing drought vulnerability would then improve the lives of pastoralists without necessarily threatening the natural resource base. The research team will develop an agent-based model to examine the impact of the domestic cycle of households on the demography of family herds and ultimately on regional livestock populations. Empirical data from previous studies will be used to parameterize the agent-based model. The model will simulate the domestic cycle of an initial population of 100 households and the demographic processes of their family herds for 250 years (or 10 generations). The simulations will allow the researchers to examine how the domestic cycle affects herd demography by examining the impact of changes in age of first marriage, increase in the number of sons, or increase in polygyny rates. In addition, the simulations will be used to examine how sensitive the growth of regional livestock populations is to changes in the herd-size threshold, i.e., whether a lower threshold leads to stronger growth of livestock populations at the regional level. Findings from this research will provide insight into livestock population dynamics in pastoral societies, in particular the question of why these populations do not seem to increase in the absence of major disasters like droughts and diseases.

人类学家使用“牧民”一词来指代依赖牲畜的经济体。长期以来，对于生活在自然资源很少的生产力较低的环境中的人们来说，牧民一直被视为一个很好的策略。但是，即使是牧民也必须担心将它们保留的动物与可用的牧场保持平衡，以喂养它们以及可以照顾他们的劳动。确实，人口模型表明，牲畜种群有可能成倍增长并消除其环境的承载能力。但是经验证据表明另有说明：在现实世界中，田园牲畜种群相对稳定。那么问题是如何实现的？到目前为止，最受欢迎的解释是干旱，疾病和其他灾难可以控制牲畜种群。但是，该奖项支持的研究将测试另一种解释：人口动态 - 随着时间的流逝，家庭规模的自然扩张和收缩 - 在牛群和家庭水平上运作可能会限制牲畜种群的增长。如果确实如此，那么正如这个跨学科研究团队所提出的那样，它对牧养社会的发展干预具有影响。改善兽医健康并减少干旱脆弱性将改善牧民的生活，而不必威胁自然资源基础。 研究团队将开发一个基于代理的模型，以研究家庭的国内周期对家庭群人口统计以及最终对地区牲畜人口的影响。先前研究的经验数据将用于参数化基于代理的模型。该模型将模拟100个家庭的初始人口的国内周期以及250年（或10代）的家人群的人口程序。这些模拟将使研究人员能够通过检查初婚年龄变化，增加儿子的数量或一夫多妻制率的增加来检查国内周期如何影响群人口统计学。此外，这些模拟将用于检查区域牲畜种群的敏感性是对牛群大小阈值的变化的敏感性，即，较低的阈值是否导致区域水平的牲畜种群的增长更强。这项研究的发现将为牧养社会的牲畜种群动态提供深入的了解，尤其是为什么在缺乏干旱和疾病（例如干旱和疾病）的主要灾害中似乎不会增加这些人群的问题。