CNH: Hydrology, Ecology, and Pastoral Societies in the Sahel: Ephemeral and Perennial Water Resources in a Dynamic Coupled System

非洲萨赫勒地区的牧场是非洲人民的重要放牧资源，为数百万头牲畜提供季节性放牧。然而，该区域经常发生干旱，牲畜饲料和地表水的供应每年都有很大的不确定性。该地区的许多小湖泊在雨季出现，但在旱季干涸，数千年来，该地区的人类社会通过开发复杂的、社会谈判的、长距离的牲畜迁徙路线来应对季节性的牲畜用水，这些路线组织并正式获得萨赫勒的放牧资源。自1970年代和1980年代的干旱以来，萨赫勒地区的水文和社会经济组织似乎正在发生变化，越来越多的水流入水池，在一些地方，这些水池现在全年为牲畜提供水源。 该项目将检验这一假设，即这些系统水平的变化是由干旱引起的，干旱减少了植被覆盖，增加了流入水池的水。在某个时候，一些湖泊变得足够深，可以持续整个旱季，在一些地区，历史上的移民社区作出反应，在湖泊附近永久定居。第二个假设是，激烈的放牧活动，现在保持在这些流域的退化和径流，使常年湖泊状态和永久定居的水平。 该项目探讨了气候、植被动态、景观水文和依赖并管理这些系统的人类社会之间复杂的相互作用和反馈。在非洲，萨赫勒是一个社会经济重要地区，对畜牧业生产很重要，但易受干旱和饥荒影响。 增加我们对萨赫勒地区人类-自然系统相互作用动态的了解，包括导致生态系统和社会经济功能迅速转变的过程，对弱势群体的福祉至关重要。 该项目将向西非的政府、非政府、畜牧和农业社区提供外联服务，扩大关于人类和自然系统耦合的大学课程，并培训研究生和本科生。 该项目包括与马里研究人员的重大国际合作，由国际科学与工程办公室的非洲，近东和南亚计划提供资金支持。

The grazing lands of the Sahel region of Africa are a vital grazing resource for the people of Africa, providing seasonal grazing for millions of animals. However, the region is subject to frequent droughts and considerable year-to-year uncertainty in availability of both fodder and surface water for cattle. Many small lakes in the region appear during the wet season but dry out during the dry season and, over millennia, human societies in the region responded to the seasonal availability of water for cattle by developing complex, socially-negotiated, long-distance herd-migration routes that organized and formalized access to the grazing resources of the Sahel. Since the droughts of the 1970s and 1980s the coupled hydrology and socioeconomic organization of the Sahel appears to be changing, with increasing drainage into pools that in some places now provide year-round water for cattle. This project will test the hypothesis that these system level changes were triggered by the drought which reduced vegetation cover and allowed increased water flows into pools. At a certain point, some lakes became deep enough to last through the dry season and, in some areas, the historically migratory communities responded by settling permanently near the lakes. A second hypothesis to be tested is that intense grazing activity now maintains a level of degradation and runoff in these watersheds that perpetuates the perennial lake state and permanent settlement. This project explores these complex interactions and feedbacks between climate, vegetation dynamics, landscape hydrology, and the human societies that depend on and manage these systems. In Africa, the Sahel is a socio-economically vital region, important for livestock production but vulnerable to drought and famine. Increasing our knowledge of coupled human-natural system dynamics in the Sahel, including the processes that lead to rapid transitions in ecosystem and socioeconomic function, is vital to the wellbeing of vulnerable populations. This project will provide outreach to governmental, non-governmental, pastoral and agricultural communities in West Africa, expand university curriculum on coupled human and natural systems, and train graduate and undergraduate students. This project includes a significant international collaboration with researchers in Mali that is supported by funding from Office of International Science and Engineering's Africa, Near East, and South Asia program.