Sahelian Savanna Disturbance Experiment

热带和亚热带季节性干旱地区的乔木(或木本灌木)和草同时存在是热带草原的定义。这种非常不同类型的植物的共存对于生态系统的功能(例如，植被生长、水的使用、碳的储存)来说是重要的，但对于人类如何从这些独特的系统中受益和如何管理(例如，放牧牛或薪柴收获)也是重要的。在非洲，热带草原是经济、文化和生物多样性的关键领域。该项目的美国和马里合作者设计了一项全面的实地实验，以考察火和大型食草动物在西非降雨梯度的五个地点的相互作用效应，这些地点从北部干燥的萨赫勒到南部潮湿的稀树草原。在每个地点，栅栏和防火装置分别将家畜或火灾排除在试验田之外。该小组将监测植被生长，以研究这些干扰如何影响树木和草的生存和生长，改变植物物种组成，以及它们在降雨梯度上的不同影响。这项实验将提供西非稀树大草原树木-草相互作用方面亟需的经验数据，并补充非洲、澳大利亚和南美洲其他地区的研究。因此，这项工作将有助于发展稀树草原的生态理论，并更好地理解干扰在植物物种共存中的作用。西非的萨赫勒-苏丹地区对赤道以北的非洲经济以及该地区牧民和农业人民的生计至关重要。该地区经常遭受干旱，存在粮食安全、环境退化和荒漠化等问题。了解人类管理做法如何影响生态过程，将加强健全的管理，以应对未来不断变化的气候。该项目将为美国和非洲学生提供独特的研究经验和国际科学/文化接触，并促进非洲和美国研究人员合作核心的发展，这种合作将持续到未来。该奖项由美国国家科学基金会国际科学与工程办公室共同资助。

Savannas are defined by the simultaneous presence of trees (or woody shrubs) and grasses in seasonally dry areas of the tropics and sub-tropics. This coexistence of very different types of plants is important in terms of the functioning of the ecosystem (e.g., vegetation growth, water use, carbon storage), but also in terms of how humans benefit from and manage these unique systems (e.g., grazing cattle or fuel-wood harvest). In Africa, savannas are key areas of economic, cultural and bio-diversity. The US and Malian collaborators in this project have designed a comprehensive field experiment to examine interactive effects of fire and large herbivores at five sites across the West African rainfall gradient, from dry Sahel in the north to wetter savannas in the south. At each site, fences and fire-breaks exclude domestic livestock or fires, respectively, from experimental plots. The team will monitor vegetation growth to examine how these disturbances affect survival and growth of trees and grasses, alter plant species composition, and differ in their effects across the rainfall gradient. The experiment will provide much needed empirical data on tree-grass interactions in West African savannas and complement research elsewhere in Africa, Australia and South America. This work thus will contribute to development of ecological theory for savannas and a better understanding of the role of disturbance in plant species coexistence.The Sahel-Sudan zone of West Africa is crucial for the economies of Africa north of the equator and for the livelihoods of the region's pastoral and agricultural peoples. The region is subject to frequent drought, with problems of food security, environmental degradation, and desertification. An understanding of how human management practices impact ecological processes will enhance sound management in the face of future changing climate. The project will provide unique research experiences and international scientific/cultural exposure to US and African students, and facilitate development of a collaborating nucleus of African and US researchers that will endure well into the future. This award is co-funded by NSF's Office of International Science and Engineering.