Collaborative Research: Convergence and Contingencies in Savanna Grasslands

草原和稀树草原占地球陆地面积的近40%，是重要的经济牧场，受人类活动的影响很大。它们还具有巨大的保护价值，是世界上剩余的大型食草动物的栖息地，特别是在非洲。管理和养护稀树草原需要对维持稀树草原最重要的因素--火和放牧--有一个基本的了解。然而，科学家们质疑不同地区的草原是否具有相似的功能。功能上的趋同将意味着生态理解和保护战略可以在世界范围内推广。但特定于一个地区的偶然因素，如历史上的差异或现有的食草动物类型，可能会导致一些稀树草原上的独特反应。这项研究的目标是将北美和南非稀树草原上的关键生态过程与火和放牧进行比较。科学家们将利用三个正在进行的长期实验来操纵这些关键因素，并比较它们在生产力、生物多样性和养分循环方面的反应。随着人类在世界范围内改变火和放牧制度，需要进行比较研究，阐明其后果，以制定能够确保稀树草原可持续性的管理战略。这项研究将提供这样做所需的基本知识，并将为年轻科学家、研究生和本科生提供培训和重要的全球和文化经验。

Grasslands and savannas occupy almost 40% of the earth's land surface, are economically important as grazing lands, and are highly impacted by human activities. They also have tremendous conservation value, housing the world's remaining large grazing animals, particularly in Africa. A fundamental understanding of the factors most important for sustaining savanna grasslands, fire and grazing, is required for their management and conservation. Yet scientists have questioned whether grasslands in different regions function similarly. Convergence in function would mean that ecological understanding and conservation strategies could be generalized worldwide. But contingent factors specific to a region, such as differences in history or the types of grazers present may lead to unique responses in some savanna grasslands. The goal of this research is to compare key ecological processes to fire and grazing in savanna grasslands in North America and South Africa. Scientists will take advantage of three ongoing long-term experiments that manipulate these key factors and compare responses in productivity, biodiversity, and nutrient cycling. As humans alter fire and grazing regimes worldwide, comparative research elucidating the consequences is needed to develop management strategies that can insure the sustainability of savanna grasslands. This research will provide the basic knowledge necessary to do so, and will afford training and important global and cultural experiences for young scientists, graduate students, and undergraduate students.