Collaborative Research: Convergence and Contingencies in Savanna Grasslands

草原和稀树草原几乎占据了地球陆地表面的40%，作为放牧地具有重要的经济意义，并且受到人类活动的高度影响。它们也具有巨大的保护价值，是世界上仅存的大型食草动物的家园，尤其是在非洲。对维持热带稀树草原最重要的因素——火和放牧——有一个基本的了解，是管理和保护稀树草原所必需的。然而，科学家们质疑不同地区的草原功能是否相似。功能的趋同意味着生态认识和保护策略可以在世界范围内推广。但是，一个地区特有的偶然因素，如历史的差异或存在的食草动物类型的差异，可能会导致一些稀树草原的独特反应。本研究的目的是比较北美和南非热带稀树草原火灾和放牧的关键生态过程。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，并比较生产力、生物多样性和营养循环方面的反应。由于人类改变了世界范围内的火灾和放牧制度，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策略。这项研究将提供必要的基本知识，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体验。

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.