Minority Postdoctoral Research Fellowship for FY2006

本项目为2006年度少数民族博士后科研资助项目。植被在景观上的斑驳分布可能是有限资源（如水和土壤养分）分配不均匀的结果，也可能是干扰（如捕食者、竞争对手或火灾的选择压力）的影响。在制定异质生态系统保护和恢复管理计划时，需要考虑物理环境和生物环境之间复杂的反馈。我建议研究克鲁格国家公园半干旱的南非稀树草原上一种重要植物养分的生物和非生物控制，以提高我们对土壤-植物相互作用以及它们如何对火灾和放牧作出反应的理解。我将重点关注硅（Si），它被用作植物防御机制，因此预计在草食动物主导的生态系统中很重要。硅还参与促进植物生长，提高植物在营养贫乏的土壤或有毒元素存在下的生存能力。我的研究将有助于我们了解影响克鲁格野生动物栖息地植被异质分布的因素。硅的循环通过土壤矿物风化过程和硅对海洋初级生产力的贡献与碳循环和全球气候联系在一起。人们对草地在全球硅循环中的作用知之甚少。同位素地球化学在生态系统生态学中的应用正在彻底改变我们对形成生态系统结构和功能的过程的理解。我对植物和环境之间的相互作用很感兴趣，尤其是土壤、大气和水文。通过我的博士后研究，我将获得新的同位素技术和地球化学方法的培训，这将使我更好地了解控制生物地球化学循环的过程和潜在机制。我希望在我的博士后接收机构，加州大学圣巴巴拉分校（UCSB），在Oliver Chadwick博士的指导下，以及在南非开展合作。我将加入少数生物地球化学家的行列，与非洲当地科学家一起建立新的研究项目。我还将有机会通过指导威特沃特斯兰德大学（University of the Witwatersrand）的一名研究生，参与后种族隔离时代南非下一代本土科学家和自然资源管理者的培训。这个机会将建立在我过去在加州大学伯克利分校的指导经验之上，并有助于我作为教师和学生顾问的准备。我将以我过去在政治学方面的学习为基础，让学生们思考科学研究和环境管理的社会和政治背景。

This project is awarded under the Minority Postdoctoral Research Fellowships and Supporting Activities Program for 2006. The patchy distribution of vegetation across a landscape may result from the non-uniform allocation of limited resources, such as water and soil nutrients, as well as the effect of a disturbance, such as selective pressure from predators, competitors, or fire. The complex feedbacks between the physical and biotic environments need to be considered when developing management plans for conservation and restoration in heterogeneous ecosystems. I propose to examine the biotic and abiotic controls on the availability of an important plant nutrient in semi-arid South African savannas at Kruger National Park, to improve our understanding of soil-plant interactions and how they respond to fire and grazing. I will focus on silicon (Si), which is used as a plant-defense mechanism, and thus expected to be important in ecosystems dominated by herbivores. Silicon is also involved in enhancing plant growth and improves plants' ability to survive in nutrient poor soils or in the presence of toxic elements. My research will contribute to our understanding of the factors shaping heterogeneous distribution of vegetation which determines wildlife habitat at Kruger. The cycle of Si is linked to the carbon cycle, and to global climate, through the process of soil mineral weathering and Si's contribution to marine primary productivity. Very little is known about the role of grasslands in the global Si cycle. The application of isotope geochemistry to ecosystem ecology is revolutionizing our understanding of the processes that shape ecosystem structure and function. I am interested in the interactions between plants and their environment, especially soils, the atmosphere, and hydrology. Through my proposed post-doctoral research, I will gain training in new isotope techniques and geochemical methods that will allow me to better understand processes and underlying mechanisms controlling biogeochemical cycling. I expect to develop collaborations at my post-doctoral host institution, U.C. Santa Barbara (UCSB) under the mentorship of Dr. Oliver Chadwick, and in South Africa. I will join a small number of biogeochemists establishing new research programs with local scientists in Africa. I will also have the opportunity to participate in the training of the next generation of indigenous scientists and natural resource managers in a post-apartheid South Africa, by mentoring a graduate student from the University of the Witwatersrand. This opportunity will build upon my past mentoring experiences at U.C. Berkeley, and contribute to my preparation as a teacher and student advisor. I will build upon my past studies in Political Science to get students to think about the social and political context of scientific research and environmental management.