DISERTATION RESEARCH: Effects of global climate change, loss of mega-herbivore biodiversity, and altered fire regimes on savanna grassland ecosystems

知识价值。人类正在通过气候和土地利用的变化改变当地和全球的环境。草原约占陆地面积的三分之一，具有重要的生态和经济意义，因此它们对环境变化的反应将对全球生产力、生物多样性和粮食生产产生重大影响。本研究由两个实地实验组成。第一部分研究了北美（NA, Konza Prairie， KS）和南非（SA, Kruger National Park）中散质草地生态系统的三个主要驱动因素——降水、放牧和火灾——的变化如何相互作用影响植物群落组成、结构和动态。可比较的实验设计和相同的取样方案在NA和SA将允许发现的普遍性。第二个实验将沿着放牧利用梯度评估SA草原小尺度斑块结构和动态对火灾的响应。该实验将为梳理林火和放牧强度对南澳草草生物多样性的影响提供信息。更广泛的影响。这项研究与克鲁格国家公园的长期管理目标直接相关，该公园实施了一项科学驱动的管理计划，该计划围绕“特别关注的威胁”建立，包括气候变化、火灾管理、放牧压力和生物多样性。此外，本研究也可广泛应用于火灾、放牧和气候变率相互作用影响生物多样性和生态系统服务的全球mesic草原。克鲁格的所有研究都是与SANParks科学服务公司合作进行的，确保了科学家和管理人员之间的密切沟通。这项研究将为一名年轻女科学家提供国际实地经验和合作研究培训。

Intellectual merit. Humans are altering the environment locally and globally through climate and land use change. Grasslands, which cover approximately one third of terrestrial lands, are ecologically and economically significant, thus their responses to environmental change will have dramatic consequences for productivity, biodiversity, and food production globally. This research consists of two field experiments. The first investigates how changes in the three main drivers of mesic grassland ecosystems - precipitation, grazing, and fire - interact to affect plant community composition, structure, and dynamics in North America (NA, Konza Prairie, KS) and South Africa (SA, Kruger National Park). The comparable experimental designs and identical sampling protocols in both NA and SA will permit generality of findings. The second proposed experiment will assess how small-scale patch structure and dynamics in SA grasslands respond to fire along a grazing utilization gradient. This experiment will provide information to tease apart how fire and grazing intensity alter grass-forb biodiversity in SA. Broader impacts. This research is directly relevant to the long-term management goals of Kruger National Park, which has implemented a scientifically driven management plan built around 'threats of particular concern,' including climate change, fire management, grazing pressure and biodiversity. In addition, this research is broadly applicable to mesic grasslands around the world where fire, grazing and climatic variability interact to affect biodiversity and ecosystem services. All research in Kruger occurs in collaboration with SANParks Scientific Services ensuring close communication between scientists and managers. This research will result in international field experience and collaborative research training for a young female scientist.