RAPID: Impact of exceptional drought on transformation of a savanna grassland

RAPID：异常干旱对稀树草原转型的影响

• 批准号: 1712786
• 负责人: Melinda Smith
• 金额: $ 7.04万
• 依托单位: Colorado State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-02-01 至 2019-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1712786&HistoricalAwards=false
• 关键词: RAPID; Impact; exceptional; drought; transformation

Kruger National Park (KNP), a biodiversity hotspot, is experiencing one of its worst droughts on record. This drought has resulted in large declines in forage for many grazing species, which have experienced significant population declines as a result. The remaining animals have been left to consume low quality, mostly unpalatable, forage. How these changes may alter future plant communities is not known. For almost a decade, scientists have been studying the impact of fire frequency and large grazers on ecosystem processes in savanna grassland in KNP under what used to be considered normal climatic conditions. With the onset of extreme drought, they now have an opportunity to study how the effects of fire and grazing may change as climatic conditions change, and what this might mean for plant productivity and populations of large grazer species. Climate models predict an intensification of climate extremes globally, a phenomenon that is already evident in weather patterns today, so there is a great need to develop a better understanding of how these rare climatic events may be reshaping ecosystems. In addition to enhancing understanding of savanna grasslands and testing fundamental ecological theory, this research will provide crucial information on the impact of climate extremes on plants and their grazers, which will be of great value to decision makers that manage national parks. The proposed research will document the effects of a historically exceptional drought on a savanna grassland (characterized by a mixture of both woody and herbaceous plants) in KNP in the context of an existing long-term grazing and fire experiment. Documenting the potentially transformational nature of rare climatic events is in itself an opportunity seldom afforded ecologists, but to have pre-treatment data and a long-term, well-replicated experiment in place that manipulates the key disturbances most likely to interact with extreme drought is unprecedented. Because forecasts are for this exceptional drought to conclude in early 2017, this RAPID project focuses on gathering data at the end of this exceptional climate event to assess the potential for drought, fire and grazing to trigger a shift in the plant community that will result in an increase in the relative abundance of palatable grasses. This research has implications for not only understanding the determinants of grassland biodiversity, but also for increasing our knowledge of how rare climate extremes may transform ecosystems. Currently, KNP managers are grappling with a long-term trend of grassland degradation which has led to the loss of palatable forage for wildlife. The current exceptional drought, while exacerbating this problem in the short-term, may increase forage quality across much of KNPs grasslands. In addition, this project will establish close collaborative ties between US researchers and scientists in South Africa. The lead scientists on this project will continue to work closely with KNP scientists to ensure that all results are communicated in a way to inform management decisions in KNP. Dissemination of all datasets and results will be achieved via a dedicated webpage, housed at Colorado State University.

生物多样性热点克鲁格国家公园（KNP）正在记录到其最严重的干旱之一。这种干旱导致许多放牧物种的饲料大幅下降，因此人口的大幅下降。 其余的动物被留下来消耗低质量（大部分是令人不快的草料）。 这些变化如何改变未来的植物社区。近十年来，科学家一直在研究火灾频率和大型放牧者对KNP中Savanna Grandsy Process的影响，在过去被认为是正常气候条件下。随着极端干旱的开始，他们现在有机会研究火灾和放牧的影响可能会随着气候条件的变化而改变，这可能对植物生产力和大型放牧物种的种群意味着什么。 气候模型预测了全球气候的强化，这是当今天气模式已经很明显的现象，因此非常需要更好地了解这些罕见的气候事件如何重塑生态系统。除了增进对稀树草原草原的理解和测试基本生态理论外，这项研究还将提供有关极端气候对植物及其放牧者的影响的重要信息，这对管理国家公园的决策者具有很大的价值。拟议的研究将记录在现有的长期放牧和火灾实验的背景下，在KNP中，历史上特殊的干旱对稀树草原草原（以木本和草本植物的混合物为特征）的影响。记录罕见气候事件的潜在变革性质本身就是很少有机会的生态学家，但要拥有预处理的数据和长期，良好复式的实验，以操纵最有可能与极端干旱相互作用的关键干扰是没有预期的。由于预测是针对2017年初结束的这种特殊干旱，因此该快速项目着重于在这一特殊气候事件结束时收集数据，以评估干旱，火灾和放牧的潜力，以触发植物社区的转变，这将导致可抵制草的相对丰富丰度增加。这项研究不仅对了解草地生物多样性的决定因素有影响，而且还对我们对罕见气候极端可能如何改变生态系统的了解。目前，KNP经理正在努力应对草地降解的长期趋势，这导致野生动植物的可口草料丧失。当前的特殊干旱在短期内加剧了这一问题的同时，可能会增加大部分Knps Grasslands的草料质量。此外，该项目将建立美国研究人员与南非科学家之间的紧密合作关系。 该项目的首席科学家将继续与KNP科学家紧密合作，以确保以一种为KNP的管理决策提供通信的所有结果。所有数据集的传播和结果将通过科罗拉多州立大学的专用网页来实现。