Spatiotemporal Dynamics of Woody Cover in a Savanna Landscape

稀树草原景观中木质覆盖的时空动态

• 批准号: 1461728
• 负责人: Todd Anderson
• 金额: $ 30.53万
• 依托单位: Wake Forest University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2020-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1461728&HistoricalAwards=false
• 关键词: Spatiotemporal; Dynamics; Woody; Cover; Savanna

Savanna ecosystems cover vast areas of the earth's land surface and play a key role in biogeochemical cycling by providing habitat for wildlife and resources for rural communities. Empirical evidence and modeling efforts suggest that many of these grass-dominated ecosystems are becoming woodier over time and that these changes will have profound effects on a wide range of ecological and socio-ecological processes of their regions. This research project will analyze the ecological mechanisms and spatial interactions that underpin the process of woody cover change in grassland and savanna systems over the past two decades. The project will provide new perspectives about the impacts that changes in these ecosystems will have in altering their functions including soil moisture dynamics, radiation, soil temperature and nutrients, and carbon cycling and storage. The insights from this project will advance basic understanding about the fundamental forces driving woody cover change across a wide range of environmental settings. Project results will help guide policy makers, governmental agencies, and resource administrators in assessing appropriate courses of action. This project also will strengthen international research collaborations among U.S. and African scientists and institutions.Interactions between grassland and woody vegetation in a savanna ecosystem depend on the spatial context where even a small change at a fine-scale may have large-scale landscape-level ramifications of modifying entire vegetation distribution patterns. Using remote sensing methods, fieldwork, and spatial modeling, the investigators will seek answers to three core sets of questions: (1) What role do spatial processes play in determining woody cover dynamics at neighborhood scales? (2) Are these spatial processes resource- or disturbance-driven, and do they shift across climate gradients? (3) Do woody cover changes exhibit gradual or abrupt transitions (regime shifts) over time, and how are these dynamics related to fine-scale spatial structure and resource and disturbance gradients? Project findings will lead to a better understanding of the impacts that widespread increases in woody cover are having on habitat structure for wildlife, ecosystem function, and economic activity.

稀树草原生态系统复盖了地球表面的广大地区，并通过为野生动物提供栖息地和为农村社区提供资源，在生物地球化学循环中发挥关键作用。经验证据和建模工作表明，随着时间的推移，许多以草为主的生态系统正在变得更加茂盛，这些变化将对其区域的广泛生态和社会生态过程产生深远影响。这项研究项目将分析过去20年来草原和稀树草原系统木质覆盖变化过程中的生态机制和空间相互作用。该项目将为这些生态系统的变化在改变其功能方面产生的影响提供新的视角，包括土壤水分动态、辐射、土壤温度和养分以及碳循环和储存。这个项目的洞察力将促进人们对推动木质覆盖物变化的基本力量在广泛的环境设置中的基本理解。项目成果将有助于指导政策制定者、政府机构和资源管理者评估适当的行动方针。该项目还将加强美国和非洲科学家和机构之间的国际研究合作。稀树草原生态系统中草原和木本植被之间的相互作用取决于空间环境，在空间环境中，即使是细微的微小变化也可能产生改变整个植被分布模式的大规模景观水平的后果。研究人员将利用遥感方法、实地调查和空间建模，寻求三个核心问题的答案：(1)空间过程在决定邻域尺度上的木本覆盖动态中起什么作用？(2)这些空间过程是资源驱动的还是干扰驱动的，它们是否在气候梯度之间转移？(3)随着时间的推移，木本覆盖变化是渐进的还是突然的转变(制度变化)，以及这些动态与细尺度空间结构以及资源和干扰梯度是如何关联的？该项目的发现将有助于更好地理解木本植物覆盖率的普遍增加对野生动物栖息地结构、生态系统功能和经济活动的影响。