Collaborative Research: Quantifying post-fire aeolian sediment transport and nutrient redistribution using rare earth element tracers

合作研究：使用稀土元素示踪剂量化火后风沉积物输送和养分重新分配

• 批准号: 1451489
• 负责人: Junran Li
• 金额: $ 12.57万
• 依托单位: University of Tulsa
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-03-01 至 2019-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1451489&HistoricalAwards=false
• 关键词: Collaborative; Research; Quantifying; post; fire

A nontechnical explanation of the project's broader significance and importanceArid and semiarid landscapes are dynamic and can undergo rapid changes in vegetation, soil composition, and topography. Some climate models indicate an increase in aridity and changes in the timing of seasonal precipitation in many semi-arid regions, including the North American deserts. This potential climate change, together with human activities, may increase the frequency and intensity of wind erosion and fire. This project will provide a quantitative assessment that examines both fire and wind erosion effects on vegetation change, soil characteristics, air quality, and landscape evolution. This study will help in the sustainable management of desert grasslands under changing climate and wildfire scenarios. A technical description of the projectGrasslands and rangelands in arid and semi arid regions of the world, which provide fundamental ecosystem services, are undergoing rapid changes in fire activity and are highly susceptible to post-fire accelerated soil erosion and redistribution by wind. Currently, many grassland systems are being encroached by woody plants leading to decline in grass productivity with the potential to jeopardize food security and environmental quality. Even though many ecosystems worldwide exist in transition between shrublands and grasslands and are affected by episodic fires, a comprehensive understanding of the rates and patterns of post-fire wind erosion and subsequent sediment redistribution is still missing. The proposed project will quantify post-fire wind erosion and subsequent nutrient redistribution from a shrub-grass system in the Chihuahuan desert (New Mexico) using a combination of extensive manipulative field experiments, laboratory analyses and modeling. We will test the hypothesis that vegetated microsites, which capture aeolian sediments in arid landscapes, may become active sediment sources following fires. This post-fire modification of sediment sources and sinks in the landscape may impact rates of resource redistribution and soil patterning, and therefore, lead to a more homogeneous landscape and reverse grassland degradation. This project will investigate the applicability of rare earth element tracers and Unmanned Aerial Systems-based LiDAR in order to monitor landscape responses to natural and human-induced disturbances and to guide future management practices.

对该项目更广泛的意义和重要性的非技术性解释干旱和半干旱的地貌是动态的，可以经历植被、土壤成分和地形的快速变化。一些气候模型表明，包括北美沙漠在内的许多半干旱地区的干旱加剧，季节性降水的时间也发生了变化。这种潜在的气候变化，加上人类活动，可能会增加风蚀和火灾的频率和强度。该项目将提供定量评估，研究火和风蚀对植被变化、土壤特性、空气质量和景观演变的影响。这项研究将有助于在气候变化和野火情景下沙漠草原的可持续管理。该项目的技术说明是，世界干旱和半干旱地区的草地和牧场提供基本的生态系统服务，它们正在经历火灾活动的快速变化，极易受到火灾后加速的土壤侵蚀和风的重新分配的影响。目前，许多草原系统正受到木本植物的侵蚀，导致牧草生产力下降，有可能危及粮食安全和环境质量。尽管世界各地的许多生态系统处于灌丛和草原之间的过渡阶段，并受到间歇性火灾的影响，但对火灾后风蚀的速度和模式以及随后的沉积物重新分配仍然缺乏全面的了解。拟议的项目将利用广泛的现场操控实验、实验室分析和建模相结合的方法，量化火灾后的风蚀和随后奇瓦瓦沙漠(新墨西哥州)灌木-草系统的养分重新分配。我们将测试这样一种假设，即在干旱地区捕获风沙沉积物的植被微站点可能在火灾后成为活跃的沉积物来源。这种火后对景观中沉淀源和汇的修改可能会影响资源再分配和土壤格局的速度，从而导致更均匀的景观和逆转草原退化。该项目将调查稀土元素示踪剂和基于无人驾驶航空系统的激光雷达的适用性，以监测地貌对自然和人为干扰的反应，并指导今后的管理做法。