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: 1451518
• 负责人: Sujith Ravi
• 金额: $ 23.42万
• 依托单位: Temple University
• 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=1451518&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.

对该项目更广泛意义和重要性的非技术性解释干旱和半干旱景观是动态的，可以在植被、土壤成分和地形上发生快速变化。一些气候模式显示，在包括北美沙漠在内的许多半干旱地区，干旱程度增加，季节性降水的时间发生了变化。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。该项目将提供一个定量评估，审查火灾和风蚀对植被变化、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况下对沙漠草原进行可持续管理。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，但在火灾活动中正在经历迅速的变化，并且非常容易受到火灾后加速土壤侵蚀和风的重新分布的影响。目前，许多草地系统被木本植物侵占，导致草地生产力下降，并有可能危及粮食安全和环境质量。尽管世界各地许多生态系统处于灌木丛和草原之间的过渡阶段，并受到间歇性火灾的影响，但仍然缺乏对火灾后风蚀和随后沉积物重新分布的速度和模式的全面了解。拟议的项目将量化火灾后的风蚀和随后的营养再分配从灌木-草系统在奇瓦瓦沙漠（新墨西哥州）使用广泛的操作现场实验，实验室分析和建模相结合。我们将测试这一假设，植被微，捕获风成沉积物在干旱的景观，可能成为活跃的沉积物来源火灾后。火灾后景观中沉积物源和汇的变化可能会影响资源重新分配和土壤模式的速度，因此，导致更均匀的景观和扭转草原退化。该项目将研究稀土元素示踪剂和基于无人机系统的激光雷达的适用性，以监测景观对自然和人为干扰的反应，并指导未来的管理实践。