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.

对该项目更广泛的意义，重要的和半干旱景观的非技术解释是动态的，并且可以在植被，土壤成分和地形上快速变化。一些气候模型表明，在包括北美沙漠在内的许多半干旱地区的季节性降水时间的干扰和季节降水时间的变化有所增加。这种潜在的气候变化以及人类活动可能会增加风侵蚀和火的频率和强度。该项目将提供定量评估，以检查火灾和风侵蚀对植被变化，土壤特征，空气质量和景观演变的影响。这项研究将有助于在不断变化的气候和野火方案下对沙漠草原的可持续管理。提供基本生态系统服务的干旱和半干旱地区的项目草和牧场的技术描述正在发生迅速的火灾活动变化，并且非常容易受到射击后加速土壤侵蚀和风的重新分配。目前，木本植物正在侵占许多草地系统，导致草生产力下降，从而危及粮食安全和环境质量。即使全世界许多生态系统都存在于灌木丛和草原之间的过渡中，并且受情节性大火的影响，但对火后风侵蚀的速度和模式的全面理解和随后的沉积物再分配仍然缺失。拟议的项目将使用广泛的操纵野外实验，实验室分析和建模的结合结合了奇瓦瓦沙漠（新墨西哥州）的灌木草系统中的射击后风侵蚀和随后的养分再分配。我们将测试以下假设：在火灾后，捕获风景景观中的风化的水陆物质可能会成为活跃的沉积物来源。景观中沉积物来源和下沉的这种火灾后修改可能会影响资源再分配和土壤模式的速度，因此导致更均匀的景观和反向草地退化。该项目将调查稀土元素示踪剂和无人空中系统的LIDAR的适用性，以监视对自然和人类引起的干扰的景观响应，并指导未来的管理实践。