Doctoral Dissertation Research: Integrating Image Spectroscopy and Microbial Biogeochemistry to Analyze Woody Shrub Encroachment

本博士论文研究将探讨半干旱地区灌木入侵对植物和土壤养分动态的影响。 灌木入侵是对全球旱地生态系统的持续威胁，通过改变植物群落多样性、净初级生产力和土壤功能，从根本上改变生态系统过程。 本博士论文研究项目将采用创新方法，将联合收割机高光谱遥感数据与土壤地球化学和微生物参数的实地测量相结合，以推断叶片化学，并量化灌木入侵对旱地养分动态的影响。 该项目将提供对通过生物地球化学循环联系在一起的微生物群落和植物群落的空间动态的更全面的了解。 该项目包括一个强有力的教育组成部分，为K-12培训提供机会，并与当地服务不足的社区开展持续的外联和教育活动。 此外，K-12教师将参与基于探究的STEM课程开发。 作为博士论文研究改进奖，该奖项将提供支持，使有前途的学生建立一个强大的独立的研究事业。高光谱图像提供了一个独特的机会，研究生态系统结构的大规模变化及其对生态系统服务的影响。 这位博士生将把土地覆盖遥感数据产品与植物和土壤养分动态的原位测量相结合，以确定灌木入侵如何影响亚利桑那州东南部景观中的植物化学、土壤微生物群落和活动以及生态系统过程。 该项目的成果将确定（1）土壤养分、地形和灌木和草的丰富度之间的联系;（2）灌木入侵对植被尺度养分动态的潜在影响;以及（3）成像光谱学为土地管理实践提供信息的实用性。 这种综合的方法提供了机会，彻底改变土壤养分供应和生态地球化学循环在景观尺度上的研究，并监测不同的植被侵蚀管理策略的影响。

This doctoral dissertation research will investigate the landscape-scale effects of shrub encroachment on plant and soil nutrient dynamics in a semi-arid region. Shrub encroachment, a persistent threat to dryland ecosystems worldwide, fundamentally alters ecosystem processes by changing plant community diversity, net primary productivity, and soil functioning. This doctoral dissertation research project will use innovative methods that combine hyperspectral remotely sensed data with field measures of soil biogeochemistry and microbial parameters to infer foliar chemistry and quantify the impacts of shrub encroachment on nutrient dynamics in drylands. The project will provide a more holistic understanding of the spatial dynamics of microbial communities and plant communities that are linked by biogeochemical cycling. The project includes a strong educational component by providing opportunities for K-12 training and ongoing outreach and education initiatives with local underserved communities. In addition, K-12 teachers will be involved in inquiry-based STEM curriculum development. As a Doctoral Dissertation Research Improvement award, this award will provide support to enable a promising student to establish a strong independent research career.Hyperspectral imagery offers a unique opportunity to study large scale shifts in ecosystem structure and their effects on ecosystem services. The doctoral student will integrate land cover remote sensing data products with in situ measurements of plant and soil nutrient dynamics to determine how shrub encroachment affects plant chemistry, soil microbial communities and activity, and ecosystem processes, across the landscape in southeastern Arizona. Outcomes from this project will determine (1) the link between soil nutrients, topography and the abundance of shrubs and grasses; (2) the potential effects of shrub encroachment on landscape-scale nutrient dynamics; and (3) the utility of imaging spectroscopy to inform land management practices. This integrative approach offers the opportunity to revolutionize research on soil nutrient availability and biogeochemical cycling at landscape scales, and monitor the effects of different vegetation encroachment management strategies.