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.
