Abstract

Dryland ecosystems are some of the most prevalent ecosystems on Earth and have recently shown stress indicators from climate change. These water-limited systems are vulnerable to increases in temperature and changes in precipitation, especially when looking at carbon cycling dynamics across biological sol crusts and vegetation mortality patterns. This dissertation aims to 1) evaluate how precipitation dynamics, vegetation location, and microclimate conditions influence biological soil crust carbon conditions, and 2) evaluate how topographic influences drive patterns of plant mortality during prolonged drought on the Colorado Plateau. Using high-resolution monitoring of long-term NEE chambers, we found that intermediately disturbed biocrusts are becoming carbon sources with increased temperatures, specifically peaking in summer months. With multi-year, ground-collected plant surveys, we found shrubland resistance to drought-induced mortality to be higher than grasslands. Utilizing UAV imagery, we mapped cactus mortality across various landcover classes and identified cactus size and proximity to other cactus as primary drivers in widespread cactus mortality events. Overall, we found that warming temperatures and increasing aridity are driving further carbon loss and higher rates of plant mortality across different plant functional groups.

Degree

PhD

College and Department

Life Sciences; Biology

Rights

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