Graduate Theses and Dissertations

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Browsing Graduate Theses and Dissertations by Author "Abreu-Vigil, Gabriel"

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    Forecasting Alaskan Boreal Ecosystem Changes: A Landscape Analysis of Permafrost Thaw and Hydrological Trajectories Resulting From Climate-Driven Change in the Fire Regime and Conifer Decline
    (University of Oregon, 2024-08-07) Abreu-Vigil, Gabriel; Lucash, Melissa
    Boreal forests, covering about 30 percent of Earth's forested area, are dominated by coniferous forests and deemed crucial reservoirs of permafrost and belowground carbon. Undergoing rapid ecological changes from a warming rate nearly three times the global average, questions remain about future interactions of increased wildfire, vegetation shifts, permafrost thaw, and soil moisture for tree growth. Utilizing the LANDIS-II landscape forest model, we simulated soil temperature and moisture, forest succession, and disturbance regimes over a century across 380,400 hectares in interior Alaska under historical and future RCP 8.5 climate scenarios. This integrated approach marks a significant advancement in simulating the dynamic and interconnected processes that define boreal forest resilience and response to climate change. [It would be good if there can be statements here about the predictive capacity of the model…calibration and validation studies, for example]. Under future climate change, permafrost at near-surface levels (3 m) is projected to disappear by mid-century with a thaw rate of 26 cm/year and 18 cm/year under extreme and moderate climate forcing respectively. Exacerbated by a changing fire regime and landscape-level shifts from insulative coniferous to less insulative hardwood coverage, these shifts are accompanied by increased soil temperatures and decreased moisture levels. The complex interplay between these dynamics in the face of a changing climate has profound implications for boreal forests and the global system alike.