Gabrielle Trudeau
Doctoral Dissertation Defense
Integrated Applied Mathematics
Friday, April 10, 2026, 1:00pm
Chase 105
Abstract
Coral reefs are vital ecosystems facing rapid decline from climate-driven stressors, yet existing monitoring approaches lack the spatial coverage and temporal resolution needed to capture ecosystem dynamics at meaningful scales. This thesis develops a scalable, integrated remote sensing framework by combining ICESat-2 LiDAR, multispectral imagery, and machine learning to move beyond static habitat maps toward quantitative, multi-factor characterization of reef structure and change. First, machine learning models were applied to ICESat-2-derived rugosity, slope, and bathymetric metrics to detect and delineate coral reef habitats at large scales. Next, a novel nonlinear spectral unmixing approach integrating Planet imagery and ICESat-2 terrain metrics was developed to produce sub-pixel, fractional estimates of benthic habitat composition. Finally, structural and compositional outputs (rugosity, slope, and coral cover) were fused with satellite derived bathymetry within a unified, multi-metric change-detection framework demonstrated at Heron Reef, Australia. Results demonstrate that rugosity is a dominant predictor of reef presence, that nonlinear unmixing captures fine-scale benthic habitat heterogeneity missed by conventional classifiers, and that the integrated change-detection framework successfully identifies spatially coherent hotspots of structural, compositional, and geomorphic change. Collectively, this work establishes an interpretable and transferable monitoring framework that advances understanding of reef degradation and recovery and provides actionable insights for conservation planning and coastal resource management.
Bio
Gabrielle Trudeau graduated with a dual degree in Mathematics and Computer Science from Westfield State University in 2021. During her time at WSU, she completed her honors thesis exploring representations of the Fibonacci sequence through the use of graph theory and linear algebra. Gabrielle has continued her education at the University of New Hampshire as a Ph.D. student in the Integrated Applied Mathematics program. After serving as a teaching assistant for the Department of Mathematics and Statistics for two years, she is currently a research assistant for the Center for Coastal and Ocean Mapping. Her thesis aims to explore the use of satellite data for coral reef monitoring purposes by utilizing different machine learning techniques. Gabrielle is passionate about mathematics and its numerous applications, and is excited to have found a meaningful way to apply these skills for the betterment of our world.
