High-Resolution UAV Mapping for Investigating Eelgrass Beds Along the West Coast of North America

Numerous efforts have been made to investigate widespread die-offs of eelgrass throughout the west coast of North America in the past three decades due to the negative impacts of wasting disease. However, rigorously quantifying ecosystem-level impacts of wasting disease to changes in the extent and density of eelgrass habitat has not yet been attempted across spatial scales. In this research, we utilize Unmanned Aerial Vehicle (UAV) mapping along the west coast of North America to measure eelgrass meadow extent, patchiness, and dynamics in Washington, Oregon, California, and Alaska. Ground-truthing an in situ sampling within each eelgrass meadow is used to validate drone mapping imagery. Object-oriented analysis is then performed to quantitatively estimate the link between extent/density of eelgrass habitat estimated by UAV mapping across latitudes. The work shows eelgrass patch characteristics, including spectral signature, object morphology, canopy density, and texture: derived from high-resolution UAV or drone mapping. Those parameters were compared to demonstrate the spatial variation of eelgrass patches along the west coast of the US.