Performing ecohydraulic assessments of salmon habitat is essential for planning and evaluating management actions. Current approaches, although accurate, can be time consuming and expensive, which limits the areal extent of the study. To address this spatial limitation, we developed and evaluated a remote sensing methodology to map salmon spawning microhabitat and predict spawning capacity using remotely piloted vehicle (RPV) collected imagery. We used RPV-based aerial imagery to model local hydraulics (depth and velocity) and substrate size (D50 and D84). We assessed model accuracy using in-situ measurements for each characteristic (RMSEdepth = 0.18 m; RMSEvelocity = 0.51 m/s; RMSED50 = 24 mm; RMSED84 = 29 mm). Using local hydraulics, we modeled habitat quality and evaluated the model with known redd locations. We found a strong statistical difference in habitat quality between utilized and non-utilized locations (p-value < 0.001). We then coupled the hydraulic model with a substrate biophysical model to estimate spawning capacity, and found the site could accommodate 7,878 to 10,755 spawners, compared to 414 redds that were mapped at the site in 2023. Our findings indicate that RPV-collected imagery can accurately model fluvial characteristics and can be used to efficiently model spawning habitat and capacity. This provides a methodology for researchers to conduct further salmon habitat modeling studies using remote sensing to map habitat quality and quantify capacity at larger spatial extents while maintaining high resolution.
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Details
Title
DEVELOPING AND EVALUATING A REMOTE SENSING METHODOLOGY TO MAP SPAWNING MICROHABITAT AND ESTIMATE REDD CAPACITY.
Creators
Jared Gary Stieve
Contributors
Alexander Fremier (Chair)
Daniel Thornton (Committee Member)
Arjan Meddens (Committee Member)
Daniele Tonina (Committee Member)
Awarding Institution
Washington State University
Academic Unit
School of the Environment (CAHNRS)
Theses and Dissertations
Master of Science (MS), Washington State University