RPAS-Based Mapping of Peatland Microtopography and Hydrology: A Case Study of Repeated Seismic Line Disturbance in Northern Alberta

Peatlands are ecologically important ecosystems in Alberta’s boreal region, yet they are extensively dissected by seismic lines created for natural resource exploration. These linear disturbances alter peatland microtopography and hydrology by compacting the surface, altering microtopographic variability and elevating water tables. Re-using existing seismic lines is often promoted as a way to minimize new disturbance footprint. However, the long-term consequences of repeated seismic line use in peatlands remain poorly understood. This thesis uses remotely piloted aircraft system (RPAS)–based LiDAR and optical imagery to assess how seismic line properties evolve across different disturbance histories. Four attributes—ground depression, hummock cover, depth to water (DTW), and surface water cover—were quantified on new (created in 2021), old (created in 1996), and re-disturbed (created in 1996, re-cut in 2021) seismic lines, as well as adjacent undisturbed peatland. New disturbances showed uniform depression, minimal hummock cover, and shallow DTW, indicative of recent compaction. Old disturbances exhibited greater heterogeneity, with evidence of partial hummock recovery alongside localized surface degradation. Re-disturbances largely reset surface structure, removing microforms that had re-established over the previous decades and producing wetter, flatter conditions. Overall, these results show that seismic line morphology and hydrology evolve along divergent trajectories over time, and that re-disturbance can substantially delay natural recovery. The compounding effects observed on re-disturbed lines indicate that re-using existing corridors should not automatically be considered a lower-impact strategy in peatlands. RPAS data provide a powerful tool for mapping these fine-scale attributes and can support evidence-based management and restoration decisions in boreal peatlands.