Monitoring Peatland Condition and Restoration Sites Using Vertical Surface Motion Data From the European Ground Motion Service

Abstract

Vertical displacement data from satellite interferometric synthetic aperture radar (InSAR) can indicate peatland condition and can therefore be used for restoration site identification or monitoring programs. However, many peatland scientists and restoration practitioners lack InSAR expertise and do not have the financial resources available to purchase data processed by commercial third parties. Conversely, the European Ground Motion Service (EGMS) freely provides pre-processed vertical displacement data derived from the Sentinel-1 satellites. Using data covering the North Pennines National Landscape, England, this study is the first to investigate the potential for using EGMS Level 3 Ortho products to monitor landscape-scale peatland condition and the impacts of site-scale restoration. Linear regression analysis showed that, despite site restoration being considered successful based on visually extensive re-vegetation and water retention, the peatland is still subsiding at rates of −1.3 to −4.4 mm/year, likely because more time is needed for peat-forming Sphagnum spp. to re-colonize the site and exceed degradation rates. Nevertheless, there were indications that restoration interventions may be slowing subsidence in some areas and seasonally linked bog breathing may be returning to the site, which was absent prior to restoration efforts. The largest drawback of the EGMS Ortho products is their limited spatial coverage in rural vegetated locations, meaning peatlands are unlikely to receive the near-full coverage possible using advanced InSAR techniques. Nonetheless, where EGMS Ortho product coverage does exist, vertical displacement data can offer useful insight into the dynamic functionality of peatlands which cannot be obtained through monitoring programs based on visual observations.