Sentinel-2 monitoring of vegetation spectral trajectories in open-cast mine plots treated with artificial soils: implications for CO2 capture

Open-pit mining generally produces severe land degradation that constrains vegetation establishment and limits carbon uptake. Within a CO₂-capture-oriented restoration project, we monitored vegetation development in five experimental plots affected by mining disturbance. One plot was fertilized with a commercial liquid product and four were amended with four artificial soil formulations that were placed on the degraded land. All plots were vegetated by planting seeds. The aim was to quantify and compare temporal trajectories of vegetation spectral response, as a proxy for canopy development, plant functioning and restoration performance under different artificial soils. 

We conducted a two-year monthly remote sensing analysis from January 2024 to December 2025 using Sentinel-2 surface reflectance imagery. For each plot, cloud- and shadow-masked imaginery were generated and summarized over plot-scale regions of interest. We analysed multi-spectral responses combining near-infrared and short-wave infrared information and a set of vegetation and moisture indices (e.g., NDVI, EVI, SAVI, red-edge based indices, and SWIR-derived moisture metrics) to capture changes in greenness, structure and water status. Temporal patterns were evaluated through trend and seasonal descriptors, inter-annual anomalies, and between-treatment contrasts to assess the consistency of artificial soils effects across years and climatic phases. The remote sensing time series were interpreted in the context of restoration objectives, emphasizing indicators relevant to biomass accumulation and potential CO₂ sequestration. 

We observed different soil-dependent spectral trajectories across the two-year period, as well as different persistence of vegetation signals during summer stress, and recovery after disturbance periods. Plots amended with artificial soils designed to improve water retention and nutrient availability exhibited earlier and more stable increases in NIR reflectance and vegetation indices, alongside lower SWIR-based stress signatures, compared with less ameliorative formulations. These differences suggest that amendments composition can modulate vegetation establishment and function at reclaimed mine sites, with direct implications for carbon capture potential. This demonstrates the utility of high-frequency Sentinel-2 monitoring to deliver reproducible, plot-scale indicators of restoration performance to support artificial soil selection, and adaptive management in CO₂-oriented mine land reclamation. 

This work was funded by the European Union under the Horizon Europe programme through the C-SINK project (Grant Agreement No. 101080377; GAP-101080377). VA thanks for her postdoctoral Ramón y Cajal contract RYC2024-048710-I funded by MICIU/AEI/10.13039/501100011033 and the FSE+.