Mapping Post-Wildfire Vegetation Recovery in Bredasdorp Nature Reserve Using Multitemporal Satellite Data

Wildfires are recurring ecological disturbances that play a vital role in shaping vegetation structure and species composition within South Africa's fynbos biome. However, changing climate patterns, land-use dynamics, and human activities have altered fire frequency and severity, creating a need for effective approaches to assess post-fire impacts and ecosystem recovery. This study mapped and monitored post-fire vegetation recovery in the Bredasdorp area of the Cape Agulhas region following the early 2024 wildfire using multi-temporal Sentinel-2 imagery and remote sensing indices implemented within the Google Earth Engine (GEE) environment.

Pre- and post-fire conditions were assessed using the Normalised Difference Vegetation Index (NDVI) and the Differenced Normalised Burn Ratio (dNBR). The NDVI was used to evaluate vegetation health and regeneration patterns over time, while the dNBR was applied to quantify burn severity and classify spatial fire impacts. Burn severity statistics were derived and classification accuracy was evaluated using a confusion matrix, with FIRMS VIIRS active-fire detections providing additional spatial validation.

The results indicate that the majority of the study area experienced low-to-moderate burn severity, while smaller areas of high-severity burns were concentrated in fynbos-dominated regions. The dNBR-based burn severity classification achieved an overall accuracy of 66.75%, demonstrating moderate reliability for regional-scale fire impact assessment. NDVI analysis revealed clear evidence of vegetation recovery between late 2024 and early 2025, with values increasing from below 0.3 immediately after the fire to above 0.5 by January 2025. Time-series NDVI trends further confirmed a consistent post-fire recovery trajectory, highlighting the resilience and regenerative capacity of fynbos tree ecosystems.

The study concludes that Sentinel- 2 imagery and spectral indices provide a cost-effective, repeatable, and spatially effective approach for assessing the impacts of wildfires and monitoring vegetation recovery in Mediterranean-type ecosystems. The findings support improved wildfire management, ecological monitoring, and evidence-based spatial decision-making in the Cape Agulhas region.