Forest fire impact assessment of the Natura 2000 site Balsa del Pulguer, Spain (2023-05-04)

Activation date: 2023-05-04

Event type: Other

Activation reason:

During the evening of 14/03/2023, a forest fire started in the Natura 2000 area of La Balsa del Pulguer. According to the Nature Protection Service, the fire affected approximately 15 hectares inside the protected area, mainly grass and scrubland. The protected area of Balsa del Pulguer is home to valuable and threatened species and habitats, serving as a site for recreational activities. With the aim of quantifying and qualifying the effects of this forest fire, including loss estimations and changed risk assessment, the following products were requested:Product 1 - Fire delineation and gradingThis product identifies the extent of the burned area and determines the effects of the fire by generating a damage grading. The extent was generated by comparing the NDVI of pre- and post-event images (dNDVI). VHR PlanetScope data were used for this analysis, considering their close proximity to the event date. The damage grading follows the IWG-SEM guidelines, classifying the dNDVI values into 4 classes ranging from slight damage to destroyed. Results indicate a high proportion of slight damage, although this is influenced by the spatial resolution and the tendency of NDVI to be underestimated in arid areas with grassland vegetation. Comparing the results of Product 1 to Product 3 provides a better understanding of the actual situation.Product 2 - Impact assessment on land cover and habitatsBased on the results of Product 1, this product evaluates the impact on land cover and habitats, specifically identifying which biotopes and corresponding species have been affected or not directly affected. This assessment provides statistics to support stakeholders in further evaluation and measurement planning. The analysis focuses on the entire protected area, not just where the fire burned, to provide a comprehensive overview of Balsa del Pulguer.Product 3 - Estimation of biomass lossTo estimate the loss of above-ground biomass, VHR pre- and post-event DSMs were compared. The post-event DSM was provided by the CEMS aerial component, offering a spatial resolution suitable for analysis. Vegetation in both DSMs was categorized into five classes based on height distribution. Forest metrics, such as mean canopy height and number of points per vegetation layer, were determined in 10m x 10m plots across the entire fire delineation area. The comparison revealed significant changes in vegetation cover, with all habitats showing a high degree of damage and vegetation being mostly completely burned by the wildfire.Product 4 - Post-event soil erosion risk assessmentThis product evaluates the risk of soil erosion using the Revised Universal Soil Loss Equation (RUSLE) formula. Input factors were sourced from local and European datasets, considering both high and low spatial resolutions. The resulting soil erosion values were classified into five categories, ranging from Low to Extreme erosion risk. Larger areas with smoother topography were found to have a low erosion risk, while agricultural fields and drainage channels exhibited mid to high erosion risk.Product 5 - Estimation of economic loss and impact on ecosystem servicesThis product assesses the economic loss resulting from the forest fire. Direct economic loss calculations consider factors such as the average price for melioration of natural environments, reconstruction period, severity of fire, and time-value of money. Prices were mapped onto the habitat map, and a qualitative assessment of the affected area was performed to estimate the deterioration of ecosystem services. The results were classified into five categories based on the proportion of the area affected by the fire.