This dataset contains the results of a study that mapped post-fire soil erosion in Portugal and identified the areas with higher post-fire erosion risk for past and future climate extremes. Two maps are provided: one at 100m resolution and another at 25m resolution. The maps express ‘predicted soil losses’ (Mg ha-1 y-1).
The study is fully described in this publication and an overview is given below.
Abstract
Wildfires are a recurrent and increasing threat in mainland Portugal, where over 4.5 million hectares of forests and shrubland have burned over the last 38 years. These fire-affected landscapes have suffered an intensification of soil erosion processes, which can negatively affect soil carbon storage, reduce fertility and forest productivity, and can become a source of pollutants. The present study provides a post-fire soil erosion risk map for the forest and shrubland areas in mainland Portugal. To this end, the semi-empirical Morgan–Morgan–Finney erosion model was used to assess the potential post-fire soil erosion according to distinct burn severity and climate scenarios, and the accuracy of the predictions was verified by an uncertainty analysis and validated against independent field datasets. The proposed approach successfully allowed mapping post-fire soil erosion in Portugal and identified the areas with higher post-fire erosion risk for past and future climate extremes. The outcomes of this study comprise a set of tools to help forest managers in their decision-making for post-fire emergency stabilization, ensuring the adequate selection of areas for mitigation to minimize the economic and environmental losses caused by fire-enhanced soil erosion.
Spatial Coverage: Portugal
Time Reference: 1980–2018
Format: GeoTIFF
Projection: Lisboa Hayford Gauss IGeoE
Release Date: 21/02/2022
Study Area: Portugal is located in Southwestern Europe with a total area ca. 900,000 km2 presenting an extensive history of wildfire recurrence. The mainland area of Portugal presents an altitude ranging from sea level in the western and southern coastal areas to about 2,000 m a.s.l. in the north-central region.
Model description and Input data: The MMF model predicts annual runoff and associated soil losses at slope scale, separating the processes in a water phase and a sediment phase. The first phase simulates overland flow generation as well as detachment of soil particles by rainfall and runoff, while the second phase models the transport capacity of the overland flow to transport the detached soil particles.
In this study, the MMF model was applied to predict annual soil losses for a 38-year period, considering three scenarios of soil burn severity (low, moderate, and high) for three land cover types (Shrubland, Pine, and Eucalypt). The maximum annual erosion rates predicted over this period of time were then used for mapping post-fire erosion risk. The MMF parameters and associated model input datasets were the following:
- Annual rainfall (mm yr-1) and days with rain: derived from the above-mentioned global rainfall datasets;
- Soil parameters: bulk density (BD, g cm−3), soil detachability index (K, g J−1), and soil surface cohesion (COH, kPa), were estimated from LUCAS dataset. The effective hydrological depth of soil (EHD, m) was calibrated with field data, and previous MMF applications in recently burned areas in north-central Portugal;
- Landform: represented as slope steepness (S, °);
- Land cover parameters: rainfall interception (A) and canopy cover (CC, %), plant height (PH, m) were approximated to 0 given the wildfire effects. The ratio of actual (Et, mm) to potential (E0, mm) evapotranspiration, crop cover management factor (C), and ground cover (GC, %) and estimated from previous MMF applications in recently burned areas in north-central Portugal;
- Maximum soil moisture at storage capacity: estimated from soil moisture dataset.
(link to higher-resolution schema)
Map:
(link to higher-resolution map)
