Bridging gaps for wildfire risk reduction in Southern Europe: integrating future territorial and climatic changes in mitigation approaches

Funder

Organizational Unit

Publications

Differentiating fire regimes and their biophysical drivers in central Portugal

Publication . Bergonse, Rafaello; Oliveira, Sandra; Zêzere, José Luís; Moreira, Francisco; Ribeiro, Paulo Flores; Leal, Miguel; Santos, José Manuel Lima

We characterize fire regimes in central Portugal and investigate the degree to which the differences between regimes are influenced by a set of biophysical drivers. Using civil parishes as units of analysis, we employ three complementary parameters to describe the fire regime over a reference period of 44 years (1975–2018), namely cumulative percentage of parish area burned, Gini concentration index of burned area over time, and area-weighted total number of wildfires. Cluster analysis is used to aggregate parishes into groups with similar fire regimes based on these parameters. A classification tree model is then used to assess the capacity of a set of potential biophysical drivers to discriminate between the different parish groups. The results allowed us to distinguish four types of fire regime and show that these can be significantly differentiated using the biophysical drivers, of which land use/land cover (LULC), slope, and spring rainfall are the most important. Among LULC classes, shrubland and herbaceous vegetation play the foremost role, followed by agriculture. Our results highlight the importance of vegetation type, availability, and rate of regeneration, as well as that of topography, in influencing fire regimes in the study area, while suggesting that these regimes should be subject to specific wildfire prevention and mitigation policies.

2023-03Journal article

Open access

Recent trends in fire regimes and associated territorial features in a fire-prone Mediterranean Region

Publication . Moreira, Francisco; Leal, Miguel; Bergonse, Rafaello; Canadas, Maria João; Novais, Ana; Oliveira, Sandra; Ribeiro, Paulo Flores; Zêzere, José Luís; Santos, José Lima

Fire regimes in Mediterranean countries have been shifting in recent decades, including changes in wildfire size and frequency. We sought to describe changes in fire regimes across two periods (1975–1995 and 1996–2018) in a fire-prone region of central Portugal, explore the relationships between these regimes and territorial features, and check whether these associations persisted across periods. Two independent indicators of fire regimes were determined at parish level: fire incidence and burn concentration. Most parishes presented higher values of both indicators in the second period. Higher values of fire incidence were associated with lower population densities, lower proportions of farmland areas and higher proportions of natural vegetation. Higher levels of burn concentration were associated with smaller areas of farmland and natural vegetation. These associations differed across periods, reflecting contrasting climatic and socio-economic contexts. Keeping 40% of a parish territory covered by farmland was effective to buffer the increased wildfire risks associated with different management and climate contexts. The effectiveness of higher population densities in keeping fire incidence low decreased in the last decades. The results can improve the knowledge on the temporal evolution of fire regimes and their conditioning factors, providing contributions for spatial planning and forest/wildfire management policies.

2023-02Journal article

Open access

Wildfire mitigation and adaptation: Two locally independent actions supported by different policy domains

Publication . Canadas, Maria João; Leal, Miguel; Soares, Filipa; Novais, Ana; Ribeiro, Paulo Flores; Schmidt, Luísa; Delicado, Ana; Moreira, Francisco; Bergonse, Rafaello; Oliveira, Sandra; Madeira, Paulo Miguel; Santos, José Lima

There is a broad consensus in the academic and policy communities over the need to shift the focus from fire suppression to fire prevention. To inform policies that effectively promote this shift, we distinguish between prevention actions aimed at more fire-resilient landscapes and those focused on the protection of people, i.e., wildfire mitigation and adaptation (WM&A), respectively. With the goal of discussing the usefulness of this distinction and identifying local factors and external resources that promote each of those preventive actions, we developed an analysis of collective WM&A actions across 116 parishes in a wildfire-prone region in Portugal, using primary and secondary data. Two principal component analyses were used to explore relationships between variables expressing collective WM&A actions. Random forest, a machine learning technique based on multiple decision trees, was used to model how those actions are related to local factors (land use/land cover, population, institutions) and access to policy funding for wildfire prevention. Our results showed that collective mitigation and adaptation responses to wildfire are locally independent, in coherence with their distinct goals, actors involved, and institutional and policy framing. Mitigation through owners’ collaboration proved to be strongly related to policy funding (notably that exclusively addressed at mitigation), local socioeconomic dynamism, and ownership structure, whereas adaptation responses are related with leadership by local governments. Considering these differences, the incipiency of adaptation actions, and the difficulties in expanding owner’s collaboratives beyond the most favourable local conditions, we conclude that mitigation and adaptation actions are currently supported by two distinct policy domains with unequal consolidation but equally underfunded.

2023Journal article

Open access

Promoting low-risk fire regimes: an agent-based model to explore wildfire mitigation policy options

Publication . Ribeiro, Paulo Flores; Moreira, Francisco; Canadas, Maria João; Novais, Ana; Leal, Miguel; Oliveira, Sandra; Bergonse, Rafaello; Zêzere, José Luís; Santos, José Lima

Landscape patterns and composition were identified as key drivers of fire risk and fire regimes. However, few studies have focused on effective policymaking aimed at encouraging landowners to diversify the landscape and make it more fire-resilient. We propose a new framework to support the design of wildfire mitigation policies aimed at promoting low-risk fire regimes based on land use/land cover choices by landowners. Using the parishes of a fire-prone region in central Portugal as analysis units, a two-step modelling approach is proposed, coupling an agent-based model that simulates land use/land cover choice and a logistic model that predicts fire regimes from a set of biophysical variables reported as important fire regime drivers in the literature. The cost-effectiveness of different policy options aimed at promoting low-risk fire regimes at the parish level is assessed. Our results are in line with those of previous studies defending the importance of promoting landscape heterogeneity by reducing forest concentration and increasing agricultural or shrubland areas as a measure to reduce the risk of wildfire. Results also suggest the usefulness of the framework as a policy simulation tool, allowing policymakers to investigate how annual payments supporting agricultural or shrubland areas, depending on the policy mix, can be very cost-effective in removing a substantial number of parishes from high-risk fire regimes.

2023-03Journal article

Open access

Mapping the wildland-urban interface at municipal level for wildfire exposure analysis in mainland Portugal

Publication . Barbosa, Bruno; Oliveira, Sandra; Caetano, Mário; Rocha, Jorge

The Wildland-Urban Interface (WUI), where vegetation and built-up structures intermingle, encompasses a variety of territorial elements that interact spatially, being variable both in space and time. Mapping the WUI at finer scales is paramount to assess wildfire exposure and define tailored mitigation strategies. Our aim was to develop a semi-automated method to map the WUI at municipal level, leveraging recent advances in data and technology. We tested the procedure in four municipalities of mainland Portugal with different fire history, biophysical conditions, and sociodemographic contexts. We considered WUI as either intermix or interface. Our approach integrates both building location data and high-resolution vegetation maps, to calculate the density of buildings and forest cover proportion within different circular moving window sizes. Within each radius, we evaluated the total area and spatial distribution of the WUI types, as well as the number of buildings within WUI and within the fire perimeters recorded between the years 2000 and 2022 and analysed the differences between municipalities. We then compared the mapped WUI with previous WUI mappings for mainland Portugal, to identify common spots and potential spatial divergences. We found that the area mapped as WUI within all four municipalities ranged from about 400 km2 to 1135 km2 depending on the radius size. A distinct distribution for each type of WUI was observed as the radius size increased: the intermix WUI showed a tendency to increase, and the interface WUI increased only between the radius of 100 and 200 m, decreasing gradually in subsequent radii. Between 39.4% and 45.5% of the nearly 200,000 buildings in the study areas were within WUI, depending on radius size and a total of 5436 buildings were within the historic fire perimeter. Although the comparison with other maps showed fair agreement, due to differences in data and methodology, common areas mapped as WUI were found, which suggests that these areas should receive greater attention from decision-makers regarding fire management strategies, since their classification as WUI remains consistent across different methodologies.

2024Journal article

Open access