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Data from: Pyrogeography across the western Palearctic: A diversity of fire regimes

Cite this dataset

Pausas, Juli G. (2022). Data from: Pyrogeography across the western Palearctic: A diversity of fire regimes [Dataset]. Dryad. https://doi.org/10.5061/dryad.k98sf7m8c

Abstract

We characterised fire regimes and estimated fire regime parameters (area burnt, size, intensity, season, patchiness, pyrodiversity) at broad spatial scales using remotely sensed individual-fire data. Specifically, we focused on the western part of the Palearctic realm, i.e., Europe, North Africa, and the Near East. We first divided the study area into eight large ecoregions based on their environment and vegetation (ecoregions): Mediterranean, Arid, Atlantic, Mountains, Boreal, Steppes, Continental, and Tundra. Then we intersected each ecoregion with individual-fire data obtained from remote sensing hotspots to estimate fire regime parameters for each environment. This allowed us to compute annual area burnt, fire size, fire intensity, fire season, fire patchiness, fire recurrence, and pyrodiversity for each ecoregion. We then related those fire parameters with the ecoregions’ climate and analysed the temporal trends in fire size. The results suggest that fire regime parameters vary across different environments (ecoregions). The Mediterranean had the largest, most intense, and most recurrent fires, but the Steppes had the largest burnt area. Arid ecosystems had the most extended fire season, Tundra had the patchiest fires, and Boreal forests had the earliest fires of the year. The spatial variability in fire regimes was largely explained by the variability of climate and vegetation, with a tendency for greater fire activity in the warmer ecoregions. There was also a temporal tendency for fires to become larger during the last two decades, especially in Arid and Continental environments. In conclusion, fire regime characteristics of each ecoregion are unique, with a tendency for greater fire activity in warmer environments, and for increasingly large fires in recent decades.

Methods

We first defined eight large ecoregions based on their environment and vegetation: Mediterranean, Arid, Atlantic, Mountains, Boreal, Steppes, Continental, and Tundra. These ecoregions were defined by aggregating 81 WWF ecoregions with the help of the bioregions (https://www.oneearth.org/bioregions-2020/). We provide the shape files with these ecoregions. 

Then we intersected each ecoregion with individual-fire data obtained from remote sensing hotspots to estimate fire regime parameters for each environment. Specifically, we computed the following fire statistics for each ecoregion and year (2001-2019): area burnt; mean fire size; fire intensity; fire season; fire patchiness (CV of the fire intensity in each fire); fire recurrence and pyrodiversity. This data was estimated based on individual-fire data provided in GlobFire (Artés et al. 2019) except fire intensity that was estimated using MODIS hotspots (Collection 6 Active Fire Products from Terra and Aqua satellites, dataset MCD14ML; downloaded from the University of Maryland, USA; period 2001-2021). Fire recurrence for each ecoregion was estimated as the number of times each patch was burnt. The pyrodiversity of each ecoregion (i.e., fire-caused landscape heterogeneity) was estimated as the Shannon diversity of fire patches, that is, considering the relative abundance (sizes) of fire-produced patches in each ecoregion. The data provided is the average by ecoregion and year, except for patchiness we provide the area of each patch in each ecoregion, and the number of times the patch burned. More details are provided in the original article.

Usage notes

The ecoregion map is in "shape" format and can be opened with most GIS softwares (e.g., QGIS). The data is provided as comma-delimited files (csv; ASCII) and can be opened with most softwares for numerical analysis (e.g. in R using the function read.csv) or with a spreadsheet (e.g., LibreOffice Spreadsheet).

Funding

European Commission, Award: GA 101003890 (fireUrisk)