Fire regime changes and major driving forces in Spain from 1968 to 2010

Fire regimes play an important role in ecosystems and climate change, affecting the structure and composition of vegetation and influencing carbon dioxide (CO2) emissions. Analyses of historical fire regimes have indicated that in many ecosystems, fire regime changes are linked to environmental and climatic changes, but these studies have often been both spatially and temporally limited. To determine whether there have been changes in the fire regime in Spain, we used a statistical change point approach to analyse the number of fires and the burned area since fire statistics were first recorded in 1968 for three pyrologically homogeneous regions over two fire seasons (vegetative season = May-November, non-vegetative season = December-April). Then, to assess the possible driving forces behind these changes, we related the significant change points for the number of fires and burned area to climate, land use and fire management variables. For the vegetative season, we observed upward and downward change points in all three regions. In the non-vegetative season, only upward change points were detected in all three regions, whereas downward changes only occurred in the Mediterranean region. Our analyses suggest that the fire regime changes have been driven by climate and land use and, more recently, have also been influenced by fire suppression policies. Our results may contribute to enhance fire management and future studies of fire ecology and climate change.