Fire severity shapes landscape heterogeneity in Mediterranean forest ecosystems

Abstract Context In Mediterranean forests, the increasing frequency of high severity fires poses a challenge to current landscape management. In addition, these areas are experiencing a generalized process of landscape homogenization leading to a major risk of large fires. In this context, it is important to understand how wildfires (e.g. fire severity) influence changes in landscape heterogeneity. Objectives Our objectives were (1) to evaluate how pre-fire landscape conditions influence the post-fire dynamics of landscape heterogeneity both in terms of composition and configuration and (2) to understand how variability in fire severity affects changes in the structural heterogeneity of landscapes. Methods We analyzed 225 landscapes within 45 fire perimeters that occurred between 2002 and 2004 in Spain. We used a novel land cover database and fire severity data to assess post-fire landscape heterogeneity dynamics. Results Landscapes with higher pre-fire diversity values were more stable (in both composition and configuration) than more homogeneous landscapes. Additionally, we identified a significant interaction between fire severity and pre-fire landscape configuration. This interaction showed that high variations in fire severity decreased the size of small and medium pre-fire patches but increased the size of larger pre-fire patches. Conclusions This work provides valuable insights into the effects of fire on mid-term (11–13 years after fire) landscape configuration and composition. The results highlight the importance of fire severity variability. They emphasize the need to consider the role of fire in landscape management, as this could help reduce the vulnerability of Mediterranean forests.