Fire disturbance induced landscape dynamics and severity patterns across spatio-temporal scale domains in Mediterranean pine forest landscapes

Analysing both spatio-temporal wildfire impacts on landscape dynamics and fire regime modifications over time is a prerequisite to adaptive fire management strategies, particularly in Mediterranean environments. We reconstructed a 40-year (1981-2021) burned areas chronology and assessed fire severity at 30-m spatial resolution , using Landsat imagery, in the Special Area of Conservation IT9130006 of the EU Natura 2000 Network encompassing a forest district composed of nine Pinus halepensis Mill. forest sites. We defined "landscapes" at different domains of scale by changing the extent component of the scale in both the spatial ('Special Area of Conservation', 'forest district' and 'forest site') and temporal dimensions (1981-2021, vs 1981-1999 and 2000-2021 observation periods). In 40 years 41 wildfires occurred in the Special Area of Conservation and 24 in the forest district (35.2 % and 55.7 % of the area respectively), including 4 large infrequent events and 9 overlapping burned areas (9.63 % of the total burned area). We assessed the effect of the reconstructed sequence of events on the landscapes' trajectory in a spatio-temporal stability/instability domain by means of two fire regime-derived parameters (fire size/landscape extent and return interval/recovery time). These were computed accounting for the cumulative effect of disturbances varying in size-severity and time-since-last-fire. A regime alteration was observed from the first to the second short observation period as well as distinct patterns of stability/instabilty conditions for individual forest sites and the overall forest district. Thus, overlooking the effect of fire history and regime modifications might be deceptive about landscape dynamics, representing a crucial issue for fire/forest management and planning.