Fire impact on forest structure in highly affected ecosystems: biodiversity alterations in a post-fire successional gradient

The work aims at analysing the impact of fire in terms of changes in both species and structural diversity within Mediterranean ecosystems that are experiencing a modification in their fire regime. A particular focus is given to the investigation on forest structure alteration. The study was conducted in Liguria (North-Western Italy); two large, high-intensity fires, occurred during august 1998 and august 2003, were chosen as study cases for the investigation; experimental surveys were performed within six 50 x 50 m plots. Several measures for both species and structural (vertical and horizontal) diversity were computed. A second-order spatial analysis applying Ripley’s K(d) function was realized. The research partially confirmed the autosuccessional mechanisms typical of the Mediterranean vegetation following a fire disturbance. Interesting results were obtained from the analysis of spatial patterns within the experimental plots. Spatial interaction phenomena consequent to wildfires were detected. A higher tendency towards aggregation in the short period was identified, however groups were internally characterized by a greater homogeneity in comparison with the pre-burned situation..