STRUTTURA DI COMUNITA' ORNITICHE IN AMBIENTE MEDITERRANEO PERCORSO DA INCENDIO (CASTELFUSANO, ROMA-ITALIA CENTRALE): STUDIO SU UN CICLO ANNUALE

Breeding bird communities in burnt and unburnt residual pinewoods were studied over 3 years by line-transect method, following a catastrophic fire event in Castelfusano (Rome, Central Italy, July 2000). We applied bootstrap procedures to evaluate whether the observed data were true or just produced by chance, and then examined the emerging patterns of three levels: community, guild and species levels. At community level, fire altered the total abundance pattern: species abundance decreased in burnt pinewood compared to unburnt, but other parameters were not significantly affected by fire. The destruction and structural simplification of camopy and shrubby components, as well as the increase of edge habitat and patchiness at landscape scale, induced a higher turnover of species in burnt pinewoods. At guild and species level, forest species decreased strongly in terms of richness and abundance in burnt pinewoods; on the contrary the species usually occurring in edge and open habitat increased.