Influence of Climate, Species Immigration, Fire, and Men on Forest Dynamics In Northern Italy, from 6000 Cal. BP To Today

Abstract

Pollen records reflect integrated effects of abiotic and biotic processes such as establishment, competition, climatic change, fire history and human impact. To disentangle these processes we compared a pollen record of Lago di Annone (Northern Italy) in the time interval 6000 cal. BP till today with simulations of a forest-dynamic model (DisCForm) under different combinations of climate, species immigration, human impact, and fire scenarios. Circularity was prevented by using input data that were independent of pollen data. While species competition, climatic change, and species immigration seem to produce model outputs with little similarities with the evaluated pollen record, the simulation of fire events and human activities reflect the main patterns of the original pollen record. The scenario for human impact slightly improves the simulation output. Species composition and abundance of Insubric forests of the time investigated seems therefore to be highly determined by fire and human impact. The simulation runs show that introduced species such as Castanea sativa are not able to coexist with indigenous species.