The anthropogenic influence on wildfire regimes : charcoal records from the Holocene and Last Interglacial at Ioannina, Greece

Abstract

Aim: To characterize the changing fire regime of a Mediterranean landscape during the Holocene and the Last Interglacial and, by comparing the two periods, to improve our understanding of the extent and timing of human alteration of natural fire regimes. Location: Lake Ioannina, north-western Greece (39 degrees 45N, 20 degrees 51E). Methods: Using a long sequence of lake sediments, we measured the charcoal content of the sediment over the course of the Holocene and the Last Interglacial. We compared the charcoal data with pollen data for the same periods. Results: Charcoal was present in all samples analysed. Charcoal influx was greater during interglacials, which at Ioannina were forested, than during glacials, when tree populations were small. Charcoal influx was greater and more variable during the Holocene than during the Last Interglacial. Main conclusions: Fire was a persistent feature throughout the periods studied, under both glacial and interglacial conditions. Overall, more biomass was burned during interglacials than during glacials, and peak burning occurred at intermediate values of moisture availability. There is little evidence that the composition of forests significantly affected burning regimes. Enhanced burning during the Holocene relative to the Last Interglacial may reflect human impact, as well as climatic or vegetational differences between the two periods.