Fire frequency and landscape management in the northwestern Pyrenean piedmont, France, since the early Neolithic (8000 cal. BP)

摘要

Both quantitative reconstruction of fire frequency from charcoal counts and pollen analysis were undertaken on a 312 cm sediment core from Gabarn peat bog. An 8000 yr cal. BP palaeofire record and vegetation history were established on the basis of nine ~(14)C (AMS) dates. As anthropogenic Inferred Fire Frequency (IFF) has seldom been studied, we test and discuss two different methods of frequency calculation. Our results shows a clear Holoccnc bipartition at c. 3500-4000 cal. BP characterized by a three times decrease in Mean Fire Interval (MFI): from 7000 to 4000 cal. BP, MFI = 530 yr: from 4000 to 400 cal. BP, MFI = 160 yr. In an Atlantic vegetation context, we hypothesize this fire regime with such episode frequency to be mainly controlled by human activities. This hypothesis is supported by comparisons with other European quantified palaeofire regimes (Swiss Alps, northern Italy) whether they are controlled by climate, man or both. Taking into account the pollen record, we interpret the Gabarn palaeofire record links with human pressure and land use. Our results suggest that the relationship between fire frequency and human pressure is not always linear. Fire frequency could also reflect land-use shifts and changing use of fire within agro-pastoral activities.