Landscape dynamics and fire regime since 17,550 cal yr BP in the Cantabrian region (La Molina peat bog, Puente Viesgo, Spain)

Abstract

Our aim with this paper is to provide insight into the landscape dynamics of the Cantabrian region (northern Iberian Peninsula) from the Last Glacial Period to the present. We present a multiproxy approach performed in a sedimentary record from La Molina peat bog, located at 484 m a. s. l. in Puente Viesgo, Cantabria (Latitude: 43.26° N; Longitude: 3.97° W), that covers the last c. 17,550 years. Analyses were performed on the organic matter, pollen and sedimentary charcoals, which have been used to characterise the fire regime at a local level. The results revealed a steppe-like formation from the basis of the sequence to the Bølling-Allerød chronozone, when the spread of woody species is detected. The dry and cold conditions of the Younger Dryas caused the decrease of mesophilous taxa until the onset of the Holocene. From that point onwards, a mixed deciduous formation composed of Betula and deciduous Quercus was established in the region. Besides, a series of biomass pulses was detected during the early Holocene, probably linked to intervals of increased rainfall. Fire episodes detected at the 9.3 and the 8.2 ka events created forest openings and probably favoured the establishment of Corylus, most likely also helped by a climate shift. There was a lack of fire activity until the Neolithic, when the fire signal increased probably linked to grazing and agricultural practices and triggered deeper changes in the Cantabrian plant landscape structure.