The synthetic analysis of several pollen records from sub-Mediterranean lowland Pre-Pyrenean regions evidences expansion of forests during the Early Holocene in Northeastern Iberia and the establishment of dense deciduous broadleaf forests during the Holocene Climate Optimum. Pollen records show the broadleaf deciduous forests resilience against cooling phases during the Mid-Holocene period, with slight regressions of oak woodlands and expansion of conifers or xerophytic taxa contemporary to some cooling episodes (i.e. 8.2 and 7.2 kyr cal. BP). Major vegetation changes influenced by climate change occurred in the transition to the Late Holocene, in terms of the start of a succession from broadleaf deciduous forests to evergreen sclerophyllous woodlands. The lack of evidence of previous occupation seems to support the Neolithisation of NE Iberia as a result of a process of migration of farming populations to uninhabited or sparsely inhabited territories. The landscape was mostly controlled by climate change until the Neolithic (from 7.4 to 7.0 kyr cal. BP onwards), when human impact started to interfere in the natural development of vegetation. However, the Neolithisation of the Iberian Peninsula occurred in a cooling episode that amplified the effect of the human impact of the first farming societies. The interaction between the cooling phase in 7.4-6.9 kyr cal. BP and the first farmers has mainly been documented in the Lake Banyoles area, where earlier Neolithic evidence is documented and where the establishment of permanent farming settlements caused the deforestation of oak woodlands. In the other two regions, the Neolithic communities settled later, after 6.7 kyr cal. BP in Vall d'en Bas and in 6.9-6.6 kyr cal. BP in the Empordà basin. Anyway, anthropogenic modifications of landscape were sustainable until recent times. In that sense, the interaction between Mid-Holocene cooling episodes and human impact transformed the landscape causing regression of broadleaf deciduous forests, but this was followed by rapid recoveries when human pressure finished.

Peer reviewed