Human-induced vegetation change in the Turaida vicinity during the Iron Age and the medieval period

A lack of detailed information on pollen from the Gauja River valley potentially limits the strength of various reconstructions (vegetation composition, human impact, dominant agricultural activities) for this territory. This study seeks to examine the human-induced changes on vegetation, in particular with regard to the arrival of the Livs in the Turaida vicinity during the Late Iron Age. Here, we present the first analyses of pollen data, macroscopic plant remains and macroscopic charcoal undertaken in the lower Gauja River valley (territory inhabited by Gauja Livs). The gathered sediment record, or the Roči bog, points to the appearance of the Livs in the territory during the 10th century. Our results show an accelerating shift in the landscape from dense forest coverage to inclusion of more open areas, which would be consistent with the clearing of areas for cultivation. The human-induced change resulted in a decrease in forest coverage, an increased presence of cultivated plants and an acute intensification of fire-related events. The sediment record shows that oat cultivation was dominant during the Late Iron Age and other crops (barley, wheat, rye) came into sustained use only at the beginning of the medieval period. The sudden decline in all cultivated crops (barley, oats, rye and wheat) in the mid-14th century could be due to sudden environmental changes or to the Black Death, but as this data contradicts research from other parts of Latvia, further study is advisable.