Abstract:

Pollen-based vegetation change has been inferred from sediments in Kalavan Red Lake. This small lake is placed in the beech-oak-hornbeam forest, about three kilometres away from the village of Kalavan (Gegharkunik Province of the Republic of Armenia) which is rich with archaeological sites spread in the Barepat River valley spanning from the Palaeolithic period onwards. It has the potential to document the Holocene forest history and climate and human impacts on the Lesser Caucasus. However, this lake happens to be formed by a large landslide.

Pollen and XRF analysis are provided over the last 3800 years. The basal age of the Kalavan sediment approximates the landslide age. This created a not vegetated slope including the lake catchment. Erosion and sedimentation processes brought coarse and heavy minerogenic elements, declining with the catchment revegetation by tall-grassland. This shift in the sedimentation continues, suggesting less erosion in the catchment when an admixture of Quercus and grasslands settled. Starting from 2000 cal. BP, arboreal pollen increases successively thanks to the step afforestation of Quercus, Carpinus orientalis and Fagus.

The comparison with available pollen reconstruction illustrates the uniqueness of the vegetation dynamic recorded at Kalavan. However, the duration of this succession is also questionable. An intermediate hypothesis is proposed: the Kalavan's dynamic is first initiated by the landslide with the tall-grass development, then paced by the regional vegetation dynamic.

Linking vegetation history and erosion with regional climate and archaeological data helps to evidence short-term climate change and human impact. Antique arid phase (2000–1600 cal. BP), the Medieval Warm Period and Little Ice Age affect the vegetation, while demography variations during the Medieval period and Modern Age are shown by habitation and pastoral activity.