Palynological reconstruction of 1500 years of vegetation history of Veisar (N Iran)

Pollen analysis and AMS radiocarbon dating of a short sediment core from a mire in Veisar (Mazandaran province, N Iran) reveals the late-Holocene vegetation history of the area. High pollen values suggest that Caucasian alder (Alnus subcordata) has been present in the vicinity of the mire throughout the record. Wingnut (Pterocarya fraxinifolia), which was previously abundantly present, shows a dramatic decline around 900 BP and gradually disappears thereafter. Being also present in other palynological studies from the central Hyrcanian forests as well as from western Georgia, the Pterocarya decline might be attributed to a regional climate change, synchronous with the Mediaeval Climatic Anomaly. The high values of beech (Fagus), hornbeam (Carpinus), oak (Quercus) and elm (Ulmus) pollen imply the presence of species-rich forest on the slopes surrounding the study area over the past 1500 years. The occurrence of anthropogenic pollen grains, e.g. Juglans and Corylus, suggests long-term human impact in the region, whereas high values of Artemisia and chenopodiaceae AND Amaranthaceae pollen indicate open vegetation on or in the immediate vicinity of the peatland.