Holocene Population Of Ambrosia On South Of Russian Far East

Abstract

Ambrosia artemisiifolia first appeared on the Eurasian continent in the 18th century. In the south of the Russian Far East Ambrosia first appeared in the middle Holocene. The presence of its pollen in the sediments on west of the lacustrine Khanka Plain is correlated with the appearance of early men. The presence of Ambrosia pollen in Holocene deposits can be considered as an indicator of ancient agriculture in the south of the Russian Far East. The interval from the 19th century to the 1960s is marked by a complete absence of Ambrosia in this region. On boundary of early Holocene and middle Holocene population of ragweed existed on eastern part of Eurasia simultaneously and independently from Northern America population. The modern isolated centre of the Ambrosia expansion in the south of the Russian Far East began later than the 1960s – 1970s. The modern secondary settling of this species in the east and west parts of Eurasia formed independently. The ranges of the species in China, Japan, the Korean Peninsula, and the south of the Russian Far East also formed independently.