Paleoecological data on the distribution of Pinus peuce Griseb. in Southwestern Bulgaria for the last 30000 years

The paleoecological information on the distribution of the Tertiary relic and Balkan endemic Pinus peuce Griseb. (Macedonian pine) is summarized on the basis of the results from pollen analysis, plant macrofossil determination and radiocarbon dating of lake and peat bog sediments in the mountains of Southwestern Bulgaria. The oldest record is of Middle Pleniglacial age (30000-24000 cal. yrs. BP) when pollen of P. peuce, together with pollen of other coniferous and deciduous trees, was established from the West Rhodopes Mountain. During the Late Glacial (14500-11600 cal. yrs. BP) stands of pines, P. peuce included, thrived among coldtolerant herb communities in the Rila, Pirin and the West Rhodopes mountains, confirmed by the first macrofossils (needles) determined. The minor participation of P. peuce in the early Holocene (11600-8800 cal. yrs. BP) Betula forests was succeeded by its wider distribution after 8200-7900 cal. yrs. BP when a coniferous belt composed by pines and Abies was shaped in the Rila and Pirin mountains. This vegetation reconstruction is supported by numerous macrofossils of P. peuce (needles, seeds, and partly stomata). Since 2600 cal. yrs. BP in the conditions of a more humid and cooler climate, the pulsating invasion of Picea abies restricted to some extent the distribution of P. peuce. Both species, together with Pinus sylvestris, shaped the timber-line at many places. The main conclusion from this survey is that populations of P. peuce survived the harsh glacial climatic conditions in montane refugia with subsequent gradual widespread during the Holocene.