Scattered late-glacial and early Holocene tree populations as dispersal nuclei for forest development in north-eastern European Russia

Abstract

Aim Concepts about patterns and rates of post‐glacial tree population migration are changing as a result of the increasing amount of palaeobotanical information being provided by macroscopic plant remains. Here we combine macrofossil, pollen and stomata records from five sites in north‐eastern European Russia and summarize the results for the late‐glacial–early Holocene transition. The late‐glacial–early Holocene transition encompasses the first indications of trees (tree‐type Betula, Picea abies, Abies sibirica and Larix sibirica) and subsequent forest development. Considerable time‐lags between the first macrobotanical and/or stomata finds of spruce (Picea abies) and the establishment of a closed forest are reconsidered. Location Pechora basin, north‐eastern European Russia. Methods We used plant macrofossil, stomata, pollen and radiocarbon analyses to reconstruct late‐glacial and early Holocene tree establishment and forest development. The data were derived from lake sediment and peat archives. Results Palaeobotanical data reveal an early Holocene presence (11,500–10,000 cal. yr bp) of arboreal taxa at all five sites. One site presently located in the northernmost taiga zone, shows the presence of spruce and reproducing tree birch during the late‐glacial. Given the current view of post‐glacial population dynamics and migration rates, it seems likely that the source area of these early tree populations in north‐eastern European Russia was not located in southern Europe but that these populations had local origins. Results thus support the emerging view that the first post‐glacial population expansions in non‐glaciated regions at high latitudes do not reflect migration from the south but were a result of an increase in the size and density of small persisting outlying tree populations. Main conclusions Results suggest that the area east of the margin of the Scandinavian ice sheet to the Ural Mountains had isolated patches of trees during the late‐glacial and early Holocene and that these small populations acted as initial nuclei for population expansion and forest development in the early Holocene.

Proxy comparison in ancient peat sediments: pollen, macrofossil and plant DNA

“…The site was forested at least until ca 6800 cal yr BP, which is in agreement with earlier vegetation and climate reconstructions [21,45]. Cooling triggered permafrost aggradation after 5000 cal yr BP [17,46], but our peat record is lacking for this period, probably owing to associated peat erosion dynamics.…”

Clinal Variation at Phenology-Related Genes in Spruce: Parallel Evolution in FTL2 and Gigantea?

“…In great parts this complex population structure reflects the extent of the glaciations in this area and the existence of at least three major postglaciation recolonization routes (e.g., Giesecke and Bennett 2004, Chen et al 2012a for spruce). In contrast, central Siberia, from where the Siberian spruce populations studied here originate, was much less affected by glaciations than northwestern Europe (Binney et al 2009;Väliranta et al 2011). Most of central and western Siberia was likely a cold desert as westerly moisture, which is today the source of both rain and snow in this region, was blocked by the Scandinavian ice sheet during the glacial periods (Velichko et al 2011).…”

“…However, macrofossils collected on lower river terraces, high floodplains, and mountain areas suggest that, while most of the region consisted of aeolian dunes, mountain areas and river valleys were a separate habitat where spruce trees were likely able to survive. Some of these populations were even found at high latitudes (Binney et al 2009;Väliranta et al 2011) and there is genetic evidence in Siberian larch that southern montane refugia did not contribute to the recolonization of western Siberia (Semerikov et al 2013). We therefore expect the population history and genetic structure of the Siberian spruce to differ markedly from that of Norway spruce and, based on what has been observed in Siberian larch (Semerikov et al 2013), to be weaker.…”

Glacial survival of trophically linked boreal species in northern Europe

“…in the Russian plains and/or in the Ural mountains (e.g. [5,44,57]), where patches of vegetation, even forests, persisted through the last glacial rspb.royalsocietypublishing.org Proc. R. Soc.…”

“…This paradigm is increasingly viewed as mistaken, however, contradicted by palaeoecological (e.g. [3][4][5][6]) and phylogeographic studies (e.g. [7,8]), as well as from species distribution modelling (SDM) (e.g.…”