摘要:Observations and general circulation model projections suggest significant temperature
increases in Siberia this century that are expected to have profound effects on Siberian
vegetation. Potential vegetation change across Siberia was modeled, coupling our Siberian
BioClimatic Model with several Hadley Centre climate change scenarios for 2020, 2050 and
2080, with explicit consideration of permafrost and fire activity. In the warmer and drier
climate projected by these scenarios, Siberian forests are predicted to decrease and shift
northwards and forest–steppe and steppe ecosystems are predicted to dominate over half of
Siberia due to the dryer climate by 2080. Despite the large predicted increases in
warming, permafrost is not predicted to thaw deep enough to sustain dark (Pinus
sibirica, Abies sibirica, and Picea obovata) taiga. Over eastern Siberia, larch (Larix
dahurica) taiga is predicted to continue to be the dominant zonobiome because
of its ability to withstand continuous permafrost. The model also predicts new
temperate broadleaf forest and forest–steppe habitats by 2080. Potential fire danger
evaluated with the annual number of high fire danger days (Nesterov index is
4000–10 000) is predicted to increase by 2080, especially in southern Siberia and
central Yakutia. In a warming climate, fuel load accumulated due to replacement
of forest by steppe together with frequent fire weather promotes high risks of
large fires in southern Siberia and central Yakutia, where wild fires would create
habitats for grasslands because the drier climate would no longer be suitable for
forests.