Climate change-induced snow thaw and subsequent accumulation of ice on the ground is
a potential, major threat to snow-dominated ecosystems. While impacts of ground-ice on
arctic wildlife are well explored, the impacts on tundra vegetation is far from understood.
We therefore tested the vulnerability of two high-arctic plants, the prostrate shrub Salix
polaris and the graminoid Luzula confusa, to ice encasement for 60 days under full environmental
control. Both species were tolerant, showing only minor negative responses to
the treatment. Subsequent exposure to simulated late spring frost increased the amount
of damaged tissue, particularly in S. polaris, compared to the pre-frost situation. Wilting
shoot tips of S. polaris increased nearly tenfold, while the proportion of wilted leaves of
L. confusa increased by 15%. During recovery, damaged plants of S. polaris responded
by extensive compensatory growth of new leaves that were much smaller than leaves of
non-damaged shoots. The results suggest that S. polaris and L. confusa are rather tolerant
to arctic winter-spring climate change, and this may be part of the reason for their wide
distribution range and abundance in the Arctic.
