Precipitation amounts and patterns at high latitude
sites have been predicted to change as a result of
global climatic changes. We addressed vegetation responses
to three years of experimentally increased summer
precipitation in two previously unaddressed tundra types:
Betula nana-dominated shrub tundra (northeast Siberia)
and a dry Sphagnum fuscum-dominated bog (northern
Sweden). Positive responses to approximately doubled
ambient precipitation (an increase of 200 mm year-1) were
observed at the Siberian site, for B. nana (30 % larger
length increments), Salix pulchra (leaf size and length
increments) and Arctagrostis latifolia (leaf size and specific
leaf area), but none were observed at the Swedish site.
Total biomass production did not increase at either of the
study sites. This study corroborates studies in other tundra
vegetation types and shows that despite regional differences
at the plant level, total tundra plant productivity is, at
least at the short or medium term, largely irresponsive to
experimentally increased summer precipitation.