Ecological significance of litter redistribution by wind and snow in arctic landscapes

During winter in the Arctic, plant litter is scoured from exposed hills and ridges by wind and snow and is redistributed to other portions of the land scape. The aim of this research was to quantify the physical and biological consequences of this litter redistribution. Litter biomass accumulation wa s ten times greater in areas of high deposition (e.g., snow drifts) than in areas of low deposition. Spring snow melt was delayed by several days and soils were cooler throughout the growing season and throughout winter in ar eas of increased litter deposition than areas with no litter. Photosyntheti cally active radiation (PAR) was reduced to near zero with small accumulati ons of litter. Annual C and N inputs from allochthonous lifter were 143 g C m(-2) and 14 g N m(-2) in high litter areas and 3.4 g C m(-2) and 0.3 g N m(-2) in non-drift, ambient litter deposition areas. Although PAR and soil temperatures were significantly reduced with increased litter deposition, w e did not observe significant delays in key plant phenological events of se veral species or measure a decrease in gross ecosystem photosynthesis. We d id measure a significant Increase in ecosystem respiration with increased l itter deposition, which resulted in a shift in the net C balance of dry hea th tundra from near zero with no litter to a net source of CO2 to the atmos phere. Our study indicates that the redistribution of litter by wind and sn ow during winter is an important mechanism of nutrient transfer across the arctic landscape and that allochthonous litter inputs are of great enough m agnitude to alter the carbon balance of some areas of the arctic landscape.