Transport and Deposition of Leaves and Seeds on Tundra: A Late-Glacial Analog

Abstract

Plant macrofossils from tundra ponds in Mount McKinley National Park, Alaska, USA, are derived from debris that is transported in winter and deposited on snowbeds facing pond margins. As the snowbeds melt in spring this debris is released directly on the pond surface but most debris is swept to the shores downwind, where it is deposited in flotsam windrows. Assemblages of leaves and seeds from these alpine snowbeds, ponds and flotsam windrows are dominated by leaves of Dryas octopetala, Vaccinium uliginosum and leaves of dwarf Salix. Seeds are relatively scarce in the snow and sediment samples but comprise a large portion of the windrows, implying selective deposition. The similarity of these leaf and seed assemblages to Late Glacial macrofossils of northeastern USA and northern Europe suggests that transport and depositional processes currently operating at McKinley Park are applicable to Late-Glacial landscapes elsewhere.