a1 Land & Soil Consultancy Services, 23 View Mount, Nelson, New Zealand
a2 Land & Soil Consultancy Services, 23 View Mount, Nelson, New Zealand
a3 University of Waikato, Department of Earth Sciences, Private Bag 3105, Hamilton, New Zealand
The speed with which tracks form as a result of trampling on exposed ground surfaces in Antarctica was investigated in the McMurdo Sound and Dry Valleys regions, by a simple treading experiment. Distinct tracks formed with fewer than 20 foot passes — as measured by stone cover, surface soil exposure, and track width — and they continued to develop with increasing traffic levels. Track development was rapid and most obvious on sandy gravel soils with a pebbly desert pavement, but slower and less distinct on soils with an extensive cover of surface boulders.
The persistence of human impact from ground disturbances, which occurred up to 30 years previously, when pits were dug during field science investigations, was assessed using a range of previously defined criteria. Recently disturbed sites, where some action had been taken to restore the site immediately after disturbance, showed the least overall impact. Impacts persisted longer at sites where no restoration had been undertaken, but the remaining impact varied with factors such as exposure to wind and the age of the land surface. These results demonstrate the fragility of Antarctic soil surfaces and the terrestrial environment, as well as the long time-scales for recovery of Antarctic ground-surface disturbances.
(Received May 1996)