A provisional method for assessing the impact on, and recovery of, Antarctic Desert Pavements from human-induced disturbances

摘要

A set of criteria were developed to quantify the relative stage of desert pavement recovery in the Ross Sea region of Antarctica. The innovative desert pavement classification system was formulated based around a number of distinguishing morphologicalfeatures that change over time as the pavement re-establishes and stabilises. Features included clast characteristics, such as embeddedness, impressions and attributes to describe clast characteristics (e.g. ventifacted, pitted); surface colour contrast; degree of deflation; varnish; pavement crust coherence and thickness; nature of pavement armour (packing and % of surface armoured); presence of salt coatings on rock undersides, as well as general surface stability (e.g. evidence of subsidence, melt,recent disturbance, and concentrations of salt). In year one (2008/2009 summer season) of a two year study the parameters were measured experimentally at five sites at Crater Hill and the vicinity of Scott Base, Ross Island. Sites had been disturbed by activities such as bulldozer scraping for road-fill and contouring for infrastructure at times ranging from one week to 50 years prior to assessment. The initial study sites were re-examined in 2009/2010 to test for repeatability and also the extent of visible recovery; and new sites were classified in the McMurdo Dry Valley region. Sites included previously disturbed sites at Marble Point, Lake Vanda in the Wright Valley, and Cape Roberts. Pavement regeneration and rates of recovery have not previouslybeen studied in the polar desert realm. The ability to predict the rate of recovery from disturbance on a range of surfaces assists with assessing the potential impacts of proposed activities in the Antarctic environment. Given knowledge of the site parent material, the application of the criteria showed it was possible to estimate the stage of desert pavement rehabilitation at each site. The system can also potentially be used to estimate the number of years since the desert pavement disturbance occurred.