The use of GIS mapping techniques to assess changes in vegetation at Cape Hallett

A detailed vegetation map of a 120m by 28m study site was published by Rudolph (1963). A paper copy of the original maps of this research was obtained from archives at the University of Ohio.The map was digitised into a GIS layer and converted to meters. In the field, the plot was found because some of the marking pegs were still present on site and aerial photographs were used to locate points. GPS was used to determine the real world coordinates of the plot location. The site was remapped using a one metre square grid and change analysis undertaken using a GIS. Rudolph's map classifies the cover of mosses, lichens and algae into four classes: Heavy (40-90%), Patch (10-40%), Scattered (less than 10%) and none (0%). The combination of these classes was used to describe the vegetation in 2004. Within each one metre square the percentage cover of mosses, lichens and algae were recorded. The x,y distance of the cell centre from the north west corner of the plot was also recorded together with a description of the surface rock, wetness and percentage under snow. Vegetation change was able to be compared between 1962 and 2004. The changes in relation to the physical characteristics of the surface of the plot, such as rock type, wetness and slope were analysed. The data was converted to a Dbase file and then imported to a GIS point layer using the xy location as the geographical coordinates. The vegetation was also described using relevee measurements to determine cover of vegetation. The grid was 20 x 10 cm (200 point relevee) and analysed to determine species association. The 2004 map was compared with the 1962 map with statistics generated that describe the change.