Patterns of variation in Australian alpine soils and their relationships to parent material, vegetation formation, climate and topography

Abstract

We tested the degree to which parent material, climate, vegetation and topography influenced the characteristics of alpine soils at two scales: across the full range of alpine vegetation in Australia and in the Snowy Mountains of New South Wales, where geological relationships with soils may be obscured by the aeolian deposition of sediment and there are strong local gradients in climate. We derived eleven soil groups from numerical analysis of the national data, three of which were confined to the island State of Tasmania and ten of which clearly fitted in one of the organosol, dermosol or rudosol soil orders. Linear mixed models indicated that climate, parent material, topographic position, and vegetation type are all important in influencing alpine soil at a national scale in Australia. Parent material was prominent in models for most attributes of the soil. Whilst vegetation formation had only a weak influence on soil characteristics at the national level, in the Snowy Mountains it interacted strongly with geology. The fact that Snowy Mountains short alpine herbfield soils were affected by geology, but tall alpine herbfield and heath soils were not, could reflect differences in accumulation of aeolian material.