Biological Agents in Regolith Processes: Case Study on the Southern Tablelands, NSW

INTRODUCTION Regolith encompasses all materials between hard rock and fresh air and can be argued to include all biota. As the interface between the four spheres, i.e., litho-, atmos-, hydros and bio-sphere, regolith reflects the interactions of both materials and processes from each. As an integral part of regolith, animals, plants and micro-organisms play a vital role in regolith development and evolution. Although organisms have long been recognised in pedology (Jenny 1941), research into the impact of organisms on the regolith is in its infancy. The detachment and transfer of material by the biota—collectively called bioturbation, is one good example of this early stage of research. Through bioturbation, mesoand macro-biota cause changes in the physical and chemical composition of the regolith and soil. To date, many of the interactions taking place are unmeasured and the cumulative effect is unknown. The way in which the results of bioturbation influence other landscape processes is even less well understood. As a result of bioturbation, regolith particles are dislodged, built, broken down, reworked and deposited in a range of different forms from where they originated. They may pass from loose, uncompacted and friable to compact, cemented and erosion resistant, or vice versa.