Auditing revegetated catchments in southern Australia: decomposition rates and collembolan species assemblages

Major government funds have been allocated to revegetation of degraded catchments in Australia in order to enhance biodiversity, protect stock and improve water quality. However, the success or otherwise of the different restoration practices used has not been assessed. To redress this deficiency we audited these practices by measuring biotic and abiotic variables in two field surveys, one at a landscape scale and the second at a local scale. The landscape survey comprised 21 sites in western Victoria, a third of the sites were revegetated and were between 8 and 12 years old, a third carried remnant native vegetation and a third were degraded and not revegetated. In the local survey the results of the landscape survey were tested by sampling sites within a small area using the same methods but including pine plantations as an untreated site. Here we report on density and species composition of soil and surface active fauna, native and exotic Collembola and decomposition rates as measured with bait laminae. Fifty seven species of Collembola were found on the landscape survey and 47 on the local survey. Densities ranged from 17,000 to 45,000 m-2 in soil. In both the surveys we found decomposition was directly related to soil moisture and in the landscape survey exotic Collembola (Hypogastrura and Ceratophysella spp) to abundance of exotic grass species. MDS analysis of soil Collembola in the landscape survey placed remnant site