Fire intensity, slopewash and bio‐transfer of sediment in eucalypt forest, Australia

Abstract

Sediment movement (slopewash and bio-transfer), runoff, and organic matter movement (mainly leaf litter, ash and charcoal) were monitored on ten plots for a six-month period following bushfires in eastern Australia in the 1990s. Plots were installed in areas which had experienced high, moderate and low intensity burns. Although between-plot variability was high, slopewash and organic matter amounts were greatest on the intensely burnt areas, and progressively less on moderate and low intensity burns. In contrast, most leaf litter input from scorched leaf fall was derived from, and collected in, moderately burnt areas. Bio-transfer of sediment (direct downslope surface movement produced by faunal activity) occurred mainly by ant mounding, and was more than ten times greater on moderately burnt areas than on plots having high or low intensity burns. Bio-transfer accounted for approximately 36 per cent of total sediment collected, with this material being recorded least often and in smallest quantities on areas of high intensity burns. Bio-transfer by ant mounding and animal scratchings contributed loose surface sediment for transport by overland flow, disproportionately increasing total sediment movement to plot aprons in areas of moderate intensity burns.

Environmental assessment of erosion following prescribed burning in the Mount Lofty Ranges, Australia

“…At the study area the degree to which bioturbation influenced the sites depended on the presence of burrowing or digging fauna species. Mound-building ants and surface-digging Superb Lyrebirds (Menura novaehollandiae) observed in the Blue Mountains (Dragovich and Morris 2002a;Richards et al 2011) were either limited (ants) or non-existent (lyrebirds) in the study area. The types of species moving surface material in the study area were Southern brown bandicoot (Isoodon obesulus), Short-beaked echidna (Tachyglossus aculeatus), worms and limited mound-building ant species.…”

“…Soil properties alter the sediment grain dispersal characteristics (Certini 2005). Bioturbation influences infiltration ) and bio-transfer (Dragovich and Morris 2002a;Cerdá and Doerr 2010;Richards et al 2011). Restoration strategies and mitigation also have the ability to influence post-fire erosion (Cerdá and Robichaud 2009).…”

Distinctiveness of wildfire effects on soil erosion in south-east Australian eucalypt forests assessed in a global context

“…Booker et al, 1993), is significant in terms of the supply and downslope transfer of sediment and also possibly the provision of infiltration routes for overland flow through the near-surface water repellent soil (e.g. Humphreys and Mitchell, 1983;Dragovich and Morris, 2002;Shakesby et al, 2003. Some of the distinctive characteristics of post-fire conditions in Australia outlined above are evident in mainstream as well as the less easily accessible publications (e.g.…”

Stream exports of coarse matter and phosphorus following wildfire in NE Victoria, Australia

“…Generally, the coefficient of determination in Figure 2 and Table III increased, which suggest that the movement of coarse matter was more controlled by stream discharge and the amount of rainfall (which were not independent) with time. However, during the first year, external processes such as hillslope failure (de Koff et al, 2006), wind erosion (Raison et al, 1984) or erosion by bio-transfer (Dragovich and Morris, 2002;Smith and Dragovich, 2008) may have contributed to the export of coarse matter, resulting in poorer correlations between coarse matter sampled and tested variables.…”