Short-term effects of a wildfire on the water quality and macroinvertebrate community of a saline stream

Abstract

The effects of a wildfire on the water quality and macroinvertebrate community of a saline stream in a semiarid, predominantly cleared catchment were investigated. Samples collected for 12 months following the fire were compared with pre-fire conditions. Small increases in filterable reactive phosphorus, total Kjeldahl nitrogen, total phosphorus, colour and turbidity and decreases in dissolved oxygen were recorded the day after the fire; however, most concentrations returned to pre-fire conditions within 2–3 months. Increases in nutrients were likely due to the deposition of ash, smoke and debris. Total phosphorus and total Kjeldahl nitrogen in the lower part of the catchment remained significantly higher for the year after the fire. No fire-related changes in the macroinvertebrate community structure were apparent. Reduced rainfall following the fire, the predominantly cleared catchment and the presence of a saline-tolerant macroinvertebrate assemblage all contributed to the reduced effects from the fire.