A large proportion of Australia’s inland waters are temporary in nature, often existing in a dry state for much of the year. Invertebrate assemblage composition within these temporary waters is a useful inclusion for water quality assessments of impacted areas. However, the duration and intensity of flushing stream flows can strongly influence the development of community assemblages within these networks and may exacerbate the impact of anthropogenic activities and associated pollution.
It is important that the monitoring of macroinvertebrate community assemblages over successive years is standardised to hydrological conditions so that shifts in community structure is not incorrectly attributed. A significant aspect of this standardisation involves an understanding of how macroinvertebrate communities respond to the most destructive flushing flows, or to successive overlapping flows as a result of heavy, prolonged rainfall. Key to this is determining the response of communities to variations in hydrograph flow and optimal sampling timeframes post-flow that account for natural temporal variability and provide reliable proxies for water quality.
This presentation will explore a conceptual model of macroinvertebrate community response in the context of mine-impacted temporary waters in the wet-dry tropics of northern Australia. The discussion will focus on pulsed flow regimes and hydrological fragmentation characteristics of temporary waters, and what indicators should guide the setting of management goals for aquatic health and water quality assessments. In addition to this, the use of alternative biological monitoring assessments such as terrestrial and hyporheic invertebrate fauna and assessment of propagule (eggs and spores) will be explored.