Research into the Lower Gwydir aquatic ecosystem in north-western NSW is producing a clearer picture of how this high-conservation-value wetland system responds to flooding. The findings will underpin future flow management decisions for this important resource.
The research, conducted through the University of New England and the Cotton Catchment Communities Cooperative Research Centre (Cotton CRC), has been funded by the Australian Government. Over the initial 12 months of fieldwork, it has produced useful insights into how fish, planktonic animals, water chemistry and wetland plants respond to environmental and other flow releases from Copeton Dam upstream.
“The Lower Gwydir channels support a diverse community of fish species, typical of many catchments across the northern Murray-Darling Basin,” said The Project Leader, Dr Glenn Wilson from Ecosystem Management at UNE. “Several of the more common species appeared to respond â€“ both in their abundance and in their breeding patterns â€“ despite the relatively small size of flows released into the area over last summer and autumn.”
“Findings from the monitoring of populations of microscopic zooplankton have shown that these may prove a useful ‘indicator’ of river system health and the ecological success of flow events,” Dr Wilson explained. “While organisms like these may appear insignificant, they play a major role as prey for fish and help keep levels of nuisance algae in check.
“Wetland systems such as the Lower Gwydir need to be viewed as an interconnected food web, where intact species assemblages are vital to long-term sustainability. For example, the large rookery areas for water birds that the wetlands are known for can only function if flows are sufficient to maintain the fish and other prey that support the growth and development of fledglings.”
“Flows from most catchments across the northern Murray-Darling Basin end up in ‘terminal’ wetland systems such as the Lower Gwydir,” Dr Wilson added, “and these habitats undoubtedly play a key role across the region in the regulation of major floods, the maintenance of aquatic biodiversity, and the recolonisation of upstream areas.
“For the Lower Gwydir, understanding these dynamics will ensure that future catchment management and environmental flow decisions for this internationally-significant ecosystem will reflect the best available science.”
Both the University of New England and the Cotton CRC continue to encourage sound scientific research on river systems where a balance needs to be achieved between human and environmental uses of water. “We see partnerships between researchers, agricultural industries and the community as being critical if we are to develop a shared understanding of the management requirements of these ecosystems,” Dr Wilson said.
THE PHOTOGRAPH displayed here was taken at “Willowlee” on the Gingham watercourse west of Moree.