Why monitor ecosystem processes?
NSW Water Sharing Plans (WSPs) have environmental objectives to maintain and improve key ecosystem functions and processes. These are the physical, chemical and biological processes that link water dependent organisms with their environment. They influence the suitability of refuge habitats, availability of nutrients and food resources.
River ecosystems are influenced by a range of factors that affect their health. Water quality characteristics such as temperature and dissolved oxygen impact the availability of refuges during drought. Changes to basal resources like nutrients, and productivity are crucial to aquatic wildlife such as fish, frogs and birds as they influence food availability, breeding, recruitment, dispersal and survival.
Protecting and maintaining river flows to support and enhance ecosystem processes is crucial for maintaining healthy and productive aquatic habitats. Our work aims to gain an improved understanding of how river flows influence ecosystem processes, and how the management of water can lead to improved environmental outcomes.
We monitor water temperature, dissolved oxygen, nutrients, organics, food web responses (including plankton abundance) as part of the Environmental Outcomes Monitoring and Research Program. This information is then used to get the best outcomes for the environment during low flow and high flow periods.
- Mapping priority river refuge pools and identifying their flow needs
- Research and monitoring river and floodplain productivity (e.g., plankton) response to different flows
- Research and monitoring of basal resources (e.g., nutrients and dissolved organic carbon) under different flow conditions
- Monitoring water temperature and dissolved oxygen to identify stratification and conditions unsuitable for aquatic organisms
Report
The 2022-24 ecosystem processes annual report introduces projects that have commenced or were further developed during the first year of the Environmental Outcomes Monitoring and Research Program.
Download the report: Ecosystem processes – monitoring river refuges, productivity and basal resources (PDF. 6.17MB)One project continued under the subtheme: Effect of flows on connectivity:
- The "Barwon-Darling/Baaka stratification: minimising persistent thermal stratification and algal blooms in weir pools" project found that historical algal data demonstrate the relationship between a blue green algae species and river flows. Further investigation using field verification is planned for next year.
Two projects continued under the Aquatic food webs and stream productivity subtheme:
- "The importance of variable river flows to wet in-channel benches. Linking flow and food web productivity in the Barwon-Darling/Baaka River" project continued. This project used an experimental mesocosm design to demonstrate the importance of high in-channel flows for boosting productivity in streams.
- The ‘Foodweb responses to floodplain inundation in the Murray-Darling Basin’ project was initiated. This project aims to understand the role of environmental water in promoting the productivity of aquatic food webs.
One project continued under the subtheme: Habitat and flows:
- The "Fragmentation of drought refugia in the Barwon-Darling/Baaka River" project was completed. This demonstrated that satellite imagery and aerial photographs could be successfully used to map drought refugia in the Barwon-Darling River. The mapped drought refugia was compared in across different years to determine that similar patterns of drying and the same pools acted as refugia in different events.
