ILWS Strategic Research Area
Dr Skye Wassens (leader), Dr Andrew Hall, Dr Ben Wolfenden, Joanne Ocock (all ILWS ); Dr Jennifer Spencer and Dr Yoshi Kobayashi, Rachel Thomas (OEH); Dr Lee Baumgartner and Julie Bindokas, (NSW DPI); Dr Kim Jenkins and Dr Gilad Bino (UNSW) and Erin Lenon (Murrumbidgee CMA)
The Murrumbidgee River system is a major river system in the Murray-Darling Basin that is of high economic, social and ecological importance. The Murrumbidgee River channel delivers irrigation water to the Murrumbidgee and Coleambally Irrigation Areas as well as to towns along its length including Wagga Wagga and Hay. Although it has been highly regulated, it still has populations of endangered species such as trout Cod and Silver perch. The mid-Murrumbidgee and the Lowbidgee wetlands are listed as nationally significant wetlands with critical habitat for waterbird breeding and endangered frogs such as the Southern Bell frog. The system has been targeted by the Australian Government for longer-term monitoring.
ILWS researchers (Dr Skye Wassens who leads this project) first began working in the Murrumbidgee system in 2000 researching frogs in the semi-arid parts of NSW and in 2007 helped develop an emergency watering strategy to save the endangered Southern Bell frog. Since then the NSW Office of Environment and Heritage (OEH) funded further research identifying the relationships between the response of fish, waterbirds and frogs following environmental flows and natural flood events. In 2010/11 NSW OEH funded research to monitor the responses of the Southern bell Frog and to assess the resilience of frog communities in the mid-Murrumbidgee following long periods of drought.
In 2011/12 CEWO provided funding to continue and expand monitoring in response to environmental watering to include more ecological indicators, and in 2012/13 further CEWO funding broadened the mid-Murrumbidgee project to include monitoring of the response to environmental watering in the Lowbidgee wetlands, the Western Lakes, and the Murrumbidgee River itself from below Burrinjuck and Blowering Dams to its end.
For this project year (2013/14) the team is continuing to testing specific predictions relating to (1) the relationships between flow, nutrients and carbon, microcrustacea and larval fish development in the Murrumbidgee River. (2) transport and exchange of nutrients, carbon and fauna between wetlands and the river, with a specific focus on the ecological responses to returning flows from the wetland into the river. (3) breeding and recruitment of the endangered Southern bell frog (Litoria raniformis). (4) identification of the hydrological and habitat characteristics that promote fish reproduction and recruitment in floodplain wetlands. (5) vegetation community change in response to wetting and drying in the mid-Murrumbidgee and (6) resilience and response of microcrustacea communities during floodplain inundation.
This project considers both wetland and in-stream responses across an entire river system at a very large scale in a single large integrated project. As it builds on past projects researchers are able to consider specific responses to individual flows within the context of longer-term datasets, with data collected right through the year. This is important because short term responses following environmental releases can often appear idiosyncratic especially in systems that have experienced high levels of modification and disturbance.
The team is developing statistical models to characterise the strength of interactions between multiple hydrological, biophysical, chemical and biological responses to flows to better predict outcomes of environmental flows and establishing long-term datasets covering a range of ecological responses under different flow conditions . These will improve predictions of responses to environmental watering taking into account other factors such as water temperature, the source of environmental water and antecedent conditions.
The project team works closely with Commonwealth and State water managers, to enable adaptive management and maximize benefits of environmental water across a range of aquatic habitats. The strategies developed as part of this project will assist other environmental watering programs in Australia and across the world.
Dr Skye Wassens
Charles Sturt University – Albury