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Abstract
Colonial waterbirds are particularly dependent on river flows for the critical breeding stage of their lifecycle. They breed in response to large flows on relatively few wetlands in Australia. Most species of colonial waterbirds require sufficient river flows, flooding and availability of suitable nesting habitat. Water resource development through water extraction and impoundment is degrading wetlands around the world, changing the natural flow regime and affecting aquatic organisms, including colonially breeding waterbirds that rely on wetland inundation. To overcome some of the significant impacts of water resource development, there is increasing focus on the management of environmental flows for ecosystems and specific organisms. Colonial waterbirds are increasingly important as a target group of organisms for the management of environmental flows, providing a measure of the success or failure of environmental flow management. My thesis examined the breeding of colonial waterbirds in Australia at a range of scales and the importance of environmental flow management. Chapter 1 set the context by briefly reviewing the impacts of water resource development and its threat to colonial waterbird breeding and then summarising each of the subsequent chapters. Chapter 2 examined the historical use (1899-2008) of wetlands for breeding by colonial waterbirds in Australia and characterised the types of wetlands used for breeding. It also identified important sites in Australia for breeding by colonial waterbirds their characteristics and assessed vulnerability to water resource development. In Chapter 3, I focussed on Narran Lakes, one of Australia’s most important colonial waterbird breeding sites and assessed the impact of water resource development on ibis breeding over the period 1921-2008. In Chapter 4, I examined the success of the 2008 ibis breeding event at Narran Lakes when, because of declining water levels, a significant volume of water was purchased to ensure that the breeding colony was successful. Finally, in Chapter 5, I reviewed the stimulus and breeding responses of colonially breeding waterbirds in Australia with the aim of identifying the key elements of environmental flows required to successfully manage colonial waterbird breeding.