Waterbirds in response to environmental flows in the Macquarie Marshes

Over the past couple of months (August 2014 - January 2015), I have provided a curious spectacle for the birds of the Macquarie Marshes. Often wearing a pair of green waders, it is easy to find yourself in an awkward situation when knee deep in mud clutching a birding scope! This has been the field season for my Master of Science Research Project (UNSW). I have identified thirty-six different waterbird species that flocked to the Marshes this water year (July-June). Magpie geese Anseranas semipalmata (vulnerable in NSW), brolga Grus rubicunda (vulnerable in NSW) and jabiru or black-necked stork Ephippiorhynchus asiaticus (endangered in NSW) were some exciting finds! The Macquarie Marshes are located in central, semi-arid NSW and are one of the largest semi-permanent freshwater wetland systems in Australia. More than 80% of the marshes are privately owned for cattle and sheep grazing as well as irrigated cotton further upstream. During a flood, the water forks out across the landscape and pools in shallow depressions on the floodplain. These wetlands provide important habitat for wildlife such as waterbirds which often travel vast distances in search of this 'boom' of resources. No one knows exactly how birds find this water. Especially the water that is released as environmental flow, as artificial releases are not always associated with high humidity or other environmental cues. Environmental flows are managed by the Commonwealth and NSW governments and are released from Burrendong dam to provide water for the environment during a water year (July - June). I collected waterbird abundance, diversity and habitat use data over a six month period to monitor how waterbirds respond to environmental flows for a relatively dry water year. Waterbirds can be categorised into functional groups according to feeding behaviour and I aim to determine how these functional groups respond to flow and other environmental variables such as rainfall and water quality. The Bigger picture? Understanding how waterbirds respond to changes in hydrology and habitat availability, allows for the development of more efficient flow thresholds (environmental release triggers) that target functionally similar groups of species and benefit the marshes as a whole. While flow thresholds are already used to trigger waterbird breeding, environmental releases designed to provide high quality foraging habitat for waterbirds have not yet been established. Environmental flow allocations are a key aspect of the Murray-Darling Basin Plan (managed across four states and a territory) in order to restore degraded river and wetland systems. Waterbirds provide an excellent indicator of wetland health. The Plan represents an important step towards managing the great Murray-Darling Basin in a socially, economically and environmentally sustainable fashion.

Research Program: 
Waterbirds
Research Themes: 
Rivers and Wetlands
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