Resilience in a aquatic ecosystems : Developing predictive models to explain the effects of anthropogenic stressors on Murray-Darling Basin billabongs
- Reid, Michael, Gell, Peter, Davidson, Thomas, Sayer, Carl, Tibby, John, Fluin, Jennie
- Authors: Reid, Michael , Gell, Peter , Davidson, Thomas , Sayer, Carl , Tibby, John , Fluin, Jennie
- Date: 2014
- Type: Text , Conference paper
- Relation: Symposium on Australia-China Wetland Network Research Partnership; Nanjing Institute of Geography and Limnology Chinese Academy of Sciences (NIGLAS) Nanjing, China; 23rd-28th December 2014 p. 61-67
- Full Text:
- Reviewed:
- Description: Freshwater ecosystems are among the most threatened in the world (MEA 2005) and have been identified as one of the ten Australian ecosystems most vulnerable to tipping points. The floodplain lakes and wetlands (billabongs) of the Murray-Darling Basin (MDB) are hotspots of productivity and diversity and provide important breeding, feeding and refuge habitat for a range of floodplain river biota, as well as important ecosystem goods and services by way of flood mitigation, nutrient cycling and sediment trapping. Nonetheless, MDB billabongs are threatened by water resource and agricultural development and climate change. In recognition of these threats, water dependent ecosystems of the MDB are currently subject to expensive and controversial management measures involving water buy backs estimated to cost up to $30 billion and the subsequent delivery of environmental water. The need to understand the critical drivers of change and the internal system interactions that underlie ecosystem responses in floodplain river ecosystems has never been greater. This project will develop ecosystem response models that will not only identify the critical threatening drivers, but also provide the guidance necessary to rehabilitate these important ecosystems.
- Authors: Reid, Michael , Gell, Peter , Davidson, Thomas , Sayer, Carl , Tibby, John , Fluin, Jennie
- Date: 2014
- Type: Text , Conference paper
- Relation: Symposium on Australia-China Wetland Network Research Partnership; Nanjing Institute of Geography and Limnology Chinese Academy of Sciences (NIGLAS) Nanjing, China; 23rd-28th December 2014 p. 61-67
- Full Text:
- Reviewed:
- Description: Freshwater ecosystems are among the most threatened in the world (MEA 2005) and have been identified as one of the ten Australian ecosystems most vulnerable to tipping points. The floodplain lakes and wetlands (billabongs) of the Murray-Darling Basin (MDB) are hotspots of productivity and diversity and provide important breeding, feeding and refuge habitat for a range of floodplain river biota, as well as important ecosystem goods and services by way of flood mitigation, nutrient cycling and sediment trapping. Nonetheless, MDB billabongs are threatened by water resource and agricultural development and climate change. In recognition of these threats, water dependent ecosystems of the MDB are currently subject to expensive and controversial management measures involving water buy backs estimated to cost up to $30 billion and the subsequent delivery of environmental water. The need to understand the critical drivers of change and the internal system interactions that underlie ecosystem responses in floodplain river ecosystems has never been greater. This project will develop ecosystem response models that will not only identify the critical threatening drivers, but also provide the guidance necessary to rehabilitate these important ecosystems.
Changing fluxes of sediments and salts as recorded in lower River Murray wetlands, Australia
- Gell, Peter, Fluin, Jennie, Tibby, John, Haynes, Deborah, Khanum, Syeda, Walsh, Brendan, Hancock, Gary, Harrison, Jennifer, Zawadzki, Atun, Little, Fiona
- Authors: Gell, Peter , Fluin, Jennie , Tibby, John , Haynes, Deborah , Khanum, Syeda , Walsh, Brendan , Hancock, Gary , Harrison, Jennifer , Zawadzki, Atun , Little, Fiona
- Date: 2006
- Type: Conference proceedings
- Full Text:
- Description: The River Murray basin, Australia's largest, has been significantly impacted by changed flow regimes and increased fluxes of salts and sediments since settlement in the 1840s. The river's flood plain hosts an array of cut-off meanders, levee lakes and basin depression lakes that archive historical changes. Pre-European sedimentation rates are typically approx. 0.1-1 mm year-1, while those in the period after European arrival are typically 10 to 30 fold greater. This increased sedimentation corresponds to a shift in wetland trophic state from submerged macrophytes in clear waters to phytoplankton-dominated, turbid systems. There is evidence for a decline in sedimentation in some natural wetlands after river regulation from the 1920s, but with the maintenance of the phytoplankton state. Fossil diatom assemblages reveal that, while some wetlands had saline episodes before settlement, others became saline after, and as early as the 1880s. The oxidation of sulphurous salts deposited after regulation has induced hyperacidity in a number of wetlands in recent years. While these wetlands are rightly perceived as being heavily impacted, other, once open water systems, that have infilled and now support rich macrophyte beds, are used as interpretive sites. The rate of filling, however, suggests that the lifespan of these wetlands is short. The rate of wetland loss through such increased infilling is unlikely to be matched by future scouring as regulation has eliminated middle order floods from the lower catchment.
- Authors: Gell, Peter , Fluin, Jennie , Tibby, John , Haynes, Deborah , Khanum, Syeda , Walsh, Brendan , Hancock, Gary , Harrison, Jennifer , Zawadzki, Atun , Little, Fiona
- Date: 2006
- Type: Conference proceedings
- Full Text:
- Description: The River Murray basin, Australia's largest, has been significantly impacted by changed flow regimes and increased fluxes of salts and sediments since settlement in the 1840s. The river's flood plain hosts an array of cut-off meanders, levee lakes and basin depression lakes that archive historical changes. Pre-European sedimentation rates are typically approx. 0.1-1 mm year-1, while those in the period after European arrival are typically 10 to 30 fold greater. This increased sedimentation corresponds to a shift in wetland trophic state from submerged macrophytes in clear waters to phytoplankton-dominated, turbid systems. There is evidence for a decline in sedimentation in some natural wetlands after river regulation from the 1920s, but with the maintenance of the phytoplankton state. Fossil diatom assemblages reveal that, while some wetlands had saline episodes before settlement, others became saline after, and as early as the 1880s. The oxidation of sulphurous salts deposited after regulation has induced hyperacidity in a number of wetlands in recent years. While these wetlands are rightly perceived as being heavily impacted, other, once open water systems, that have infilled and now support rich macrophyte beds, are used as interpretive sites. The rate of filling, however, suggests that the lifespan of these wetlands is short. The rate of wetland loss through such increased infilling is unlikely to be matched by future scouring as regulation has eliminated middle order floods from the lower catchment.
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