Restoring Murray River floodplain wetlands : does the sediment record inform on watering regime?
- Authors: Gell, Peter
- Date: 2020
- Type: Text , Conference paper
- Relation: River Research and Applications Vol. 36, p. 620-629
- Full Text: false
- Reviewed:
- Description: The floodplain wetlands of the southern Murray Darling Basin (MDB) have been subject to the impacts of catchment and water resource development for more than a century. Their current degraded state is attributed to the regulation of the rivers and abstraction of water volume for irrigation. The MDB Plan is to return at least 2,750 Gl of mean annual flow to the system to restore the condition of waterways. Considerable recent investment in infrastructure enables water to be released into the basin's floodplain wetlands. The proposed watering regime is underpinned by modelling that suggests that, before regulation, overbank flows would have occurred regularly as discharge peaked in winter and spring. Sediment cores have been extracted from over 50 floodplain wetlands of the southern Murray Basin. Those from several, large meander wavelength billabongs extend for 1,000–5,000 years suggesting that these sites were permanently inundated over that time. Others extend to ~200 years and are presumed not to have accumulated sediment until more recently. The records of most wetlands, however, only extend to the onset of river regulation in the 1920s, suggesting that before then they were not inundated for sufficient duration for net accumulation to occur. Preserved diatoms suggest that the shallow, plant-dominated wetlands of the past have transitioned to deep, turbid water systems today. As rivers are identified as a source of sediment to wetlands, less regular inundation, rather than more, is a viable option in restoring the ecological function of these floodplain wetlands and in slowing sediment infill. © 2019 John Wiley & Sons, Ltd.
- Description: E1
First human impacts and responses of aquatic systems : A review of palaeolimnological records from around the world
- Dubois, Nathalie, Saulnier-Talbot, Emilie, Mills, Keely, Gell, Peter, Battarbee, Rick, Bennion, Helen, Chawchai, Sakonvan, Dong, Xuhui, Francus, Pierre, Flower, Roger, Gomes, Doriedson, Gregory-Eaves, Irene, Humane, Sumedh, Kattel, Giri, Jenny, JeanPhilippe, Langdon, Peter, Massaferro, Julieta, McGowan, Suzanne, Mikomagi, Annika, Ngoc, Nguyen, Ratnayake, Amila, Reid, Michael, Rose, Neil, Saros, Jasmine, Schillereff, Daniel, Tolotti, Monica, Valero-Garces, Blas
- Authors: Dubois, Nathalie , Saulnier-Talbot, Emilie , Mills, Keely , Gell, Peter , Battarbee, Rick , Bennion, Helen , Chawchai, Sakonvan , Dong, Xuhui , Francus, Pierre , Flower, Roger , Gomes, Doriedson , Gregory-Eaves, Irene , Humane, Sumedh , Kattel, Giri , Jenny, JeanPhilippe , Langdon, Peter , Massaferro, Julieta , McGowan, Suzanne , Mikomagi, Annika , Ngoc, Nguyen , Ratnayake, Amila , Reid, Michael , Rose, Neil , Saros, Jasmine , Schillereff, Daniel , Tolotti, Monica , Valero-Garces, Blas
- Date: 2018
- Type: Text , Journal article , Review
- Relation: Anthropocene Review Vol. 5, no. 1 (2018), p. 28-68
- Full Text:
- Reviewed:
- Description: Lake sediments constitute natural archives of past environmental changes. Historically, research has focused mainly on generating regional climate records, but records of human impacts caused by land use and exploitation of freshwater resources are now attracting scientific and management interests. Long-term environmental records are useful to establish ecosystem reference conditions, enabling comparisons with current environments and potentially allowing future trajectories to be more tightly constrained. Here we review the timing and onset of human disturbance in and around inland water ecosystems as revealed through sedimentary archives from around the world. Palaeolimnology provides access to a wealth of information reflecting early human activities and their corresponding aquatic ecological shifts. First human impacts on aquatic systems and their watersheds are highly variable in time and space. Landscape disturbance often constitutes the first anthropogenic signal in palaeolimnological records. While the effects of humans at the landscape level are relatively easily demonstrated, the earliest signals of humaninduced changes in the structure and functioning of aquatic ecosystems need very careful investigation using multiple proxies. Additional studies will improve our understanding of linkages between human settlements, their exploitation of land and water resources, and the downstream effects on continental waters.
- Description: Lake sediments constitute natural archives of past environmental
- Authors: Dubois, Nathalie , Saulnier-Talbot, Emilie , Mills, Keely , Gell, Peter , Battarbee, Rick , Bennion, Helen , Chawchai, Sakonvan , Dong, Xuhui , Francus, Pierre , Flower, Roger , Gomes, Doriedson , Gregory-Eaves, Irene , Humane, Sumedh , Kattel, Giri , Jenny, JeanPhilippe , Langdon, Peter , Massaferro, Julieta , McGowan, Suzanne , Mikomagi, Annika , Ngoc, Nguyen , Ratnayake, Amila , Reid, Michael , Rose, Neil , Saros, Jasmine , Schillereff, Daniel , Tolotti, Monica , Valero-Garces, Blas
- Date: 2018
- Type: Text , Journal article , Review
- Relation: Anthropocene Review Vol. 5, no. 1 (2018), p. 28-68
- Full Text:
- Reviewed:
- Description: Lake sediments constitute natural archives of past environmental changes. Historically, research has focused mainly on generating regional climate records, but records of human impacts caused by land use and exploitation of freshwater resources are now attracting scientific and management interests. Long-term environmental records are useful to establish ecosystem reference conditions, enabling comparisons with current environments and potentially allowing future trajectories to be more tightly constrained. Here we review the timing and onset of human disturbance in and around inland water ecosystems as revealed through sedimentary archives from around the world. Palaeolimnology provides access to a wealth of information reflecting early human activities and their corresponding aquatic ecological shifts. First human impacts on aquatic systems and their watersheds are highly variable in time and space. Landscape disturbance often constitutes the first anthropogenic signal in palaeolimnological records. While the effects of humans at the landscape level are relatively easily demonstrated, the earliest signals of humaninduced changes in the structure and functioning of aquatic ecosystems need very careful investigation using multiple proxies. Additional studies will improve our understanding of linkages between human settlements, their exploitation of land and water resources, and the downstream effects on continental waters.
- Description: Lake sediments constitute natural archives of past environmental
Past and future ecosystem change in the coastal zone
- Authors: Gell, Peter
- Date: 2017
- Type: Text , Conference proceedings , Conference paper
- Relation: 2nd International Conference on Tropical and Coastal Region Eco Development 2016, ICTCRED 2016; Bali, Indonesia; 25th-27th October 2016; published in IOP Conference Series: Earth and Environmental Science Vol. 55, p. 1-8
- Full Text:
- Reviewed:
- Description: The coastal zone is in a constant state of flux. Long term records of change attest to high amplitude sea level changes. Relative stability though the Late Holocene has allowed for the evolution of barrier dune systems, estuaries and coastal lakes with associated plant and faunal associations. This evolution has been interspersed with changes in the balance between climate driven changes in outflow from catchments. These interactions have been considerably disturbed through the impacts of industrialised people who have diverted and consumed water and invested in infrastructure that has impacted on river flows and the tidal prism in estuaries. This has impacted their provisioning services to humans. It has also impacted their regulating services in that development along the coastline has impacted on the resilience of the littoral zone to absorb natural climate extremes. Looking from the past we can see the pathway to the future and more easily recognise the steps needed to avoid further coastal degradation. This will increasingly need to accommodate the impacts of future climate trends, increased climate extremes and rising seas. Coastal societies would do well to identify their long term pathway to adaptation to the challenges that lie ahead and plan to invest accordingly. © Published under licence by IOP Publishing Ltd.
- Description: IOP Conference Series: Earth and Environmental Science
- Authors: Gell, Peter
- Date: 2017
- Type: Text , Conference proceedings , Conference paper
- Relation: 2nd International Conference on Tropical and Coastal Region Eco Development 2016, ICTCRED 2016; Bali, Indonesia; 25th-27th October 2016; published in IOP Conference Series: Earth and Environmental Science Vol. 55, p. 1-8
- Full Text:
- Reviewed:
- Description: The coastal zone is in a constant state of flux. Long term records of change attest to high amplitude sea level changes. Relative stability though the Late Holocene has allowed for the evolution of barrier dune systems, estuaries and coastal lakes with associated plant and faunal associations. This evolution has been interspersed with changes in the balance between climate driven changes in outflow from catchments. These interactions have been considerably disturbed through the impacts of industrialised people who have diverted and consumed water and invested in infrastructure that has impacted on river flows and the tidal prism in estuaries. This has impacted their provisioning services to humans. It has also impacted their regulating services in that development along the coastline has impacted on the resilience of the littoral zone to absorb natural climate extremes. Looking from the past we can see the pathway to the future and more easily recognise the steps needed to avoid further coastal degradation. This will increasingly need to accommodate the impacts of future climate trends, increased climate extremes and rising seas. Coastal societies would do well to identify their long term pathway to adaptation to the challenges that lie ahead and plan to invest accordingly. © Published under licence by IOP Publishing Ltd.
- Description: IOP Conference Series: Earth and Environmental Science
Assessing change in floodplain wetland condition in the Murray Darling Basin
- Authors: Gell, Peter , Reid, Michael
- 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. 27-35
- Full Text:
- Reviewed:
- Description: Lowland Australian rivers and their floodplains have been affected by the progressive introduction of agriculture, flow regulation and invasive exotic species for more than a century. In the context of this complex suite of stressors, our capacity to understand and mitigate the causes of ecosystem change is limited by the lack of historical records of the condition of ecosystems over the past 200 to 300 years. However, records of change over this critical time period can be established through analysis of sedimentary records. Such records can be used to provide benchmarks of the range of natural conditions prior to European settlement and, by providing a long time series of conditions, enhanced capacity to detect trends and trajectories of change. Over the past two decades, more than 50 sediment records from billabongs, lagoons and waterholes throughout the Murray-Darling Basin have been subject to palaeoecological analysis. The picture that emerges from these studies is of ecosystems that have undergone substantial ecological change in response to human activities; however, there are also intriguing differences in the timing and nature of change experienced by aquatic ecosystems in different parts of the Murray-Darling Basin. These patterns of ecosystem response appear to reflect underlying differences in the resilience of these ecosystems in relation to different anthropogenic stressors, which, in turn, may result in contrasting hydrologic, geomorphologic and climatic contexts. This paper presents an attempt to systematically compile and summarise the palaeoecological evidence of change in the aquatic ecosystems of the Murray-Darling Basin and, in so doing, shed light on what the principal drivers of change are in floodplain wetlands across the basin, and hence provide guidance as to how these systems can be best preserved and restored.
- Authors: Gell, Peter , Reid, Michael
- 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. 27-35
- Full Text:
- Reviewed:
- Description: Lowland Australian rivers and their floodplains have been affected by the progressive introduction of agriculture, flow regulation and invasive exotic species for more than a century. In the context of this complex suite of stressors, our capacity to understand and mitigate the causes of ecosystem change is limited by the lack of historical records of the condition of ecosystems over the past 200 to 300 years. However, records of change over this critical time period can be established through analysis of sedimentary records. Such records can be used to provide benchmarks of the range of natural conditions prior to European settlement and, by providing a long time series of conditions, enhanced capacity to detect trends and trajectories of change. Over the past two decades, more than 50 sediment records from billabongs, lagoons and waterholes throughout the Murray-Darling Basin have been subject to palaeoecological analysis. The picture that emerges from these studies is of ecosystems that have undergone substantial ecological change in response to human activities; however, there are also intriguing differences in the timing and nature of change experienced by aquatic ecosystems in different parts of the Murray-Darling Basin. These patterns of ecosystem response appear to reflect underlying differences in the resilience of these ecosystems in relation to different anthropogenic stressors, which, in turn, may result in contrasting hydrologic, geomorphologic and climatic contexts. This paper presents an attempt to systematically compile and summarise the palaeoecological evidence of change in the aquatic ecosystems of the Murray-Darling Basin and, in so doing, shed light on what the principal drivers of change are in floodplain wetlands across the basin, and hence provide guidance as to how these systems can be best preserved and restored.
Assessing change in floodplain wetland condition in the Murray Darling Basin, Australia
- Authors: Gell, Peter , Reid, Michael
- Date: 2014
- Type: Text , Journal article
- Relation: Anthropocene Vol. 8, no. (2014), p. 39-45
- Full Text: false
- Reviewed:
- Description: Lowland Australian rivers and floodplains have been affected by agriculture and flow regulation for more than a century. Our capacity to understand the complex causes of ecosystem change is limited by the lack of historical records of ecosystem condition. Records of change over this critical period are available through analysis of sedimentary records. These provide benchmarks of the range of natural conditions and, by providing a long time series of conditions, trends and trajectories of change. Over recent decades, 51 sediment records from billabongs and lagoons throughout the southern Murray Darling Basin have been subject to palaeoecological analysis. The picture that emerges from this synthesis is that ecosystems have undergone substantial ecological change in response to human activities. Diatom assemblages preserved in wetland sediments attest to salinisation in 34% of sites and increased nutrient concentrations in 48%. More extensive is the impact of increased sediment flux with evidence for increased sedimentation rate, turbidity or macrophyte loss in 80% of sites. Intriguing differences exist in the timing and nature of change experienced by aquatic ecosystems in different parts of the Basin. These patterns of ecosystem response suggest underlying differences in the resilience of these ecosystems to different anthropogenic stressors, which may result from contrasting hydrologic, geomorphologic and climatic contexts. This systematic compilation of the palaeoecological evidence of change in the aquatic ecosystems of the Basin sheds light on what are the principal drivers of change across the region and provides guidance as to how these systems can be best restored. © 2014 Elsevier Ltd. All rights reserved.
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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