Community structure and ecological responses to hydrological changes in benthic algal assemblages in a regulated river : application of algal metrics and multivariate techniques in river management
- Authors: Atazadeh, Ehsan , Gell, Peter , Mills, Keely , Barton, Andrew , Newall, Peter
- Date: 2021
- Type: Text , Journal article
- Relation: Environmental Science and Pollution Research Vol. 28, no. 29 (2021), p. 39805-39825
- Full Text: false
- Reviewed:
- Description: The flow regime of the Wimmera River was substantially modified due to the construction of a water supply reservoir. Samples of diatoms and soft algae and measurements of water quality were analysed at ten sampling sites for 3 years (between February 2012 and November 2014) along the MacKenzie River, a tributary of the Wimmera River, in different seasons and under different flow regimes, to understand the spatial and temporal variation in the relationship between algal communities, water quality and stream condition. Baseline information on algal communities and water quality was collected during base flow conditions, while experiments on the effect of water releases on algal communities were based on flow regime variations (manipulated flow regimes), specifically on the algae community structure, water quality and ecosystem function. Algal species composition changed along the river under different flow regimes and different seasons. Under base flow, Bacillariophyta (diatoms) were more abundant upstream, and filamentous green algae were more abundant downstream. The results showed that the algal composition shifted downstream after water release events. Chlorophyta (green algae), Cyanophyta (blue-green algae) and Chrysophyta gradually increased from upstream to downstream under base flow conditions and before water releases, whereas diatoms were greater upstream and increased downstream after water releases. The results are presented to tailor discharge and duration of the river flows by amalgamation of consumptive and environmental flows to improve the condition of the stream thereby supplementing the flows dedicated to environmental outcomes. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
Ecological and statistical models to configure flow regime for environment benefit in highly engineered rivers : a case study in the MacKenzie River, Southeast Australia
- Authors: Atazadeh, Ehsan , Gell, Peter , Mills, Keely , Barton, Andrew , Newall, Peter
- Date: 2024
- Type: Text , Journal article
- Relation: Environmental Science and Pollution Research Vol. 31, no. 5 (2024), p. 7408-7427
- Full Text: false
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- Description: Ecological and statistical models were developed using freshwater algal assemblages to assess water quality and ecological health of a regulated river. These models were used to inform configuration of flows to maintain or improve environmental conditions of the waterway whilst meeting consumptive water supply commitments. The flow regime of the MacKenzie River, western Victoria, Australia, has been substantially modified since the construction of a water supply reservoir on its upper reach in 1887. Water is withdrawn at several locations downstream of the reservoir, creating a substantially modified flow regime, impacting key environmental values of the river. To assess the impact of the different flow regimes on river health and ecosystem function, ten sites were repeatedly sampled along the river between February 2012 and April 2014. Physical and chemical characteristics of water, including pH, temperature, turbidity, electrical conductivity, dissolved oxygen, total nitrogen, total phosphorous, cations, and anions, were measured. Biological properties of the algal periphyton communities, including dry mass, ash-free dry mass, chlorophyll-a concentration, and species composition, were also measured. Exploration of the algal assemblage and water chemistry data using the computationally unconstrained ordination technique such as principal component analysis principal component analysis (PCA), correspondence analysis (CA), detrended correspondence analysis (DCA), and canonical correspondence analysis (CCA) indicated two strong gradients in the data sets. Furthermore, the quantitative ecosystem response models have been developed as the prototype tool to assist in the future configuration of flows in this river. The empirical data and models showed the lower reaches of the river to be in poor condition under low flows, but this condition improved under flows of 35 ML/day, as indicated by the reduction in green algae and cyanobacteria and improvement. Finally, the results are presented to tailor discharge and duration of water volume by amalgamation of consumptive and environmental flows to improve the condition of the stream thereby supplementing the flows dedicated to environmental outcomes. © 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
Configuring consumptive water transfers for ecolgical benefit: An algal response model for water resource operations
- Authors: Atazadeh, Islam , Mills, Keely , Barton, Andrew , Gell, Peter
- Date: 2012
- Type: Text , Conference paper
- Relation: 34th Hydrology and Water Resources Symposium
- Full Text: false
- Reviewed:
Morphology, ecology and biogeography of Stauroneis pachycephala P.T. Cleve (Bacillariophyta) and its transfer to the genus Envekadea
- Authors: Atazadeh, Islam , Edlund, Mark , Van Der Vijver, Bart , Mills, Keely , Spaulding, Sarah , Gell, Peter , Crawford, Simon , Barton, Andrew , Lee, Sylvia , Smith, Kathryn , Newall, Peter , Potapova, Maria
- Date: 2014
- Type: Text , Journal article
- Relation: Diatom Research Vol. 29, no. 4 (2014), p. 455-464
- Full Text: false
- Reviewed:
- Description: Stauroneis pachycephala was described in 1881 from the Baakens River, Port Elizabeth, South Africa. Recently, it was found during surveys of the MacKenzie River (Victoria, Australia), the Florida Everglades (USA) and coastal marshes of Louisiana (USA). The morphology, ecology and geographic distribution of this species are described in this article. This naviculoid species is characterised by lanceolate valves with a gibbous centre, a sigmoid raphe, an axial area narrowing toward the valve ends, and capitate valve apices. The central area is a distinct stauros that is slightly widened near the valve margin. The raphe is straight and filiform, and the terminal raphe fissures are strongly deflected in opposite directions. Striae are fine and radiate in the middle of the valve, becoming parallel and eventually convergent toward the valve ends. The external surface of the valves and copulae is smooth and lacks ornamentation. We also examined the type material of S. pachycephala. Our observations show this species has morphological characteristics that fit within the genus Envekadea. Therefore, the transfer of S. pachycephala to Envekadea is proposed and a lectotype is designated.
- Description: C1
Development of an algal response model to inform water resource system operations
- Authors: Atazadeh, Islam , Barton, Andrew , Gell, Peter , Mills, Keely , Newall, Peter
- Date: 2014
- Type: Text , Conference proceedings
- Full Text: false
- Description: An algal response model is being developed to inform the operational characteristics of a water supply system. The intent of this research is to refocus approaches to water allocations from a contest over volume, towards a cooperative approach between all users with multiple socioeconomic and environmental benefits. The algal response model will ultimately be used to aid in the development of a framework, and operational principles, to configure consumptive water transfers to complement dedicated environmental flows. A constraint imposed within this framework will be that whilst providing beneficial environmental outcomes, any flow configuration identified will not compromise consumptive water users. Field trials have begun in the MacKenzie River in western Victoria, Australia. This River has experienced a highly modified flow regime since the construction of Wartook Reservoir in 1887. Water released from the reservoir is regulated at several locations for water supply and also, more recently, for the specific provision of environmental flows. With baseline monitoring of the waterway now completed, preliminary results are available to commence evaluating the complex environmental response patterns and benefits that may accrue from flows dedicated to consumptive use. A number of artificial substrates have also been deployed to elicit the broadest range of responses from algal communities present in the waterway.
Climate variability in south-eastern Australia over the last 1500 years inferred from the high-resolution diatom records of two crater lakes
- Authors: Barr, Cameron , Tibby, John , Gell, Peter , Tyler, Jonathan , Zawadzki, Atun , Jacobsen, Geraldine
- Date: 2014
- Type: Text , Journal article
- Relation: Quaternary Science Reviews Vol. 95, no. (July 2014 2014), p. 115-131
- Full Text: false
- Reviewed:
- Description: Climates of the last two millennia have been the focus of numerous studies due to the availability of high-resolution palaeoclimate records and the occurrence of divergent periods of climate, commonly referred to as the 'Medieval Climatic Anomaly' and 'The Little Ice Age'. The majority of these studies are centred in the Northern Hemisphere and, in comparison, the Southern Hemisphere is relatively under-studied. In Australia, there are few high-resolution, palaeoclimate studies spanning a millennium or more and, consequently, knowledge of long-term natural climate variability is limited for much of the continent. South-eastern Australia, which recently experienced a severe, decade-long drought, is one such region.Results are presented of investigations from two crater lakes in the south-east of mainland Australia. Fluctuations in lake-water conductivity, a proxy for effective moisture, are reconstructed at sub-decadal resolution over the past 1500 years using a statistically robust, diatom-conductivity transfer function. These data are interpreted in conjunction with diatom autecology. The records display coherent patterns of change at centennial scale, signifying that both lakes responded to regional-scale climate forcing, though the nature of that response varied between sites due to differing lake morphometry. Both sites provide evidence for a multi-decadal drought, commencing ca 650 AD, and a period of variable climate between ca 850 and 1400 AD. From ca 1400-1880 AD, coincident with the timing of the 'Little Ice Age', climates of the region are characterised by high effective moisture and a marked reduction in inter-decadal variability. The records provide context for climates of the historical period and reveal the potential for more extreme droughts and more variable climate than that experienced since European settlement of the region ca 170 years ago.
Human impacts on Lacustrine ecosystems
- Authors: Battarbee, Richard , Bennion, Helen , Gell, Peter , Rose, Neil
- Date: 2012
- Type: Text , Book chapter
- Relation: The SAGE Handbook of Environmental change p. 47-70
- Full Text: false
- Reviewed:
Ten complementary measures to assist with environmental watering programs in the Murray-Darling river system, Australia
- Authors: Baumgartner, Lee , Gell, Peter , Thiem, Jason , Finlayson, Colin , Ning, Nathan
- Date: 2020
- Type: Text , Journal article
- Relation: River Research and Applications Vol. 36, no. 4 (May 2020), p. 645-655
- Full Text: false
- Reviewed:
- Description: Restoration programmes for degraded aquatic ecosystems frequently focus on flow restoration or reinstatement, including recovery targets for volumes of water to be used for environmental benefit. Australia's Murray-Darling Basin is an example of a major system undergoing substantial water reform to balance the needs of competing users, including the environment, within the constraints of an arid climate. This reform revolves around accounting for finite volumes of water that have been shared amongst water users. We argue that while recovering water will provide good outcomes, as a sole intervention, it is not enough to deliver the desired environmental benefits of the reform given the significantly altered state of the catchment. Here, we present 10 measures that could be used to complement planned water recovery actions. These "complementary measures" integrate recovery actions, which when strategically combined with water delivery would significantly enhance water reform efforts to generate environmental outcomes in a highly modified system.
Ecological response to hydrological variability and catchment development : Insights from a shallow oxbow lake in Lower Mississippi Valley, Arkansas
- Authors: Bhattacharya, Ruchi , Hausmann, Sonja , Hubeny, J. Bradford , Gell, Peter , Black, Jessica
- Date: 2016
- Type: Text , Journal article
- Relation: Science of the Total Environment Vol. 569-570, no. (2016), p. 1087-1097
- Full Text:
- Reviewed:
- Description: The ecological response of shallow oxbow lakes to variability in hydrology and catchment development in large river floodplain ecosystems (RFE) in Arkansas remains largely unknown. Investigating these responses will advance our understanding of ecological evolution of oxbow lakes in response to the major environmental drivers, which will establish baseline conditions required to develop effective management practices for RFE. In this pilot study, we examined the potential of using a dated surface sediment core from Adams Bayou, a floodplain lake located within the Cache-Lower White River Ramsar site in SE Arkansas. Stratigraphic records of diatoms and sediment geochemistry were used to ascertain variation in Adams Bayou's ecological condition. During 1968–2008, in response to hydrological and anthropogenic changes, Adams Bayou's diatom assemblages progressed from predominantly benthic (Gomphonema parvulum and Meridion circulare) to primarily planktonic assemblage (Aulacoseira granulata and Cyclotella meneghiniana), along with a decrease in magnetic susceptibility (k) and % silt. Statistical analyses reveled that during 1968–2000, higher hydrological connectivity and catchment alterations drove Adams Bayou's ecosystem. After 2000, lower hydrological connectivity and increase in cultivation were the major drivers. The potential impact of increasing air temperature was also noted. The shift in Adams Bayou from a connected, clear, mesotrophic state to a relatively isolated, turbid and nutrient enriched state is consistent with regime shift models and highlights its sensitivity to a combination of environmental stresses prevalent in the catchment. Although fluvial systems pose challenges in establishing clear chronologies, oxbow lake sediments can be a effective paleoecological archives. Our work provides clear evidence for the change in the ecological character of this wetland of international significance and flags the need for a wider assessment of water bodies across this site under obligations to the Ramsar Convention.
- Description: The ecological response of shallow oxbow lakes to variability in hydrology and catchment development in large river floodplain ecosystems (RFE) in Arkansas remains largely unknown. Investigating these responses will advance our understanding of ecological evolution of oxbow lakes in response to the major environmental drivers, which will establish baseline conditions required to develop effective management practices for RFE. In this pilot study, we examined the potential of using a dated surface sediment core from Adams Bayou, a floodplain lake located within the Cache-Lower White River Ramsar site in SE Arkansas. Stratigraphic records of diatoms and sediment geochemistry were used to ascertain variation in Adams Bayou's ecological condition. During 1968–2008, in response to hydrological and anthropogenic changes, Adams Bayou's diatom assemblages progressed from predominantly benthic (Gomphonema parvulum and Meridion circulare) to primarily planktonic assemblage (Aulacoseira granulata and Cyclotella meneghiniana), along with a decrease in magnetic susceptibility (k) and % silt. Statistical analyses reveled that during 1968–2000, higher hydrological connectivity and catchment alterations drove Adams Bayou's ecosystem. After 2000, lower hydrological connectivity and increase in cultivation were the major drivers. The potential impact of increasing air temperature was also noted. The shift in Adams Bayou from a connected, clear, mesotrophic state to a relatively isolated, turbid and nutrient enriched state is consistent with regime shift models and highlights its sensitivity to a combination of environmental stresses prevalent in the catchment. Although fluvial systems pose challenges in establishing clear chronologies, oxbow lake sediments can be a effective paleoecological archives. Our work provides clear evidence for the change in the ecological character of this wetland of international significance and flags the need for a wider assessment of water bodies across this site under obligations to the Ramsar Convention. © 2016 Elsevier B.V.
Wetland and terrestial vegetation change since European settlement
- Authors: Bickford, Sophie , Gell, Peter , Hancock, Gary
- Date: 2008
- Type: Text , Journal article
- Relation: Holocene Vol. 18 , no. 3 (2008), p. 425-436
- Full Text: false
- Reviewed:
- Description: Microfossil, sediment and documentary records provide a history of European land use and its impact on the vegetation of the Fleurieu Peninsula, South Australia. Two sedimentary cores were analysed for their fossil pollen and charcoal composition. Chronologies were established using a combination of 210Pb, 14C and microfossil markers. Primary and secondary evidence for the spatial expansion of land uses in the region were compiled providing local-, bioregional- and regional-scaled European settlement histories. The settlement and land-use histories of the major vegetation types in the region were different and were closely determined by the nature of the vegetation itself. The sedimentary and microfossil records indicate that wetland and terrestrial vegetation have undergone sequential changes of composition. There is evidence of a decline in fire-sensitive understorey species and the decline is likely due to intensive firing and grazing of scleropyllous woodlands and forests early in European settlement. Early-settlement native forestry practices were intensive, however they did not alter overstorey tree composition. Mid-twentieth-century wholesale vegetation clearance is clearly marked in the pollen record by a decline in Eucalyptus and increase in herbaceous species. Wetland vegetation was highly impacted by European land practices through changes to sediment inputs and hydrological conditions that began prior to catchment clearance, during the phase of intensive firing and grazing. Through the integration of multiscaled, ecosystem-specific historical settlement histories and palaeoecological analysis, correlations between past land uses and biotic responses can be confidently demonstrated.
A history of Australia's riverine habitats and vegetation
- Authors: Bickford, Sophie , Reid, Michael , Gell, Peter , Kenyon, Christine
- Date: 2016
- Type: Text , Book chapter
- Relation: Vegetation of Australian riverine landscapes : biology, ecology and management Chapter 4 p. 45-58
- Full Text: false
- Reviewed:
- Description: Vegetation communities in Australia's riverine landscapes are ecologically, economically and culturally significant. They are also among the most threatened ecosystems on the continent and have been dramatically altered as a result of human activities and climate change. Vegetation of Australian Riverine Landscapes brings together, for the first time, the results of the substantial amount of research that has been conducted over the last few decades into the biology, ecology and management of these important plant communities in Australia.
Distribution of modern diatom assemblages among small playas
- Authors: Boggs, D. A. , Gell, Peter , Eliot, I. , Knott, B.
- Date: 2008
- Type: Text , Journal article
- Relation: Australian Journal of Botany Vol. 56, no. 2 (2008), p. 131-143
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- Description: Diatom diversity of six small playa lakes within the Yarra Yarra drainage system, Western Australia, and the environmental variables likely to influence their distribution was investigated. Thirty-one pennate diatom taxa were identified. Taxa consisted of facultative planktonic and periphytic, circumneutral to alkaliphilous or pH-indifferent forms with known adaptations to saline conditions and fluctuations in salinity in NaCl dominated waters. Data were analysed by ordination (MDS and PCA), hierarchical clustering (CLUSTER), permutation-based hypothesis testing (ANOSIM) and comparative tests on similarity matrices (RELATE). Water depth accounted for the majority of variation in the environmental data. REALTE comparisons of environmental and taxa data did not produce a significant correlation value. We propose that the poor concurrence of the datasets was influenced by the wide ecological tolerances of the taxa recorded, some crucial unmeasured environmental variable/s, possible geographical regionalisation and/or unsampled taxa variability owing to the stochastic nature of the wetlands. Broad patterns of distribution were related to hydroperiod and some taxa groups were loosely associated with environmental groups consistent with established ecological tolerances for the taxa. © CSIRO 2008.
- Description: C1
Regime shifts, thresholds and multiple stable states in freshwater ecosystems; a critical appraisal of the evidence
- Authors: Capon, Samantha , Lynch, Jasmyn , Bond, Nick , Chessman, Bruce , Davis, Jenny , Davidson, Nick , Finlayson, C. Max , Gell, Peter , Hohnberg, David , Humphrey, Chris , Kingsford, Richard , Nielsen, Daryl , Thomson, James , Ward, Keith , Mac Nally, Ralph
- Date: 2015
- Type: Text , Journal article
- Relation: Science of the Total Environment Vol. , no. (2015), p.
- Full Text: false
- Reviewed:
- Description: The concepts of ecosystem regime shifts, thresholds and alternative or multiple stable states are used extensively in the ecological and environmental management literature. When applied to aquatic ecosystems, these terms are used inconsistently reflecting differing levels of supporting evidence among ecosystem types. Although many aquatic ecosystems around the world have become degraded, the magnitude and causes of changes, relative to the range of historical variability, are poorly known. A working group supported by the Australian Centre for Ecological Analysis and Synthesis (ACEAS) reviewed 135 papers on freshwater ecosystems to assess the evidence for pressure-induced non-linear changes in freshwater ecosystems; these papers used terms indicating sudden and non-linear change in their titles and key words, and so was a positively biased sample. We scrutinized papers for study context and methods, ecosystem characteristics and focus, types of pressures and ecological responses considered, and the type of change reported (i.e., gradual, non-linear, hysteretic or irreversible change). There was little empirical evidence for regime shifts and changes between multiple or alternative stable states in these studies although some shifts between turbid phytoplankton-dominated states and clear-water, macrophyte-dominated states were reported in shallow lakes in temperate climates. We found limited understanding of the subtleties of the relevant theoretical concepts and encountered few mechanistic studies that investigated or identified cause-and-effect relationships between ecological responses and nominal pressures. Our results mirror those of reviews for estuarine, nearshore and marine aquatic ecosystems, demonstrating that although the concepts of regime shifts and alternative stable states have become prominent in the scientific and management literature, their empirical underpinning is weak outside of a specific environmental setting. The application of these concepts in future research and management applications should include evidence on the mechanistic links between pressures and consequent ecological change. Explicit consideration should also be given to whether observed temporal dynamics represent variation along a continuum rather than categorically different states.
Blooms of cyanobacteria in a temperate Australian lagoon system post and prior to European settlement
- Authors: Cook, Perran , Jennings, Miles , Holland, Daryl , Beardall, John , Briles, Christy , Zawadzki, Atun , Doan, Phuong , Mills, Keely , Gell, Peter
- Date: 2016
- Type: Text , Journal article
- Relation: Biogeosciences Vol. 13, no. 12 (2016), p. 3677-3686
- Full Text:
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- Description: Blooms of noxious N2 fixing cyanobacteria such as Nodularia spumigena are a recurring problem in some estuaries; however, the historic occurrence of such blooms in unclear in many cases. Here we report the results of a palaeoecological study on a temperate Australian lagoon system (the Gippsland Lakes) where we used stable isotopes and pigment biomarkers in dated cores as proxies for eutrophication and blooms of cyanobacteria. Pigment proxies show a clear signal, with an increase in cyanobacterial pigments (echinenone, canthaxanthin and zeaxanthin) in the period coinciding with recent blooms. Another excursion in these proxies was observed prior to the opening of an artificial entrance to the lakes in 1889, which markedly increased the salinity of the Gippsland Lakes. A coincident increase in the sediment organic-carbon content in the period prior to the opening of the artificial entrance suggests that the bottom waters of the lakes were more stratified and hypoxic, which would have led to an increase in the recycling of phosphorus. After the opening of the artificial entrance, there was a ∼60-year period with low values for the cyanobacterial proxies as well as a low sediment organic-carbon content suggesting a period of low bloom activity associated with the increased salinity of the lakes. During the 1940s, the current period of re-eutrophication commenced, as indicated by a steadily increasing sediment organic-carbon content and cyanobacterial pigments. We suggest that increasing nitrogen inputs from the catchment led to the return of hypoxia and increased phosphorus release from the sediment, which drove the re-emergence of cyanobacterial blooms. © 2016 Author(s).
What’s happening to the world’s wetlands?
- Authors: Davidson, Nick , Finlayson, C. , McInnes, Rob , Rostron, Chris , Simpson, Matthew , Gell, Peter
- Date: 2023
- Type: Text , Book chapter
- Relation: Ramsar Wetlands: Values, Assessment, Management Chapter 9 p. 219-235
- Full Text: false
- Reviewed:
- Description: Wetlands worldwide are in trouble. Their area and condition have been, and are, in continuing decline. Through drainage and conversion to other land uses, the area of natural wetlands is decreasing, although the extent of losses is uncertain: since 1700 AD loss is likely to be less than 87% but more than 21%-36%. Although more wetlands are currently reported to be in good than poor ecological character state, more are deteriorating than improving in state, and deterioration is becoming increasingly widespread. There continue to be challenges in making quantitative assessments of wetland state and trends in state, including in defining baseline and reference conditions. Longer-term palaeoecological records can help separate change from variation, and inform establishing appropriate baselines for wetland assessment and management. © 2023 Elsevier Inc. All rights reserved.
When trends intersect : The challenge of protecting freshwater ecosystems under multiple land use and hydrological intensification scenarios
- Authors: Davis, Jenny , O'Grady, Anthony , Dale, Allan , Arthington, Angela , Gell, Peter , Driver, Patrick , Bond, Nick , Casanova, Michelle , Finlayson, C. Max , Watts, Robyn , Capon, Samantha , Nagelkerken, Ivan , Tingley, Reid , Fry, Brian , Page, Timothy , Specht, Alison
- Date: 2015
- Type: Text , Journal article
- Relation: Science of the Total Environment Vol. 534, no. (2015), p. 65-78
- Full Text: false
- Reviewed:
- Description: Intensification of the use of natural resources is a world-wide trend driven by the increasing demand for water, food, fibre, minerals and energy. These demands are the result of a rising world population, increasing wealth and greater global focus on economic growth. Land use intensification, together with climate change, is also driving intensification of the global hydrological cycle. Both processes will have major socio-economic and ecological implications for global water availability. In this paper we focus on the implications of land use intensification for the conservation and management of freshwater ecosystems using Australia as an example. We consider this in the light of intensification of the hydrologic cycle due to climate change, and associated hydrological scenarios that include the occurrence of more intense hydrological events (extreme storms, larger floods and longer droughts). We highlight the importance of managing water quality, the value of providing environmental flows within a watershed framework and the critical role that innovative science and adaptive management must play in developing proactive and robust responses to intensification. We also suggest research priorities to support improved systemic governance, including adaptation planning and management to maximise freshwater biodiversity outcomes while supporting the socio-economic objectives driving land use intensification. Further research priorities include: i) determining the relative contributions of surface water and groundwater in supporting freshwater ecosystems; ii) identifying and protecting freshwater biodiversity hotspots and refugia; iii) improving our capacity to model hydro-ecological relationships and predict ecological outcomes from land use intensification and climate change; iv) developing an understanding of long term ecosystem behaviour; and v) exploring systemic approaches to enhancing governance systems, including planning and management systems affecting freshwater outcomes. A major policy challenge will be the integration of land and water management, which increasingly are being considered within different policy frameworks. © Published by Elsevier B.V.
A history of aquatic plants in the Coorong, a Ramsar-listed coastal wetland, South Australia
- Authors: Dick, J. , Haynes, Deborah , Tibby, John , Garcia, Adriana , Gell, Peter
- Date: 2011
- Type: Text , Journal article
- Relation: Journal of Paleolimnology Vol. 46, no. 4 (2011), p. 623-635
- Full Text: false
- Reviewed:
- Description: The Coorong in South Australia is an internationally recognised ecologically significant coastal lagoon that extends 140 km south-east from the mouth of the River Murray. The Coorong has increasingly been impacted by a variety of human activities. Declining migratory bird abundance has been linked to the loss of Ruppia tuberosa, an aquatic plant that is the main feedstock for a wide variety of water birds. Analysis of Ruppia remains from a radiometrically dated core in the southern lagoon of The Coorong shows that the salt-tolerant annual Ruppia tuberosa has only been present at this site in recent times. By contrast, the perennial Ruppia megacarpa, which has limited tolerance to elevated salinity, appears to have been present at the site for several millennia, although it had never been observed in ecological surveys of this part of The Coorong. Diatom analysis from the same core reveals a shift from estuarine/marine assemblages to an assemblage reflective of elevated salinity levels. Charophyte, ostracod and foraminifera remains also indicate that the change in the aquatic plant community is associated with increased salinity at the study site since European settlement. Elevated salinity is the result of catchment modifications which have reduced freshwater inflows at the northern and southern extremities of The Coorong, and marine input via the Murray Mouth. This study demonstrates the utility of multiproxy palaeoecological data in addressing complex management questions. In the absence of such information, managers must ultimately rely on data sourced only from the historical record which, more often than not, is already skewed by the impact of European settlement. © 2011 Springer Science+Business Media B.V.
First human impacts and responses of aquatic systems : A review of palaeolimnological records from around the world
- 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
The status of wetlands and the predicted effects of global climate change : The situation in Australia
- Authors: Finlayson, C. Max , Davis, J. A. , Gell, Peter , Kingsford, Richard , Parton, Kevin
- Date: 2011
- Type: Text , Journal article
- Relation: Aquatic Sciences Vol.75, no.1 (2013), p.73-93
- Full Text: false
- Reviewed:
- Description: The condition of many wetlands across Australia has deteriorated due to increased water regulation and the expansion and intensification of agriculture and increased urban and industrial expansion. Despite this situation, a comprehensive overview of the distribution and condition of wetlands across Australia is not available. Regional analyses exist and several exemplary mapping and monitoring exercises have been maintained to complement the more general information sets. It is expected that global climate change will exacerbate the pressures on inland wetlands, while sea level rises will adversely affect coastal wetlands. It is also expected that the exacerbation of these pressures will increase the potential for near-irreversible changes in the ecological state of some wetlands. Concerted institutional responses to such pressures have in the past proven difficult to sustain, although there is some evidence that a more balanced approach to water use and agriculture is being developed with the provision of increasing funds to purchase water for environmental flows being one example. We identify examples from around Australia that illustrate the impacts on wetlands of long-term climate change from palaeoecological records (south-eastern Australia); water allocation (Murray-Darling Basin); dryland salinisation (south-western Australia); and coastal salinisation (northern Australia). These are provided to illustrate both the extent of change in wetlands and the complexity of differentiating the specific effects of climate change. An appraisal of the main policy responses by government to climate change is provided as a basis for further considering the opportunities for mitigation and adaptation to climate change. © 2011 Springer Basel AG.
Role of palaeoecology in describing the ecological character of wetlands
- Authors: Finlayson, C. Max , Clarke, Stewart , Davidson, Nick , Gell, Peter
- Date: 2016
- Type: Text , Journal article
- Relation: Marine and Freshwater Research Vol. 67, no. 6 (2016), p. 687-694
- Full Text: false
- Reviewed:
- Description: While it is acknowledged that changes in the condition of a wetland can be detected through contemporary monitoring programs, this paper explores the extent to which palaeoecological approaches can be used in concert with contemporary techniques to understand benchmark conditions, rates and direction of change. This is done within the context of the Ramsar Convention on Wetlands that addresses the conservation of internationally important wetlands and the wise use of all wetlands. Over time the Convention has adopted a considerable body of guidance on detecting, reporting and responding to change in ecological character. In recognition that there remain gaps in available guidance on ecological character the Convention has requested further advice on the determination of appropriate reference conditions for assessing change and establishing the range of natural variability of wetlands. As palaeoecological approaches provide a ready means of considering the trajectories of change, and the nature and drivers of change over time, they can assist in qualifying established ecological descriptions. They can also help understand the timing and nature of any departure from normal conditions, and provide early warnings of future change, especially when integrated with contemporary monitoring and modelling. Journal compilation © CSIRO 2016.