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
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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 Water is withdrawn at several locations downstream of the reservoir, creating a substantially modified flow regime, impacting key environmental values of the river.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.
The carbon stock potential of the restored mangrove ecosystem of Pasarbanggi, Rembang, Central Java
- Authors: Soeprobowati, Tri , Sularto, Raden , Hadiyanto, H. , Puryono, Sri , Rahim, Aulia , Jumari, Jumari , Gell, Peter
- Date: 2024
- Type: Text , Journal article
- Relation: Marine Environmental Research Vol. 193, no. (2024), p.
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- Description: Mangrove ecosystems can absorb significant amounts of carbon and help mitigate climate change. However, their existence continues to be endangered by natural and human forces. Therefore, mangrove restoration is regarded as a crucial component of the global climate change agenda. This study aims to estimate the potential total carbon stock of restored mangrove ecosystems in Pasarbanggi, Rembang, Central Java. The above-below-ground (root) carbon stock was calculated using several published allometric equations. The loss-on-ignition method analyzed leaf litter and sediment carbon stocks. This study estimates the Pasarbanggi mangrove ecosystem's total carbon stock potential at 0.02 × 106 MgC, which is equivalent to the potential CO2 emission of 0.08 × 106 MgCO2e, with up to 65% stored in sediments. This study highlights the critical role of restored mangrove ecosystems on the climate change mitigation agenda by reducing the concentration of atmospheric CO2. © 2023 Elsevier Ltd
An introduction to the Ramsar Convention on wetlands
- Authors: Gell, Peter , Finlayson, C. , Davidson, Nick
- Date: 2023
- Type: Text , Book chapter
- Relation: Ramsar Wetlands: Values, Assessment, Management Chapter 1 p. 1-36
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- Description: The Ramsar Convention on the conservation and wise use of the World’s wetlands was agreed in response to widespread recognition of the declining condition of wetlands and the impact of this on wetland habitats and associated fauna. Since 1971, over 2000 wetlands have been listed as internationally important by 172 countries and covering more than 2,000,000km2. There have been considerable advances in the scientific understanding of wetlands, and today, the monitoring of these systems draws on multiple disciplinary approaches. The Convention itself has responded to these advances and the ongoing challenge to conserve the world’s wetlands. Importantly, signatory nations regularly report on the condition of wetlands, update listings, and have adopted a framework to ensure wise use of all wetlands. In turn, healthy wetlands are increasingly seen to afford considerable ecosystem services to human communities that rely on them for the provision of food and water and recreation and for their cultural and aesthetic values. Whilst the Convention has now passed its 50th anniversary, it is increasingly recognised that wetlands continually change over many time scales and that direct human pressures are merely one of the drivers that affect wetlands. The monitoring of these changes continues to allow the Convention and signatory nations to amend the framework to reflect emerging understanding of wetland change. These advances enable the Convention to encourage, and better allow, signatory nations to pursue social and economic outcomes whilst continuing to contribute to the pursuit of conserving the natural assets accommodated within the global network of significant wetlands. © 2023 Elsevier Inc. All rights reserved.
Comparing catastrophes : the influence of impacts and timelines on prioritising crises
- Authors: Gell, Peter
- Date: 2023
- Type: Text , Journal article
- Relation: AIP Conference Proceedings Vol. 2683, no. 1 (2023), p. 030001
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- Description: Across time society has been confronted with a wide range of crises that have required measured responses. The COVID-19 pandemic was widely forecast, but governmental preparation was lacking. Even when it was spreading, its risks to society were downplayed in some quarters. The climate change crisis has also been widely forecast, and preparation has been slow, with vested interests also denying the science or downplaying the risk. The pandemic is an acute crisis with rapid onset and highly visible impacts on human life and wellbeing. Through vaccine technology, however, there is a short term and likely effective management measure available. Climate change is a diffuse crisis with long lead times. In contrast to Covid, it has momentum and, once thresholds are exceeded, measures to reverse the change will have limited effectiveness. While the implications of carbonising our atmosphere were known over 50 years ago, the socio-economic response is only now taking hold. The slow nature of this crisis has subdued the political response, and the Earth is now committed to considerable impacts, even if we collectively act decisively now. The gradual nature of this crisis, its opaque direct impacts on humanity, and the scale of its complexity render it a ‘wicked’ problem that will persist through this century and beyond. Scenarios of impact across multiple quarters assure us that the costs of unabated climate change will result in a global scale crisis, played out in many individual locations for many decades. Aware of this, society is already investing in adapting to the changes that are foreseen while also beginning the process of mitigating carbon emissions to limit the scale of the challenge. In some places, this may mean preparing economies for drier climates, while in others, it may mean a managed retreat from the present coastline. Providing refuge from heatwaves will be a widespread adaptation measure. For nature, its capacity to adapt will be strengthened if the pressure from humans is also mitigated.
Cultural landscapes : human impacts on wetlands
- Authors: Mills, Keely , Jones, Matthew , Hunt, Laura , Saulnier-Talbot, Emilie , Elias, Deevena , Nankabirwa, Angela , Lejju, Julius , Gell, Peter
- Date: 2023
- Type: Text , Book chapter
- Relation: Ramsar Wetlands: Values, Assessment, Management Chapter 10 p. 237-258
- Full Text: false
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- Description: Wetlands provide a wealth of ecosystem services to people, including ecological, economic, and socio-cultural benefits. However, more than 30% of freshwater species are threatened with extinction, and freshwater biodiversity is declining faster than that observed in oceans or forests. When it comes to the management of wetlands, it often occurs too late and when ecosystem services to people are at risk of being lost. It is easy to observe and monitor the recent impacts of people on wetland systems, but the changes we see today are a product of hundreds, even thousands of years of direct and indirect human impact. Without a deeper understanding of the long-term context of human impacts on wetland systems, it is impossible to manage the problems they experience (such as changes in hydrology, nutrient loading, acidification, and salinisation). Despite the 20th century being the period in which humans have exerted the greatest impact on wetland systems, it was also the period in which we developed a greater appreciation of wetlands as anthropogenically altered landscapes, and, maybe paradoxically, the benefits that accrue from healthy wetlands. Palaeolimnological approaches allow an understanding of wetland system variability over millennial scales, providing background context for anthropogenically forced change. This palaeo-perspective enables a deeper understanding of the long-term context of human impacts on wetland systems and can provide a fresh perspective when managing impacted systems. © 2023 Elsevier Inc. All rights reserved.
Diatom index of Galela Lake, Halmahera, Indonesia in relation to human activities
- Authors: Soeprobowati, Tri , Saraswati, Tyas , Jumari, Jumari , Sari, Kenanga , Gell, Peter
- Date: 2023
- Type: Text , Journal article
- Relation: International Journal of Environmental Science and Technology Vol. 20, no. 7 (2023), p. 7707-7722
- Full Text: false
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- Description: Diatoms, silicious microalgae, have been used successfully as bioindicators of water quality assessment in aquatic ecosystems. Diatoms have a degree of tolerance to the water quality and some diatoms are a good indicator for several water quality variables. Diatom indices have been developed to assess river water quality, mostly in Europe. This study aims to apply diatom indices developed in Europe for the tropical lake of Galela adjacent to residential areas influenced by human activities. Galela Lake is one of the biggest lakes in Halmahera Utara, Indonesia with its main functions being domestic water supply, irrigation, fisheries, and tourism. Human activities have impacted the area around the lake. The 90-cm and 85-cm long sediment cores were collected using a piston corer from Site 1 and 2, respectively. Sediment samples were sliced every 5 cm, separated from sediment by adding HCl and H2O2. The diatom valves were identified under a microscope with 1,000 × magnification. The water quality status of each layer was inferred with diatom indices performed using OMNIDIA software version 6.0. Forty-nine and 63 diatoms species were identified from Site 1 and Site 2, respectively. The number of species and diversity of diatoms was higher in the lower layers than those in the upper layers. The preserved diatom assemblages reflect past physical and chemical water quality. Generic Diatom Index and Specific Pollution Sensitivity Index provided the best evidence for change in Galela Lake—they integrated 70–100% of the diatom taxa from the sediment core samples. © 2022, The Author(s) under exclusive licence to Iranian Society of Environmentalists (IRSEN) and Science and Research Branch, Islamic Azad University.
Fire responses by bird guilds and species in heathy dry forests in central Victoria, Australia
- Authors: Kuchinke, Diana , di Stefano, Julian , Loyn, Richard , Gell, Peter , Palmer, Grant
- Date: 2023
- Type: Text , Journal article
- Relation: Forest Ecology and Management Vol. 535, no. (2023), p.
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- Description: Predicted increases in fire frequency and extent are being realised across Australia, bringing changes to the fire regime which may influence the availability of essential resources required by birds. However, few studies have examined either the impacts of fire frequency on birds or the impacts from both wildfire and planned burns, com bined. Birds were surveyed eight times across 84 sites in heathy dry forests in central Victoria, south-east Australia, from 2012 to 2014. Fire history records were retrieved from the 1970’s onwards, the time from which accurate planned burn records were kept. We developed mixed models to investigate how birds responded to time-since-fire and fire frequency, analysing total bird abundance, ten foraging guilds and 30 individual species. We found distinct responses by all modelled guilds and species to time-since-fire, along with evidence for responses to fire frequency. The greatest shifts in species’ abundances occurred during the first ten years post fire, with bird species commonly present across the stages greater than ten years since fire. For total bird abundance there was no statistically detectible difference between recently burnt forest (0-6 months) and other age classes. However, some guilds showed a significant drop in abundance in newly burnt vegetation (e.g. bark foragers, damp ground insectivores, those that feed on seeds close to the ground, tall shrub foragers). It is with guild and species’ responses that more differences across vegetation age classes became apparent. Significant increases in abundance were apparent in both the regrowth and new growth vegetation age classes, compared with older habitat (e.g. canopy foragers, damp ground insectivores, tall shrub foragers); open ground foragers were especially common in post-fire regrowth but then significantly declined. Other responses were more complex, with species’ preferences reflecting their foraging ecology. Some birds showed preferences across two age classes: sites that were young post-fire regrowth (6 months–2.5 years since fire) along with sites of old habitat (>35 years since fire), (e.g. Crimson Rosella, Scarlet Robin, Sulphur-crested Cockatoo), while some ground-foraging species became scarce in dense new-growth vegetation that appears 2.5–10 years post fire (e.g. Australian Magpie, Laughing Kookaburra and White-winged Chough). Such species may deserve specific management strategies to maintain populations in forests where substantial areas are burnt by wildfire or planned burns, over short periods of time. The model for total bird abundance showed a significant fire frequency response with birds preferring sites twice burnt within 35 years (e.g. bark and canopy-foraging guilds). Four guilds demonstrated a preference for sites frequently burnt, increasing in abundance as number of burns increased (nectarivores, open-ground foragers, seeds in trees foragers, tall shrub foragers). In contrast, two species appeared to prefer sites that had experienced low fire frequencies, a response not common to their guilds. Laughing Kookaburra (carnivore) and White-winged Chough (forages on open ground among trees) generally declined in abundance with increasing fire frequency. © 2023 Elsevier B.V.
Management effectiveness of wetland-protected areas
- Authors: McInnes, Rob , Gell, Peter , Finlayson, C.
- Date: 2023
- Type: Text , Book chapter
- Relation: Ramsar Wetlands: Values, Assessment, Management Chapter 14 p. 357-376
- Full Text: false
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- Description: The effective management of wetlands requires a sound policy foundation that recognises the full range of states through which a wetland may pass, the drivers of change and their periodicity, and the trajectory of present change relative to past conditions. A management plan should suit the local requirements, and be as large or complex as is required for any specific site. While the format and presentation of a management plan can vary, the process comprises six steps to implement actions to achieve the management goals, namely: Why are we here? What have we got? What are the important features? What are the important influences? What do we want? What must we do? Based on general requirements for effectiveness tracking in protected areas, a specific Ramsar Site Management Effectiveness Tracking Tool (R-METT) has been formally adopted by the Ramsar Convention. This is designed to be simple and rapid to assist site managers and to facilitate wide uptake of the approach. The evaluation questions in R-METT were designed to be easily answered by the management authority without any additional research or intense and costly data collection. © 2023 Elsevier Inc. All rights reserved.
The response of wetlands to long-term climate change
- Authors: Riedinger-Whitmore, Melanie , Gell, Peter , Mills, Keely
- Date: 2023
- Type: Text , Book chapter
- Relation: Ramsar Wetlands: Values, Assessment, Management Chapter 8 p. 195-217
- Full Text: false
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- Description: The Earth has been subjected to cyclical climatic variations that are attributable to a range of forces that have return times ranging from days to many millennia. Most of the world’s wetlands were formed since the last glaciation, yet they have varied greatly in condition even through the relatively stable climates of the Holocene. Many wetlands listed under the Ramsar Convention have experienced conditions that are different than those observed at the time they were listed. Cyclical changes that drive natural variation will continue to influence wetlands. These natural drivers, however, will combine with anthropogenic influences that will alter the natural ecological character. As many wetlands change, Ramsar reporting will be faced with assessing changes in condition and accommodating the expectations of nations to provide guidance that can help manage these driving forces. © 2023 Elsevier Inc. All rights reserved.
Water quality status of mangrove ecosystem in Bedono, Sayung, Demak, Central Java
- Authors: Soeprobowati, Tri , Jumari, Jumari , Hidayat, Jafron , Muhammad, Fuad , Falah, Mirza , Cahyani, Ni , Gell, Peter
- Date: 2023
- Type: Text , Journal article
- Relation: Pollution Vol. 9, no. 4 (2023), p. 1374-1385
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- Description: Mangrove ecosystems have many functions for coastal areas, including ecological, social, and economic services. These functions have a systemic impact on the environment of other coastal ecosystems and human life. The mangrove ecosystem covering an area of 197.92 ha in Bedono, Demak Regency, Central Java was threatened due to the wave abrasion and high tides. Some parts of Bedono Village had become inundated and flooded permanently, zink as part of the ocean. This research was conducted to quantify water pollution in the mangrove ecosystem of Bedono Village using the Storage and Retrieval (STORET) method and the pollution index (PI). The fieldwork was conducted June 2022, by collecting water samples for laboratory analysis tests and in-situ water quality measurement. The parameter of the water quality that exceeded threshold of the Government Regulation of the Republic of Indonesia Number 22 of 2021 are the dissolved oxygen (DO) ranges between 4.39-8.78 mg L-1, BOD ranges between 30-32.4 mg L-1, phosphate ranges between 0.063-0.074 mg L-1, ammonia ranges between 0.148-0.48 mg L-1, Cr ranges between 0.071-0.21 mg L-1, and Pb ranges between 0.071-0.21 mg L-1. Based on the STORET method, the water quality in the mangrove ecosystem was found to be in the category of moderately (-16, for harbor function) – heavily polluted (-80, for tourism and -90, marine biota), whereas based on the PI index it was lightly polluted (1.77-4.12, for harbor function) – moderately polluted (11.06-13.83for tourism, and 9.96-11.85, marine biota). © The Author(s) 2023.
Wetlands and future change—Implications and opportunities with the Ramsar Convention
- Authors: Gell, Peter , Davidson, Nick , Finlayson, C. , Herb, Andy , McInnes, Rob , Pittock, Jamie , Pritchard, Dave
- Date: 2023
- Type: Text , Book chapter
- Relation: Ramsar Wetlands: Values, Assessment, Management Chapter 20 p. 555-561
- Full Text: false
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- Description: In the face of global-scale decline in the extent and state of the world’s wetlands, the Ramsar Convention has mobilised most of the world’s nations to support the conservation and wise use of wetlands. Whilst wetlands continue to be lost and their condition overall continues to decline, the Convention has played a significant part in assisting nations to mitigate pressures and preserve values and ecological assets. The pressures on wetlands will continue, and the Convention could continue its valuable contribution by increasing the awareness of the value of, and risks to wetlands, assisting Contracting Parties to plan for and accommodate change in wetland state, including that driven by climate change, recognising wetlands as socio-ecological systems, and refining the practice of wetland restoration. There remains much opportunity to extend the technical and management capacity that can be catalysed by the Convention to all nations to address the conservation and wise use of wetlands across the globe. © 2023 Elsevier Inc. All rights reserved.
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
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- 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.
Multiproxy approach to track changes in the ecological condition of wetlands in the Gunbower Forest, a Ramsar site
- Authors: Mall, Neeraj , Gell, Peter , Kattel, Giri , Gadd, Patricia , Zawadzki, Atun
- Date: 2022
- Type: Text , Journal article
- Relation: Marine and Freshwater Research Vol. 73, no. 10 (2022), p. 1196-1211
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- Description: Gunbower Forest is bordered by the Murray River and Gunbower Creek and hosts several floodplain wetlands listed under the Ramsar Convention. Sediment cores were retrieved from three wetlands to trace changes to their ecological state over time. The basal sediments of the wetlands date back to the beginning of river regulation in the 1930s, suggesting that only after then were they inundated sufficiently often to allow for net sediment accumulation. The diatoms preserved in the lower levels of all cores suggest clear, freshwater conditions prevailed during that period. Increased sediment and nutrient loads are inferred by increased epiphytic forms and nutrient indicators. Over recent decades the wetlands have transitioned to plankton dominance, reflecting greater connectivity to the river and distributary, and a reduced light environment. This pattern resembles to that recorded both upstream and downstream, suggesting a regional-scale change in the wetlands of the southern Murray-Darling Basin. © CSIRO 2022.
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
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- 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.
Continuing the discussion about ecological futures for the lower Murray River (Australia) in the Anthropocene
- Authors: Finlayson, C. Max , Gell, Peter , Conallin, John
- Date: 2021
- Type: Text , Journal article
- Relation: Marine and Freshwater Research Vol. 73, no. 10 (2021), p. 1241-1244
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- Description: The lower Murray River (Australia) has been subject to considerable change from human activities, including the conversion of a variable flow system to one with regulated water levels and the conversion of the estuary to a freshwater system. These conditions will face further pressures owing to reduced flows and higher sea levels associated with climate change. Policy decisions to retain present target conditions could be reconsidered to improve habitat conditions for wetlands, native fish and waterbirds. Contrary to many views, this would be permissible under the Ramsar Convention and, by increasing the diversity of conditions, may assist managers to retain functional systems. This paper encourages a new conversation across the broader community to develop pathways to prepare for emerging pressures on the riverine ecosystems, and move into anthropogenic futures for the Lower Murray. © 2021 CSIRO. All rights reserved.
Land-use changes concerning the riparian vegetation in Galela Lake, North Maluku, Indonesia
- Authors: Soeprobowati, Tri , Jumari, Jumari , Saraswati, Tyas , Suhry, Hendro , Gell, Peter
- Date: 2021
- Type: Text , Journal article
- Relation: Ecological Engineering Vol. 170, no. (2021), p.
- Full Text: false
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- Description: Galela Lake is the largest lake in the Halmahera Utara Regency, North Maluku Province, Indonesia, and is used for domestic water supply, irrigation, aquaculture, and tourism. However, its catchment has been cleared and developed for intensive agriculture. Therefore, there is a need to examine the land-use changes impacting the riparian vegetation of Galela Lake to establish a basis for the development of lake management plans. Research has been conducted at four research sites within the forest (Site I), farmland (Site II), a tourism area (Site III), and near the river inlet (Site IV). In each site, the riparian vegetation was surveyed from the lake banks to 500 m into the neighboring terrestrial habitat. Evidence for changes in the spatial distribution of land-use types in the vicinity of Galela Lake in 2002, 2015, and 2019 were obtained from Landsat images. Galela Lake (302.05 Ha) is exposed to various kinds of human use. During 2002–2019, barren land had been converted into build-up land, and much of the water body of the lake was converted into a riparian zone through the pressures of population growth. Ten of 89 plant species observed within the riparian vegetation around Galela Lake are included in The International Union for Conservation of Nature and Natural Resources (IUCN) Red List threatened species 2010. Coconut (Cocos nucifera), sugar palm (Arenga pinnata), fig (Ficus variegata), nutmeg (Myristica fragrans), and mango (Mangifera indica) were found to be the most important riparian trees. The second generation stands of riparian vegetation (pole and sapling strata) of several species exhibit potential as conservation plants for land and aquatic ecosystems, such as guest tree (Kleinhovia hospita), bamboo (Bambusa vulgaris), the figs (Ficus septica and F. variegata), and sugar palm (A. pinnata). © 2021 Elsevier B.V.
Using long-term data to inform a decision pathway for restoration of ecosystem resilience
- Authors: Gillson, Lindsey , Dirk, Cherié , Gell, Peter
- Date: 2021
- Type: Text , Journal article
- Relation: Anthropocene Vol. 36, no. (2021), p.
- Full Text: false
- Reviewed:
- Description: Landscapes change over time in response to multiple interacting drivers, including climate, disturbance, and land-use, which all leave a lasting legacy on ecosystem structure and function. As the dynamic nature of ecosystems is increasingly recognised, long-term data is essential to contextualise recent changes and provide a frame of reference for planning appropriate restoration responses. Knowledge of ecological function and process can underpin management thresholds and decision pathways that consider the history and resilience of ecosystems. This paper reviews and synthesizes literature relevant to process-based approaches to restoration ecology that incorporates a long-term perspective. In doing so, we identify alternative descriptors to frame reference conditions, useful theoretical principles for restoration ecology, and a management decision-support framework based on these principles. Such tools enable exploration of possible future scenarios and adaptation pathways for social-ecological resilience in a no-analogue future. © 2021 Elsevier Ltd
Background concentrations of mercury in Australian freshwater sediments : the effect of catchment characteristics on mercury deposition
- Authors: Lintern, Anna , Schneider, Larissa , Beck, Kristen , Mariani, Michela , Gell, Peter
- Date: 2020
- Type: Text , Journal article
- Relation: Elementa Vol. 8, no. 1 (2020), p.
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- Description: Waterways in the Southern Hemisphere, including on the Australian continent, are facing increasing levels of mercury contamination due to industrialization, agricultural intensification, energy production, urbanization, and mining. Mercury contamination undermines the use of waterways as a source of potable water and also has a deleterious effect on aquatic organisms. When developing management strategies to reduce mercury levels in waterways, it is crucial to set appropriate targets for the mitigation of these contaminated waterways.These mitigation targets could be (1) trigger values or default guideline values provided by water and sediment quality guidelines or (2) background (pre-industrialization) levels of mercury in waterways or sediments. The aims of this study were to (1) quantify the differences between existing environmental guideline values for mercury in freshwater lakes and background mercury concentrations and (2) determine the key factors affecting the spatial differences in background mercury concentrations in freshwater lake systems in Australia. Mercury concentrations were measured in background sediments from 21 lakes in Australia. These data indicate that background mercury concentrations in lake sediments can vary significantly across the continent and are up to nine times lower than current sediment quality guidelines in Australia and New Zealand. This indicates that if waterway managers are aiming to restore systems to ‘pre-industrialization’ mercury levels, it is highly important to quantify the site-specific background mercury concentration. Organic matter and precipitation were the main factors correlating with background mercury concentrations in lake sediments. We also found that the geology of the lake catchment correlates to the background mercury concentration of lake sediments.The highest mercury background concentrations were found in lakes in igneous mafic intrusive regions and the lowest in areas underlain by regolith. Taking into account these findings, we provide a preliminary map of predicted background mercury sediment concentrations across Australia that could be used by waterway managers for determining management targets. Copyright: © 2020 The Author(s). **Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliate “Peter Gell” is provided in this record**
Integration of palaeo-and-modern food webs reveal slow changes in a river floodplain wetland ecosystem
- Authors: Kattel, Giri , Eyre, Bradley , Gell, Peter
- Date: 2020
- Type: Text , Journal article
- Relation: Scientific Reports Vol. 10, no. 1 (2020), p.
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- Description: Large rivers, including the Murray River system in southeast Australia, are disturbed by many activities. The arrival of European settlers to Australia by the mid-1800s transformed many floodplain wetlands of the lower Murray River system. River impoundment and flow regulation in the late 1800s and, from the 1930s, resulted in species invasion, and elevated nutrient concentrations causing widespread eutrophication. An integrated palaeoecology, and palaeo-and-modern food web approach, incorporating mixing models, was undertaken to reveal changes in a regulated wetland (i.e. Kings Billabong). The lack of preserved sediment suggests the wetland was naturally intermittent before 1890. After this time, when used as a water retention basin, the wetland experienced net sediment accumulation. Subfossil cladocerans, and δ13C of Daphnia, chironomid, and bulk sediment, all reflected an early productive, likely clear water state and shifts in trophic state following river regulation in the 1930s. Food web mixing models, based on δ13C and δ15N in subfossil and modern Daphnia, fish, and submerged and emergent macrophytes, also indicated a shift in the trophic relationships between fish and Daphnia. By the 1970s, a new state was established but a further significant alteration of nitrogen and carbon sources, and trophic interactions, continued through to the early 2000s. A possible switch from Daphnia as a prey of Australian Smelt could have modified the food web of the wetland by c. 2006. The timing of this change corresponded to the expansion of emergent macrophytes possibly due to landscape level disruptions. The evidence of these changes suggests a need for a broader understanding of the evolution of wetlands for the management of floodplains in the region. © 2020, The Author(s).
- Description: Funding details: National Key Research and Development Program of China Stem Cell and Translational Research, #2016YFC0402900 Funding details: National Key Research and Development Program of China Stem Cell and Translational Research, #2016YFE0201900 Funding details: Centre of Excellence for Electromaterials Science, Australian Research Council, ARC;ACES, DP160100248 Funding details: Centre of Excellence for Electromaterials Science, Australian Research Council, ARC;ACES, LE0668495
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
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- 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