River management and environmental water allocation in regulated ecosystems of arid and semi-arid regions – a review
- Authors: Atazadeh, Ehsan , Barton, Andrew , Shirinpour, Mozhgan , Zarghami, Mahdi , Rajabifard, Abbas
- Date: 2020
- Type: Text , Journal article
- Relation: Fundamental and Applied Limnology Vol. 193, no. 4 (2020), p. 327-345
- Full Text: false
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- Description: Rivers make a significant contribution in providing goods and services for human well-being. Today, many rivers and streams have been heavily regulated to ensure adequate provision of water resources for anthropogenic uses. Riverine ecosystems, especially those in arid and semi-arid regions, are experiencing severe stress due to the increasing demands on the ecosystem services they provide, coupled with anthropogenic catchment-scale impacts and factors associated with natural and human-induced climate variability and change. In this paper, the various flow components in regulated riverine ecosystems and the methods to determine environmental flows are reviewed. The review also focuses on the concurrent developments of eco-hydrological models and on the new opportunities for improving environmental flows of rivers by sustainably adjusting consumptive flows to fine-tune environmental flows and maximize the ecological benefit. In fact, the present paper highlights the role of consumptive flows, towards improving environmental flows, which has largely been neglected by river scientists and water managers. Indeed, consumptive flows can provide an opportunity to improve and support environmental flows in regulated riverine ecosystems. Addressing these challenges may aid water management efforts in finding sustainable solutions in riverine ecosystems by balancing environmental/ecological and human water requirements. © 2020 E. Schweizerbart’sche Verlagsbuchhandlung, Stuttgart, Germany.
Palaeoecological evidence for sustained change in a shallow Murray River (Australia) floodplain lake: regime shift or press response?
- Authors: Kattel, Giri , Gell, Peter , Zawadzki, Atun , Barry, Linda
- Date: 2017
- Type: Text , Journal article
- Relation: Hydrobiologia Vol. 787, no. 1 (2017), p. 269-290
- Full Text: false
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- Description: Paleolimnological techniques can reveal long-term perturbations and associated stable state transitions of lake ecosystems. However, such transitions are difficult to predict since changes to lake ecosystems can be abrupt or gradual. This study examined whether there were past transitions in the ecological regime of Kings Billabong, a shallow River Murray wetland in southeast Australia. A 94-cm-long core, covering c. 90 years of age, was analysed at 1 cm resolution for subfossil cladocerans, diatoms and other proxies. Prior to river regulation (c. 1930), the littoral to planktonic ratios of cladocerans and diatoms, and bulk sediment delta C-13 values were high, while the period from c. 1930 to c. 1970 experienced considerable changes to the wetland ecosystem. The abrupt nature of changes of planktonic cladocerans and diatoms, particularly after the onset of river regulation (1930s), was triggered by inundation, high rates of sedimentation and shifts in bulk sediment delta N-15 values. However, the transition of a once littoral-dominated community, to one favouring an increasingly turbid, plankton-dominated trophic condition following river regulation was relatively slow and lasted for decades. The progression to a new regime was likely delayed by the partial recovery of submerged plant communities and related internal dynamics.
The response of Cladocerans to recent environmental forcing in an Alpine Lake on the SE Tibetan Plateau
- Authors: Kong, Lingyang , Yang, Xiangdong , Kattel, Giri , Anderson, N. J. , Hu, Zhujun
- Date: 2017
- Type: Text , Journal article
- Relation: Hydrobiologia Vol. 784, no. 1 (2017), p. 171-185
- Full Text: false
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- Description: Global environmental change has affected aquatic ecosystems of the southeast Tibetan Plateau during the past 200 years, altering the composition and biomass of primary producers (e.g. algae). However, the response of primary consumers (e.g. cladocerans) to this recent environmental forcing is not well documented. Samples of cladoceran remains from sediment traps (1-year deployment), surface sediments covering a range of water depths and a short 22.5-cm sediment core were analysed in a small, remote alpine lake (Moon Lake) in Sichuan Province (SW China). Littoral forms, notably Chydorus sphaericus and Acroperus harpae, together with Daphnia pulex dominated the cladoceran community. Remains of these cladocerans were well represented in the sediment core assemblages as indicated by their relative abundance in the surface sample. There was a marked increase in the abundance of D. pulex and total cladoceran fluxes in the sediment core from ca. 1880 AD, coinciding with the changes in diatom assemblages and pigments. Analysis of the multi-proxy data (cladocerans, diatom, pigment, total organic carbon, C/N ratio, air temperature and atmospheric NO3 (-) records) suggests that both direct and indirect climatic forcing, coupled with enhanced nutrient supply (e.g. NO3 (-) deposition) effects on primary producers have changed cladoceran community dynamics in Moon Lake over the last similar to 200 years.
Climate drying amplifies the effects of land-use change and interspecific interactions on birds
- Authors: Bennett, Joanne , Clarke, Rohan , Horrocks, Gregory , Thomson, James , Mac Nally, Ralph
- Date: 2015
- Type: Text , Journal article
- Relation: Landscape Ecology Vol. 30, no. 10 (2015), p. 2031-2043
- Full Text: false
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- Description: Context: Climate change may amplify the effects of land-use change, including induced changes in interspecific interactions. Objectives: To investigate whether an avifauna changed over a period of severe drought, and if changes in avifaunas were related to changes in vegetation characteristics and the irruption of a despotic native species, the noisy miner Manorina melanocephala. Methods: In the box–ironbark forests of south-eastern Australia, we resurveyed the avifaunas and remeasured vegetation characteristics in 120 forest transects in 2010–2011 that had previously been measured in 1995–1997. Results: The avifauna changed markedly over the prolonged drought, and changes were more marked in smaller fragments of remnant vegetation in which more pronounced vegetation change had occurred. The noisy miner increased differentially in smaller remnants adding to the declines, especially for small-bodied birds. Conclusions: Long droughts interspersed with short wet periods are projected for the region, so the imposition of climate effects on an already much-modified region has profound implications for the avifauna. The noisy miner has (and continues) to benefit from both land-use and climate change, so future sequences of drought interspersed with short wet periods are likely to lead to further changes in the avifauna as the miner extends its occupancy. Differential reductions in small nectarivores and insectivores will affect ecosystem processes, including the control of defoliating insects, seed dispersal and pollination. © 2015, Springer Science+Business Media Dordrecht.
Effects of varying organic matter content on the development of green roof vegetation: A six year experiment
- Authors: Bates, Adam , Sadler, Jon , Greswell, Richard , Mackay, Rae
- Date: 2015
- Type: Text , Journal article
- Relation: Ecological Engineering Vol. 82, no. September (2015), p. 301-310
- Full Text: false
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- Description: Green roofs can potentially be used to tackle a variety of environmental problems, and can be used as development mitigation for the loss of ground-based habitats. Brown (biodiversity) roofs are a type of green roof designed to imitate brownfield habitat, but the best way of engineering these habitats requires more research. We tested the effects of altering organic matter content on the development of vegetation assemblages of experimental brown (biodiversity) roof mesocosms. Three mulch treatments were tested: (1) sandy loam, where 10 mm of sandy loam mulch (about 3% organic matter by dry weight) was added to 100 mm of recycled aggregate; (2) compost, where the mulch also contained some garden compost (about 6% organic matter by dry weight); and (3) no mulch, where no mulch was added. Mesocosms were seeded with a wildflower mix that included some Sedum acre, and vegetation development was investigated over a six-year period. Species richness, assemblage character, number of plants able to seed, and above-ground plant biomass were measured. Drought disturbance was an important control on plant assemblages in all mulch treatments, but there were significant treatment response interactions. The more productive compost treatment was associated with larger plant coverage and diversity before the occurrence of a sequence of drought disturbances, but was more strongly negatively affected by the disturbances than the two less productive treatments. We suggest that this was due to the over-production of plant biomass in the more productive treatment, which made the plants more vulnerable to the effects of drought disturbance, leading to a kind of 'boom-bust' assemblage dynamic. The 'ideal' amount of added organic matter for these green roof systems was very low, but other types of green roof that have a larger water holding capacity, and/or more drought resistant plant floras, will likely require more organic matter or fertiliser. Nonetheless, nutrient-supported productivity in green roof systems should be kept low in order to avoid boom-bust plant assemblage dynamics. Research into the best way of engineering green roof habitats should take place over a long enough multi-year time period to include the effects of temporally infrequent disturbances. © 2015 Elsevier B.V.
Hydrological change in the Coorong Estuary, Australia, past and present : Evidence from fossil invertebrate and algal assemblages
- Authors: Reeves, Jessica , Haynes, Deborah , Garcia, Adriana , Gell, Peter
- Date: 2015
- Type: Text , Journal article
- Relation: Estuaries and Coasts Vol. 38, no. 6 (2015), p. 2101-2116
- Full Text: false
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- Description: Estuaries are defined by change; both on a diurnal basis, balancing tidal inflow with riverine outflow, and over hundreds or thousands of years through geomorphic evolution and sea level variability. However, contemporary management and protection underpinned by international agreements, such as the Ramsar Convention, presume that wetlands change within only limited ranges based on their contemporary conditions. Adaptive management strategies for cyclic or even directional change are more robust if underpinned by evidence from longer-term records, such as those obtained from palaeoecological records preserved in sediment cores. Such is the case for the Coorong lagoon in southern Australia; here analysis of assemblage changes of key invertebrates and algae preserved in the sediments reveals the variability of natural conditions well before the instrumental record. During the mid-Holocene to late Holocene and up until the mid-twentieth century, assemblage changes in microfauna and flora indicate variable salinity and water clarity associated with both fresh continental and marine water inputs. By contrast, in the south lagoon, the proxies indicate periodically enhanced salinity. The most significant changes in ecology and sedimentation are apparent after the 1950s; hydrological modifications have changed the influence of both continental and tidal water, producing conditions that are unusual in the long-term history of the site. © 2014, Coastal and Estuarine Research Federation.
Identification of observed factors that predict bather water-immersions at beaches
- Authors: Morgan, Damian , Ozanne-Smith, Joan
- Date: 2013
- Type: Text , Journal article
- Relation: Ocean and Coastal Management Vol. 84, no. (2013), p. 180-183
- Full Text: false
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- Description: Coastal managers require accurate and relevant visitor information to manage visitor's leisure and recreation experiences. The study reports the development of a predictive model of bather water-immersions at selected beaches in Victoria, Australia for the daily peak-bathing period. Criterion variable data were collected over two summer periods to provide external validation. Predictor variables were observed on site or from secondary data. Results showed a statistically significant model meeting the required assumptions: Adjusted R2 = 0.65: F2, 292 = 270.50, p < 0.001; R2 95% CI: 0.58 to 0.71. Significant predictor variables were daily maximum air temperature and level of service (no service, toilet/water, or kiosk/club). Further research is required to assess the model generalisability to other beach locations and time frames
The aerial invertebrate fauna of subantarctic Macquarie Island
- Authors: Hawes, Timothy , Greenslade, Penelope
- Date: 2013
- Type: Text , Journal article
- Relation: Journal of Biogeography Vol. 40, no. 8 (2013), p. 1501-1511
- Full Text: false
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- Description: Aim: The extent and diversity of invertebrate aerial dispersal both on remote islands and in polar regions has long been of interest to biogeographers. We therefore monitored the airborne dispersal of insects and other micro- and macroinvertebrates to and on Macquarie Island in order to assess (1) the magnitude and composition of local aerial dispersal activity by the island's invertebrate fauna, and (2) the potential for exotic arrival and establishment. Location: Macquarie Island. Methods: Two robust wind-traps were run year-round on Macquarie Island from 1991 to 1994 to collect airborne insects and other micro- and macroinvertebrates. Results: More than 3000 invertebrates were caught in these traps over the sampling period in the most comprehensive aerial survey of subantarctic invertebrates to date. Representatives of seven orders of Insecta were captured: Psocoptera, Thysanoptera, Hemiptera, Coleoptera, Diptera, Lepidoptera and Hymenoptera. Other taxa captured included other arthropods (Arachnida and Collembola) but also terrestrial Gastropoda. Evidence of possible long-distance dispersal (LDD) was limited to two exotic catches (one species of Collembolon, and one species of Thysanoptera). The abundance and composition of indigenous invertebrates caught in the traps indicates that the frequency of short-distance dispersal (SDD) movements on the island far exceeds that which had previously been realized. Main conclusions: More than half the total catch (53%) was of flightless (i.e. passively dispersed) invertebrates, with 84% of them flightless in one of the two traps. The extent of passive dispersal movements is consistent, with most invertebrates being widely distributed at a whole-island scale. Aerial dispersal may act as a conduit for non-indigenous arrivals but this occurs infrequently. Other explanations for exotic species in traps are equally likely. The implications of these findings are discussed in relation to terrestrial invertebrate biogeography. © 2013 Blackwell Publishing Ltd.
- Description: 2003011217
Spatial and temporal changes in estuarine water quality during a post-flood hypoxic event
- Authors: Wong, Vanessa , Johnston, Scott , Bush, Richard , Sullivan, Leigh , Clay, Christina , Burton, Edward , Slavich, Peter
- Date: 2010
- Type: Text , Journal article
- Relation: Estuarine, Coastal and Shelf Science Vol. 87, no. 1 (2010), p. 73-82
- Full Text: false
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- Description: A major fish kill occurred in the Richmond River estuary in January 2008 due to oxygen depletion following extensive overbank flooding. This paper examines spatial and temporal changes in the chemistry of main channel waters, thereby identifying the primary sources of deoxygenating water. Over 40 km of the mid- to lower estuary main channel was deoxygenated within seven days of the flood peak. Hypoxia was confined to downstream of the confluences with mid-estuary backswamp basins and occurred during the later phase of the flood recession. Water chemistry at key locations in the estuary indicated elevated concentrations of redox sensitive species associated with acid sulfate soils (ASS) during the hypoxic period. Peak concentrations of Fe
Changes in water quality following tidal inundation of coastal lowland acid sulfate soil landscapes
- Authors: Johnston, Scott , Bush, Richard , Sullivan, Leigh , Burton, Edward , Smith, Douglas , Martens, Michelle , McElnea, Angus , Ahern, Col , Powell, Bernard , Stephens, Luisa , Wilbraham, Steve , Van Heel, Simon
- Date: 2009
- Type: Text , Journal article
- Relation: Estuarine, Coastal and Shelf Science Vol. 81, no. 2 (2009), p. 257-266
- Full Text: false
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- Description: This study examines the remediation of surface water quality in a severely degraded coastal acid sulfate soil landscape. The remediation strategy consisted of partial restoration of marine tidal exchange within estuarine creeks and incremental tidal inundation of acidified soils, plus strategic liming of drainage waters. Time-series water quality and climatic data collected over 5 years were analysed to assess changes in water quality due to this remediation strategy. A time-weighted rainfall function (TWR) was generated from daily rainfall data to integrate the effects of antecedent rainfall on shallow groundwater levels in a way that was relevant to acid export dynamics. Significant increases in mean pH were evident over time at multiple monitoring sites. Regression analysis at multiple sites revealed a temporal progression of change in significant relationships between mean daily electrical conductivity (EC) vs. mean daily pH, and TWR vs. mean daily pH. These data demonstrate a substantial decrease over time in the magnitude of creek acidification per given quantity of antecedent rainfall. Data also show considerable increase in soil pH (2-3 units) in formerly acidified areas subject to tidal inundation. This coincides with a decrease in soil pe, indicating stronger reducing conditions. These observations suggest a fundamental shift has occurred in sediment geochemistry in favour of proton-consuming reductive processes. Combined, these data highlight the potential effectiveness of marine tidal inundation as a landscape-scale acid sulfate soil remediation strategy. © 2008 Elsevier Ltd. All rights reserved.
Pore water sampling in acid sulfate soils : A new peeper method
- Authors: Johnston, Scott , Burton, Edward , Keene, Annabelle , Bush, Richard , Sullivan, Leigh , Isaacson, Lloyd
- Date: 2009
- Type: Text , Journal article
- Relation: Journal of Environmental Quality Vol. 38, no. 6 (2009), p. 2474-2477
- Full Text: false
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- Description: This study describes the design, deployment, and application of a modified equilibration dialysis device (peeper) optimized for sampling pore waters in acid sulfate soils (ASS). The modified design overcomes the limitations of traditional-style peepers, when sampling firm ASS materials over relatively large depth intervals. The new peeper device uses removable, individual cells of 25 mL volume housed in a 1.5 m long rigid, high-density polyethylene rod. The rigid housing structure allows the device to be inserted directly into relatively firm soils without requiring a supporting frame. The use of removable cells eliminates the need for a large glove-box after peeper retrieval, thus simplifying physical handling. Removable cells are easily maintained in an inert atmosphere during sample processing and the 25-mL sample volume is sufficient for undertaking multiple analyses. A field evaluation of equilibration times indicates that 32 to 38 d of deployment was necessary. Overall, the modified method is simple and effective and well suited to acquisition and processing of redox-sensitive pore water profiles > 1 m deep in acid sulfate soil or any other firm wetland soils. Copyright © 2009 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.