Australian waterbirds - time and space travellers in dynamic desert landscapes

2010 ◽  
Vol 61 (8) ◽  
pp. 875 ◽  
Author(s):  
R. T. Kingsford ◽  
D. A. Roshier ◽  
J. L. Porter
Keyword(s):  
Resource Availability ◽  
Environmental Flows ◽  
Anthropogenic Impacts ◽  
Aquatic Organisms ◽  
River Regulation ◽  
Population Declines ◽  
Time And Space ◽  
Regulated Rivers ◽  
Spatial And Temporal Scales ◽  
Resource Patches

Australia’s waterbirds are mostly nomadic, capitalising on highly variable aquatic resources in the arid interior (70% of the continent) for feeding and breeding. Waterbirds, unlike most aquatic organisms, can move between catchments, exploiting habitat wherever it occurs. In Australia, patterns of resource availability for waterbirds are mostly pulsed with peaks of productivity, coinciding with flooding and differing in time and space, affecting individuals, species and functional groups of waterbirds. Australian waterbirds are no different from waterbirds elsewhere, with their behaviour reflecting broad-scale resource availability. They respond to changing patterns of resource distribution, with rapid movements at spatial and temporal scales commensurate with the dynamics of the resource. The most serious conservation threat to waterbirds is a bottleneck in resource availability, leading to population declines, increasingly forced by anthropogenic impacts. River regulation and other threats (e.g. draining) reduce the availability of wetland habitat and decrease the probability of viable resource patches. It is axiomatic that waterbirds need water and such population bottlenecks may occur when the availability of water across the continent is limited. The rehabilitation of regulated rivers with environmental flows and protection of naturally flowing rivers in the arid region are essential for long-term sustainability of Australia’s waterbird populations.

Constraints on the recovery of invertebrate assemblages in a regulated snowmelt river during a tributary-sourced environmental flow regime

2011 ◽  
Vol 62 (12) ◽  
pp. 1407 ◽  
Author(s):  
Andrew J. Brooks ◽  
Matthew Russell ◽  
Robyn Bevitt ◽  
Matthew Dasey
Keyword(s):  
Flow Regime ◽  
Environmental Flows ◽  
River Regulation ◽  
Environmental Flow ◽  
Regulated Rivers ◽  
Macroinvertebrate Assemblages ◽  
Fine Sediments ◽  
Tributary Stream ◽  
Invertebrate Assemblages ◽  
And Control

The impacts of river regulation on aquatic biota have been extensively studied, but long-term assessments of the restoration of biota by environmental flows and the principal mechanisms of recovery have rarely occurred. We assessed whether the provision of an environmental flow regime (EFR) via the decommissioning of an aqueduct on a tributary stream altered downstream macroinvertebrate assemblages in the highly regulated Snowy River, Australia. Macroinvertebrate assemblages of the Snowy River, reference and control sites remained distinct despite the provision of environmental flows. Invertebrate assemblages detrimentally affected by regulation probably remained impaired due to either constraints on colonisation from the tributary stream (dispersal constraints) or unsuitable local environmental conditions in the Snowy River caused by flow regulation (e.g. high levels of fine sediments, elevated temperature regime) suppressing new colonists or recovery of extant populations. Our study showed that restoration may be ineffective if EFRs are too small to ameliorate local environmental factors constraining the recovery of affected biota. Other barriers to recovery, such as dispersal constraints, also need to be overcome. Successful restoration of regulated rivers using environmental flows requires an understanding of the mechanisms and pathways of recovery, together with identification and amelioration of any potential barriers to recovery.

scholarly journals Conservation management of rivers and wetlands under climate change - a synthesis

2011 ◽  
Vol 62 (3) ◽  
pp. 217 ◽  
Author(s):  
Richard T. Kingsford
Keyword(s):  
Climate Change ◽  
Adaptive Management ◽  
Conservation Management ◽  
Good Governance ◽  
Environmental Flows ◽  
Management Strategies ◽  
Flow Regimes ◽  
Regulated Rivers ◽  
Socioeconomic Impacts ◽  
Spatial And Temporal Scales

Dams, diversion of water, invasive species, overharvesting and pollution are degrading rivers and wetlands. Climate change may exacerbate impacts of these threats through predicted reductions in rainfall and increased temperature, decreasing flow and altering timing and variability of flow regimes. Papers in this special issue identify conservation-management strategies for wetlands and rivers through recovery of flow regimes, alteration of dam operations, protected-area management and improved governance and adaptive management. On most regulated rivers, flow regimes should be recovered by increasing environmental flows. Alteration of dam operations can also improve river health through structures on dams (e.g. fishways, multi-level offtakes), reinstating floodplains and improving flow delivery. Further, time-limited licensing for dams and accompanying regular assessments of safety and of environmental and socioeconomic impacts could improve operations. Protected areas remain the core strategy for conservation, with recent improvements in their identification and management, supported by analytical tools that integrate across large spatial and temporal scales. Finally, effective conservation requires good governance and rigorous adaptive management. Conservation management of rivers and wetlands can be significantly improved by adopting these strategies although considerable challenges remain, given increasing human pressures on freshwater resources, compounded by the impacts of climate change.

A simulation tool for managing environmental flows in regulated rivers

2015 ◽  
Vol 73 ◽  
pp. 117-132 ◽  
Author(s):  
C.M.M. Steinfeld ◽  
R.T. Kingsford ◽  
E.C. Webster ◽  
A. Sharma
Keyword(s):  
Environmental Flows ◽  
Simulation Tool ◽  
Regulated Rivers

Modelling the economic impact of environmental flows for regulated rivers in New South Wales, Australia

2003 ◽  
Vol 48 (7) ◽  
pp. 157-164
Author(s):  
R.T. Jayasuriya
Keyword(s):  
Economic Impact ◽  
Environmental Flows ◽  
New South ◽  
New South Wales ◽  
Water Source ◽  
Regulated Rivers ◽  
Community Based ◽  
South Wales ◽  
Groundwater Aquifers

The management of water resources across Australia is undergoing fundamental reform in line with the priorities identified by the Council of Australian Governments (COAG) in 1994. This includes reforms to the specification of property rights, the way the resource is shared between the environment, irrigators and other users, charges for water use and the operational management of the river systems. In New South Wales (NSW), a series of water sharing plans (WSPs) is being developed for each water source in the State including regulated rivers, unregulated rivers and groundwater aquifers. These plans, which are the mechanisms by which COAG reforms are being implemented, are being developed by community-based water management committees (WMCs). The role of the WMCs is to develop a plan that achieves a balance between environmental, economic and social outcomes. NSW Agriculture has assisted a number of WMCs by quantifying the economic impact of proposed WSP options on the irrigation community. This paper outlines the approach taken by NSW Agriculture to quantifying economic impacts on irrigators in regulated catchments and provides results of case studies in the Lachlan River Catchment which is heavily developed for irrigation.

scholarly journals Isolating causal pathways between flow and fish in the regulated river hierarchy

2015 ◽  
Vol 72 (11) ◽  
pp. 1731-1748 ◽  
Author(s):  
Ryan A. McManamay ◽  
Brandon K. Peoples ◽  
Donald J. Orth ◽  
Charles A. Dolloff ◽  
David C. Matthews
Keyword(s):  
Structural Equation ◽  
Large Scale ◽  
Fish Assemblages ◽  
Causal Structure ◽  
River Regulation ◽  
Regulated River ◽  
Equation Modeling ◽  
Regulated Rivers ◽  
Causal Pathways ◽  
The Hierarchical Structure

Unregulated river systems are organized in a hierarchy in which large-scale factors (i.e., landscape and segment scales) influence local habitats (i.e., reach, meso-, and microhabitat scales), and both differentially exert selective pressures on biota. Dams, however, create discontinua in these processes and change the hierarchical structure. We examined the relative roles of hydrology and other instream factors, within a hierarchical landscape context, in organizing fish communities in regulated and unregulated tributaries to the Upper Tennessee River, USA. We used multivariate regression trees to identify factors that partition fish assemblages based on trait similarities, irrespective of spatial scale. We then used classical path analysis and structural equation modeling to evaluate the most plausible hierarchical causal structure of specific trait-based community components, given the data. Both statistical approaches suggested that river regulation affects stream fishes through a variety of reach-scale variables, not always through hydrology itself. Although we observed different changes in flow, temperature, and biotic responses according to regulation types, the most predominant path in which dam regulation affected biota was via temperature alterations. Diversion dams had the strongest effects on fish assemblages. Diversion dams reduced flow magnitudes, leading to declines in fish richness but increased temperatures, leading to lower abundances in equilibrium species and nest guarders. Peaking and run-of-river dams increased flow variability, leading to lower abundances in nest-guarding fishes. Flow displayed direct relationships with biotic responses; however, results indicated that changes in temperature and substrate had equal, if not stronger, effects on fish assemblage composition. The strength and nature of relationships depended on whether flow metrics were standardized for river size. We suggest that restoration efforts in regulated rivers focus on improving flow conditions in conjunction with temperature and substrate restoration.

Controls of alluvial aquifers on continental drainage

2020 ◽  
Author(s):  
Stefan Kollet ◽  
Wendy Sharples ◽  
Bibi Naz
Keyword(s):  
Water Resource Management ◽  
Large Scale ◽  
Dynamic Equilibrium ◽  
Anthropogenic Impacts ◽  
Monitoring Networks ◽  
Spatial Continuity ◽  
Spatial And Temporal Scales ◽  
Alluvial Aquifers ◽  
Continental Scale ◽  
Surface Water Flow

<p>Continental-scale hydrological research is becoming more important as climate variability and change, and anthropogenic impacts on groundwater, are increasing over large spatial and temporal scales. Groundwater quantities and flows are usually difficult to observe due to sparse or spatially limited monitoring networks.  Thus, large-scale hydrological models are needed to provide continuous predictions of hydrological states and fluxes for water resource management. A large part of groundwater consumed comes from alluvial aquifers, which constitute valley fills of continental catchments. While the role of alluvial aquifers as a significant water store has been subject of many previous studies, the importance of the spatial extent and continuity of alluvial aquifers in the drainage characteristics of freshwater from the continental interior to the oceans is unclear. We present a high resolution (3km) hydrological model of continental Europe using ParFlow, a 3D, parallel groundwater and surface water flow model, which uses detailed hydrofacies information as input. We discuss the effect of spatial continuity and extent of alluvial aquifers on continental lateral groundwater flow and discharge to the oceans, water table depth, streamflow, and surface and subsurface storage. The results suggest that the alluvial valleys act as conduits that manage the drainage and retention of continental freshwater in sync with the atmospheric forcing. This dynamic equilibrium may be significantly disturbed by human interventions such as pumping and irrigation leading to a new equilibrium in terms of continental water quantity and also quality.</p>

Growth, episodic recruitment and age truncation in populations of a catadromous percichthyid, Macquaria colonorum

2010 ◽  
Vol 61 (4) ◽  
pp. 397 ◽  
Author(s):  
Chris T. Walsh ◽  
Charles A. Gray ◽  
Ron J. West ◽  
Dylan E. van der Meulen ◽  
Lindsay F. G. Williams
Keyword(s):  
Habitat Degradation ◽  
Environmental Flows ◽  
Anthropogenic Impacts ◽  
Fish Length ◽  
Commercial Fishing ◽  
Marginal Increment ◽  
History Of ◽  
Young Of The Year ◽  
Three Rivers ◽  
Episodic Recruitment

Temperate basses and perches (family Percichthyidae) worldwide have declined in distribution and abundance during the past few decades due to anthropogenic impacts such as fishing, habitat degradation and alteration to river flows. This study examined differences in the age, growth and longevity of Macquaria colonorum among three south-eastern Australian coastal rivers. Estimates of ages were made by counting opaque zones in sectioned otoliths. Ages were validated by using marginal increment analysis, staining fish otoliths with oxytetracycline and sampling young-of-the-year fish. Length-at-age data from 1644 fish indicated that growth of M. colonorum is rapid in the first 3 to 4 years, after which it slows considerably. Females grew faster and reached larger asymptotic lengths than males. The species was found to be long lived, with the oldest fish estimated at 41 years. Population age structures indicated variable year-class strengths in all three rivers and there was an absence of larger, older (>10 years) individuals in the populations from the two rivers with a history of commercial fishing. These results indicate that M. colonorum populations, similar to other global percichthyid and estuarine-dependent fishes, have been subjected to episodic recruitment and age truncation and that these are likely influenced by environmental flows and fishing pressure.

Patterns in apparent survival of Atlantic salmon (Salmo salar) parr in relation to variable ice conditions throughout winter

2010 ◽  
Vol 67 (11) ◽  
pp. 1744-1754 ◽  
Author(s):  
Tommi Linnansaari ◽  
Richard A. Cunjak
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Anthropogenic Impacts ◽  
River Regulation ◽  
Ice Formation ◽  
Winter Period ◽  
Winter Mortality ◽  
Apparent Survival ◽  
Atlantic Salmon Salmo Salar ◽  
Salmon Parr

Apparent within-site survival of Atlantic salmon ( Salmo salar ) parr, individually tagged with passive integrated transponders, was not constant throughout the winter period in a 3-year study (2003–2006) in Catamaran Brook, New Brunswick, Canada. Highest decline in apparent survival (19.4%–33.3% of the study population) occurred prior to any ice formation and coincided with early winter acclimatization period (dynamic temperature and discharge regime). Stream discharge and parr maturity were identified to be relevant factors explaining emigration prior to ice formation. Apparent survival was improved during the period affected by subsurface ice and considerably better when surface ice was prevailing, with a decline in population size between 0% and 15.4%. Overall, observed within-site winter mortality was low (4.4%), and the majority of the loss of tagged salmon parr occurred because of emigration. On average, the within-site population of tagged salmon parr declined by 31.7% over the whole winter (November–April). Our data suggest that anthropogenic impacts, like climate change or river regulation, are likely to affect the apparent survival rate and distribution of juvenile Atlantic salmon because of their effects on natural ice regime in streams.

Cryptic and cumulative impacts on the wintering habitat of the endangered black-faced spoonbill (Platalea minor) risk its long-term viability

2017 ◽  
Vol 45 (2) ◽  
pp. 147-154 ◽  
Author(s):  
EVAN J. PICKETT ◽  
MELANIE CHAN ◽  
WENDA CHENG ◽  
JOHN ALLCOCK ◽  
SIMBA CHAN ◽  
...  
Keyword(s):  
Climate Change ◽  
Habitat Loss ◽  
Population Change ◽  
Anthropogenic Impacts ◽  
Population Viability Analysis ◽  
Cumulative Impacts ◽  
Population Declines ◽  
Distribution Models ◽  
Waterbird Species

SUMMARYThe East Asian–Australasian flyway contains some of the most threatened habitats in the world, with at least 155 waterbird species reliant on the tidal habitats it comprises. The black-faced spoonbill (Platalea minor) is an iconic endangered species distributed across the coast of East Asia. Its population suffered a severe decline into the 1990s, but extensive monitoring and conservation interventions have aided a substantial recovery of the species. We used a population viability analysis based on data collected over the past two decades in conjunction with species distribution models to project spatially explicit models of population change for the next 35 years. Over nearly all scenarios of habitat loss and climate change, the global spoonbill population was projected to increase in the short-term due to low population numbers likely well below current population carrying capacities. However, climate change and habitat loss together threaten the recovery of the spoonbill population such that, by 2050, population declines are apparent as a consequence of these cumulative impacts. These threats are also cryptic and represent a challenge to the conservation of species recovering from anthropogenic impacts; observed population increases can hide large reductions in habitat suitability that threaten the long-term viability of species.

scholarly journals Responses of grasses to experimental submergence in summer: implications for the management of unseasonal flows in regulated rivers

2020 ◽  
Vol 54 (4) ◽  
pp. 985-999
Author(s):  
Lyndsey M. Vivian ◽  
Joe Greet ◽  
Christopher S. Jones
Keyword(s):  
Survival Rates ◽  
River Regulation ◽  
Grass Species ◽  
Riparian Zones ◽  
Regulated Rivers ◽  
Light Reduction ◽  
Riparian Plants ◽  
Eastern Australia ◽  
Survival And Growth ◽  
Careful Management

Abstract River regulation has altered the seasonal timing of flows in many rivers worldwide, impacting the survival and growth of riparian plants. In south-eastern Australia, demand for irrigation water in summer often results in high river flows during a season that would naturally experience low flows. Although unseasonal high summer flows are thought to significantly impact waterways, their effects on vegetation are poorly quantified. We investigated the responses of five grass species commonly occurring in riparian zones to different durations of submergence in summer. We experimentally tested the response of three exotic and two native grasses to four submergence treatments (4 weeks, 8 weeks, 2-week pulses and no submergence), and two levels of shading (no shading and 80% light reduction), over 8 weeks in summer and early autumn. All submergence treatments, including the 2-week pulse, resulted in the death of all plants of three species (Bromus catharticus, Dactylis glomerata and Rytidosperma caespitosum). Lolium perenne exhibited moderate survival rates in the shorter-duration unshaded submergence treatments, while Poa labillardierei largely survived all treatments. Similar responses across species were observed for plant height and biomass, although height generally increased while biomass growth was reduced by shading. These results show that even 2-week periods of summer submergence can reduce growth and cause the death of some riparian grasses. Although some species may survive longer submergence durations, impacts on other aspects of fitness, and ongoing effects of repeated unseasonal submergence, remain uncertain. Our study highlights that the impacts of unseasonal flows require further investigation and careful management.

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