Hydrological changes and ecological impacts associated with water resource development in large floodplain rivers in the Australian tropics

Leigh, Catherine; Sheldon, Fran

doi:10.1002/rra.1125

Cited by 56 publications

(41 citation statements)

References 49 publications

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“…, 2011). By virtue of their steep elevations, insular streams have largely remained untouched by human development in the Australian Wet Tropics, although the coastal lowland reaches of these streams are subject to increasing pressure from development in this region and on oceanic islands (Brasher, 2003; Schoenfuss & Blob, 2007; Leigh & Sheldon, 2008; Kennard et al. , 2010).…”

Section: Discussionmentioning

confidence: 99%

Flow velocity underpins microhabitat selection by gobies of the Australian Wet Tropics

2013

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Summary 1. Water flow is a critical driver of aquatic ecosystem health and function. Amid rising concerns over changing flow regimes, there is an urgent need to understand the functional mechanisms by which flow influences patterns of freshwater biodiversity. 2. We explored the functional link between flow velocity and microhabitat specialisation in a speciose group of freshwater gobies (comprising over half the total fish species richness) within insular streams of the Australian Wet Tropics under base flow conditions. We addressed two particular questions: (i) What is the relative selectivity of species towards streambed composition and water flow velocity? and (ii) Can patterns of microhabitat occupation be explained by differences in intrinsic flow performance among species? To answer these questions, we combined visual field observations of microhabitat use with flow tank assessments of flow speed performance. 3. Tropical freshwater gobies displayed strong specificity towards flow velocities, while being relatively non‐selective towards streambed composition. At opposite extremes of the spectrum, we found Sicyopterus lagocephalus occupying high‐flow (>1.0 ms−1) microhabitats while Redigobius bikolanus selected slower‐flow (<0.05 ms−1) areas. These patterns of microhabitat flow specificity were largely explained by the different abilities of species to swim and/or cling to the substratum under these different flow settings. 4. Our findings confirm suggestions that predictable base flows in tropical streams support habitat specialists, which include one species capable of occupying areas of extremely high flow that very few other fishes can withstand. 5. The functional link between flow and gobioid fish distribution patterns could occur throughout tropical streams of the Indo‐Pacific and Caribbean as a widespread phenomenon that may help inform stream flow management guidelines to maintain this substantial component of tropical freshwater biodiversity around the globe.

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Section: Discussionmentioning

confidence: 99%

Flow velocity underpins microhabitat selection by gobies of the Australian Wet Tropics

2013

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“…The characteristic hydrological seasonality has been proposed as a strong driver of biotic assemblages and ecological processes in rivers and floodplains of Australia’s wet–dry tropics (Douglas et al. , 2005; Leigh & Sheldon, 2008). We hypothesise that four key features of the flow regime underpin the structure and function of these tropical Australian river systems: (i) peak wet season flows and their variability, (ii) the drawdown period of flows and flood residence times during the transition from the wet to the dry season, (iii) the low and disconnected flows during the dry season, and (iv) the initial flushing flows during the transition from the dry to the wet season (Fig.…”

Section: Key Flow Features Underpinning Ecosystem Structure and Procementioning

confidence: 99%

The ‘wet-dry’ in the wet-dry tropics drives river ecosystem structure and processes in northern Australia

et al. 2011

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SUMMARY1. Northern Australia is characterised by a tropical wet-dry climate that regulates the distinctive character of river flow regimes across the region. There is marked hydrological seasonality, with most flow occurring over only a few months of the year during the wet season. Flow is also characterised by high variability between years, and in the degree of flow cessation, or intermittency, over the dry season. 2. At present, the relatively low human population density and demand for water in the region means that most rivers have largely unmodified flow regimes. These rivers therefore provide a good opportunity to understand the role of natural flow variability in river ecosystem structure and processes. 3. This review describes the major flow regime classes characterising northern Australian rivers, from perennial to seasonally intermittent to extremely intermittent, and how these regimes give rise to marked differences in the ecological character of these tropical rivers, particularly their floodplains. 4. We describe the key features of these flow regimes, namely the wet and dry seasons and the transitions between these seasons, and how they regulate the biophysical heterogeneity, primary productivity and movement of biota in Australia's wet-dry tropical rivers. 5. We develop a conceptual model that predicts the likely hydrological and ecological consequences of future increases in water abstraction (e.g. for agriculture), and suggest how such impacts can be managed so that the distinctive ecological character of these rivers is maintained.

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“…Modelling the impact of water-resource development on the hydrology of rivers in Australia's wet-dry tropics, Leigh and Sheldon (2008) suggested that those rivers with a 'dryland' flow signal (high levels of flow variability) were likely to suffer increasing regularity, with a reduced frequency of both low flows and high flows under water-resource development, namely flow abstraction. This reflects the situation in many regulated rivers in the northern Murray-Darling Basin, Australia, which are either highly regulated and no longer experience periods of 'low-flow', and therefore waterhole disconnection, or are subject to extreme levels of water abstraction for irrigated agriculture and therefore greatly reduced connection both spatially and temporally (Kingsford 2000a;Thoms and Sheldon 2000b).…”

Section: Conclusion and Impacts Of Water-resource Development On Refmentioning

confidence: 99%

Ecological roles and threats to aquatic refugia in arid landscapes: dryland river waterholes

Sheldon

Bunn

Hughes

et al. 2010

Mar. Freshwater Res.

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170

138

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Dryland rivers are renowned for their periods of 'boom' related to the episodic floods that extend over vast floodplains and fuel incredible production, and periods of 'bust' where the extensive channel network is restricted to the permanent refugial waterholes. Many of these river systems are unregulated by dams but are under increasing pressure, especially from water abstraction and overland flow interception for agriculture and mining. Although some aquatic organisms with desiccation-resistant life stages can utilise ephemeral floodplain habitats, the larger river waterholes represent the only permanent aquatic habitat during extended periods of low or no flow. These waterholes act as aquatic refugia in an otherwise terrestrial landscape. Variable patterns of connection and disconnection in space and time are a fundamental driver of diversity and function in these dryland river systems, and are vital for dispersal and the maintenance of diverse populations, generate the spatial and temporal variability in assemblage structure for a range of different organisms and fuel the productivity that sustains higher trophic levels. Changes to natural patterns of connection and disconnection of refugial waterholes, owing to water-resource development or climate change, will threaten their persistence and diminish their functional capacity to act as aquatic refugia.

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Hydrological changes and ecological impacts associated with water resource development in large floodplain rivers in the Australian tropics

Cited by 56 publications

References 49 publications

Flow velocity underpins microhabitat selection by gobies of the Australian Wet Tropics

Flow velocity underpins microhabitat selection by gobies of the Australian Wet Tropics

The ‘wet-dry’ in the wet-dry tropics drives river ecosystem structure and processes in northern Australia

Ecological roles and threats to aquatic refugia in arid landscapes: dryland river waterholes

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