Darren Ryder's research while affiliated with University of Canberra and other places

Publications (75)

Article
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Globally, river regulation has degraded wetlands, including parts of the Murray-Darling Basin (MDB), an ecologically significant basin in Australia. Frogs in a floodplain environment largely depend on habitats created by river flows, but little is known about how frogs in the northern MDB are impacted by river regulation. We tested how wetland inun...
Presentation
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Globally, river regulation has degraded wetlands, and continues to threaten wetland dependent biota including parts of the Murray-Darling Basin (MDB), an ecologically significant drainage basin in Australia. Frogs in floodplain wetlands largely depend on habitats created by river flows but little is known about how frog chorusing activities, a meas...
Article
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Floodplain wetlands play a significant role in the storage of sediment and water and support high levels of nutrient cycling driven by intermittent inundation. In regulated rivers, the frequency and duration of floodplain inundation are often reduced. Managed water inundation is used as a tool to help restore floodplains, but its outcome on wetland...
Preprint
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Floodplain wetlands play a significant role in the storage of sediment and water and support high levels of nutrient cycling that lead to substantial primary production and high biodiversity. This storage, cycling and production system is driven by intermittent inundation. In regulated rivers the link between channel flows and floodplain inundation...
Article
Understanding energy flow through ecosystems and among sub‐habitats is critical for understanding patterns of biodiversity and ecosystem function. It can also be of considerable applied interest in situations where managing for connectivity among habitats is important for restoring degraded ecosystems. Here, we describe patterns of basal resource q...
Article
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Increasing demand for freshwater during the last century has so severely degraded many wetland ecosystems that they are some of the most seriously impacted environments in the world. Environmental flows are used as a management tool to restore parts of the hydrological regime altered by human water use, to rehabilitate these wetlands. Research and...
Article
Adaptive management is central to improving outcomes of environmental water delivery. The Australian Government's Murray−Darling Basin (MDB) Plan 2012 explicitly states that adaptive management should be applied in the planning, prioritisation and use of environmental water. A Long Term Intervention Monitoring (LTIM) program was established in 2014...
Article
Human activities are known to impact the physical template of river channels. These impacts can result from deliberate, direct modifications as well as via indirect processes linked to broadscale landscape change. This study examined changes in the physical template of the Barwon-Darling River, a dryland river in southeastern Australia. Historical...
Article
Aim We tested four hypotheses (a) that pioneer trees at distribution margins would receive fewer visits from pollinators and pollinator parasitoids than would trees in larger, established populations; (b) that predator release (lower rates of pollinator parasitism) would result in higher pollinator reproductive success; (c) that less competition am...
Article
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Floodplain wetlands are some of the most productive ecosystems available to aquatic and terrestrial organisms. However, regulation of lowland rivers can disrupt ecological processes occurring in the river–floodplain ecosystems, and environmental water can be delivered to affected wetlands to maintain productivity. It is not well understood at what...
Article
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The use of freshwater for human consumption and agriculture has resulted in many wetland ecosystems being some of the most seriously impacted ecosystems in the world. In attempts to rehabilitate wetland ecosystems environmental flows are used to restore parts of the hydrological regime altered by human water use. The use of environmental water inte...
Article
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This study investigated how changes in reservoir water level affect mosquito abundance and malaria transmission in Ethiopia. Digital elevation models of three Ethiopian dams at lowland, midland and highland elevations were used to quantify water surface area and wetted shoreline at different reservoir water levels (70, 75, 80, 85, 90, 95 and 100% f...
Article
The Murray–Darling Basin in south‐eastern Australia contains over 70,000 km2 of wetlands and floodplains, many of which are in poor condition. In response, Australian governments have committed to a major restoration program, the Murray–Darling Basin Plan that includes management of 2,750 Gl of environmental water to protect and restore aquatic eco...
Article
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Background A growing body of evidence suggests that dams intensify malaria transmission in sub-Saharan Africa. However, the environmental characteristics underpinning patterns in malaria transmission around dams are poorly understood. This study investigated local-scale environmental and meteorological variables linked to malaria transmission aroun...
Technical Report
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This report is the product of the fourth year of monitoring and evaluation in the Gwydir Valley under the Commonwealth Environmental Water Office’s Long Term Intervention Monitoring (LTIM) Project. The report evaluates the contribution of Commonwealth environmental water to environmental outcomes in 2017-187, complementing the first three years of...
Article
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Background Water level management has been suggested as a potential tool to reduce malaria around large reservoirs. However, no field-based test has been conducted to assess the effect of water level management on mosquito larval abundance in African settings. The objective of the present study is to evaluate the effects of water level drawdown rat...
Technical Report
Full-text available
This report is the product of the third year of monitoring and evaluation in the Gwydir Valley under the Commonwealth Environmental Water Office’s Long Term Intervention Monitoring (LTIM) Project. The report evaluates the contribution of Commonwealth environmental water to environmental outcomes in 2016-17, complementing the first two years of LTIM...
Article
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Background Dams are important to ensure food security and promote economic development in sub-Saharan Africa. However, a poor understanding of the negative public health consequences from issues such as malaria could affect their intended advantages. This study aims to compare the malaria situation across elevation and proximity to dams. Such infor...
Article
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Of all ecosystems, freshwaters support the most dynamic and highly concentrated biodiversity on Earth. These attributes of freshwater biodiversity along with increasing demand for water mean that these systems serve as significant models to understand drivers of global biodiversity change. Freshwater biodiversity changes are often attributed to hyd...
Article
Environmental flows are designed to enhance aquatic ecosystems through a variety of mechanisms however, to date most attention has been paid to the effects on habitat quality and life-history triggers, especially for fish and vegetation. The effects of environmental flows on food webs have so far received little attention, despite food-web thinking...
Article
Estuaries are dynamic systems at the transition between freshwater and marine ecosystems. In this study, a spatially and temporally explicit Bayesian network (BN) was developed for a tidally connected estuary in southeastern Australia. The BN provides an environmental risk assessment (ERA) for the probability of a shift to a eutrophied state based...
Conference Paper
It is critical that the ecological outcomes of environmental watering events are detected, monitored and reported on for both the restoration of freshwater systems and auditing the use of water resources. Biomonitoring of river and wetland systems underpins most water resource management and has received significant funds and research effort during...
Article
Bayesian Belief Networks (BBNs) are being increasingly used to develop a range of predictive models and risk assessments for ecological systems. Ecological BBNs can be applied to complex catchment and water quality issues, integrating multiple spatial and temporal variables within social, economic and environmental decision making processes. This p...
Article
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The construction of dams in sub-Saharan Africa is pivotal for food security and alleviating poverty in the region. However, the unintended adverse public health implications of extending the spatial distribution of water infrastructure are poorly documented and may minimize the intended benefits of securing water supplies. This paper reviews existi...
Article
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Floodplain wetlands in semi-arid regions have intricate channel-floodplain networks with highly variable and unpredictable wet and dry phases related to changes in hydrology and geomorphology. We tested the hypothesis that the presence of different hydro-geomorphic habitats in those systems drives structural and functional differences in aquatic co...
Article
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Key to Bhutan's economic development strategy is the expansion of the country's hydropower projects, which requires the construction of a number of large dams. As dams affect the natural hydrological regime of rivers, the objective of this study was to assess these impacts on water quality and macroinvertebrate communities. Baseline physical and ch...
Article
A previous water quality risk assessment of source water supply reservoirs in subtropical southeast Queensland (Australia) evaluated little black cormorants (Phalocrocorax sulcirostris) roosting on intake infrastructure as potentially posing an extreme risk of microbial contamination through direct deposition of fecal matter to the aquatic environm...
Article
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Studies on freshwater invertebrate fauna on islands are rare but a few suggest species richness can be high. A survey of the freshwater invertebrates of Lord Howe Island (LHI) yielded 38 taxa, bringing the total recorded from LHI to 54. The majority of the taxa from the survey were from the Insecta, with 15 Diptera (true flies), five hemipterans (t...
Article
We examined the effects of grazing exclusion over a period of 14 years on the species richness and community composition of three plant communities with different dominant species and water regimes in the Gwydir Wetlands in eastern Australia. Responses to grazing exclusion varied among the three plant communities, and were most likely to be evident...
Article
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Suspended sediments in fluvial systems originate from a myriad of diffuse and point sources, with the relative contribution from each source varying over time and space. The process of sediment fingerprinting focuses on developing methods that enable discrete sediment sources to be identified from a composite sample of suspended material. This revi...
Article
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Gross primary productivity (GPP) of phytoplankton and planktonic respiration (PR) (i.e., planktonic metabolism) are critical pathways for carbon transformation in many aquatic ecosystems. In inland floodplain wetlands with variable inundation regimes, quantitative measurements of GPP and PR are rare and their relationships with wetland environmenta...
Article
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Environmental flow rules are developed to provide a flow regime necessary to maintain healthy river and floodplain ecosystems in rivers regulated for human uses. However, few studies have experimentally assessed potential ecological mechanisms causing declines in the health and productivity of freshwater fish assemblages in regulated rivers to info...
Article
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The decomposition of Eucalyptus viminalis leaves was examined over 8 weeks in 3 streams, each with two sites, in New South Wales, Australia. Invertebrate colonization of litter bags was negligible. Recovered leaves were aerated to induce sporulation by aquatic hyphomycetes. Conidial numbers generally started to increase after 28 days of stream expo...
Article
Dominance of invasive species is often assumed to be due to a superior ability to acquire resources. However, dominance in plant communities can arise through multiple interacting mechanisms, including disturbance. Inter-specific competition can be strongly affected by abiotic conditions, which can determine the outcome of competitive interactions....
Article
A field survey was conducted during flow pulses to investigate the longitudinal spatial patterns in water quality, dissolved inorganic and organic matter, phytoplankton, planktonic bacteria, zooplankton, gross primary productivity (GPP) of phytoplankton and planktonic respiration (PR) in channels of the large floodplain system (∼124 km in length) o...
Article
Regulated flow releases are key components in the ecological restoration of river ecosystems. Understanding relationships among hydrology, habitat inundation, and ecological processes at appropriate spatial scales is required to optimise ecological outcomes. This study used high-resolution remotely sensed data to develop a three-dimensional (3D) ch...
Article
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Many river restoration projects fail. Inadequate project planning underpins many of the reasons given for failure (such as setting overly ambitious goals; selecting inappropriate sites and techniques; losing stakeholder motivation; and neglecting to monitor, assess, and document projects). Another major problem is the lack of an agreed guiding imag...
Article
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Integrative research has been the dominant theme in this Special Issue, demonstrated by contemporary examples of effective collaborations and solutions for the successful engagement of scientists in the policy and management arena. Evident in these papers is the increasing use of the term 'best available science' (BAS) as a basis for well-informed...
Data
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Executive Summary During 1997-99 the (then) Murray-Darling Basin Commission (MDBC) undertook a review of the operation of Hume and Dartmouth Dams, establishing an independent stakeholder Reference Panel to assist with this task. Their aim was to consider how the operating rules might be amended to better address the competing objectives of water s...
Book
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http://www.nwc.gov.au/__data/assets/pdf_file/0015/10437/waterlines_16_pulsed_Flows_full_version.pdf
Article
Floodplain wetlands in arid and tropical environments are intermittently or seasonally flooded, drying for months and up to years in arid wetlands between floods. Aquatic food webs in these systems are adapted to this variable water regime; pulsing in productivity and diversity after floods, yet dependent on nutrients generated during dry cycles. I...
Chapter
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In this chapter we reflect on a relatively small but influential example of adaptive management which seeks to enhance the environmental benefits of the flow re-gime in the highly regulated Mitta Mitta River in Australia‟s Murray-Darling Ba-sin. In 1999 an operational review recommended the reintroduction of greater in-stream flow variability in th...
Article
Environmental flows were released to the Macquarie Marshes (~210,000ha) in north-west NSW of Australia between October and December 2005, inundating an estimated 24,600ha of floodplain area. According to the flood pulse concept, the marsh floodplains would have stored large amounts of nutrients and carbon during dry antecedent conditions, which wou...
Article
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Models of carbon transport are an important mechanism for conceptualizing and assessing the significance of matter and energy sources in streams. The development of a fingerprinting technique that identifies the origins of dissolved organic carbon (DOC) would be invaluable for the development of more sophisticated carbon budget models and improving...
Article
Scour is one of the most important regulators of biofilm structure and function, especially in floodplain rivers where low gradients and flood frequencies limit potential for scouring. In this study, we experimentally examined the effects of flow velocity on the biomass and taxonomic composition of epixylic biofilms from floodplain reaches of the M...
Article
Successful stream restoration requires the setting of appropriate goals and an ability to measure restoration success using quantitative ecological indicators. At present, a dichotomy exists between the setting of restoration goals to enhance ecosystem ‘processes’ or ‘functions’ such as sustainability, and measuring the success of these goals using...
Article
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Wetlands in arid and semi-arid areas face intensifying pressure for their water resources yet harbour unique biota and ecological processes that rely on the “boom and bust” regime of alternating flood and drought. Recent research in Australia has revealed that models of ecosystem processes derived from northern temperate zone wetlands are often ina...
Article
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In this study we have used stable isotope analysis to identify major food resources driving food webs in commercial rice agroecosystems and to examine the effects of agricultural management practices on the trophic structure of these food webs. Potential carbon sources and aquatic macroinvertebrate consumers were collected from large-scale rice far...
Article
Managed flow releases can influence biomass and productivity of littoral biofilms in regulated lowland rivers by varying the frequency and duration of inundation and desiccation. I examined the effects of inchannel water level variability on the productivity of littoral biofilms growing on woody substrata in the highly regulated Murrumbidgee River,...
Article
Summary Biological indicators have been widely used in Australian riverine systems to assess the effectiveness of past and current management. The short generation time, sessile nature, responsiveness to environmental conditions and the availability of sound, quantitative methodologies make biofilms suitable as a monitoring tool in these systems. T...
Article
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A well-designed monitoring program is critical for determining the extent of human impacts and the effectiveness of restoration activities in aquatic ecosystems. This project considers the Nymboida River, northern NSW, as a case study for developing a biological monitoring program. Water extraction from the Nymboida weir pool alters the flow regime...

Citations

... The resulting detritus appears to provide an abundant and productive food resource for consumers (McInerney et al., 2017). Such observations are at odds with our understanding of the nutritional value of detritus, which is characterised by what is thought to be a low-quality FA profile; lack of LC-PUFAS and dominance of saturated FAs indicative of heterotrophic decomposers (e.g., 10:0, 15:0, 17:0 and their branched iso and anteiso-homologues, McInerney et al., 2020). ...
... Characterising the diet of many aquatic consumers is problematic owing to the difficulty of identifying diverse, partially-digested taxa, and differential digestion rates among prey can lead to biased inferences about the relative importance of different prey to a consumer (e.g., Amundsen & Sánchez-Hernández, 2019). Modification of rivers also can transform the nutritional composition of resources at the base of freshwater food webs by altering the composition of organic material, associated microorganisms, and primary consumers (e.g., Atkinson et al., 2009;Dwyer et al., 2018;Growns et al., 2020). However, the consequences of nutritional transformations to consumer performance remain poorly understood (e.g., Dwyer et al., 2020;Ruess & Müller-Navarra, 2019). ...
... There remain critical knowledge gaps that are limiting the ability to adapt environmental water management to a non stationary future (Capon et al., 2018). An encouraging start to closing the knowledge gap is the monitoring of environmental water outcomes and adaptive management that is currently occurring in south east Australia (Watts et al., 2020). However, the lack of future hydrologic modelling and vulnerability assessments that can help determine the ability of a species or ecosystem to withstand, or how it may change, in response to a changing climate and more frequent extreme events is greatly lacking. ...
... Regarding biodiversity, the hypothesis is to find an increase in abundance and diversity at low trophic levels (Figure 1) under a fluctuating water level. This hypothesis is based on an expected increase in overall productivity of the system under a fluctuating water level (Bayley, 1991;Growns et al., 2020), and on other studies concluding that temporary drawdown events have a positive effect in the subsequent years on the diversity and richness of water macrofauna (Van de Meutter et al., 2006), zooplankton (Arnott & Yan, 2002) and birds and macrophytes (Hanson & Butler, 1994). ...
... A waterhole is a landform in which water is of better quality, greater abundance, or easier access than other local landforms. Drylands waterholes preserve water after flow ceases, and their distribution and qualities are ecologically, commercially and culturally important (Duguid et al., 2005;Fensham et al., 2011;Pearson et al., 2020;Silcock, 2009). To sustain life between flow events, a refuge waterhole must hold more water than it will lose through evaporation or seepage. ...
... This provides an incomplete picture since dispersal barriers, as well as different local biotic communities and climate, may influence the insect communities associated with widespread plant species. Similarly, many plants can also occur across environmental gradients, over either long or short physical distances, which may also influence the insect communities that they host (Andrew & Hughes, 2005;Mackay et al., 2020). Studies along climatic gradients can also provide a 'space-for-time' substitution to exploring the likely effects of climate change on communities (Hodkinson, 2005). ...
... This could be a mechanism adopted by the vector population to evade indoor intervention (LLINs and IRS) (Thomsen et al., 2016b). Anopheles pharoensis, the less important vector however, showed consistently outdoor feeding behavior as it has been documented in other studies (Lelisa et al., 2017;Kibret et al., 2019;Degefa et al., 2021). ...
... This suggests that environmental flows also can enhance longitudinal connectivity, enabling movements for foraging and retreat to refuge pools. However, it is often difficult to discern whether movements made by individuals or populations are a response to actively managed environmental flows with the intention of eliciting ecological responses, flows released for other purposes such as agricultural irrigation, or natural flows (Gawne et al., 2020;Poff et al., 2017). It is even more difficult to determine the ecological benefits that may result from such movement responses, such as increased access to high-quality habitat (e.g., for feeding, spawning and/or rearing), or increased recruitment success. ...
... These figures decreased during the low transmission season, with 41.3%, 34.4%, 11.5%, and 7.8%, in Navrongo (Ghana), Mali, Benin, and The Gambia, respectively [20]. This variation of malaria prevalence across different settings is likely related to differences in malaria transmission intensity, malaria prevention measures used and coverage, and environmental patterns [21][22][23][24]. This variation could also be related to the variation of protective immunity levels according to the geographic area and the number of pregnancies of the woman [25][26][27]. ...