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Murray-Darling Freshwater Research CentreMDFRC item.Understanding how floodplain wetland vegetation is influenced by water regimes can inform the management of regulated river systems by targeting appropriate environmental water allocations. In this study, we examined plant community structure in 21 floodplain wetlands adjacent to the Murray River between Hume Reservoir and Tocumwal, south-eastern Australia. Correlations between the water regime of the previous 25 years, and wetland type were investigated. We found the structure of plant communities, as assessed by the richness and percentage cover of plants, to be related to water regime, with clear differences between the communities of wetlands with historical ‘Wet’, ‘Dry’ and ‘Intermediate’ water regimes. Plant community structure was also related to wetland type, with differences being found between the communities of floodplain depressions, flood-runners and cut-off meanders. Managers of riverine/floodplain ecosystems need to consider both wetland type and water regime when planning strategies for the restoration or conservation of floodplain wetland vegetation in regulated river systems.

MDFRC item.Extreme low and high flow periods associated with droughts and floods regularly influence many river system, yet little is known regarding their role in shaping riverine zooplankton communities. This study investigated zooplankton dynamics in response to the transition from drought to flooding in four southern Murray–Darling Basin rivers managed by different levels of flow regulation. Results indicated that the onset of flooding was associated with an increase in the taxon richness and total transport (abundance) of zooplankton in the unregulated Ovens and Kiewa Rivers, and an increase in the total transport of zooplankton in the mildly regulated Broken River. In comparison, no significant flood effects on zooplankton taxon richness or transport were detected in the highly regulated Murray River. This suggests that the flooding was beneficial for enhancing zooplankton abundance in the Ovens, Kiewa and Broken Rivers, whereas any potential benefits were comparatively short-term and/or reduced in the Murray River. We hypothesise that the relatively short-term and/or reduced response of the zooplankton community to the flooding in the Murray River was probably largely due to the occurrence of a hypoxic blackwater event in suppressing zooplankton emergence.

"October 2007".Project Number: Monitoring of Wetlands Disconnection in New South Wales/DD247/M-BUS-247.MDFRC item.Murray-Darling Freshwater Research Centre (MDFRC) was contracted by the Department of Environment and Climate Change (NSW) to undertake an ecological assessment of flora and fauna of Euston Lakes. Euston Lakes have been identified as potential sites for water saving by the Murray Wetland Working Group (MWWG) and NSW Department of Environment and Climate Change (DECC), by either installing temporary regulators or block-banks to prevent the wetlands filling. Prior to works commencing there is a requirement to undertake a Review of Environmental Factors to identify any adverse effects of drying on either water quality or threatened flora and fauna. The four wetlands at Euston Lakes identified for water saving are: This report contains the following information: Flora and fauna assessments (including macrophytes, birds, amphibians and fish), with particular interest in threatened species, populations and/or ecological communities; 7-part test for all threatened species, populations and ecological communities identified; and Site assessment for potential adverse impacts (e.g. potential for acidification) and recommend options to ameliorate potential impacts.

MDFRC item.November 2011. DOI: 10.1111/j.1365-2427.2011.02657.x A publication output from MDFRC project: Impact of sulfidic sediments on the viability of dormant propagules - M/BUS/328.1. The formation of sulfidic sediments in response to factors such as secondary salinisation and fertiliser usage is an emerging concern for the management of many freshwater wetlands. However, fundamental knowledge regarding the influence of sulfidic sediments on the aquatic biota is still lacking. 2. This study investigated the potential for biota to recolonise wetlands affected by sulfidic sediments, by assessing zooplankton hatching and aquatic plant germination following inundation with freshwater. Sediment samples were collected from 16 wetlands in the southern Murray-Darling Basin, Australia, that ranged in condition from non-impacted to possessing a known history of sulfidic sediments and/or acidification. 3. Principal Components Analysis indicated that the wetlands separated out into five different groups based on their sediment chemistry: non-impacted, sulfidic, sulfidic and highly saline (sediment EC 46 800–209 000 μS cm−1), sulfidic and potentially acidic (sediment pH 5.81–6.45 and ANC 0.07–0.31% CaCO3), and sulfidic and acidic (sediment pH 4.37 and ANC 0.00% CaCO3). 4. A viable dormant propagule bank was present in all wetlands, but the taxon richness of zooplankton and aquatic plants was significantly lower in wetlands affected by sulfidic sediments compared with those that were non-affected. 5. This suggests that zooplankton and aquatic plants will be capable of recolonising wetlands that have accumulated sulfidic sediments via their propagule banks if the appropriate remediation measures are undertaken, although the communities developing are likely to be less diverse compared with those in non-affected wetlands.

"June 2009".Project Number: Monitoring of wetlands disconnection in New South Wales: Locks 8 and 9 weir pool manipulation - M/BUS/252.MDFRC item.1 of 2 reports associated with project see (Weir Pool Manipulation (In-channel and wetland effects) - Report on Pre-drawdown Monitoring: Weir Pools & Wetlands).The Murray-Darling Freshwater Research Centre (MDFRC) was engaged by the former Murray-Darling Basin Commission, to undertake ecological monitoring of nine wetlands connected to Locks 8 and 9 weir pools on the Murray River. These two were under consideration to be drawn down as a water saving measure during the drought which would result in disconnection of the wetlands from the Murray River. The aim of the monitoring program was to (i) identifying water quality threats; (ii) monitor the response of fish and macrophytes in response to the disconnection; (iii) assessing the response of tree condition to changing water levels. The MDFRC undertook monitoring of fish, aquatic and riparian vegetation and water quality within the nine wetlands between December 2007 and December 2008. During this period the expected drawdown of the weir pools did not eventuate and disconnection of the wetlands from the Murray River did not occur. This report summarises the data obtained from the monitoring program, however, interpretation of the data needs to consider that only four sampling events occurred within the 12-month period. Conclusive comments on the communities associated within and between wetlands cannot be made given the limited number of sampling events and short time frame, any statistical analysis undertaken would not detect any differences. Any differences observed could be through natural variability due to seasonality or life cycle processes. Key findings from this monitoring are: -Sediment within five of the wetlands had low pH (

"October 2006".Project Number: The exchange of organic material between the Murray River Channel and Barmah Forest during the 2005 floodplain watering - M/BUS/102 AA185.MDFRC item.The release of the 2005/2006 Barmah-Millewa Forest Environmental Water Allocation (513GL) supplemented by natural flows from the Kiewa and Ovens Rivers between October 2005 and March 2006, resulted in peak flows of up to 28 000 ML/day in the Murray at Tocumwal between October 2005 and December 2005. Significant areas of floodplain were inundated. This study quantified the exchange of material between the Barmah-Millewa Forest and the Murray River channel by measuring concentrations of materials in the river sites upstream and downstream of the forest, and their impact on primary and secondary production. It also provided data to refine the Blackwater Model developed for the Barmah-Millewa Forest. Water quality In response to the changes in flow and inundation of the floodplain there were marked changes in water quality parameters at both of the sites downstream of the forests. Total nitrogen, total phosphorus, dissolved organic carbon and electrical conductivity increased in the Murray and Edward Rivers while total suspended solids, particulate organic carbon, dissolved oxygen, pH and chlorophyll a decreased at these sites over the same period. Blackwater modelling The increase in dissolved organic carbon and the decrease in dissolved oxygen were consistent with a blackwater event. The Blackwater Model predicted significant changes in dissolved oxygen and dissolved organic matter associated with the flood. The predicted dissolved oxygen concentrations are higher than those we would expect on the floodplain, based on the concentrations we measured in the rivers at the time of the flood. Both the starting dissolved oxygen and the minimum dissolved oxygen were higher than that measured, reflecting the fact that some reduction in water quality had occurred before the water entered the floodplain, and this is not reflected in the model. The current model uses historical data to predict temperatures and forecast blackwater conditions, but it may be modified so that actual temperatures may be directly entered, potentially reducing some of the variability in the predicted dissolved oxygen concentrations and, linking this model with an appropriate hydrological model would improve its ability predict the impact of blackwater on the rivers. Transfer of materials between the river and the floodplain There was evidence of lateral transfer of materials between the main channel of the river and the floodplain. The heavier suspended particulates remained trapped on the floodplain as the water is dispersed, while soluble nutrients and carbon were rapidly released into the water on the floodplain and flowed back to the river. The abundance of planktonic microinvertebrates declined during the flood but increased rapidly during the falling limb of the hydrograph potentially due to bacterial productivity associated with the dissolved carbon and nutrient pulse. There was no effect on the taxonomic richness of the microinvertebrate communities. All sites were Barmah-Millewa Floodplain Watering 2005/2006 dominated by small taxa (rotifers) characterised by rapid growth and population renewal rates and less likely to be preyed upon by planktivorous fish due to their size compared with the larger microcrustaceans. Flooding and productivity The 2005/2006 allocation of water to the Barmah-Millewa Forest led to a significant exchange of material between the floodplain and main channel that appeared to stimulate production. This highlights the need for consideration of main channel impacts in the allocation of environmental flows to icon sites Two issues will need to be resolved by future monitoring. First, the extent to which the exchange of organic matter, nutrients and organisms between the floodplain varies in response to variations in the flooding regime. Second, the downstream or long term ecological significance of the material returned to the main channel, as it is possible that this material may have an impact on processes such as algal production or initiate a cascade up the food-web.

MDFRC item.June 2012 doi:.Understanding temporal trophic interactions in riverine food webs is essential for predicting river ecosystem function and improving management of these ecosystems. Temporal changes in energy flows through riverine food webs are readily assumed but are rarely tested. Temporal variability in food webs from two reaches of a lowland river (Ovens River, south-eastern Australia) with differing levels of floodplain connectivity were examined over 12 months. We investigated how seasonal changes, flow variability and floodplain connectivity influence (i) stable isotope signatures of basal organic carbon sources (terrestrial sources: trees and grasses; aquatic sources: seston, biofilm and filamentous algae) and consumers (macroinvertebrates and fish) and (ii) the relative proportions of organic carbon sources contributing to consumer biomass using mixing models.We hypothesized (i) that during high flows, increased floodplain connectivity would increase the lateral exchange of terrestrial carbon subsidies to main channel consumers and (ii) that during low flow periods, main channel consumers would derive the majority of their carbon from aquatic benthic sources. Results indicated that isotope signatures for basal sources and for most of the consumers varied temporally and spatially. Mixing models indicated that increased floodplain connectivity did not increase terrestrial subsidies to consumers during high flows. Seston was the primary source during high flows whilst terrestrial vegetation increased in importance during low flows. Filamentous algae was also important during low flows for some consumers. These findings indicate that it is essential to include temporal variability in order to understand energy flows in lowland rivers, thus allowing for the dynamic nature of these ecosystems.

Murray-Darling Freshwater Research CentreMDFRC item.We evaluated a new technique to characterise resting stage zooplankton assemblages in both riverine slackwater habitats and floodplain wetlands, using coconut fibre mats (CFMs). Results obtained using the CFMs were compared with those obtained using the conventional sediment coring technique, over three different mat-setting durations. Presently, there is a paucity of suitable sampling techniques available for characterising resting stage zooplankton assemblages, particularly for assessing resting stage production and/or use in intervention experiments. Results from this study indicate that, for slackwaters and wetlands, the structure and composition of resting stage communities obtained using mats did not differ from that obtained using the sediment coring technique, irrespective of the mat-setting duration. This suggests that the CFM technique can be used as an effective surrogate for the sediment coring technique to characterise resting stage assemblages in slackwaters and floodplain wetlands. In addition, the CFM technique offers the capacity to measure resting stage production over a known time period, and can be used in intervention experiments. Hence, the mats should prove to be useful in a number of settings, ranging from investigative research to management applications.

MDFRC item.1. Salinisation has had a major effect on the diversity of biota associated with freshwater wetlands. However, there is no information available about whether elements of the biotic communities would be able to recover if the concentration of salts within secondarily salinised wetlands was lowered to levels more typical of freshwater wetlands. 2. We tested the hypothesis that dormant eggs of zooplankton are able to persist in wetlands with elevated salinities for extended periods of time by using zooplankton communities that had developed in mesocosms exposed to either salt concentrations of 13 500 mg L-1 or freshwater (

MDFRC item.Competing demands for water have resulted in many wetlands becoming either more permanently flooded or more permanently dry. It has been stated that such changes may lead to a loss of diversity in wetland communities; yet to date, this has not been tested experimentally. In this study, we experimentally test the hypothesis that increasing the hydrologic stability of wetlands results in reduced abundance, richness and diversity of aquatic biota emerging from wetland sediments. Sediment was collected from 19 wetlands that were divided into five groups (permanently flooded and wetlands that had been dry for 2, 7, 11 and 30 years). Aquatic plant communities germinating from the sediment of wetlands that had been permanently inundated and those that had been dry for 30 years had lower species richness and number of individuals than wetlands with intermediate flooding histories. For microfaunal communities, significantly less individuals but more taxa hatched from wetlands that had been permanently flooded or dry for 2 years than the other wetland groups. These results provide evidence of reduced biotic diversity as hydrological stability is increased under the common management scenarios of making wetlands more permanently wet or dry.Funding Information Note: The authors acknowledge the funding and support of Patricia Murray and the Murrumbidgee Catchment Management Authority. This project was funded as part of the Land & Water Australia project NDW32—‘Improving the management of wetlands of the Murrumbidgee River floodplain’.

"March 2008".Project Number: Monitoring of wetlands disconnection in New South Wales: Locks 8 and 9 weir pool manipulation - M/BUS/252.MDFRC item.1 of 2 reports associated with project see (Monitoring of selected wetlands associated with Lock 8 and 9 weir pools on the Murray River).Weir pool drawdowns are one of the ten interventions identified as part of the TLM Intervention Monitoring Assessment Framework. The major impacts of weir pool draw down identified by the IMAF process were effects on aquatic vegetation that were thought to then provide additional habitat and food for invertebrates fish and potentially birds. The weir pool drawdowns provide an opportunity to see if weir pool manipulation can achieve vegetation benefits. If this is found to be the case then future monitoring may be extended to examine the effect on invertebrates, fish or birds. The major risks associated with a weir pool manipulation are in the area of water quality where changes in current speed within the weir pool will lead to the entrainment of sediment and organic matter and lower water levels may lead to inflow of salty groundwater. There is also some risk of acid-sulphate sediments developing as water levels are drawn down. Locks 8 and 9 are under consideration for drawdown and will be monitored for changes to vegetation understorey, water quality, blue-green algae (BGA), and groundwater. Lock 11 is the control weir pool for this project and will have the same parameters measured throughout the duration of the project. The wetlands which are monitored are those associated with Locks 8 and 9. There are four wetlands being monitored for Lock 8 and five for Lock 9. The Great Darling Anabranch is the largest of the wetlands being monitored.

Murray-Darling Freshwater Research CentreMDFRC item.The natural Australian landscape sustains a mosaic of wetlands that range from permanently wet to temporary. This diversity of wetland types and habitats provides for diverse biotic communities, many of which are specific to individual wetlands. This paper explores the prospects for southern Australian wetlands under modified water regime and salinity induced by climatic changes. Extended droughts predicted as a consequence of climate change (lower rainfall and higher temperatures) combined with human-induced changes to the natural hydrological regime will lead to reductions in the amount of water available for environmental and anthropogenic uses. Reduced runoff and river flows may cause the loss of some temporary wetland types that will no longer hold water long enough to support hydric communities. Species distributions will shift and species extinctions may result particularly across fragmented or vulnerable landscapes. Accumulation of salts in wetlands shift species-rich freshwater communities to species-poor salt tolerant communities. Wetlands will differ in ecological response to these changes as the salinity and drying history of each wetland will determine its resilience: in the short term some freshwater communities may recover but they are unlikely to survive and reproduce under long term increased salinity and altered hydrology. In the long term such salinized wetlands with altered hydrology will need to be colonized by salt tolerant species adapted for the new hydrological conditions if they are to persist as functional wetlands. As the landscape becomes more developed, to accommodate the need for water in a warmer drying climate, increasing human intervention will result in a net loss of wetlands and wetland diversity.

"January 2006".Project Number: Environmental Review of the Lower Balonne Floodplain - M/BUS/93.MDFRC item.The Lower Balonne system extends from St George in Queensland to the Barwon River in northern NSW. The Lower Balonne system begins as a single channel of the Balonne River downstream of Beardmore Dam at St George in Queensland and extends to the Barwon River in New South Wales. Water is pumped from the rivers and distributary channels of the Lower Balonne during flood periods and flood overflows are diverted to storage for crop irrigation, mainly cotton. (Cullen et al. 2003). Consequently, modification of the natural flow regimes are likely to impact on the ecological communities of the rivers, floodplains and wetlands of the Lower Balonne system (McCosker 1996). The Queensland Water Resource (Condamine Balonne) Plan 2004 includes a strategy for event-based management to deliver flows to the Lower Balonne floodplain, especially to ensure that adequate flows reach the Ramsar-listed Narran Lake Nature Reserve to meet Australia’s international obligations under the Ramsar Convention. The Water Resource Plan proposes requires a comprehensive review five years after commencement, which must assess the effectiveness of the plan’s performance indicators, including event-based management rules, in delivering the desired outcomes of the plan. This Scoping Study is intended to assist in addressing the water needs of the Lower Balonne Floodplain as well as providing input to the upcoming five-year review. Cullen et al. (2003) identified important ecological assets in the Lower Balonne that need to be managed in terms of water resource planning. These assets are “the biota of the rivers, distributary channels and wetlands of the Lower Balonne, the internationally recognised Narran Lakes, the National Parks of the Culgoa floodplain, and the Darling River itself”. This review excludes examining the knowledge concerning the Narran Lakes as this has previously been reviewed by Thoms et al. (2003) and is currently under an extensive ecosystem study; and the Darling River itself, which is outside the scope of this brief. The floodplains of the Lower Balonne comprise a complex mosaic of vegetation communities. These include important native grassland, shrubland and woodland communities of riparian and floodplain habitats, with the floodplains of the Culgoa, Birrie and Narran rivers supporting the largest area of native grasslands in New South Wales (Dick, 1993). The plant communities in the Lower Balonne are reliant on intermittent flooding for recruitment and survival. Compared with River Red Gums, little data is available on the water requirements of key floodplain vegetation species found on the Lower Balonne floodplain, such as Coolibah, Black Box and Lignum, although the latter is a component of the Narran Lakes Project (Narran Lakes Newsletters http://mooki.canberra.edu.au/narran).Vertebrate fauna surveys of the Coolibah floodplains of the Birrie and Culgoa (NSW reaches) record 19 species of native mammal, 112 birds, 23 reptiles and 6 frogs, while the trees themselves supply a habitat and refuge for a variety of mammals, birds and reptiles (Dick and Andrew 1993). The aquatic invertebrate and fish communities throughout the lowland catchment of the Darling River are considered threatened (NSW Fisheries Management Act 1994). One aquatic invertebrate, four fish and four water bird that have been listed under either federal (EPBC) or NSW legislation as threatened, vulnerable or endangered are recorded within the Lower Balonne system. A large amount of data about the Lower Balonne floodplain has been collected, although some of it is not readily accessible. It also varies widely in both temporal and spatial scales, as well as in quality and purpose of collection. These factors make it difficult to compare and relate the different sets of data in order to draw conclusions about the ecological condition of the Lower Balonne floodplain. There are some different conclusions drawn by the Technical Advisory Panel (TAP) to the WAMP, the Cullen report, and subsequent research regarding the ecological condition of the Lower Balonne system. The TAP report suggests that the biotic communities, particularly fish and invertebrates are moderately degraded in the lower sections of the Balonne systems and indicate that modification of the natural flow regime is a potential cause. The Cullen Report (Cullen et al. 2003) suggests that there is no scientific evidence to indicate that these communities are currently degraded to any extent but have not yet felt the impact of water resource development that occurred in the 1990’s. However, it is clear that flow dependent assets may suffer from the impacts of water resource development. Therefore it is recommended that: 1. All ecological assessments must take on a whole of catchment approach, therefore including the NSW portion of the Lower Balonne system; 2. The NSW portion of the Lower Balonne system must be assessed with the same rigour as QLD portion in terms of the number of sites monitored; 3. There should be an overarching continuity of the ecological assets assessed, even if it is to be divided amongst available expertise of various agencies i.e. riparian vegetation, macrophytes, fish, macroinvertebrates, water birds, frogs, turtles; and 4. Rigorous re-analysis of the annual monitoring data by SKM and EM in terms of indicators used and statistical significances of between-site variations.Defining the environmental water requirements for the Lower Balonne is difficult due to the absence of published scientific work (Cullen et al. 2003) and there is limited specific knowledge of the water requirements of most flood dependent ecosystems and biota. To effectively manage flood dependent ecosystems, we need knowledge of: 1. How flooding and drying influence habitat availability 2. How flooding and drying influence the movement and dispersal of biota (fish, invertebrates, plants) within floodplain ecosystems 3. How flooding and drying trigger recruitment for a suite of biota (i.e. germination of plants) 4. What is the role of flooding and drying in maintaining biodiversity 5. How connectivity between riverine and floodplain environments influences carbon and nutrients dynamics 6. What extent of floodplain needs to be inundated to support viable riparian communities 7. What extent of wetland needs to be inundated to conserve “X” amount of biodiversity 8. What is the cost to the community as a consequence of lost productivity of flood plain ecosystems 9. What are the commence to flow values for flood-dependent wetlands In light of the considerable knowledge gaps and the lengthy time lag before the impacts of changes become apparent, it is critically important that the Precautionary Principle should be followed. There are many contradictions in the interpretation of the limited data available for the Lower Balonne system, with no direct link able to be made between modification to the hydrology due water extraction and water storages and possible degradation of the biotic communities. However both the TAP Report (QLD DNR 2000) and the Cullen Report (Cullen et al. 2003) both stress that if the current level of water extraction continues, in all likelihood there will be substantial impacts on the biota of the channels and floodplains that comprise the Lower Balonne system. It needs to be acknowledged that there will be a considerable time lag between changes in water extraction and biological responses and the impact of current water extraction may not be detectable for many years due to the inherent natural variation in flows (QLD DNR 2000; Cullen et al. 2003).Research and monitoring recommendations Recommendation 1 - A joint taskforce of Qld and NSW natural resource agencies develop a cohesive monitoring program following the approach suggested by Scholz et al. (2005) in designing monitoring programs (Appendix 4). This program would require the full support of state agencies and community groups and developed within an adaptive management framework with clearly stated objectives and testable hypotheses. The monitoring program would eventually be able to describe the current condition and give an assessment of the biodiversity, abundance and community composition of instream and floodplain biota. The information gained from such surveys can then be used by managers to determine the extent of floodplain that needs to be inundated to preserve a proportion of the associated biodiversity (i.e. surveys might indicate that 20% of the floodplain area needs to be inundated for three months to preserve 90% of the current biodiversity). Recommendation 2 - A detail investigation is carried out to determine the watering requirements for Coolibah and Lignum plant communities. This investigation should use a combination of tradition plant survey methods combined with measurements of changes in plant vigour (or health) using remote sensing techniques. Recommendation 3 - A detailed investigation on the rates of sedimentation within the Lower Balonne under different flow regimes be undertaken. There is little knowledge of what the critical ecological processes in riverine and floodplain habitats are or how changes to the flooding regime may affect primary productivity and the exchange of material between components. Over the forthcoming years, the floodplain and riverine environments will experience a range of flood frequencies and intensities in response to increased water extraction and changing climatic conditions. Recommendation 4 - A detailed investigation be undertaken of the role of connectivity between the river channels of the Lower Balonne and associated floodplains and wetlands and three critical metabolic functions (primary production, nutrient cycling and decomposition).The study would examine the response of each component to inundation to deter

"May 2007".Project Number: Ecological Survey and ‘Rapid Assessment’ Surveys for Drought Water Recovery - M/BUS/218.MDFRC item.1 of 2 reports associated with project see (Water Saving Through Wetland Drying: Review of Environmental Factors Back Creek and Tumudgery Creek).Murray-Darling Freshwater Research Centre (MDFRC) was contracted by the New South Wales Department of Natural Resources (DNR) to undertake flora, fauna and site assessments of seven wetlands identified as potential sites for water saving. The study area is in the Lower Murray River Catchment, stretching along the Murray River from below Lake Hume to upstream of the Yarrawonga Weir. This report contains the following information: Flora and fauna assessments (microfauna, macrophytes and birds), with particular interest in threatened species, populations and/or ecological communities; 7-part test for all threatened species, populations and ecological communities identified (including fish); and Site assessment for potential adverse impacts (e.g. potential for acidification) and recommend options to ameliorate potential impacts. Site assessments were undertaken from Monday 8th to Thursday 11th January 2007. The wetlands were assessed by traversing as much of the perimeter as practical, identifying the range of flora and fauna (microfauna, macrophytes and birds) within the study area. The weather conditions experienced during the field investigation were clear skies, temperatures ranging from 28°C to 43°C, with wind conditions ranging from calm to moderate breezes. The seven wetlands assessed were: Wetland Name Identifier*; Cooks Lagoon 8212; Quatt Quatta Lagoon 7413; Barrens Big Lagoon 7410; Chick Logie East Lagoon 7369; Chick Logie Lagoon 7339; Snake Island Lagoon 7312; Croppers Lagoon 7804. *Identifier refers to the Murray Wetlands Working Group’s wetland database. The survey methods employed during these assessments were: Direct observation of any flora or fauna species within or adjacent to the site; Water quality was tested with a Hydrolab, variables measured included water temperature (°C), conductivity (μs/cm), dissolved oxygen (mg/L), pH and turbidity (NTU); Observations were made of the distribution and presence of woody debris (aquatic and riparian zones), which may act as potential habitat for fish, birds and other animals; Diurnal area searches for bird species were employed. This involved visually searching the study sites from multiple locations around each wetland, including both the aquatic and riparian zones. All birds observed (seen or heard) were identified to establish species diversity; Indirect observations of scats and tracks were recorded to identify the presence of animals within the study area; Active search of both the aquatic and riparian zones was conducted to identify plant species and were recorded to establish species diversity; Sediment testing was determined from using Baldwin’s (2006) Decision Support Tool and from previous surveys by Baldwin 2006 and Hall et al 2006; NSW Department of Primary Industries (DPI) surveyed all wetlands for fish; and A desk top study to locate past surveys of these wetlands to identify threatened species in the region.This study by design was a brief and preliminary site assessment. Therefore no trapping, spotlighting or vegetation quadrat sampling techniques were used. Given the timing of the survey, the daily temperatures and due to current drought conditions, it is possible species were overlooked, particularly vegetation which usually flowers in spring and may not be identifiable in the absence of flowers or seeds, also birds who take refuge in vegetation during high temperature days. Data obtained has been used to compile a list of species that could potentially occur in the area. The data obtained from these surveys is not exhaustive in terms of sampling and should be viewed as an indication of species diversity, representing only a small percentage of what the total species pool could be present seasonally or permanently in the study area. The Lower Murray River Catchment, incorporating the natural drainage system of creeks, rivers, associated lagoons, billabongs and lakes below Lake Hume is listed as an endangered aquatic community under NSW legislation, Fisheries Management Act 1994 (FM Act). Listing of this ecological community gives all native fish and invertebrate species within its boundaries the protected status of endangered species, therefore any potential impacts on these communities must be considered during any development process. There is potential for three other endangered ecological communities, as listed under the Threatened Species Conservation Act 1995 (TSC Act) as amended by Threatened Species Legislation Amendment Act 2004 to occur within the region, (i) White Box, Yellow Box, Blakely's Red Gum Woodland; (ii) Inland Grey Box Woodland in the Riverina, NSW South Western Slopes, Cobar Peneplain, Nandewar and Brigalow Belt South Bioregions; and (iii) Myall Woodland in the Darling Riverine Plains, Brigalow Belt South, Cobar Peneplain, Murray-Darling Depression, Riverina and NSW South Western Slopes bioregions. As the proposal is likely to have a significant effect on threatened species, populations or ecological communities, factors covered in the 7-part test in accordance with the Environment Planning and Assessment Act 1979 No. 203 Part 1 Section 5A(2), were considered. All vulnerable and threatened species, populations and communities as listed under the FM Act and TSC Act that were either observed to occur, recorded to previously have occurred or have a former distribution range in the region were included in this test.A range of migratory birds included in the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) are listed under international conventions. Many of these migratory birds are often observed in the vicinity of inland waters within Australia, including the Murray River floodplains. An assessment on the guidelines of significance for these bird species was completed for the following international conventions: Chinese-Australian Migratory Bird Agreement (CAMBA); Japanese-Australian Migratory Bird Agreement (JAMBA); Republic of Korea-Australian Migratory Bird Agreement (ROKAMBA); and Convention on the Conservation of Migratory Species of Wild Animals – Bonn, 1979 (CMS), also known as the Bonn Convention. These agreements state each signatory will strive to protect birds listed, conserving or restoring habitat areas, mitigating obstacles and controlling other factors that might impede migration. As listed under the EPBC Act, two endangered ecological communities potentially occur in the region, the Buloke Woodlands of the Riverina and Murray-Darling Depression Bioregions and White Box-Yellow Box-Blakely's Red Gum Grassy Woodland and Derived Native Grassland. A significant criteria assessment has been completed for these communities in accordance with PART 3, Subdivision C (18) of the EPBC Act. Based on the site assessment and desk top study: The Lower Murray River Catchment, in which all seven wetlands occur, is listed as an endangered ecological community. Modifications to hydrological regimes within these wetlands will lead to changes in the structure of the community and potentially result in the loss of species; Three wetlands were identified to defiantly contain sulfidic sediments, Cooks Lagoon, Quatt Quatta Lagoon and Croppers Lagoon. On drying and re-wetting these lagoons there is a high risk these wetlands will become acidified, cause deoxygenation of the water column and pose aesthetic concerns, resulting in substantial changes to the habitat structure of associated communities. These impacts potentially will degrade habitat areas, resulting in weed invasion by acid tolerant plant species, reducing aquatic food resources, reducing the migration potential of fish and impacting on survival and growth rates of a range of aquatic species and health of surrounding vegetation; Four wetlands were identified to possibly contain sulfidic sediments, Big Barren Lagoon, Chick Logie East Lagoon, Chick Logie Lagoon and Snake Island Lagoon. The rating of possibly is at the lower end of the risk rating matrix for wetlands in relation to sulfidic sediments, although are not identified to be clear or at a low risk. There is still the possibility that these wetlands will become acidified after a drying and re-wetting regime; 11 bird species listed in international conventions either have been observed or potentially use the wetlands while migrating. Each migratory bird species considered have extensive ranges within the region and each species has a wide distribution of potential habitat throughout the region.19 vulnerable bird species and two endangered as listed under the TSC Act either have been observed, potentially use or have former distribution in the habitat areas within these wetlands. Woodland birds can tolerate fluctuating water levels as long as food resources, suitable habitat and alternate water sources are not impacted on; 14 native fish species were recorded to be present during recent surveys. Of these, five are listed as threatened under the FM Act and/or three under the EPBC Act. The proposal has the potential to disturb, remove or modify habitat important to native fish and impact on the movements of native fish, potentially stranding them in the drying wetlands; Two vulnerable plant species have distribution in the region. One of these species habitat is not related to wetlands while the other is dependant on wetlands for all parts of its life cycle; There is potential for the Inland Grey Box Woodland Endangered Ecological Community, Myall Woodland in the Darling Riverine Plains, Brigalow Belt South, Cobar Peneplain, Murray-Darling Depression, Riverina and NSW South Western Slopes bioregions and the White Box, Yellow Box, Blakely’s Red Gum Woodland to occur in

"July 2003".Project Number: AFFA FishRehab Program - Project MD2001.MDFRC item.The aim of this project was to demonstrate whether the re-establishment of submerged macrophytes in lowland rivers would improve the availability of nursery habitat and enhance the food resources to support larval and juvenile fish. The hypothesis to be tested is that the provision of macrophyte beds increases the occurrence of newly hatched fish by improving both food availability and habitat structure. Several specific objectives were identified to address the aim: Measure the change in primary productivity resulting from the installation of artificial macrophytes (AM). Measure the change in zooplankton and macro-invertebrates resulting from the installation of AM. Measure the abundance of larval and juvenile fish with and without AM. Assess if the provision of macrophyte beds increases the occurrence and persistence of larval and juvenile fish. Assess the major food sources used by the larval and juvenile fish during their development phase in the AM. Identify the influence of AM patch size on biological responses.

"September 2009".Project Number: Impacts of land use and water quality on organic matter dynamics and secondary production in floodplain wetlands - M/BUS/260.MDFRC item.The lower Murrumbidgee (lowbidgee) floodplain is a nationally important floodplain system, recognised for important river red gum and lignum vegetation communities, bird breeding events, and important habitat for the endangered southern bell frog. The floodplain has been extensively modified through past and present land use practises (including grazing, cropping and timber harvesting) which have altered flood regimes and vegetation communities. These land use practices may have altered ecosystem functioning and trophic dynamics in floodplain wetlands through changes to the quality and quantity of the organic matter resources forming the basis of the food web. This project aimed to determine how land use on the lowbidgee floodplain has altered trophic dynamics in wetlands through changes in resource quantity and quality. This was done by determining the type and quality of organic matter being incorporated into the wetland food web, using stable isotope and stoichiometric analysis. The results indicated that: wetland food webs on the lowbidgee appear to be influenced by the presence of vegetation on the adjacent floodplain, which provided a source of energy in some wetlands, and macrophyte biomass which provided a substrate for the development of the major food source - biofilm - in one wetland; contrary to other studies, resource quality was not related to nutrient enrichment, indicating that land use activities which alter nutrient dynamics alone may not impact the nutritional requirements of consumers; and land use intensity appears to impact the nutritional value of food sources for particular invertebrate functional feeding groups – for example, the nutritional value of leaf litter to detritivore shredders increased with increasing land use intensity, whereas for other taxa there was no clear relationship between land use and resource nutritional value. The project has assisted the Department of Environment and Climate Change and Water’s, NSW Rivers Environmental Restoration Program (RERP) in the characterisation of lowbidgee wetlands. This will enable the prioritisation of watering for wetlands which provide high quality resources to aquatic consumers and enable better understanding of the impacts of land use on ecosystem functioning so that decisions about watering events on private properties may be done with more confidence of achieving the desired outcomes.

"July 2005".Project Number: The effects of increasing salinity on ecosystem function, resilience and diversity - M/BUS/42; CRCFE Project C240.MDFRC item.The objectives of the project are therefore: To quantify the effect of a gradient of salinity on key biodiversity (microbes, algae, zooplankton and aquatic plants) and ecological processes (microbial activity, algal production and respiration, zooplankton and aquatic plant recruitment) and, To explore the relationships between the function, diversity and resilience of aquatic systems along a gradient of salinity. These objectives will test the following hypothesis A. Community diversity and structure hypotheses Increased salinity: i) changes the species richness and abundance of biotic groups (aquatic plants, microinvertebrate, phytoplankton and microbes) under experimental mesocosm conditions. ii) decreases the numbers and richness of grazers, causing the numbers and richness of algal populations to increase through reduced grazing and increased nutrient availability. B. Functional hypotheses Increased salinity: iii) will promote a decrease in methanogenesis. If this occurs in association with sulfate-containing waters, a shift to sulfate reduction as the terminal anaerobic respiration process will result, leading to changes in phosphorus dynamics. iv) decreases the sediment’s capacity to retain ammonia, but increases mobilization of iron, leading to a decrease in available phosphorus in sediments and overlying water. v) reduces the concentrations of dissolved nutrients so that the relative importance of benthic algae increases over phytoplankton. vi) affects the capacity of algae to take in nutrients, with the impact being dependent on salt concentration, salt composition and relative nutrient concentration. This impacts productivity and community composition. vii) differentially restricts the photobiology of algae causing changes in primary production, system productivity (and community composition). viii) changes the capacity of biotic groups to reproduce. ix) will change recruitment of microinvertebrates and aquatic plants.

"June 1998".Project Number: Effects of water level fluctuations in experimental billabongs, permanent and ephemeral - M/03/5105; LWRRDC R&D Project MDR11.MDFRC item.9 pages.Sixteen artificial billabongs were constructed to permit experiments designed to test the hypothesis that a change in the temporal patterns of inundation affected invertebrate fauna. Results indicate that the response of invertebrate communities to flooding is not effected by the season in which flooding occurs nor are they effected by the duration of the flood. There was, however, a significant effect of flooding on macrophyte assemblages and diversity. Interaction between planktivorous fish and large mobile invertebrate predators appears to cause some displacement of taxa.

"March 2007".Project Number: Ecological Survey and ‘Rapid Assessment’ Surveys for Drought Water Recovery - M/BUS/218.MDFRC item.1 of 2 reports associated with project see (Water Saving Through Wetland Drying: Review of Environmental Factors - Albury to Corowa).Murray-Darling Freshwater Research Centre (MDFRC) was contracted by the Department of Natural Resources (NSW) to undertake flora, fauna and site assessments of two wetlands that had been identified as potential sites for water saving. The study area is in the Lower Murray River Catchment on the Edward-Wakool River system near Deniliquin. This report contains the following information: Flora and fauna assessments (microfauna, macrophytes and birds), with particular interest in threatened species, populations and/or ecological communities; 7-part test for all threatened species, populations and ecological communities identified (including fish); and Site assessment for potential adverse impacts (e.g. potential for acidification) and recommend options to ameliorate potential impacts. A site assessment was undertaken on 6th March 2007 of the two wetlands, Back Creek and Tumudgery Creek. The wetlands were assessed by traversing as much of the perimeter as practical, identifying the range of flora and fauna (microfauna, macrophytes and birds) within the study area. The weather conditions experienced during the field investigation were clear skies, temperature of 30°C and light winds. The survey methods employed during these assessments were: • Direct observation of any flora or fauna species within or adjacent to the site; Water quality was tested with a Hydrolab, variables measured included water temperature (°C), conductivity (µs/cm), dissolved oxygen (mg/L), pH and turbidity (NTU); Observations were made of the distribution and presence of woody debris (aquatic and riparian zones), which may act as potential habitat for fish, birds and other animals; Diurnal area searches for bird species were employed. This involved visually searching the study sites from multiple locations around each wetland, including both the aquatic and riparian zones. All birds observed (seen or heard) were identified to establish species diversity; Indirect observations of scats and tracks were recorded to identify the presence of animals within the study area; Active search of both the aquatic and riparian zones was conducted to identify plant species and were recorded to establish species diversity; Sediment testing was completed using Baldwin’s (2006) Decision Support Tool; NSW Department of Primary Industries (DPI) surveyed both wetlands for fish; and A desk top study to locate past surveys of these wetlands to identify threatened species in the region.This study by design was a brief and preliminary site assessment. Therefore no trapping, spotlighting or vegetation quadrat sampling techniques were used. Given the timing of the survey, early autumn, and due to current drought conditions, it is possible species were overlooked, particularly vegetation which usually flowers in summer or spring and may not be identifiable in the absence of flowers or seeds. Data obtained has been used to compile a list of species that could potentially occur in the area. The data obtained from these surveys is not exhaustive in terms of sampling and should be viewed as an indication of species diversity, representing only a small percentage of what the total species pool could be present seasonally or permanently in the study area. This report has addressed issues with reference to the provisions and requirements of the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act), the New South Wales Fisheries Management Act 1994 (FM Act), the Environment Planning and Assessment Act 1979 (EP&A Act) as amended by the Threatened Species Conservation Act 1995 (TSC Act) and Threatened Species Legislation Amendment Act 2004. Under these Acts various factors need to be considered in deciding whether the proposed actions are likely to have a significant impact on threatened species, populations, ecological communities or their habitat. An assessment of significance, as outlined in the EP&A Act, otherwise known as the 7-part test, is required for all identified threatened species, populations and ecological communities as listed under the FM Act or the TSC Act. Only species listed as threatened under either the FM Act or TSC Act identified within the study region have undertaken further assessment. Other species not listed on these Acts observed or known distribution is within the study area have been included in the report to signify species diversity. A range of migratory birds included in the EBPC Act are listed under international conventions. Many of these are often observed in the vicinity of inland waters within Australia, including the study region. International conventions discussed include: Chinese-Australian Migratory Bird Agreement (CAMBA); Japanese-Australian Migratory Bird Agreement (JAMBA); Republic of Korea-Australian Migratory Bird Agreement (ROKAMBA); and Convention on the Conservation of Migratory Species of Wild Animals – Bonn, 1979 (CMS), also known as the Bonn convention. These agreements state each signatory will strive to protect birds listed, conserving or restoring habitat areas, mitigating obstacles and controlling other factors that might impede migration.Based on the site assessment and desk top study: 15 bird species listed in the international conventions either have been observed or potentially use the wetlands while migrating. Each migratory bird species considered have extensive ranges within the region and each species has a wide distribution of potential habitat throughout the region. Therefore it could be considered no significant area of known habitat for migratory bird species is likely to be removed as a result of the proposed action; Six native fish species were recorded to be present during recent surveys. An additional four native fish species, three threatened and one endangered population, have former distribution within the region; The proposal does have the potential to disturb, remove or modify habitat important to native fish and impact on the movements of native fish. However, due to current drought conditions and as long as both regulators are managed to allow water flow back into the wetland during surplus flows, the direct and indirect impact on the quality of habitat is unlikely to affect the presence of these species in the long term. Short term impacts will see fish species that have not managed to escape the drying wetland to become stranded. As the wetlands are naturally drying, under drought conditions this stranding without barriers potentially would occur naturally; An endangered invertebrate specie has former distribution in the region. This specie with limited dispersal abilities, previously has inhabited river systems as well as irrigation drain pipes in NSW, although was not observed during recent surveys; An endangered amphibian specie has a known distribution in the region. This specie is dependant on both aquatic and terrestrial habitat areas; Distributions of three endangered and 13 vulnerable woodland birds occur within the region and are considered to have an extensive range within the region. Woodland birds can tolerate fluctuating water levels as long as food resources, suitable habitat and alternate water sources are not impacted on; One endangered and four vulnerable waterbirds have distribution within the region.These wetlands are already suffering forms of degradation due to drought conditions. As no known significant habitat areas are present at these wetlands for these waterbirds, it can be considered no known habitat is likely to be removed as a result of the proposed actions, as long as management considers a re-wetting phase when surplus water flows become available; Two vulnerable plant species, both terrestrial forbs, have been recorded in the region. These species habitat is not related to, or dependant on wetlands; Two endangered and one vulnerable mammal species have been recorded in the region. Mammals may be considered dependant on wetlands as they require access to water, none of these threatened mammals recorded in the region spend their entire life cycle in wetland habitats; The lower Murray River in which these two wetlands occur is listed as an endangered ecological community. Modifications to hydrological regimes within these two wetlands will lead to changes in the structure of the community and potentially result in the loss of species. However, this will be balanced by re-instating a wetting cycle when surplus water is available, this may benefit some species; There is potential for the Inland Grey Box Woodland Endangered Ecological Community (final determination under the TSC Act made on 27th April 2007) and the Buloke Woodlands Ecological Community of the Riverina and Murray-Darling Depression Bioregions (EPBC Act) to occur at these wetlands. These communities’ are characterised by a number of plant species and are important habitat areas for many fauna species. Modification to the hydrological regimes within these two wetlands is unlikely to impact on these communities; The landscape surrounding the wetlands is well represented with forests, nature reserves, rivers and creek systems. Due to widespread drought conditions across most of the State, these areas are suffering various forms of degradation. The drying of wetlands during these drought conditions is likely to add further stress to other wetlands, creeks and rivers, through an increase in abundance of species looking for alternative water sources and habitat. • In both wetlands the risk of sulfidic sediments occurring is low. On re-wetting it is unlikely that either wetland will become acidified It is recommended the following points be considered to minimise disturb

Murray-Darling Freshwater Research CentreMDFRC item.Microinvertebrates play a critical role in riverine food webs, and recent studies have hypothesized that slackwaters, non-flowing regions associated with the main channel, are important for their reproduction and recruitment. However, little is known regarding the population and community dynamics of microinvertebrate communities in slackwater regions, or how they compare with those in mid-channel regions. This study examined microinvertebrate communities in the epibenthic and pelagic zones of slackwater and mid-channel regions (i.e. four habitats) of an Australian floodplain river in relation to physico-chemical parameters and food availability (as estimated by chlorophyll-a concentration) between September 2005 and November 2006. Results from this study indicate that microinvertebrate abundance and diversity were greater in slackwater habitats than mid-channel habitats overall, corresponding with the slower current velocities associated with the former. Nevertheless, communities in all four habitats were most abundant and diverse in late spring (coinciding with an increase in water temperature), and followed similar seasonal trajectories in terms of density, taxon richness and community structure. These findings support the view that slackwaters are important for in-channel microinvertebrate production, and suggest that animals frequently disperse (either actively or passively) among slackwater and other main channel regions year round. Given the critical importance of microinvertebrates in riverine food webs, rivers should be managed with a view to maintaining a natural variety of accessible slackwater regions in order to support the production and survival of microinvertebrate communities.

"May 2005".Project Number: Ecological impacts of groundwater disposal to Billabong Creek - M/BUS/69.MDFRC item.Background: A field survey of the general water quality, fish, macroinvertebrates, and aquatic/riparian plants was carried out at three sites on Billabong Creek near Walla Walla on the 13 December 2004. Sampling was completed before 1:00 pm. Site 1: The Walla Walla-Henty road bridge, approximately 1.5 km upstream of the proposed discharge. Site 2: Billabong Creek, where the in-stream discharge is proposed to take place. Site 3: Brooklyn Bridge, approximately 2.5 km downstream of discharge point Site assessment. The electrical conductivity (EC) of the river increased between site 1 (1053 μs/cm), site 2 (1175 μs/cm) and site 3 (1430 μs/cm), presumably as a consequence of the previously-described saline intrusion into the creek at site 2. Electrical conductivity above 1500 EC units have been predicted to have adverse impacts on freshwater aquatic biota. The in-stream temperature of the water was approximately 22ºC. Macroinvertebrates were collected using standard sweep net techniques from all sites and identified to Family taxonomic resolution. Twenty one taxa were collected from site1, 19 from site 2 and 15 from site 3. All taxa collected were typical of lowland rivers in the Murray region. Fish were sampled using a back-pack electrofisher. No fish were caught but European carp were observed. Site 2 is a known popular angling hole for Golden Perch and this species is apparently regularly caught from site 2. Riparian vegetation was dominated by mature red gums with little evidence of regeneration. Patches of Phragmites spp. occurred at all sites. Based on our initial survey and reading of associated literature on Billabong Creek, there is little doubt that Billabong Creek is a degraded waterway. Identifiable risks and potential Impacts There are three immediately identifiable potential impacts of the discharge into Billabong Creek on the associated biota: 1. There is a risk that the discharged waters will raise the ambient temperatures, particularly over winter. This may have a negative impact on the biota immediately downstream of the discharge point. However, any impact would decrease as distance increases downstream and would be expected to be undetectable within a few hundreds of meters. 2. Billabong Creek is a naturally ephemeral system experiencing frequent periods of no or low flows. There is a risk that providing increased and more permanent flows down Billabong Creek would result in the loss of wetting and drying cues that form an important part in triggering aspects of the life cycles of some biota. Ground water removal that is not ultimately returned to the Creek, i.e., the proposed scheme continues no pumped water is returned to the creek, will result in the stream experiencing extended periods of lower base flow (extended dry periods). The latter will have negative impacts on biota. 3. A reduction in salinity will potentially be beneficial to the aquatic biota of Billabong Creek, many of which may currently be near their salt threshold, particularly at site 3. The decrease in salinity is likely to have some, albeit small, benefit to the aquatic biota in Billabong Creek. Concluding remarks: The effects of pumping groundwater will depend on the mechanism used for disposal of the pumped water: 1) If all the pumped water is returned to the creek then organisms requiring wetting/drying cycles will be affected as the dry (or low flow) periods will be diminished. The extent of this effect would be determined by the extent and timing of the flow. 2) If no water is returned to the creek then biota will be subjected to extended periods of low flow or longer periods of dry conditions. 3) Given that Billabong Creek already is currently in a degraded state, in our opinion, the best operation would be to return pumped water to the creek in such a fashion as to promote periods of increased flow, but also to retain periods of low flow. We strongly advise introducing a monitoring programme for stream biota and water quality. Determining the impacts of changes to flow requires compiling a comprehensive data set on the ecology of the system prior to changes as well as continuing sampling after the introduction of flow changes. These monitoring programmes should be designed within an adaptive management framework.

La Trobe University Faculty of Science, Technology and Engineering Murray Darling Freshwater Research CentreMDFRC item.1. The effect of increasing salinity on the emergence of zooplankton eggs and the germination of aquatic plant seeds from the sediment of two wetlands was examined. Salinity was found to cause reductions in species richness and abundance of aquatic plants and zooplankton at salinities between 1000 and 5000 mg L−1. Aquatic plants also had an associated decrease in above ground biomass.2. Individual taxa showed different responses to salinity, and four response patterns were identified: (i) increased number of organisms emerging at 1000 mg L−1; (ii) decreased number of organisms emerging above 1000 mg L−1; (iii) decreased number of organisms emerging between 300 and 1000 mg L−1; (iv) no difference in number of organisms emerging across the range of salinities. Response patterns (iii) and (iv) were common to both plants and zooplankton, whereas response patterns (i) and (ii) were only identified for zooplankton.3. Results indicate that there is potential for the increasing salinity in Australian rivers and wetlands to decrease the species richness of aquatic communities resulting in loss of wetland biodiversity.

MDFRC item.1. Floodplain wetlands are productive components of lowland rivers and are thought to be important habitat and nurseries for many fish species. Fish assemblages inhabiting floodplain wetlands vary considerably through space and time and are largely shaped by wetting ⁄drying cycles, although there is little understanding how many aspects of flooding (e.g. magnitude, timing, duration, frequency) influence the fish assemblages. As a consequence, decisions on flooding of wetlands by managers aimed at restoring native fish assemblages are often based on limited knowledge. 2. This study examined the importance of total duration of flooding on the temporal and spatial dynamics of wetland fish assemblages in the Murray River, in south-eastern Australia. The study examined: (i) how the abundance of 0+ and 1+ fish varied with wetland, season and the duration of wetland filling; (ii) how environmental parameters, including food production changed in relation to the duration of wetland filling; (iii) changes in condition indices for the most abundant species and (iv) changes in species richness and total abundance over time. 3. The 0+ fish assemblage varied more through space and time than the 1+ assemblage. Longer cumulative river–wetland filling was associated with greater total abundances of newly recruited (0+) fish; this was particularly true for common carp (Cyprinus carpio, alien) and carp gudgeon (Hypseleotris spp., native). The body condition of carp gudgeon also increased with the duration of filling, even though static measures of food production declined. The small flooding events that occurred as part of this study did not translate into measurable improvements in the fish assemblage over the longer term (3 years), but did prevent wetlands from drying and thus maintained these habitats as refuges.

"June 2011".Project Number: Part 3 - Natural versus Artificial watering of floodplains and wetlands - M/BUS/248.MDFRC item.1 of 4 reports associated with project see (Ecosystem Services and Productive Base for the Basin Plan), (Clarification of Definitions in the Water Act 2007) and (Feasibility Assessment of Ecological Outcomes (indicators) proposed for the Basin Plan Monitoring and Evaluation Program).At a global scale, society's desire to control water for a range of purposes (e.g. irrigation, industry, stock and domestic supply, flood mitigation) has led to the regulation of a significant proportion of the world's rivers. Alteration of flow regimes is regarded as the most serious and continuing threat to ecological sustainability of rivers and their associated floodplain wetlands. Long-term drying has severely altered the ecology of many freshwater ecosystems, causing unprecedented, long-term or potentially irreversible damage (i.e. species extinctions). It is considered that much of the natural capacity (both resistance and resilience) of aquatic ecosystems to cope with drought has been lost. Re-establishment of natural flow regimes represents a neat theoretical objective. However, the reality is that this is impractical as the demands of society preclude returning our rivers to natural flow. The existing impacts of regulation combined with future impacts of climate change imply that in many river systems, overbank flows may no longer occur frequently enough to maintain ecological processes, and many wetlands and floodplains will become increasingly reliant on targeted environmental water allocations (EWA). New approaches to management will be essential in order to maintain a larger active floodplain than possible under the current water sharing arrangements. However, in order for managers to be successful in achieving the stated ecological objectives of river restoration and ecological management programs, it is necessary to have an appreciation of the role of flow in natural systems and the limitations of methods of delivering EWA. Within this synthesis we: 1. Briefly summarise the role of flow in unregulated floodplain ecosystems; 2. Define key state variables that characterise the flow regime of a floodplain system; 3. Discuss the major types of EWA currently in use; 4. Summarise key ecological processes and the impact of method of EWA delivery; 5. Outline the prevailing management paradigm; and 6. Identify management considerations for progress towards sustainable river systems. Flow is regarded as the key driver regulating processes and diversity in river systems and can be regarded as the master variable. The processes which are influenced by flow and floodplain inundation include hydrodynamics, biogeochemistry and primary productivity. Higher order organisms respond to these habitat and primary productivity drivers. It is not just the presence of water that is important for maintenance of ecosystem function; the provision of water is a critical link in the ecology of wetland and floodplain systems but that does not automatically imply that the link is functional. Flow magnitude, frequency, timing, duration, variability, rate of change and sequence all hold major ecological significance. It is important to note that the quality of water (i.e. chemical and thermal properties) is equally as important as the quantity of water or the temporal patterns of flow. In this context, the method of maintaining inundation (i.e. ponded flood versus flowing flood) and the resultant dilution and downstream dispersal of carbon and nutrients will have a significant impact on water quality via biogeochemically mediated processes. In unmodified catchments natural flooding regimes that are completely unaltered represent the reference condition. However, due to the extent of regulation and development throughout the MDB, there are very few sub-catchments that experience an unimpeded, natural flood. In modified catchments the closest approximation is an uncontrolled flow where the effects of storages and in-stream structures have largely been nullified. River management has skewed river channels and floodplains in opposite directions; towards an anti-drought an engineered drought scenario respectively. Regulated river systems are therefore likely to be in an extreme state of precariousness. Management needs to focus on reinstating resilience as the most pragmatic and effective way of managing ecosystems in order to withstand future droughts and provide ecosystem services. The concept of downsizing rivers has some merit but in reality it is a process of reinstating the small floods that river regulation has removed. It also overlooks the role of the interface between the aquatic (regularly inundated) and terrestrial (never inundated) zones in subsidising terrestrial food webs. Abandonment of large sections of floodplain may create an extremely dysfunctional and potential hostile zone or 'no-man's land' that is neither aquatic or terrestrial, generating a new barrier to energy flux. Enacted as an emergency measure, pumping water to targeted wetlands pumping water into individual sites has been highly successful in achieving a limited set of objectives. There is an emerging risk that construction and operation of new, large infrastructure specifically designed, constructed and operated for environmental outcomes is seen as an alternative to unregulated overbank floods to maintain ecosystems. It is essential to recognise that there there are a number of critical limitations associated with this approach; primarily related to spatial, connectivity and water quality issues. The expectation that fragmented sites will function as refuges that serve as the major sources of propagules and colonists for other areas and lead to improvement of the Murray-Darling Basin is unproven. Furthermore, it is critical to recognise that using a regulator to inundate large floodplains under low flow conditions has not been used as a restoration technique anywhere in the world. Consequently there is no precedence for this management activity and actual responses may differ from those expected. Releases of large volumes of water from storages may lead to the provision of flow-associated cues and conditions otherwise absent during base flows. However, water released from an upstream storage and transferred as an EWA into an individual site during periods of in-channel flow may restrict the ecological outcomes as the productivity gains from upstream flooding are not available to be transported into the managed site. The "missing pieces" are likely to include plant and invertebrate propagules dispersed from upstream sites, increased carbon and nutrient concentrations and other chemical cues resulting from inundation of floodplain soils and plant material, eggs and larvae of fish and other organisms spawned at upstream sites. We propose that there is a hierarchical time scale relationship between inundation events and ecological responses that is associated with all inundations. This relationship can be described as follows; Instantaneous (occur within minutes-hours of inundation), Fast (occur within hours-weeks of inundation), Slow (occur weeks-months after inundation), Delayed (processes that occur within months-years after inundation), and Cumulative (responses that may only occur/be realised after a series of events). We consider that the influence of any EWA delivery method will be related to the rate at which different processes occur. For example, chemically mediated processes occur very quickly (instantaneous) and are therefore unlikely to be affected by the method of delivery of EWA. In contrast, many biogeochemically mediated and biotic processes occur over longer time scales and are more likely to be influenced by the method of EWA delivery. This will be driven by the lag phase in ecological response providing opportunities for differences in responses/processes between natural and managed floods to cascade across multiple levels and manifest into large differences in the quality of outcomes. Methods of delivering environmental water that do not maximise (i) connectivity (i) the provision of appropriate habitat; and (ii) the development of appropriate food resources will deliver minimal benefits and compromise the ability of the EWA to achieve positive ecological outcomes. It must be recognised that the use of EWA's is fundamentally a large-scale manipulative experiment. We currently lack sufficient ecological knowledge to predict how floodplains in different conditions will respond. This represents a major hurdle for managers as volumes of environmental water are limited and resilience is an ecosystem property that can be either created or destroyed. Investment in recovering water and construction of infrastructure for delivery of EWA's needs to be underpinned by investment in research to inform adaptive management to ensure that critical ecological processes and functions are reinstated. If this is not undertaken, there is no way that EWA's will be able to reinstate resilience. The most appropriate method for delivery of an EWA to any site will vary accordingly with a range of factors including but not limited to; availability of water, connectivity of site to water source, and management targets. Environmental water allocations cannot replace the function of natural overbank flows and there is no ‘Silver Bullet' for repairing water-dependant ecosystems deprived of a natural flooding regime. Consequently pragmatic solutions are required to ensure environmental watering at intervals sufficient to enable system preservation and recovery. Reinstating flows and reoperation of existing infrastructure should be actively used during wet and median conditions to build resilience at the system scale. Delivery of EWA to isolated sites should be relegated to use during dry and extreme dry conditions to avoid long-t

"April 2007".Project Number: Develop and submitted a standardised wetland assessment protocol for assessing the suitability of permanent wetlands for disconnection and development of an ongoing monitoring programme for disconnected wetlands - M/BUS/232 XA225.MDFRC item.As agreed by First Ministers, a number of measures including the disconnection of wetlands have been progressively implemented over recent months. Additional wetlands in South Australia and NSW have been identified as having the potential to return relatively high yields in evaporative savings (Murray-Darling Basin, Dry Inflow Contingency Planning Overview Report to First Ministers April 2007). The restoration of the natural wetting and drying regimes is typically expected to improve habitat availability for indigenous flora and fauna. However, within the current management context there are a number of site specific conditions that may expose wetlands to long-term or irreversible damage. These conditions include acidification potential, shallow groundwater, and the role of the wetland as critical drought refugia for threatened or rare species persistence. Both these factors will be considered in the proposed assessment. It is recommended that these wetlands undergo ecological assessment to ensure that long-term or permanent ecological damage will not be sustained, before commencement of construction of works to disconnect them. Sites that are identified as supporting threatened species are likely to require assessments under the Environmental Protection and Biodiversity Conservation Act 1999 (EPBC Act). The States have agreed in MDBC Out-of-Session Resolution 138 that the Environmental Watering Group (EWG) will consider and provide advice to the MDBC on a standardised rapid flora and fauna assessment protocol and an ongoing wetland monitoring programme identifying environmental trigger points to guide the management of the closure and reopening of wetlands. The monitoring program will enable a clear evaluation of both short term and long term impacts of drying on the ecology of the wetland.

MDFRC item.April 2011 DOI: 10.1007/s10750-010-0593-0.Benthic biofilms have been identified using stable isotope analysis (SIA) as an important resource supporting many freshwater food webs. However, biofilm δ¹³C signatures are highly variable in freshwaters, which may hamper our understanding of energy flow through food webs in these systems. There has been little consideration of the influence that substratum may have on biofilm δ¹³C signature variability and energy flows to primary consumers. We investigated the effect of organic and inorganic substrata on biofilm dynamics by examining: (1) temporal variability of biofilm stable isotope (δ¹³C, δ¹⁵N) signatures on allochthonous leaf-litter (Eucalyptus camaldulensis) and cobble substrata over 12 months in a lowland river in south-eastern Australia; and (2) the effect of substrata on biofilm energy flows to a grazer snail, Physa acuta (Gastropoda: Physidae), using SIA and ecological stoichiometry in a laboratory experiment. The temporal study indicated that cobble biofilm varied significantly in δ¹³C signature during the 12 months (up to 11‰), whereas the δ¹³C signature of leaf biofilm was less variable (less than 2‰). In contrast, biofilm δ¹⁵N signatures varied temporally on both cobble (2.6‰) and leaf (1‰) substrata. This suggests that leaf biofilm was more reliant on leaf tissue for carbon and therefore less limited by carbon supply than cobble biofilm whereas for nitrogen biofilm on both substrata was reliant on external sources. In the laboratory experiment, snails fed leaf biofilm reflected more of an allochthonous δ¹³C signature than cobble biofilm fed snails, suggesting assimilation of leaf carbon via the heterotrophic microbial community within the biofilm. Snails grew largest on cobble biofilm, which had lower C:N ratios than leaf biofilm. Our results demonstrate that the type of substratum can influence the temporal variability of biofilm δ¹³C signatures and energy flow to primary consumers.

MDFRC item.February 2011 DOI:10.1007/s10750-010-0525-z.Dormancy may be an important aspect influencing the ecology of riverine microfauna, yet fundamental knowledge concerning riverine egg bank communities is still scant compared with that for communities in floodplain habitats. We investigated the microfaunal egg bank communities in slackwater habitats of an Australian floodplain river, and compared them with the communities occurring in nearby floodplain wetlands. This was achieved by taking replicate sediment cores from paired examples of each habitat and later incubating the resting stages within these sediment cores. Results from the study indicated that the egg bank communities in each habitat differed in both composition and structure, with only 12 of the 31 taxa recorded being common to both habitat types. This suggests that in addition to supporting microfaunal persistence in the main channel, riverine egg bank communities represent an important source of microfaunal diversity together with floodplain egg bank communities in river-floodplain systems.