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Urrbrae, Australia

Ellis I.M.,La Trobe University | Stoessel D.,Arthur Rylah Institute for Environmental Research | Hammer M.P.,Museums and Art Galleries of the Northern Territory | Wedderburn S.D.,University of Adelaide | And 2 more authors.
Marine and Freshwater Research

Approximately 40% of Australian freshwater fish species are of conservation concern, largely because of the impacts of river regulation, habitat fragmentation and alien fishes. Murray hardyhead is a threatened fish endemic to the southern Murray-Darling Basin in Australia, which has declined significantly in range and abundance since European settlement. Conservation of the species has relied largely on environmental watering of off-channel wetlands where isolated populations persist. This became problematic during recent drought (1997-2010) because of competing demands for limited water, and resentment towards environmental watering programs from communities that themselves were subject to reduced water entitlements. In response, emergency conservation measures prioritised the delivery of environmental water to minimise applied volumes. Captive maintenance programs were established for fish rescued from four genetically distinct conservation units, with varying levels of breeding success. Several translocations of wild and captive-bred fish to surrogate refuge sites were also conducted. Future recovery of the species should secure existing natural and stocked populations and translocate fish to additional appropriate sites to spread risk and reinstate natural pathways for dispersal. The approach to the conservation of Murray hardyhead during extreme environmental conditions provides insights to inform the management of fishes in other drought-prone regions of the world. Journal compilation © CSIRO 2013. Source

Molsher R.,Water and Natural Resources | Townsend M.,Deakin University

Environmental volunteering (EV) can provide a unique way to optimise the wellbeing of participants while fostering environmental stewardship. However, the potential of EV to create human health benefits remains an under-researched area. This study provides evidence for improved wellbeing and mood state for 32 participants from diverse backgrounds undertaking EV activities. Most participants also reported improved environmental stewardship with a greatly improved understanding of the environment and the need to conserve it. Other benefits included: 31% of those seeking work obtained it; and 50% joined a volunteer group at program completion. EV provides a unique mechanism to enhance the wellbeing of the participants, while conserving the environment. © 2015 International Association for Ecology and Health Source

Lamontagne S.,CSIRO | Taylor A.R.,CSIRO | Herpich D.,Water and Natural Resources | Hancock G.J.,CSIRO
Journal of Environmental Radioactivity

The Tertiary Limestone Aquifer (TLA) is one of the major regional hydrogeological systems of southern Australia. Submarine groundwater discharge (SGD) of freshwater from the TLA occurs through spring creeks, beach springs and diffusively through beach sands, but the magnitude of the total flux is not known. Here, a range of potential environmental tracers (including temperature, salinity, 222Rn, 223Ra, 224Ra, 226Ra, 228Ra, and 4He) were measured in potential sources of SGD and in seawater along a 45km transect off the coastline to evaluate SGD from the TLA. Whilst most tracers had a distinct signature in the sources of water to the coastline, salinity and the radium quartet had the most distinct SGD signal in seawater. A one-dimensional advection-dispersion model was used to estimate the terrestrial freshwater component of SGD (Qfw) using salinity and the recirculated seawater component (Qrsw) using radium activity in seawater. Qfw was estimated at 1.2-4.6m3s-1, similar in magnitude to previously measured spring creek discharge (~3m3s-1) for the area. This suggests that other terrestrial groundwater discharge processes (beach springs and diffuse discharge through beach sands) were no more than 50% of spring creek discharge. The largest component of total SGD was Qrsw, estimated at 500-1000m3s-1 and possibly greater. The potential for wave, storm, or buoyancy-driven porewater displacement from the seafloor could explain the large recirculation flux for this section of the Southern Ocean Continental Shelf. © 2014. Source

Mutze G.,Biosecurity SA | Cooke B.,University of Canberra | Lethbridge M.,Flinders University | Jennings S.,Water and Natural Resources
Rangeland Journal

European rabbits are severe environmental pests in Australia but reporting of density-damage relationships has been hindered by a lack of simple methods to estimate the density of rabbit populations in native vegetation. A methodology for quantifying rabbit densities suitable for use in sparse populations of rabbits in conjunction with surveys of the condition of native vegetation is proposed. Dung pellets were counted in 11629 regularly-spaced quadrats of 0.1m2 in semiarid, coastal and cool-temperate areas of southern Australia. Mean pellet counts in latrines and the relationship between dung counts outside of latrines and the proportion of quadrats falling on latrines were quantified. This allowed density of dung pellets to be estimated by using a correction factor for latrines instead of attempting to count all pellets within quadrats that included parts of latrines. Rabbit density was calculated from pellet density based on mean pellet size, pellet breakdown rate and estimates of rabbits' dry matter intake and digestive efficiency. Results were validated against estimates of rabbit density from long-term studies using a combination of spotlight transect counts and burrow entrance counts. The proposed methodology allows estimates of rabbit density in native vegetation to be obtained from just a few hours work and can be used in conjunction with surveys of the condition of native vegetation to quantify rabbit impacts. This methodology is seen as particularly useful in providing a tool to allow rabbit densities to be estimated and then compared with the thresholds, determined separately, at which damage occurs for given ecosystems. © Australian Rangeland Society 2014. Source

Liversage K.,Water and Natural Resources
Transactions of the Royal Society of South Australia

Marine-springs containing relic intertidal species can be used to observe how assemblages usually found only on open coasts are structured when free from disturbances associated with water movement. This study tested if two previously described patterns from disturbance-prone boulder habitats occurred within a South Australian marine-spring. I aimed to determine how species are associated with the interface between boulders and the surface of the bottom sediment, a habitat feature suggested to be important for some key benthic invertebrates. Testing species associations to this feature is normally difficult because boulders and sediment are regularly disturbed, but on stable marine-spring boulders, finescale associations of species with this interface could be measured. Also investigated was a previously described negative correlation of peracaridan (Crustacea) densities with boulder size. This could possibly occur due to variability in disturbance related to bouldersize/ stability, in which case the correlation would not be expected in this sheltered lake. Seven rocky-benthic marine species were found. The boulder-sediment interface could be easily located on overturned boulders. An anemone (Isanemonia australis) was highly abundant within 5 mm of this interface, providing evidence of this habitat feature's importance. As found previously, correlations were significant between boulder size and densities of peracaridans (in this case, the isopod Zuzara venosa). This correlation, which has been described widely for similar species, has previously been attributed to disturbance. This study found it occurring in extremely sheltered environments, however, so disturbance is unlikely to be involved. Additional larger-scale comparisons could provide further information about the effects of sheltered/ exposed conditions on these taxa. © 2016 Royal Society of South Australia. Source

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