Aquasave Nature Glenelg Trust

Mount Gambier, Australia

Aquasave Nature Glenelg Trust

Mount Gambier, Australia
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Whiterod N.S.,Aquasave Nature Glenelg Trust | Zukowski S.,Aquasave Nature Glenelg Trust | Asmus M.,Australian Department of Primary Industries and Fisheries | Gilligan D.,Australian Department of Primary Industries and Fisheries | And 2 more authors.
Marine and Freshwater Research | Year: 2017

Understanding dispersal traits and adaptive potential is critically important when assessing the vulnerability of freshwater species in highly modified ecosystems. The present study investigates the population genetic structure of the Murray crayfish Euastacus armatus in the southern Murray-Darling Basin. This species has suffered significant population declines in sections of the Murray River in recent years, prompting the need for information on natural recruitment processes to help guide conservation. We assessed allele frequencies from 10 polymorphic microsatellite loci across 20 sites encompassing the majority of the species' range. Low levels of gene flow were observed throughout hydrologically connected waterways, but significant spatial autocorrelation and low migration rate estimates reflect local genetic structuring and dispersal limitations, with home ranges limited to distances ,50-km. Significant genetic differentiation of headwater populations upstream of barriers imposed by impoundments were also observed; however, population simulations demonstrate that these patterns likely reflect historical limitations to gene flow rather than contemporary anthropogenic impacts. Dispersal limitations, coupled with its biological traits, suggest that local populations are vulnerable to environmental disturbance with limited potential for natural recolonisation following population decline. We discuss the implications of these findings in the context of managing the recovery of the species. Journal compilation. © CSIRO 2017.

Hammer M.P.,Museum and Art Gallery of the Northern Territory | Hammer M.P.,South Australian Museum | Hammer M.P.,University of Adelaide | Goodman T.S.,Aquasave Nature Glenelg Trust | And 8 more authors.
Biological Conservation | Year: 2015

There are high rates of regional and global extinctions among freshwater species and few chances for recovery. We report here on the rediscovery after 30. years of a small fish, the southern-purple spotted gudgeon (Mogurnda adspersa), once widespread in the southern Murray-Darling Basin of south-eastern Australia. The rediscovery was in a region, the Lower Murray, where temperate riverine and wetland habitats are modified by a broad spectrum of changes including intensive flow regulation and diversions. There was some doubt whether the rediscovered population was a true remnant or a recent introduction, particularly as there was a translocated population in a nearby artificial habitat. Fortunately, a non-government organisation acted to rescue into captivity about 50 specimens as the remaining wetland habitat dried completely, soon after rediscovery, as a consequence of a decade-long drought and water diversions. We describe the habitat and ecology of fish in the rediscovery site, and provide genetic data, both nuclear (50 allozyme loci) and mtDNA (1141 base pairs; two genes), to show that they were true remnants of the regional native population. This information allows clear planning for future recovery including reintroductions, and is a case study that provides strategies, and hope, for conservation and management concerning other modified habitats. Specifically, it highlights the need for a rapid response to conserve threatened species, the recognition of remnant natural values in altered environments, and the treatment of new finds as native until there is alternate evidence. © 2015 Elsevier Ltd.

Zukowski S.,Charles Sturt University | Whiterod N.S.,Aquasave Nature Glenelg Trust | Watts R.J.,Charles Sturt University
Freshwater Crayfish | Year: 2013

The implementation of fishing regulations becomes increasingly complex where the natural state of fisheries resources is unknown. Comparing populations in fished and non-fished areas can provide information that is vital for the management and protection of species. We conducted field surveys of Euastacus armatus in non-fished and fished reservoirs and provide comparisons with a heavily fished area of the River Murray. The non-fished population (Talbingo Reservoir) of E. armatus exhibited almost equal sex ratios, robust normally-distributed population structure and a high proportion of mature and berried females. The parameters defining two fished populations (Blowering Reservoir and the River Murray) deviated significantly, to varying degrees, from the benchmark population (Talbingo). These differences suggest that recreational fishing may impose a considerable impact on the population parameters of E. armatus. Comparison with the benchmark defined in the present study will allow tracking of the population recovery under the new fishing regulations for E. armatus in the southern Murray-Darling Basin. Copyright ©2013 International Association of Astacology.

Miller A.D.,University of Melbourne | Sweeney O.F.,Water and Natural Resources | Whiterod N.S.,Aquasave Nature Glenelg Trust | Van Rooyen A.R.,Cesar | And 2 more authors.
Endangered Species Research | Year: 2014

The Glenelg spiny freshwater crayfish Euastacus bispinosus is a large endangered freshwater invertebrate of southeastern Australia that has suffered major population declines over the last century. Disjunct populations in the state of South Australia are in a particularly critical condition, restricted to a few isolated rising-spring habitats and in an ongoing state of decline. We assessed genetic diversity and gene flow within E. bispinosus across its current range using allele frequencies from 11 nuclear microsatellite loci and DNA sequence data from a single mitochon -drial locus (cytochrome oxidase subunit I). Populations were characterized by low levels of genetic diversity and found to be highly structured, with gene flow restricted both within and across catchments, highlighting the species' vulnerability to further habitat fragmentation and the importance of managing environmental threats on local scales across its current natural range. South Australian populations were characterized by critically low levels of genetic diversity generally, highlighting their potential vulnerability to localized extinction. Holistic conservation efforts are necessary to conserve populations, including local habitat management and, potentially, translocations to increase genetic diversity and evolutionary potential, and reduce possible inbreeding effects and the threat of extinction. © Inter-Research 2014.

Hammer M.P.,Museum and Art Gallery of the Northern Territory | Bice C.M.,SARDI Aquatic Sciences Center | Hall A.,Khan Research Laboratories | Frears A.,Khan Research Laboratories | And 5 more authors.
Marine and Freshwater Research | Year: 2013

The lower reaches of the expansive Murray-Darling Basin, Australia, are a hotspot for freshwater biodiversity. The regional ecosystem, however, has been significantly altered by river regulation, including local and catchment-wide water abstraction. Freshwater fishes have suffered from the resultant altered flow regime, together with other threats including habitat degradation and alien species. Impacts reached a critical point (imminent species extinction) during a prolonged drought (1997-2010) that lead to broad-scale habitat loss and drying of refuges during 2007-2010, and urgent conservation measures were subsequently instigated for five threatened small-bodied fish species. A critical response phase included ad hoc interventions that were later incorporated within a broader, coordinated multi-agency program (i.e. the Drought Action Plan and Critical Fish Habitat projects). On-ground actions included local translocation, alien species control, in situ habitat maintenance (e.g. earthworks, environmental water delivery), fish rescues, artificial refuge establishment and captive breeding. Improved river flows signalled an initial phase of recovery in 2011-2012 that included reintroductions. The present paper aims to document the actions undertaken in the Lower Murray, and review successes and lessons from practical examples that will help guide and inform management responses to conserve fish in modified systems subjected to severe water decline. Journal compilation © CSIRO 2013.

Miller A.D.,cesar 293 Royal Parade | Miller A.D.,University of Melbourne | Van Rooyen A.,cesar 293 Royal Parade | Sweeney O.F.,Water and Natural Resources | And 3 more authors.
Molecular Biology Reports | Year: 2013

The Glenelg spiny crayfish, Euastacus bispinosus, is an iconic freshwater invertebrate of south eastern Australia and listed as 'endangered' under the Environment Protection and Biodiversity Conservation Act 1999, and 'vulnerable' under the International Union for Conservation of Nature's Red List. The species has suffered major population declines as a result of over-fishing, low environmental flows, the introduction of invasive fish species and habitat degradation. In order to develop an effective conservation strategy, patterns of gene flow, genetic structure and genetic diversity across the species distribution need to be clearly understood. In this study we develop a suite of polymorphic microsatellite markers by next generation sequencing. A total of 15 polymorphic loci were identified and 10 characterized using 22 individuals from the lower Glenelg River. We observed low to moderate genetic variation across most loci (mean number of alleles per locus = 2.80; mean expected heterozygosity = 0.36) with no evidence of individual loci deviating significantly from Hardy-Weinberg equilibrium. Marker independence was confirmed with tests for linkage disequilibrium, and analyses indicated no evidence of null alleles across loci. Individuals from two additional sites (Crawford River, Victoria; Ewens Ponds Conservation Park, South Australia) were genotyped at all 10 loci and a preliminary investigation of genetic diversity and population structure was undertaken. Analyses indicate high levels of genetic differentiation among sample locations (F ST = 0.49), while the Ewens Ponds population is genetically homogeneous, indicating a likely small founder group and ongoing inbreeding. Management actions will be needed to restore genetic diversity in this and possibly other at risk populations. These markers will provide a valuable resource for future population genetic assessments so that an effective framework can be developed for implementing conservation strategies for E. bispinosus. © 2013 Springer Science+Business Media Dordrecht.

Whiterod N.S.,Aquasave Nature Glenelg Trust | Sweeney O.F.,Water and Natural Resources | Hammer M.P.,Aquasave Nature Glenelg Trust
Aquatic Conservation: Marine and Freshwater Ecosystems | Year: 2015

Many species of freshwater crayfish of the endemic Australian genus Euastacus are threatened with extinction. Routine monitoring of most Euastacus species is minimal, and a subsequent lack of information has hampered prioritization of conservation and management efforts. The present study investigated population parameters and temporal changes in abundance in a disjunct population of Euastacus bispinosus. This occurs at the western extent of the range of the species in the state of South Australia (SA) and inhabits a groundwater-dependent karst habitat distinct from the larger population in the Victorian Glenelg basin. Euastacus bispinosus was recorded at sites within seven karst rising-springs as well as two isolated locations (sinkhole and cave), which expanded the extent of occurrence of the species in SA, but the area of occupancy remains limited. Most subpopulations contained low numbers, had little or no signs of recruitment, were dominated by large crayfish, and demonstrated a high incidence of gonopore aberrations. Declines in abundance were observed across these subpopulations between 2006 and 2011, although these declines were not statistically significant. Of critical importance to the conservation of the species in SA is ensuring that groundwater discharge is maintained in karst rising-springs, hydrological connectivity is enhanced between subpopulations and degradation within habitats is reversed. Further monitoring and research is necessary to gain a clear understanding of the status of subpopulations of the species over time. © 2015 John Wiley & Sons, Ltd.

Whiterod N.S.,Aquasave Nature Glenelg Trust | Hammer M.P.,Aquasave Nature Glenelg Trust | Vilizzi L.,Mula Sitki Kocman University
Fundamental and Applied Limnology | Year: 2015

Temporary streams naturally experience flow intermittence and hydrologic discontinuity that act to shape fish community structure. Yet, alteration of the flow regime of temporary rivers may lessen the resilience of fish communities to tolerate hydrologic change imposed by droughts. This long-term study (2001-2013) predicted spatial structuring (across catchments and amongst reaches) in fish community composition and abundance across a hydrologically-altered Mediterranean-type region dominated by temporary streams. Shifts from freshwater specialist and diadromous species to more generalist and tolerant species (i.e.freshwater generalist, aliens and estuarine species) were anticipated as the region experienced low flows (2001-2006) and critical water shortage (2007-2010) associated with a most severe drought. It was anticipated that changes in composition and abundance would be revealed during flood (2011) and post-flood (2012-2013) periods after the drought. Contrary to these predictions, fish community structure was broadly consistent across catchments, despite varying climatic and hydrologic (mainly, flow intermittence) regimes. As expected, significant spatial variability was revealed at the reach scale, with significant differences between upper reaches and terminal wetlands, and with a clear transition in fish community structure between these reach types. Significant temporal variability was also revealed with the reduced abundance of diadromous species (although Pseudaphritis urvillii did increase) and increases in the abundance of aliens and surprisingly freshwater specialists over the period of critical water shortage relative to antecedent low flows. This was followed by mixed reach-dependent responses of fish during the flood and post-flood periods. The differential responses of fish communities across reaches and temporal periods must be considered as part of the management of threatened species in hydrologically-altered regions dominated by temporary streams. © 2015 E. Schweizerbart'sche Verlagsbuchhandlung, Stuttgart, Germany.

Ellis I.,La Trobe University | Whiterod N.,Aquasave Nature Glenelg Trust | Linklater D.,La Trobe University | Bogenhuber D.,La Trobe University | And 2 more authors.
Austral Ecology | Year: 2015

The spangled perch Leiopotherapon unicolor is considered a rare vagrant in the southern Murray-Darling Basin, Australia, due to its intolerance of the relatively cool water temperatures that prevail during winter months. This study details 1342 records of the species from 68 locations between 2010 and 2014 outside its accepted 'core adult range' following widespread flooding during 2010 and 2011. Although records of the species declined over 2013, L.unicolor remained resident in the southern Murray-Darling Basin as of April 2014. The species persisted in several locations for three consecutive winters with recruitment documented at two sites. This study represents the first identification of the dispersal of large numbers of L.unicolor into the southern Murray-Darling Basin, persistence beyond a single winter, and recruitment by the species in habitats south of its recognized 'core adult range'. Targeted research would determine the potential for predicted environmental changes (artificially warmer drainage wetlands, climate change and greater floodplain connectivity) to facilitate longer term persistence and range expansion by the species in the southern Murray-Darling Basin. © 2015 Ecological Society of Australia.

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