https://ogma.newcastle.edu.au/vital/access/ /manager/Index en-au 5 https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:48961 Wed 19 Apr 2023 12:34:46 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:28845 litoria aurea, l. castanea, and l. raniformis. there is considerable debate about the role of threatening processes in the decline and uncertainty in how best to develop conservation mitigation strategies for these species. to develop a clear picture of the research priorities necessary to enhance the conservation outcomes for the three species we conducted a literature review to focus on the critical gaps in ecological understanding that prevents consensus, and to set research priorities to address these gaps. Unresolved questions were identified and prioritized, and a set of priority research directions and management actions considered to be integral for the persistence of the species were formulated.]]> Sat 24 Mar 2018 07:33:21 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:29935 Gambusia holbrooki, have been implicated in the decline of amphibians, which suffer high extinction rates globally. Although G. holbrooki is one of the most studied freshwater fish, its diet shows wide geographic variation and its impact on amphibian populations remains unclear. Stable isotopes ¹³C and ¹⁵N were used in 10 urban ponds in Sydney, Australia to compare the diet of G. holbrooki in January, April and May 2013 using a stable isotope mixing model. Gambusia holbrooki was carnivorous and fed on invertebrates (24–39%), tadpoles (25–32%) and conspecifics (20–45%). In contrast to previous studies, primary producers were a negligible part of Gambusia holbrooki diet (<10%). Its diet in late autumn comprised a high proportion of conspecifics (up to 45%) owing to the depletion of other food sources before winter (metamorphosis of larvae). This study provides evidence of high rates of predation on native tadpoles and invertebrates by a highly invasive fish. This knowledge should be incorporated into amphibian releases through head-starting tadpoles or using soft releases where tadpoles are placed in predator-free enclosures until larvae are large enough to avoid predation. Considering the dire conservation status of amphibians globally and the growing interest for invertebrates, it is suggested that stable isotopes are valuable to identify threats from predation in order to target conservation practice toward suitable priorities.]]> Sat 24 Mar 2018 07:31:02 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:29797 Batrachochytrium dendrobatidis, a pathogen that can cause the fatal disease chytridiomycosis. We measured the infection load and observed signs of disease in Litoria aurea. Receiver operating characteristic curves were used to quantify the dissimilarity between the infection loads of L. aurea that showed signs associated with chytridiomycosis and those that did not. Litoria aurea had a 78% probability of developing chytridiomycosis past a threshold of 68 zoospore equivalents (ZE) per swab and chytridiomycosis occurred within a variable range of 0.5–490 ZE. Studies should incorporate a species-specific threshold as a predictor of chytridiomycosis, rather than a binary diagnosis. Measures of susceptibility to chytridiomycosis must account not only for the ability of B. dendrobatidis to increase its abundance on the skin of amphibians but also to determine how each species tolerates these infection loads.]]> Sat 24 Mar 2018 07:30:36 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:30517 Litoria aurea) and the introduced eastern gambusia (Gambusia holbrooki) in Sydney, Australia. From 2003 to 2012 we drained ponds to temporarily remove gambusia and examined the effect of removal on the numbers of male, female, and juvenile frogs, and tadpoles. We found that males preferentially selected fish-free ponds as breeding sites. In addition, the removal of gambusia increased tadpole abundance to over 140 times that of an undrained pond. Pond draining did not influence female or juvenile abundances. The ability to detect and avoid gambusia may be mitigating the effect of predation to a certain extent. We conclude that pond draining to remove exotic fish is an effective strategy that can be used to greatly increase the reproductive success of this and potentially other threatened amphibian species in the presence of exotic predators.]]> Sat 24 Mar 2018 07:25:07 AEDT ]]>