https://nova.newcastle.edu.au/vital/access/ /manager/Index ${session.getAttribute("locale")} 5 https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:51257 Wed 30 Aug 2023 10:09:20 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:43659 Lechriodus fletcheri) based on a visual analysis of their natural skin features. We collected photographs of marked individuals in the field over three breeding seasons using a smartphone device. This photo-database was used to create an online survey to determine how easily members of the general public could photo-match individuals by a comparison of two facial skin features; black banding that runs horizontally above the tympanum and a background array of tubercles present in this region. Survey participants were provided with 30 closed, multiple choice questions in which they were asked to match separate images of a query frog from small image pools of potential candidate matches. Participants were consistently able to match individuals with a low matching error rate (mean ± SD of 26 ± 5) despite the relatively low quality of photographs taken from a smartphone device in the field, with most query frogs being matched by a majority of participants (mean ± SD of 86.02 ± 9.52%). These features were found to be unique and stable among adult males and females. Thus, photo-identification is likely to be a valid, non-invasive method for capture-mark-recapture for L. fletcheri, and likely many anurans that display similar facial skin features. This may become an important alternative to artificial marking techniques, with the challenges of manual photo-matching reduced by spreading workloads among members of the public that can be recruited online.]]> Wed 28 Sep 2022 13:31:57 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:52161 Wed 28 Feb 2024 11:00:35 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:44996 Batrachochytrium dendrobatidis is an emerging infectious pathogen present on every continent except Antarctica. It causes the disease chytridiomycosis in a subset of species but does not always result in disease or death for every host. Ambient temperature influences both amphibian metabolism and chytrid pathogenicity, however the interactive effects on host physiology is not well understood. We investigated the sublethal effect of B. dendrobatidis infection on a susceptible host, Litoria aurea to test (1) whether the infection load, metabolic activity, body fat and gonad size differed in L. aurea at either 24 °C or 12 °C ambient temperatures and (2) whether previous Bd infection caused long-term changes to body fat and gonad size. Litoria aurea in 12 °C treatments had higher infection loads of B. dendrobatidis and lower survivorship. Metabolic rate was higher and fat mass was lower in infected individuals and in animals in 24 °C treatments. Male L. aurea previously infected with B. dendrobatidis had smaller testes 5 months-post clearance of infection, an effect likely to translate to fitness costs in wild populations. These experiments demonstrate a physiological cost to sublethal B. dendrobatidis infection, which suggests a reduction in host fitness mediated by temperature in the host’s environment regardless of whether infection leads to mortality.]]> Wed 26 Oct 2022 09:28:56 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:53343 50% for each). Theoretically, it has been suggested that increased NPCP concentration should improve cell survival by increasing the rate and extent of cell dehydration. We suggest, however, that the elevated osmolality in the unfrozen water fraction when 10% sucrose is used may be causing damage to cells via excessive cell shrinkage and solute effects as proposed in the two-factor hypothesis of cryoinjury. We showed this response in sperm across a range of frog species, providing compelling evidence for this hypothesis. We suggest protocol development using the PCP/NPCP ratios demonstrated in our study will be broadly applicable to many amphibian species.]]> Wed 22 Nov 2023 10:19:22 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:46841 Lechriodus fletcheri. We quantified preferences for spawning in pools that were unused by conspecifics, as well as pools with conspecific spawn or tadpoles present, or both. The study included two ecological contexts: a system of naturally occurring breeding pools and a field experiment with 40 artificial pools that controlled for habitat variation. Mothers preferred to oviposit in pools that already contained conspecific spawn, despite the likelihood of intense resource competition upon offspring hatching. This could be due to the potential benefits obtained by providing offspring access to a significant nutrient supply upon hatching via cannibalism of conspecific tadpoles and might be an important adaptation for completing tadpole development in highly ephemeral and resource-limited pools prior to desiccation. In contrast, mothers avoided ovipositing in pools with conspecific tadpoles, a probable adaptation to avoid their own offspring from becoming victims of cannibalism themselves prior to hatching. Such nuances in the effect of conspecific presence on offspring survival highlight the often complex decision-making process that amphibians need to make when selecting oviposition sites, as well as the influence cannibalism can have on the evolution of reproductive behaviour.]]> Wed 22 Mar 2023 17:31:21 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:35503 Wed 19 Aug 2020 11:21:51 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:48961 Wed 19 Apr 2023 12:34:46 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:46347 Wed 16 Nov 2022 08:47:07 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:29590 Wed 11 Apr 2018 17:18:53 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:2858 Wed 11 Apr 2018 17:08:42 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:22315 Mixophyes (family Myobatrachidae) has amongst the highest proportion of endangered species of all the Australian amphibians. This study developed and optimised the induction of oviposition in a non-threatened member of this taxon, the great barred frog (Mixophyes fasciolatus). Methods: Gravid female M. fasciolatus were induced to oviposit on one or more occasions by administration of human chorionic gonadotropin (hCG) with or without priming with pregnant mare serum gonadotropin (PMSG). Treatments involved variations in hormone doses and combinations (administered via injection into the dorsal lymph sacs), and timing of administration. Pituitary homogenates from an unrelated bufonid species (Rhinella marina) were also examined with hCG. Results: When injected alone, hCG (900 to 1400 IU) induced oviposition. However, priming with two time dependent doses of PMSG (50 IU, 25 IU) increased responses, with lower doses of hCG (200 IU). Priming increased response rates in females from around 30% (hCG alone) to more than 50% (p = 0.035), and up to 67%. Increasing the interval between the first PMSG dose and first hCG dose from 3 to 6 days also produced significant improvement (p<0.001). Heterologous pituitary extracts administered with hCG were no more effective than hCG alone (p = 0.628). Conclusions: This study found that M. fasciolatus is amongst the few amphibian species (including Xenopus (Silurana) and some bufonids) that respond well to the induction of ovulation utilising mammalian gonadotropins (hCG). The optimal protocol for M. fasciolatus involved two priming doses of PMSG (50 IU and 25 IU) administered at 6 and 4 days respectively, prior to two doses of hCG (100 IU), 24 hours apart. This study is also the first to demonstrate in an amphibian species that responds to mammalian gonadotropins that an increase in the ovulation rate occurs after priming with a gonadotropin (PMSG) with FSH activity.]]> Wed 11 Apr 2018 16:14:56 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:19056 Wed 11 Apr 2018 15:45:47 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:29348 Wed 11 Apr 2018 11:27:40 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:15115 Wed 11 Apr 2018 10:17:31 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:14928 Wed 11 Apr 2018 10:08:24 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:33311 Litoria aurea were placed in water collected from ponds that were used by this species for breeding and ponds where breeding was not detected at Sydney Olympic Park, Australia. After 19 days, the tadpoles were placed in enclosures in the same breeding and non‐breeding ponds, and monitored until they metamorphosed. There was no difference in tadpole survival, time to metamorphosis or body condition between the two treatments, indicating that poor water quality was not a cause of low pond occupancy by tadpoles at the site and resources should be directed towards investigating other potential causes. We suggest that this method of an ex situ followed by an in situ exposure study is an effective approach to eliminating or confirming poor water quality as a cause of population declines and reduced occupancy, for species that are aquatic for at least part of their life cycle. Other applications include establishing that artificially created habitat provides suitable water chemistry, or identifying a potential location for a reintroduction project.]]> Wed 10 Oct 2018 12:10:24 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:48200 Wed 05 Jul 2023 15:14:46 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:48232 Wed 05 Jul 2023 14:49:21 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:52153 Wed 04 Oct 2023 10:48:44 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:49076 Wed 03 May 2023 16:15:16 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:41413 Wed 03 Aug 2022 11:45:22 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:23928 Litoria aurea, which exhibits high temporal variability in population size due to its fast life-history traits. Projections of population size from the viability model were highly variable, and removing parametric uncertainty only slightly improved overall model certainty, thus demonstrating the limits of population viability analysis for predicting abundance in fast life-history species. Sensitivity analysis identified recruitment of adults, female survival, male survival and rate of maturity as having the most impact on population viability. This population viability model provides a starting point to incorporate future research findings and better elucidate the causes of local extinction in this species. This study also reinforces the importance of egg-juvenile survival for amphibian populations, but also exemplifies the variability of amphibian viability analyses for identifying important parameters. As a case study for amphibian conservation, this analysis shows the utility of population viability analyses for fast life-history species, even with incomplete knowledge of all life-history stages.]]> Tue 31 Jul 2018 16:35:16 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:44935 Tue 25 Oct 2022 10:36:39 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:35505 Tue 25 Jul 2023 09:29:43 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:37426 Tue 17 Nov 2020 10:22:21 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:43094 Tue 13 Sep 2022 12:33:35 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:50582 Tue 08 Aug 2023 13:56:37 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:34867 Tue 03 Sep 2019 18:01:56 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:50548 Tue 01 Aug 2023 10:55:18 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:48898 Thu 27 Jul 2023 15:54:46 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:49026 Thu 27 Jul 2023 15:40:16 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:46003 Thu 27 Jul 2023 15:13:07 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:47274 Thu 23 Mar 2023 14:01:02 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:38371 Thu 20 Jul 2023 15:59:39 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:42281 Thu 20 Jul 2023 15:43:55 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:49009 Thu 20 Jul 2023 15:02:29 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:26207 Thu 19 Aug 2021 10:51:41 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:17628 Thu 18 Jun 2015 09:53:25 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:36152 Lechriodus fletcheri) by conspecific tadpoles as a likely adaptation to limited nutrient availability within highly ephemeral pools in which it is an obligate breeder. Field observations revealed L. fletcheri tadpoles actively preyed on conspecific eggs of recently oviposited spawn bodies, which were commonly consumed whole. When tadpoles were exposed to spawn for the first time in laboratory trials, they quickly engaged in extended periods of consumption, gorging themselves until they appeared to be full. We found this behaviour to be common in the field and suggest that conspecific eggs form a significant food resource for tadpoles of this species in the otherwise nutrient poor systems in which they breed. This feeding strategy might be common among anurans exploiting temporary aquatic systems that are nutrient-poor and gives rise to many questions surrounding how individuals can utilise cannibalism to increase their fitness while simultaneously avoiding becoming victims of this behaviour themselves. [Final citation details to be advised.]]]> Thu 17 Jun 2021 13:46:10 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:48415 Thu 16 Mar 2023 14:03:57 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:40479 Thu 14 Jul 2022 08:42:35 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:38566 Thu 04 Nov 2021 13:30:07 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:50737 Thu 03 Aug 2023 16:36:36 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:47070 Thu 03 Aug 2023 13:40:37 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:31415 Litoria aurea) to compare differences in microhabitat-use patterns in both a remnant and a constructed habitat. A detectability study was also conducted to determine detection probabilities among microhabitats. Key results: Aquatic vegetation was used more than expected in both the remnant and constructed habitats, and rock piles were utilised less than expected in the constructed habitat, despite their recommendation in most habitat templates. We found that detection probabilities altered the outcomes of abundance estimates for nearly all the measured microhabitat variables. Conclusions: Future management for this species should focus on providing high proportions of aquatic vegetation. Furthermore, although rock piles have been utilised greatly in past L. aurea habitat creation, placing large rocks on a managed site is expensive and time consuming. Future management initiatives may need to focus on providing smaller proportion of rocks, which would be a more appropriate use of resources. Implications: With conservation management projects increasing over the next few decades, understanding habitat use before implementing strategies should be a priority as it will provide important insights and inform decision-making for optimum habitat creation and restoration. Furthermore, accounting for detectability in microhabitat use studies is essential to avoid wrong conclusions that may negatively affect the success of ecological management strategies.]]> Sat 24 Mar 2018 08:43:55 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:19514 Sat 24 Mar 2018 08:02:07 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:20082 Sat 24 Mar 2018 08:00:08 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:20083 Sat 24 Mar 2018 08:00:05 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:19302 Sat 24 Mar 2018 07:56:07 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:19194 Sat 24 Mar 2018 07:54:59 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:21237 Litoria aurea) did not avoid or decrease their activity when exposed to solutions of conspecific macerate, suggesting that the chemicals released into the water by dead/injured conspecifics do not function as an alarm pheromone. This non-avoidance of dead conspecific chemicals may explain why green and golden bell frog tadpoles have seemingly not developed any avoidance behaviour to the presence of introduced mosquito fish, and may render attempts to teach naïve tadpoles to avoid this novel predator more difficult.]]> Sat 24 Mar 2018 07:53:02 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:21362 Sat 24 Mar 2018 07:51:24 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:26888 B. dendrobatidis infection, and survival were monitored at 1, 4, and 12 months. The effect of salt on the abundance of nontarget organisms was also investigated in before and after style analyses. Salinities remained constant over time with little intervention. Hosts in water bodies with 4 ppt salt had a significantly lower prevalence of chytrid infection and higher survival, following metamorphosis, than hosts in 0 ppt salt. Tadpoles in the 4 ppt group were smaller in length after 1 month in the release site than those in the 0 and 2 ppt groups, but after metamorphosis body size in all water bodies was similar . In water bodies with 4 ppt salt, the abundance of dwarf tree frogs (Litoria fallax), dragonfly larvae, and damselfly larvae was lower than in water bodies with 0 and 2 ppt salt, which could have knock-on effects for community structure. Based on our results, salt may be an effective field-based B. dendrobatidis mitigation tool for lentic amphibians that could contribute to the conservation of numerous susceptible species. However, as in all conservation efforts, these benefits need to be weighed against negative effects on both target and nontarget organisms.]]> Sat 24 Mar 2018 07:41:41 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:26282 Litoria aurea) has a number of behavioural traits which suggest conspecific attraction occurs via a vocal mechanism, including a loud conspicuous call and large chorusing aggregations. To date, attempts to repopulate restored and created habitat through natural immigration and active translocation of tadpoles and juveniles have been met with limited success for this species. We used L. aurea to determine if distribution could be manipulated via conspecific attraction using artificial communication cues. We placed speaker systems in uninhabited areas of five inhabited ponds across two locations and broadcast calls of L. aurea to see if we could manipulate distribution into previously unoccupied pond areas. Surveys undertaken before and after broadcast indicate that we successfully manipulated L. aurea distribution for adults increasing both occupancy and calling around the speaker locations. This occurred in four of five replicate ponds over three months of experimental treatment, but controls remained low in abundance. We suggest that manipulation of distribution via conspecific attraction mechanisms could be a useful conservation tool for endangered amphibian habitat restoration and creation programmes, resulting in increased occupancy and programme success.]]> Sat 24 Mar 2018 07:40:12 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:29688 Batrachochytrium dendrobatidis limits population recovery and conservation actions for threatened amphibians. As such, the effect of reservoirs on disease risk within host community assemblages needs to be considered, but rarely is. Aims: In this study we aimed to determine if amphibian species co-occurring with the green and golden bell frog Litoria aurea, a declining species susceptible to B. dendrobatidis, act as alternate hosts. Methods: We quantified B. dendrobatidis infection levels, sub-lethal effects on body condition and terminal signs of disease in amphibian communities on Kooragang Island and Sydney Olympic Park in New South Wales, Australia, where two of the largest remaining L. aurea populations persist. Key results: We found L. aurea carried infections at a similar prevalence (6–38%) to alternate species. Infection loads ranged widely (0.01–11 107.3 zoospore equivalents) and L. aurea differed from only one alternate host species (higher median load in Litoria fallax) at one site. There were no terminal or sub-lethal signs of disease in any species co-occurring with L. aurea. Conclusion: Our results suggest that co-occurring species are acting as alternate hosts to L. aurea and whether their presence dilutes or amplifies B. dendrobatidis in the community is a priority for future research. Implications: For L. aurea and many other susceptible species, confirming the existence of reservoir hosts and understanding their role in community disease dynamics will be important for optimising the outcomes of threat mitigation and habitat creation initiatives for their long-term conservation.]]> Sat 24 Mar 2018 07:38:49 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:26808 Sat 24 Mar 2018 07:36:28 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:27266 Sat 24 Mar 2018 07:34:28 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:30290 Batrachochytrium dendrobatidis (Bd) infection has led to the decline of many amphibian species. Despite increasing knowledge on how Bd varies in its effects among species, little is known on the interaction between susceptibility and development within host species. We compared the ontogenetic susceptibility of post-metamorphic green and golden bell frogs Litoria aurea to chytridiomycosis by simultaneously measuring three host-pathogen responses as indicators of the development of the fungus—infection load, survival rate, and host immunocompetence—following Bd exposure in three life stages (recently metamorphosed juveniles, subadults, adults) over 95 days. Frogs exposed to Bd as recently metamorphosed juveniles acquired higher infection loads and experienced lower immune function and lower survivorship than subadults and adults, indicating an ontogenetic decline in chytridiomycosis susceptibility. By corresponding with an intrinsic developmental maturation in immunocompetence seen in uninfected frogs, we suggest these developmental changes in host susceptibility in L. aurea may be immune mediated. Consequently, the physiological relationship between ontogeny and immunity may affect host population structure and demography through variation in life stage survival, and understanding this can shape management targets for effective amphibian conservation.]]> Sat 24 Mar 2018 07:33:34 AEDT ]]> https://nova.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://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:29286 Sat 24 Mar 2018 07:32:51 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:29028 Litoria aurea, are attracted to conspecifics and form schools. We conducted two choice experiments for captive breed tadpoles of this species to test their grouping preferences. Tadpoles preferred to aggregate with conspecifics to heterospecifics of a sympatric species; however, when conspecifics were absent they preferred to aggregate with the heterospecifcs than to remain alone. Tadpoles also preferred unfamiliar kin to unfamiliar non-kin conspecifics, but had no preferences between unfamiliar and familiar siblings. Once widespread in southeast Australia, the green and golden bell frog has suffered considerable declines and local extinctions in recent decades. Susceptibility to chytridiomycosis is likely the major threat for most remaining fragmented populations and the major challenge for reintroduction programs. The strong gregarious behaviour of this species may affect disease dynamics, especially chytridiomicosis that continues to threaten remaining wild populations.]]> Sat 24 Mar 2018 07:31:06 AEDT ]]> https://nova.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://nova.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://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:26628 Batrachochytrium dendrobatidis has been a major contributing factor to the global decline of amphibians. Knowledge of the distribution of B. dendrobatidis can contribute to understanding patterns of species decline and prioritizing action. Therefore, we surveyed four spatially distinct populations of a B. dendrobatidis susceptible species, the green and golden bell frog (Litoria aurea), for evidence of infection in the population. Three mainland populations were infected at a prevalence of 3.5-28.3 %, with median infection loads of 0.28-627.18 genomic equivalents (GE). Conversely, we did not detect infection in an island population 3 km from the mainland; the isolation and infrequent visitation of the island suggests that the pathogen has not arrived. Management actions for B. dendrobatidis and conservation of susceptible frog species are heavily dependent on the presence and absence of the pathogen in the population. Prevention of the accidental introduction of B. dendrobatidis and safe guarding genetic diversity of L. aurea is necessary to preserve unique diversity of the island population, whereas containment and control of the pathogen can be directed towards mainland populations. Knowledge of disease dynamics also provides a context to understand the ecology of remaining populations as variation in the physiology or habitat of the mainland populations have facilitated persistence of these populations alongside B. dendrobatidis. Other islands should be a priority target in disease surveillance, to discover refuges that can assist conservation.]]> Sat 24 Mar 2018 07:26:48 AEDT ]]> https://nova.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 ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:24913 Sat 24 Mar 2018 07:14:50 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:23886 Litoria aurea) using radio tracking methods during winter when detection is low and knowledge is limited. We followed 26 individuals between May and July, 2011 to determine whether they selected specific overwintering microhabitats and related this to levels of individual exposure to predators, distance from the edge of the water and temperature of microhabitats. We found that overwintering bell frogs inhabited reeds and rock gabions more frequently than expected and that females used a reduced subset of microhabitats compared to males. Additionally, microhabitats used were more likely to conceal an individual from view, and the majority of overwintering sites were located within 5m of the edge of the water which may be important for reducing the risk of predation and desiccation. Rock gabions had significantly warmer (1.2°C-1.8°C) mean temperatures than the other microhabitats used. The information presented here can be used in habitat creation and reintroduction programmes to provide habitat which is suitable during both the breeding and non-breeding season for the conservation of other populations.]]> Sat 24 Mar 2018 07:13:40 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:23914 Litoria aurea) have suffered considerable shrinking of their original distribution in south-eastern Australia since the 1970s. Currently, with only about 40 populations remaining, the species is considered nationally threatened. In natural conditions, these frogs are aggregated in the landscape and do not seem to occupy all suitable ponds within the occurrence area. To date, studies focusing on the frogs' habitat have failed in finding a general habitat feature that explains current or past occupancy. This led us to the hypothesis that social cues may play a key role in habitat selection in this species. Using two choice experiments, we tested the preference of juvenile green and golden bell frogs for habitats containing cues of conspecifics of similar size versus habitats without conspecific cues. Tested frogs did not show a preference for habitats containing only scent from conspecifics but did prefer habitats where conspecifics were present. Our results show that conspecific attraction is a determining factor in juvenile green and golden bell frog habitat selection. To our knowledge, this is the first time the behaviour is shown to occur in juvenile frogs in the habitat selection context. From a conservation management point of view, the behaviour may help to explain the failure of reintroductions to areas where the frogs have been extinct, and the non-occupation of suitable created habitats in areas where they still inhabit and develop appropriated management strategies.]]> Sat 24 Mar 2018 07:10:02 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:42613 Mon 22 May 2023 10:52:38 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:37903 Mon 21 Jun 2021 15:18:27 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:48479 Mon 20 Mar 2023 09:17:56 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:44520 Mon 17 Oct 2022 08:35:24 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:54771 50%) when preserved with 15% v/v DMSO and 1% w/v sucrose; and (3) spermic urine stored at 5 ◦C retained motility for up to 14 days. Our findings demonstrate that the protocols developed in this study allowed for successful induction and recovery of high-quality spermatozoa from a threatened Australian anuran, L. aurea, providing a prime example of how ARTs can contribute to the conservation of rare and threatened species.]]> Mon 11 Mar 2024 15:07:50 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:41219 Fri 29 Jul 2022 09:46:33 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:32085 Batrachochytrium dendrobatidis (Bd) is correlated with several environmental variables, including salinity, temperature, and moisture content, which influence the pathogen’s growth and survival. Habitats that contain these environmental variables at levels outside of those optimal for Bd growth and survival may facilitate the survival of susceptible host species. Therefore, manipulation of environmental salinity is a potential management strategy to help conserve Bd-susceptible species. However, host behaviour also influences disease dynamics, and the success of habitat manipulation programs depends on how hosts use this altered habitat. Aims: To assess if the Bd-susceptible green and golden bell frog, Litoria aurea, will select waterbodies with a salinity increased to S = 3; if this selection is affected by infection; and if a frog’s time in a waterbody of this salinity affects infection load or blood physiology. Methods: We conducted a filmed choice experiment and a 3-year field study where infected and uninfected frogs could choose between fresh or saline waterbodies. Key results: In both the laboratory experiment and field study, Bd-infected L. aurea spent a significantly greater amount of time in or closer to a waterbody than uninfected frogs. Experimentally infected frogs tended to prefer the saline water over fresh, but their choice of water usage did not differ statistically from uninfected frogs. In the field, frogs began to avoid ponds when salinities rose above S = 5. Conclusions: Because both wild and captive, and infected and uninfected L. aurea readily selected waterbodies with a salinity of S = 3, this salinity could potentially be used as a passive method for reducing the severity of Bd when managing this species. However, further testing is needed to understand the efficacy of this treatment, and care must be taken to prevent salinities rising above S = 5, because this level seems to produce an avoidance response and therefore may not be suitable in every location. Implications: Manipulation of aquatic habitats may be a worthwhile focus for Bd management in habitats where water level fluctuations are minimal.]]> Fri 27 Apr 2018 14:12:51 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:48628 Fri 24 Mar 2023 09:46:36 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:50809 Fri 18 Aug 2023 11:23:20 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:50819 Fri 18 Aug 2023 11:09:25 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:44399 Fri 17 May 2024 14:35:40 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:49405 Fri 12 May 2023 14:48:07 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:49400 Fri 12 May 2023 14:41:06 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:46135 Hydaticus parallelus) ovipositing their eggs within spawn of an amphibian species (sandpaper frog, Lechriodus fletcheri). This behavior was found among several pools used by L. fletcheri for reproduction. Beetle eggs oviposited in frog spawn were found to hatch within 24 h of the surrounding L. fletcheri eggs, with the larvae becoming voracious consumers of the hatched tadpoles. Although it has yet to be established experimentally whether this is an adaptive behavior, the laying of eggs among potential future tadpole prey in this instance should confer significant fitness benefits for the offspring upon hatching, ensuring that they are provided an immediate source of food at the start of their development and potentially throughout. This oviposition behavior might be common among diving beetles and could form a significant predatory threat for amphibians with a free‐swimming larval stage in ephemeral freshwater habitats.]]> Fri 11 Nov 2022 16:17:48 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:38175 Fri 06 Aug 2021 14:14:50 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:45728 A$49 900), RPAS thermal imaging surveys were cost-effective, detecting the highest number of koalas per dollar spent. Modelling also suggested that RPAS thermal imaging requires the lowest survey effort to detect koalas within the range of publicly available koala population densities (~0.006–18 koalas ha−1) and would provide long-term cost reductions across longitudinal monitoring programs. RPAS thermal imaging would also require the lowest average survey effort costs at a landscape scale (A$3.84 ha−1), providing a cost-effective tool across large spatial areas. Conclusions: Our analyses demonstrated drone thermal imaging technology as a cost-effective tool for conservation practitioners monitoring koala populations. Our analyses may also form the basis of decision-making tools to estimate survey effort or total program costs across any koala population density. Implications: Our novel approach offers a means to perform various economic comparisons of available survey techniques and guide investment decisions towards developing standardised koala monitoring approaches. Our results may assist stakeholders and policymakers to confidently invest in RPAS thermal imaging technology and achieve optimal conservation outcomes for koala populations, with standardised data collection delivered through evidence-based and cost-effective monitoring programs.]]> Fri 04 Nov 2022 09:52:04 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:49805 Fri 02 Jun 2023 16:59:49 AEST ]]>