https://nova.newcastle.edu.au/vital/access/ /manager/Index ${session.getAttribute("locale")} 5 https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:53680 10-fold mean increase in detection rates of cats by 5 years after the loss of V. panoptes, reflecting relative increases of 3.3–8.7 individual cats per site. Conclusions: Although some unknown factor may have caused an increase in cats, their similar trophic position and niche to V. panoptes suggests that toads facilitated cats by effectively removing the lizards from the animal community. This interaction likely reflects one type of invasional meltdown, whereby a non-native species (cane toad) facilitated any aspect of another’s (feral cat) invasion (e.g. survival, reproduction, resource acquisition), but the latter has no detected influence on the former (+/0 interaction). Implications: Because both invaders cause declines in animal populations and are difficult to control, the potentially synergistic tandem of cane toads and feral cats could have chronic, irreversible effects on animal communities.]]> Wed 10 Jan 2024 10:20:29 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:54807 Thu 14 Mar 2024 14:11:15 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:54810 Thu 14 Mar 2024 14:10:46 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:54806 Thu 14 Mar 2024 14:10:37 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:35232 Rhinella marina) has invaded over 50 countries and is a serious conservation issue in Australia. Because the cane toad has taken several decades to colonise northern Australia, due to the large size of the continent and the east–west invasion axis, there is scope for making testable predictions about how toads will invade new areas. The western toad invasion front is far from linear, providing clear evidence for heterogeneity in invasion speed. Aims: Several ad hoc hypotheses have been offered to explain this heterogeneity, including the evolution of traits that could facilitate dispersal, and spatial heterogeneity in climate patterns. Here an alternative hypothesis is offered, and a prediction generated for the spatiotemporal pattern of invasion into the Kimberley Region – the next frontier for the invading toads in Australia. Methods: Using observations of spatiotemporal patterns of cane toad colonisation in northern Australia over the last 15 years, a conceptual model is offered, based on the orientation of wet season river flows relative to the invasion axis, as well as toad rafting and floating behaviour during the wet season. Key results: Our model predicts that toads will invade southern areas before northern areas; an alternative model based on rainfall amounts makes the opposite prediction. The models can now be tested by monitoring the spread of invasion front over the next 5–10 years. Conclusions: Our conceptual models present a pleuralistic approach to understanding the spatiotemporal invasion dynamics of toads; such an approach and evaluation of the models could prove useful for managing other invasive species. Implications: Although control of cane toads has largely proved ineffective, knowledge of the spatiotemporal pattern of the toad invasion in the Kimberley could: (1) facilitate potential management tools for slowing the spread of toads; (2) inform stakeholders in the local planning for the invasion; (3) provide researchers with a temporal context for quantifying toad impacts on animal communities; and (4) reveal the mechanism(s) causing the heterogeneity in invasion speed.]]> Thu 04 Jul 2019 13:56:20 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:20281 Sat 24 Mar 2018 07:59:54 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:19323 Sat 24 Mar 2018 07:51:54 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: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:40429 Rhinella marina) has decimated populations of a keystone predator, the yellow-spotted monitor (Varanus panoptes), causing trophic cascades in Australian animal communities. Paradoxically, some V. panoptes populations coexist with toads. Demonstrating patterns in heterogeneous population-level impacts could reveal mechanisms that mediate individual effects, and provide managers with the ability to predict future impacts and assist in population recovery. Aims: The aim of the present study was to search for spatial patterns of population resilience of V. panoptes to invasive cane toads. Methods: Published literature, unpublished data, reports and anecdotal information from trained herpetologists were used to test the emerging hypothesis that resilient predator populations are mainly coastal, whereas non-resilient populations are mostly inland. Key results: Post-toad invasion data from 23 V. panoptes populations supported the idea that toad impacts on V. panoptes were heterogeneous; roughly half the populations could be designated as resilient (n = 13) and half as non-resilient (n = 10). Resilient populations had longer times since toad invasion than did non-resilient populations (39 versus 9 years respectively), supporting the idea that some recovery can occur. Non-resilient populations were exclusively inland (n = 10), whereas resilient populations were split between inland (n = 5) and coastal (n = 8) populations. Resilient inland populations, however, were mainly confined to areas in which decades had passed since toad invasion. Conclusions: The findings suggest that coastal V. panoptes populations fare much better than inland populations when it comes to surviving invading cane toads. Implications: Unambiguous recovery of monitor populations remains undemonstrated and will require long-term population monitoring before and after toad invasion.]]> Fri 22 Jul 2022 14:30:26 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:41766 Fri 12 Aug 2022 11:49:19 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 ]]>