Dr Michelle Stockwell

Conjoint Fellow

School of Environmental and Life Sciences

Career Summary

Biography

Research Expertise
My research interests are strongly conservation focused, involving any projects with applied outcomes for population management or threat mitigation. I’m currently involved in projects using species distribution and extinction probability models to identify causal agents and outcomes of decline, identifying habitat use and occupancy patterns for habitat creation initiatives, investigating population and meta-population dynamics for viability models and management scenario projections, trialling the manipulation of social cues to alter distributions and investigating relationships between amphibian hosts, the chytrid fungus and the environment for the purpose of identifying management strategies.

Administrative Expertise
Jan 2013 - Present: Category B member of the University of Newcastle Animal care and Ethics Committee Aug 2013 - Aug 2014: Member of the Animal Care and Ethics Executive

Qualifications

  • Doctor of Philosophy, University of Newcastle

Keywords

  • Amphibian biology and behaviour
  • Conservation biology
  • Conservation decision making
  • Disease ecology
  • Habitat restoration
  • Population management
  • Population modelling

Fields of Research

Code Description Percentage
050202 Conservation and Biodiversity 50
060207 Population Ecology 25
060307 Host-Parasite Interactions 25
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Publications

For publications that are currently unpublished or in-press, details are shown in italics.


Journal article (31 outputs)

Year Citation Altmetrics Link
2017 Pollard CJ, Stockwell MP, Bower DS, Garnham JI, Pickett EJ, Darcovich K, et al., 'Removal of an exotic fish influences amphibian breeding site selection', Journal of Wildlife Management, 81 720-727 (2017)

© The Wildlife Society, 2017 For pond-breeding species, the distribution of larvae is a reflection of habitat suitability and adult breeding site selection. Some species preferen... [more]

© The Wildlife Society, 2017 For pond-breeding species, the distribution of larvae is a reflection of habitat suitability and adult breeding site selection. Some species preferentially breed in ephemeral ponds, which can provide benefits for larvae. An alternative strategy used by adults to increase offspring survival is to detect aquatic predators and avoid them when selecting breeding sites. We investigated whether either of these types of breeding site selection are contributing to the negative correlation between the distributions of tadpoles of the threatened green and golden bell frog (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. © 2017 The Wildlife Society.

DOI 10.1002/jwmg.21232
Co-authors John Clulow
2017 Valdez JW, Klop-Toker K, Stockwell MP, Fardell L, Clulow S, Clulow J, Mahony MJ, 'Informing compensatory habitat creation with experimental trials: a 3-year study of a threatened amphibian', ORYX, 1-11 (2017)

Copyright © Fauna & Flora International 2017 The creation or restoration of habitat to mitigate biodiversity loss is a common conservation strategy. Evidence-based research... [more]

Copyright © Fauna & Flora International 2017 The creation or restoration of habitat to mitigate biodiversity loss is a common conservation strategy. Evidence-based research via an extensively monitored trial study should be undertaken prior to large-scale implementation to predict success and identify potential limiting factors. We constructed an experimental trial habitat for the threatened green and golden bell frog Litoria aurea, in Australia, to inform a broader programme of compensatory habitat creation. Individuals were released into the trial plot and a nearby natural wetland for comparison to determine if the created habitat would support their growth, survival and persistence. Half of the trial waterbodies were enclosed within an exclusion fence to separate the effects of habitat suitability from ecological processes. We found the habitat provided L. aurea with sufficient resources to grow, survive and persist for 3 years. However, no breeding occurred, and further investigations need to focus on understanding the drivers of reproduction. Although a disease outbreak occurred during the study, persistence continued for the next 2 years. This was attributed to the large number of individuals released, a strategy we recommend for future mitigation strategies to account for low survival and high turnover rates. Dispersal probably affected abundance in the unfenced areas, and landscape-level initiatives are suggested for this species. This study demonstrates that experimental trials are valuable, as they can inform future habitat management by identifying limitations that could hinder success prior to the implementation of large-scale initiatives.

DOI 10.1017/S0030605317000394
Co-authors Simon Clulow, John Clulow
2017 Valdez JW, Klop-Toker K, Stockwell MP, Fardell L, Clulow S, Clulow J, Mahony MJ, 'Differences in microhabitat selection patterns between a remnant and constructed landscape following management intervention', WILDLIFE RESEARCH, 44 248-258 (2017) [C1]
DOI 10.1071/WR16172
Co-authors John Clulow, Simon Clulow
2017 Pollard CJ, Stockwell MP, Bower DS, Clulow J, Mahony MJ, 'Combining ex situ and in situ methods to improve water quality testing for the conservation of aquatic species', Aquatic Conservation: Marine and Freshwater Ecosystems, 27 559-568 (2017)

Copyright © 2016 John Wiley & Sons, Ltd. Determining whether water quality is suitable is an important part of managing aquatic species for conservation, although it is oft... [more]

Copyright © 2016 John Wiley & Sons, Ltd. Determining whether water quality is suitable is an important part of managing aquatic species for conservation, although it is often challenging to achieve. Past approaches have largely consisted of tests exposing individuals to artificial solutions, or field studies that examine the effect of a subset of water quality parameters on the distribution or abundance of a species. Owing to the complex nature of water chemistry in natural systems, which is difficult to replicate using laboratory studies or to capture entirely with correlational field studies, these types of study may not be suitable for determining accurately whether or not water quality at a particular site is suitable for a target species. In situations where conservation outcomes rely heavily on achieving this, an alternative approach is therefore needed. Embryos of the threatened green and golden bell frog 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. Copyright © 2016 John Wiley & Sons, Ltd.

DOI 10.1002/aqc.2700
Co-authors John Clulow
2016 Klop-Toker K, Valdez J, Stockwell M, Fardell L, Clulow S, Clulow J, Mahony M, 'We Made Your Bed, Why Won't You Lie in It? Food Availability and Disease May Affect Reproductive Output of Reintroduced Frogs', PLOS ONE, 11 (2016) [C1]
DOI 10.1371/journal.pone.0159143
Citations Scopus - 2Web of Science - 2
Co-authors Simon Clulow, John Clulow
2016 Abu Bakar A, Bower DS, Stockwell MP, Clulow S, Clulow J, Mahony MJ, 'Susceptibility to disease varies with ontogeny and immunocompetence in a threatened amphibian', Oecologia, 181 997-1009 (2016) [C1]

© 2016, Springer-Verlag Berlin Heidelberg. Ontogenetic changes in disease susceptibility have been demonstrated in many vertebrate taxa, as immature immune systems and limited pr... [more]

© 2016, Springer-Verlag Berlin Heidelberg. Ontogenetic changes in disease susceptibility have been demonstrated in many vertebrate taxa, as immature immune systems and limited prior exposure to pathogens can place less developed juveniles at a greater disease risk. By causing the disease chytridiomycosis, 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 ontogeneti c 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.

DOI 10.1007/s00442-016-3607-4
Citations Scopus - 3Web of Science - 1
Co-authors John Clulow, Simon Clulow
2016 Pizzatto L, Stockwell M, Clulow S, Clulow J, Mahony M, 'Finding a place to live: conspecific attraction affects habitat selection in juvenile green and golden bell frogs', Acta Ethologica, 19 1-8 (2016) [C1]

© 2015, Springer-Verlag Berlin Heidelberg and ISPA. Conspecific attraction plays an important role in habitat selection of several taxa and can affect and determine distribution ... [more]

© 2015, Springer-Verlag Berlin Heidelberg and ISPA. Conspecific attraction plays an important role in habitat selection of several taxa and can affect and determine distribution patterns of populations. The behaviour is largely studied and widespread among birds, but in amphibians, its occurrence seems limited to breeding habitats of adults and gregarious tadpoles. The Australian green and golden bell frogs (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.

DOI 10.1007/s10211-015-0218-8
Citations Scopus - 4Web of Science - 2
Co-authors Simon Clulow, John Clulow
2016 Valdez J, Klop-Toker K, Stockwell MP, Clulow S, Clulow J, Mahony MJ, 'Microhabitat selection varies by sex and age class in the endangered green and golden bell frog Litoria aurea', Australian Zoologist, 38 223-234 (2016) [C1]

Although amphibians are one of the most threatened animal groups, little published evidence exists on effective management programs. In order for conservation initiatives to be su... [more]

Although amphibians are one of the most threatened animal groups, little published evidence exists on effective management programs. In order for conservation initiatives to be successful, an understanding of habitat use patterns is required to identify important environmental features. However, habitat use may differ between the different sexes and age classes due to different behavioural and resource requirements. For this study, we compared microhabitat use during the active breeding season among the sexes and age classes in the endangered green and golden bell frog Litoria aurea, a species which has had several failed management programs. We found aquatic vegetation was selected for by every L. aurea class, and should be the focus of future management plans for this species. Females were the only class to select for terrestrial vegetation more than availability. Increasing the amount of terrestrial vegetation around ponds may help encourage female occupancy, and possibly improve management outcomes, as they are typically a limiting resource. Although large rock piles have been used in past L. aurea habitat management, they were selected for by adults and juveniles, but not metamorphs. Therefore, large rocks may not be necessary for captive breeding portions of management initiatives, which typically only involve tadpoles and metamorphs prior to release. The results indicate that the most appropriate management plans should contain a habitat mosaic of various microhabitats, such as a large proportion of aquatic and terrestrial vegetation with patches of bare ground and a small proportion of rocks for basking and shelter. Recognizing differences in microhabitat use patterns between individuals in a population and implementing them into management strategies should be a pivotal step in any conservation plan.

DOI 10.7882/AZ.2016.031
Co-authors Simon Clulow, John Clulow
2016 Stockwell MP, Garnham JI, Bower DS, Clulow J, Mahony MJ, 'Low disease-causing threshold in a frog species susceptible to chytridiomycosis', FEMS MICROBIOLOGY LETTERS, 363 (2016) [C1]
DOI 10.1093/femsle/fnw111
Citations Scopus - 1Web of Science - 1
Co-authors John Clulow
2016 Pickett EJ, Stockwell MP, Clulow J, Mahony MJ, 'Modelling the population viability of a threatened amphibian with a fast life-history', Aquatic Conservation: Marine and Freshwater Ecosystems, 26 9-19 (2016) [C1]

© 2015 John Wiley & Sons, Ltd. A bias in conservation research has meant that population viability analysis has focused primarily on mammals and birds with slow life histories.... [more]

© 2015 John Wiley & Sons, Ltd. A bias in conservation research has meant that population viability analysis has focused primarily on mammals and birds with slow life histories. The global amphibian decline has demonstrated the capacity for fast life-history species to experience decline. However, little is known about the viability of remnant populations of these species as patterns of decline cannot be inferred from other species with different life-history strategies. Population viability analysis was performed on the threatened frog, 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.

DOI 10.1002/aqc.2564
Citations Scopus - 4Web of Science - 2
Co-authors John Clulow
2016 Stockwell MP, Bower DS, Clulow J, Mahony MJ, 'The role of non-declining amphibian species as alternative hosts for Batrachochytrium dendrobatidis in an amphibian community', WILDLIFE RESEARCH, 43 341-347 (2016) [C1]
DOI 10.1071/WR15223
Co-authors John Clulow
2016 Pizzatto L, Stockwell M, Clulow S, Clulow J, Mahony M, 'How to form a group: Effects of heterospecifics, kinship and familiarity in the grouping preference of green and golden bell frog tadpoles', Herpetological Journal, 26 157-164 (2016) [C1]

© 2016, British Herpetological Society. All rights reserved. Social aggregations are widespread among animal groups. They are relatively common in amphibian larvae, likely confer... [more]

© 2016, British Herpetological Society. All rights reserved. Social aggregations are widespread among animal groups. They are relatively common in amphibian larvae, likely conferring protection against predators, advantages for microhabitat selection, foraging efficiency, and thermoregulatory efficiency. Group formation involves selection of individuals to group with by the other members, and several tadpoles are reported to recognise and prefer to aggregate with siblings or familiar individuals. In Australia, tadpoles of the endangered green and golden bell frog, 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.

Co-authors Simon Clulow, John Clulow
2015 Stockwell MP, Storrie LJ, Pollard CJ, Clulow J, Mahony MJ, 'Effects of pond salinization on survival rate of amphibian hosts infected with the chytrid fungus', Conservation Biology, 29 391-399 (2015) [C1]

© 2014 Society for Conservation Biology. The chytrid fungus Batrachochytrium dendrobatidis has been implicated in the decline and extinction of amphibian populations worldwide, b... [more]

© 2014 Society for Conservation Biology. The chytrid fungus Batrachochytrium dendrobatidis has been implicated in the decline and extinction of amphibian populations worldwide, but management options are limited. Recent studies show that sodium chloride (NaCl) has fungicidal properties that reduce the mortality rates of infected hosts in captivity. We investigated whether similar results can be obtained by adding salt to water bodies in the field. We increased the salinity of 8 water bodies to 2 or 4 ppt and left an additional 4 water bodies with close to 0 ppt and monitored salinity for 18 months. Captively bred tadpoles of green and golden bell frog (Litoria aurea) were released into each water body and their development, levels of 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.

DOI 10.1111/cobi.12402
Citations Scopus - 9Web of Science - 8
Co-authors John Clulow
2015 Stockwell MP, Bower DS, Bainbridge L, Clulow J, Mahony MJ, 'Island provides a pathogen refuge within climatically suitable area', Biodiversity and Conservation, (2015) [C1]

Surveillance of pathogens can lead to significant advances towards making effective decisions in research and management for species threatened by disease. Batrachochytrium dendro... [more]

Surveillance of pathogens can lead to significant advances towards making effective decisions in research and management for species threatened by disease. 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.

DOI 10.1007/s10531-015-0946-0
Citations Scopus - 6Web of Science - 5
Co-authors John Clulow
2015 Stockwell MP, Clulow J, Mahony MJ, 'Evidence of a salt refuge: chytrid infection loads are suppressed in hosts exposed to salt', Oecologia, 177 901-910 (2015) [C1]

© 2014, Springer-Verlag Berlin Heidelberg. With the incidence of emerging infectious diseases on the rise, it is becoming increasingly important to identify refuge areas that pro... [more]

© 2014, Springer-Verlag Berlin Heidelberg. With the incidence of emerging infectious diseases on the rise, it is becoming increasingly important to identify refuge areas that protect hosts from pathogens and therefore prevent population declines. For the chytrid fungus Batrachochytrium dendrobatidis, temperature and humidity refuge areas for amphibian hosts exist but are difficult to manipulate. Other environmental features that may affect the outcome of infection include water quality, drying regimes, abundance of alternate hosts and isolation from other hosts. We identified relationships between water bodies with these features and infection levels in the free-living hosts inhabiting them. Where significant relationships were identified, we used a series of controlled experiments to test for causation. Infection loads were negatively correlated with the salt concentration of the aquatic habitat and the degree of water level fluctuation and positively correlated with fish abundance. However, only the relationship with salt was confirmed experimentally. Free-living hosts inhabiting water bodies with mean salinities of up to 3.5 ppt had lower infection loads than those exposed to less salt. The experiment confirmed that exposure to sodium chloride concentrations > 2 ppt significantly reduced host infection loads compared to no exposure (0 ppt). These results suggest that the exposure of amphibians to salt concentrations found naturally in lentic habitats may be responsible for the persistence of some susceptible species in the presence of B. dendrobatidis. By manipulating the salinity of water bodies, it may be possible to create refuges for declining amphibians, thus allowing them to be reintroduced to their former ranges.

DOI 10.1007/s00442-014-3157-6
Citations Scopus - 10Web of Science - 9
Co-authors John Clulow
2015 Garnham JI, Stockwell MP, Pollard CJ, Pickett EJ, Bower DS, Clulow J, Mahony MJ, 'Winter microhabitat selection of a threatened pond amphibian in constructed urban wetlands', Austral Ecology, 40 816-826 (2015) [C1]
DOI 10.1111/aec.12256
Citations Scopus - 2Web of Science - 1
Co-authors John Clulow
2015 Valdez JW, Stockwell MP, Klop-Toker K, Clulow S, Clulow J, Mahony MJ, 'Factors driving the distribution of an endangered amphibian toward an industrial landscape in Australia', Biological Conservation, 191 520-528 (2015) [C1]

© 2015 Elsevier Ltd. Although human-modified habitats often result in a loss of biodiversity, some have been found to serve as habitat refuges for threatened species. Given the g... [more]

© 2015 Elsevier Ltd. Although human-modified habitats often result in a loss of biodiversity, some have been found to serve as habitat refuges for threatened species. Given the globally declining status of amphibians, understanding why some species are found in heavily modified environments is of considerable interest. We used the endangered green and golden bell frog (. Litoria aurea) as a model to investigate the factors influencing their distribution toward industrial areas within a landscape. The number of permanent waterbodies within a kilometer of surveyed sites was the best predictor of L. aurea occupancy, abundance and reproduction. It appears that industrial activities, such as dredging and waste disposal inadvertently created refuge habitat for L. aurea to fortuitously persist in a heavily modified landscape. Future conservation plans should mimic the positive effects of industrialization, such as increasing the number of permanent waterbodies, especially in areas containing ephemeral or isolated waterbodies and threatened with drought. Our findings also suggest that despite amphibians being relatively small animals, some species may require a larger landscape than anticipated. Recognizing life history traits, in combination with a landscape-based approach toward species with perceived limited motility, may result in more successful conservation outcomes. Identifying why threatened species persist in heavily disturbed landscapes, such as industrial sites, can provide direction toward future conservation efforts to prevent and reverse their decline.

DOI 10.1016/j.biocon.2015.08.010
Citations Scopus - 4Web of Science - 4
Co-authors Simon Clulow, John Clulow
2015 Bainbridge L, Stockwell M, Valdez J, Klop-Toker K, Clulow S, Clulow J, Mahony M, 'Tagging tadpoles: retention rates and impacts of visible implant elastomer (VIE) tags from the larval to adult amphibian stages', HERPETOLOGICAL JOURNAL, 25 133-140 (2015) [C1]
Citations Scopus - 1Web of Science - 3
Co-authors Simon Clulow, John Clulow
2015 James MS, Stockwell MP, Clulow J, Clulow S, Mahony MJ, 'Investigating behaviour for conservation goals: Conspecific call playback can be used to alter amphibian distributions within ponds', Biological Conservation, 192 287-293 (2015) [C1]

© 2015. Conspecific attraction can prevent occupancy of restored or created habitats by limiting dispersal to unoccupied areas. This may cause problems for threatened taxa where ... [more]

© 2015. Conspecific attraction can prevent occupancy of restored or created habitats by limiting dispersal to unoccupied areas. This may cause problems for threatened taxa where habitat restoration and creation programmes are implemented as part of species recovery plans. Studies on birds have found that the introduction of artificial communication cues such as calling can increase occupancy of restored habitat. The endangered green and golden bell frog (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.

DOI 10.1016/j.biocon.2015.10.001
Citations Scopus - 4Web of Science - 4
Co-authors Simon Clulow, John Clulow, Melanie S James
2014 Pizzatto L, Stockwell M, Clulow S, Clulow J, Mahony M, 'Chemical communication in green and golden bell frogs: do tadpoles respond to chemical cues from dead conspecifics?', Chemoecology, (2014) [C1]

Captive bred animals often lack the ability of predator recognition and predation is one of the strongest causes of failure of breed and release projects. Several tadpole and fish... [more]

Captive bred animals often lack the ability of predator recognition and predation is one of the strongest causes of failure of breed and release projects. Several tadpole and fish species respond defensively to chemical cues from injured or dead conspecifics, often referred to as alarm pheromones. In natural conditions and in species that school, the association of chemical cues from predators to alarm pheromones released by attacked conspecifics may lead to the learning of the predator-related danger without experiencing an attack. In the laboratory, this chemical communication can also be used in associative learning techniques to teach naïve tadpoles to avoid specific predators and improve survivorship of released animals. In our experimental trials, tadpoles of the threatened green and golden bell frog (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. © 2014 Springer Basel.

DOI 10.1007/s00049-014-0159-0
Co-authors John Clulow, Simon Clulow
2014 Pickett EJ, Stockwell MP, Bower DS, Pollard CJ, Garnham JI, Clulow J, Mahony MJ, 'Six-year demographic study reveals threat of stochastic extinction for remnant populations of a threatened amphibian', Austral Ecology, 39 244-253 (2014) [C1]

Sustained demographic studies are essential for early detection of species decline in time for effective management response. A paucity of such background data hindered the potent... [more]

Sustained demographic studies are essential for early detection of species decline in time for effective management response. A paucity of such background data hindered the potential for successful conservation during the global amphibian decline and remains problematic today. The current study analysed 6 years of mark-recapture data to determine the vital demographic rates in three habitat precincts of the threatened frog, Litoria aurea (Hylidae) and to understand the underlying causes of variability in population size. Variability in population size of L.aurea was similar to many pond-breeding species; however this level of fluctuation is rare among threatened amphibians. Highly variable populations are at greater risk of local extinction and the low level of connectivity between L.aurea populations means they are at a greater risk of further decline due to stochastic extinction events and incapacity to recolonize distant habitat. We recommend that management of this species should encourage recolonization through creation of habitat corridors and reintr oduction of L.aurea to areas where stochastic extinction events are suspected. © 2013 Ecological Society of Australia.

DOI 10.1111/aec.12080
Citations Scopus - 8Web of Science - 5
Co-authors John Clulow
2014 Bower DS, Pickett EJ, Stockwell MP, Pollard CJ, Garnham JI, Sanders MR, et al., 'Evaluating monitoring methods to guide adaptive management of a threatened amphibian ( Litoria aurea)', ECOLOGY AND EVOLUTION, 4 1361-1368 (2014) [C1]
DOI 10.1002/ece3.980
Citations Scopus - 6Web of Science - 5
Co-authors John Clulow
2013 Pickett EJ, Stockwell MP, Bower DS, Garnham JI, Pollard CJ, Clulow J, Mahony MJ, 'Achieving no net loss in habitat offset of a threatened frog required high offset ratio and intensive monitoring', BIOLOGICAL CONSERVATION, 157 156-162 (2013) [C1]
DOI 10.1016/j.biocon.2012.09.014
Citations Scopus - 34Web of Science - 30
Co-authors John Clulow
2013 Bower DS, Stockwell MP, Pollard CJ, Pickett EJ, Garnham JI, Clulow J, Mahony MJ, 'Life stage specific variation in the occupancy of ponds by Litoria aurea, a threatened amphibian', Austral Ecology: a journal of ecology in the Southern Hemisphere, 38 543-547 (2013) [C1]
DOI 10.1111/j.1442-9993.2012.02452.x
Citations Scopus - 11Web of Science - 7
Co-authors John Clulow
2013 Mahony MJ, Hamer AJ, Pickett EJ, McKenzie DJ, Stockwell MP, Garnham JI, et al., 'Identifying Conservation and Research Priorities in the Face of Uncertainty: A Review of the Threatened Bell Frog Complex in Eastern Australia.', Herpetological Conservation and Biology, 8 519-538 (2013) [C1]
Citations Scopus - 23Web of Science - 22
Co-authors John Clulow, Simon Clulow
2013 Lettoof DC, Greenlees MJ, Stockwell M, Shine R, 'Do invasive cane toads affect the parasite burdens of native Australian frogs?', International Journal for Parasitology: Parasites and Wildlife, 2 155-164 (2013) [C1]

One of the most devastating impacts of an invasive species is the introduction of novel parasites or diseases to native fauna. Invasive cane toads (Rhinella marina) in Australia c... [more]

One of the most devastating impacts of an invasive species is the introduction of novel parasites or diseases to native fauna. Invasive cane toads (Rhinella marina) in Australia contain several types of parasites, raising concern that the toads may increase rates of parasitism in local anuran species. We sampled cane toads and sympatric native frogs (Limnodynastes peronii, Litoria latopalmata, and Litoria nasuta) at the southern invasion front of cane toads in north-eastern New South Wales (NSW). We dissected and swabbed these anurans to score the presence and abundance of nematodes (Rhabdias lungworms, and gastric encysting nematodes), myxozoans, and chytrid fungus. To determine if cane toad invasion influences rates of parasitism in native frogs, we compared the prevalence and intensity of parasites in frogs from areas with toads, to frogs from areas without toads. Contrary to the situation on the (rapidly-expanding) tropical invasion front, cane toads on the slowly-expanding southern front were heavily infected with rhabditoid lungworms. Toads also contained gastric-encysting nematodes, and one toad was infected by chytrid fungus, but we did not find myxozoans in any toads. All parasite groups were recorded in native frogs, but were less common in areas invaded by toads than in nearby yet to be invaded areas. Contrary to our predictions, toad invasion was associated with a reduced parasite burden in native frogs. Thus, cane toads do not appear to transfer novel parasites to native frog populations, or act as a reservoir for native parasites to 'spill-back' into native frogs. Instead, cane toads may reduce frog-parasite numbers by taking up native parasites that are then killed by the toad's immune defences. © 2013 The Authors.

DOI 10.1016/j.ijppaw.2013.04.002
Citations Scopus - 10
2012 Pickett EJ, Stockwell MP, Pollard CJ, Garnham JI, Clulow J, Mahony MJ, 'Estimates of sex ratio require the incorporation of unequal catchability between sexes', Wildlife Research, 39 350-354 (2012) [C1]
Citations Scopus - 6Web of Science - 6
Co-authors John Clulow
2012 Stockwell MP, Clulow J, Mahony MJ, 'Sodium chloride inhibits the growth and infective capacity of the amphibian chytrid fungus and increases host survival rates', PLoS One, 7 (2012) [C1]
DOI 10.1371/journal.pone.0036942
Citations Scopus - 18Web of Science - 15
Co-authors John Clulow
2010 Stockwell MP, Clulow J, Mahony MJ, 'Efficacy of SYBR 14/propidium iodide viability stain for the amphibian chytrid fungus Batrachochytrium dendrobatidis', Diseases of Aquatic Organisms, 88 177-181 (2010) [C1]
DOI 10.3354/dao02165
Citations Scopus - 7Web of Science - 8
Co-authors John Clulow
2010 Stockwell MP, Clulow J, Mahony MJ, 'Host species determines whether infection load increases beyond disease-causing thresholds following exposure to the amphibian chytrid fungus', Animal Conservation, 13 62-71 (2010) [C1]
DOI 10.1111/j.1469-1795.2010.00407.x
Citations Scopus - 34Web of Science - 34
Co-authors John Clulow
2008 Stockwell MP, Clulow S, Clulow J, Mahony MJ, 'The impact of the amphibian Chytrid Fungus Batrachochytrium dendrobatidis on a Green and Golden Bell Frog Litoria aurea reintroduction program at the Hunter Wetlands Centre Australia in the Hunter Region of NSW', Australian Zoologist, 34 379-386 (2008) [C1]
Citations Scopus - 31
Co-authors Simon Clulow, John Clulow
Show 28 more journal articles

Conference (11 outputs)

Year Citation Altmetrics Link
2014 Valdez J, Stockwell M, Klop-Toker K, Bainbridge L, Clulow S, Clulow J, Mahony M, 'Ensuring successful habitat creation despite ecological experimental design constraints.', 4th International Statistical Ecology Conference. Book of Abstracts (2014) [E3]
Co-authors John Clulow, Simon Clulow
2013 Klop-Toker K, Stockwell M, Valdez J, Bainbridge L, Clulow S, Clulow J, Mahony M, 'A pathogen's impact on the reintroduction of a threatened frog species', EcoTas 13 Handbook (2013) [E3]
Co-authors Simon Clulow, John Clulow
2013 Valdez J, Stockwell M, Klop-Toker K, Clulow S, Clulow J, Mahony M, 'Comparison of habitat selection by an endangered amphibian in a natural and created landscape', EcoTas 13 Handbook (2013) [E3]
Co-authors John Clulow, Simon Clulow
2012 Bower DS, Stockwell MP, Garnham JI, Pollard CJ, Pickett EJ, Clulow J, Mahony MJ, 'Monitoring monitoring: Predicting calling activity to maximize detection in the vulnerable frog Litoria aurea', 2012 World Congress of Herpetology (2012) [E3]
Co-authors John Clulow
2012 Pickett EJ, Stockwell MP, Bower DS, Garnham JI, Pollard CJ, Clulow J, Mahony MJ, 'Growth, survival, uncertainty and the impact on viability of a remnant population of a threatened frog', 2012 World Congress of Herpetology (2012) [E3]
Co-authors John Clulow
2012 Stockwell MP, Clulow J, Mahony MJ, 'Chytrid management scenarios from models of host population dynamics: Costs vs benefits', 2012 World Congress of Herpetology (2012) [E3]
Co-authors John Clulow
2010 Garnham JI, Stockwell MP, Clulow J, Mahony MJ, 'The role of overwintering habitat on the body temperature of an endangered amphibian (Litoria aurea) and its effect on a pathogenic fungus', Australian Society of Herpetologists: Conference Abstracts (2010) [E3]
Co-authors John Clulow
2010 Pickett EJ, Stockwell MP, Garnham JI, Pollard CJ, Clulow J, Mahony MJ, 'Population viability of an endangered generalist amphibian', Australian Society of Herpetologists: Conference Abstracts (2010) [E3]
Co-authors John Clulow
2010 Garnham JI, Stockwell MP, Mahony MJ, Clulow J, 'Temporal variation of chytrid infection and its effect on sodium and potassium exchange of the endangered green and golden bell frog (Litoria aurea)', Emerging Amphibian Diseases Conference (2010) [E3]
Co-authors John Clulow
2009 Stockwell MP, Clulow J, Mahony MJ, 'Identification of an environmental inhibitor of the amphibian chytrid fungus (Batrachochytrium dendrobatidis)', 10th International Congress of Ecology Abstracts (2009) [E3]
Co-authors John Clulow
2007 Stockwell MP, Clulow J, Mahony MJ, 'Water solutes inhibit the growth and infective capacity of the amphibian chytrid fungus (Batrachochytrium dendrobatidis)', ASH 2007 Program and Abstracts (2007) [E3]
Co-authors John Clulow
Show 8 more conferences
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Grants and Funding

Summary

Number of grants 6
Total funding $2,902,435

Click on a grant title below to expand the full details for that specific grant.


20161 grants / $224,959

Research Project - Green and Golden Bell Frog$224,959

Funding body: Newcastle Coal Infrastructure Group (NCIG)

Funding body Newcastle Coal Infrastructure Group (NCIG)
Project Team Doctor John Clulow, Professor Michael Mahony, Doctor Simon Clulow, Doctor Michelle Stockwell
Scheme Research Grant
Role Investigator
Funding Start 2016
Funding Finish 2016
GNo G1600050
Type Of Funding Grant - Aust Non Government
Category 3AFG
UON Y

20141 grants / $7,218

Trialling a novel method of estimating environmental concentrations of the chytrid fungus Batrachochytrium dendrobatidis, an infectious pathogen of amphibians.$7,218

Funding body: University of Newcastle - Faculty of Science & IT

Funding body University of Newcastle - Faculty of Science & IT
Project Team Doctor Michelle Stockwell
Scheme Faculty Early Career Research Grant
Role Lead
Funding Start 2014
Funding Finish 2014
GNo G1401055
Type Of Funding Internal
Category INTE
UON Y

20131 grants / $6,440

Investigating the role of hydrology and salinity in the persistence of green and golden bell frog populations at North Avoca and Davistown.$6,440

Funding body: Gosford City Council

Funding body Gosford City Council
Project Team Professor Michael Mahony, Mr David Wright, Doctor Michelle Stockwell
Scheme Ecological Research Grant
Role Investigator
Funding Start 2013
Funding Finish 2015
GNo G1300480
Type Of Funding Other Public Sector - Local
Category 2OPL
UON Y

20111 grants / $1,405,781

Research and monitoring program for BHP Billiton's Litoria Aurea (Green and Golden Bell frog) compensatory habitat program for the period 2010-2015$1,405,781

Funding body: Newcastle Innovation

Funding body Newcastle Innovation
Project Team Professor Michael Mahony, Doctor John Clulow, Doctor Michelle Stockwell, Doctor Simon Clulow
Scheme Administered Research
Role Investigator
Funding Start 2011
Funding Finish 2015
GNo G1000939
Type Of Funding Internal
Category INTE
UON Y

20102 grants / $1,258,037

Landscape and population dynamics of Kooragang and Ash Island bell frogs$995,226

Funding body: Port Waratah Coal Services Limited

Funding body Port Waratah Coal Services Limited
Project Team Professor Michael Mahony, Doctor John Clulow, Doctor Michelle Stockwell, Doctor Simon Clulow
Scheme Research Project
Role Investigator
Funding Start 2010
Funding Finish 2017
GNo G1000779
Type Of Funding Grant - Aust Non Government
Category 3AFG
UON Y

Establishing a captive breeding and translocation program for the reintroduction of the endangered Green and Golden Bell Frog into trial habitat areas on Kooragang and Ash Island$262,811

Funding body: Newcastle Innovation

Funding body Newcastle Innovation
Project Team Doctor Simon Clulow, Doctor Michelle Stockwell, Doctor John Clulow, Professor Michael Mahony
Scheme Administered Research
Role Investigator
Funding Start 2010
Funding Finish 2011
GNo G1000440
Type Of Funding Internal
Category INTE
UON Y
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Research Supervision

Number of supervisions

Completed2
Current1

Total current UON EFTSL

PhD0.05

Current Supervision

Commenced Level of Study Research Title Program Supervisor Type
2013 PhD Mitigating Disease for Successful Biological Introductions PhD (Environmental Sc), Faculty of Science, The University of Newcastle Co-Supervisor

Past Supervision

Year Level of Study Research Title Program Supervisor Type
2017 PhD Habitat Use and Occupancy Patterns of the Endangered Green and Golden Bell Frog (Litoria aurea)- Implications for Conservation Management PhD (Environmental Sc), Faculty of Science, The University of Newcastle Co-Supervisor
2017 PhD Assessing How Multiple Threats Impact the Green and Golden Bell Frog For the Purpose on Improved Conservation PhD (Environmental Sc), Faculty of Science, The University of Newcastle Co-Supervisor
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Dr Michelle Stockwell

Position

Conjoint Fellow
Amphibian Research Laboratory
School of Environmental and Life Sciences
Faculty of Science

Contact Details

Email michelle.stockwell@newcastle.edu.au
Phone +61 2 49212045

Office

Room BLG.11
Building Biological Sciences
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