scholarly journals Ecological immunization: in situ training of free-ranging predatory lizards reduces their vulnerability to invasive toxic prey

2016 ◽  
Vol 12 (1) ◽  
pp. 20150863 ◽  
Author(s):  
G. Ward-Fear ◽  
D. J. Pearson ◽  
G. P. Brown ◽  
Balanggarra Rangers ◽  
R. Shine
Keyword(s):  
Taste Aversion ◽  
Conditioned Taste Aversion ◽  
Population Declines ◽  
Apex Predators ◽  
Rhinella Marina ◽  
Invasion Front ◽  
In Situ Training ◽  
Free Ranging ◽  
The Impact

In Australia, large native predators are fatally poisoned when they ingest invasive cane toads ( Rhinella marina ). As a result, the spread of cane toads has caused catastrophic population declines in these predators. Immediately prior to the arrival of toads at a floodplain in the Kimberley region, we induced conditioned taste aversion in free-ranging varanid lizards ( Varanus panoptes ), by offering them small cane toads. By the end of the 18-month study, only one of 31 untrained lizards had survived longer than 110 days, compared to more than half (nine of 16) of trained lizards; the maximum known survival of a trained lizard in the presence of toads was 482 days. In situ aversion training (releasing small toads in advance of the main invasion front) offers a logistically simple and feasible way to buffer the impact of invasive toads on apex predators.

In situ simulation and its effects on patient outcomes: a systematic review

2019 ◽  
Vol 6 (1) ◽  
pp. 3-9 ◽  
Author(s):  
Daniel Goldshtein ◽  
Cole Krensky ◽  
Sachin Doshi ◽  
Vsevolod S. Perelman
Keyword(s):  
Quality Improvement ◽  
Patient Outcomes ◽  
Simulation Training ◽  
Hospital Setting ◽  
Direct Benefit ◽  
In Situ Simulation ◽  
In Situ Training ◽  
Improvement Programme ◽  
The Impact

BackgroundThe use of in situ simulation has previously been shown to increase confidence, teamwork and practical skills of trained professionals. However, a direct benefit to patient outcomes has not been sufficiently explored. This review focuses on the effect of in situ simulation training in a hospital setting on morbidity or mortality.MethodsA combined search was conducted in PUBMED, OVID, WEB OF SCIENCE, CINAHL, SCOPUS and EMBASE. 478 studies were screened with nine articles published between 2011 and 2017 meeting the inclusion criteria for analysis.ResultsThis review selected eight prospective studies and one prospective-retrospective study. Three studies isolated in situ simulation as an experimental variable while the remaining studies implemented in situ programmes as a component of larger quality improvement initiatives. Seven studies demonstrated a significant improvement in morbidity and/or mortality outcomes following integrated in situ simulation training.ConclusionExisting literature, albeit limited, demonstrates that in situ training improves patient outcomes either in isolation or within a larger quality improvement programme. However, existing evidence contains difficulties such as isolating the impact of in situ training from various potential confounding factors and potential for publication bias.

scholarly journals The cost of chemical defence: the impact of toxin depletion on growth and behaviour of cane toads ( Rhinella marina )

2019 ◽  
Vol 286 (1902) ◽  
pp. 20190867 ◽  
Author(s):  
Ryann A. Blennerhassett ◽  
Kim Bell-Anderson ◽  
Richard Shine ◽  
Gregory P. Brown
Keyword(s):  
Chemical Defence ◽  
Toxin Production ◽  
Substantial Cost ◽  
Rhinella Marina ◽  
Chemical Defences ◽  
Trade Offs ◽  
The Cost ◽  
Rates Of Growth ◽  
Free Ranging ◽  
The Impact

Many animals capable of deploying chemical defences are reluctant to use them, suggesting that synthesis of toxins imposes a substantial cost. Typically, such costs have been quantified by measuring the elevation in metabolic rate induced by toxin depletion (i.e. during replenishment of toxin stores). More generally, we might expect that toxin depletion will induce shifts in a broad suite of fitness-relevant traits. In cane toads ( Rhinella marina ), toxic compounds that protect against predators and pathogens are stored in large parotoid (shoulder) glands. We used correlational and experimental approaches in field and laboratory settings to investigate impacts of toxin depletion on growth rate and behaviour in cane toads. In free-ranging toads, larger toxin stores were associated with smaller gonads and livers, suggesting energetic trade-offs between toxin production and both reproduction and energy metabolism. Experimental removal of toxin (by manually squeezing parotoid glands) reduced rates of growth in body mass in both captive and free-ranging toads. Radio tracking demonstrated that de-toxined toads dispersed more slowly than did control toads. Given that toxin stores in cane toads take several months to fully replenish, deploying toxin to repel a predator may impose a substantial cost, explaining why toads use toxin only as a final line of defence.

scholarly journals Divergent long-term impacts of lethally toxic cane toads (Rhinella marina) on two species of apex predators (monitor lizards, Varanus spp.)

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0254032
Author(s):  
Lachlan Pettit ◽  
Mathew S. Crowther ◽  
Georgia Ward-Fear ◽  
Richard Shine
Keyword(s):  
Synergistic Effects ◽  
Food Sources ◽  
Apex Predators ◽  
Natural Ecosystems ◽  
Rhinella Marina ◽  
Eastern Australia ◽  
Monitor Lizards ◽  
Alternative Food Sources ◽  
Induced Changes ◽  
The Impact

Biological invasions can massively disrupt ecosystems, but evolutionary and ecological adjustments may modify the magnitude of that impact through time. Such post-colonisation shifts can change priorities for management. We quantified the abundance of two species of giant monitor lizards, and of the availability of their mammalian prey, across 45 sites distributed across the entire invasion trajectory of the cane toad (Rhinella marina) in Australia. One varanid species (Varanus panoptes from tropical Australia) showed dramatic population collapse with toad invasion, with no sign of recovery at most (but not all) sites that toads had occupied for up to 80 years. In contrast, abundance of the other species (Varanus varius from eastern-coastal Australia) was largely unaffected by toad invasion. That difference might reflect availability of alternative food sources in eastern-coastal areas, perhaps exacerbated by the widespread prior collapse of populations of small mammals across tropical (but not eastern) Australia. According to this hypothesis, the impact of cane toads on apex predators has been exacerbated and prolonged by a scarcity of alternative prey. More generally, multiple anthropogenically-induced changes to natural ecosystems may have synergistic effects, intensifying the impacts beyond that expected from either threat in isolation.

scholarly journals Rapidly increasing methyl mercury in endangered ivory gull ( Pagophila eburnea ) feathers over a 130 year record

2015 ◽  
Vol 282 (1805) ◽  
pp. 20150032 ◽  
Author(s):  
Alexander L. Bond ◽  
Keith A. Hobson ◽  
Brian A. Branfireun
Keyword(s):  
High Latitude ◽  
Methyl Mercury ◽  
Body Burden ◽  
The Arctic ◽  
Population Declines ◽  
Apex Predators ◽  
Dietary Shift ◽  
Marine Food Webs ◽  
Ivory Gull ◽  
The Impact

Mercury (Hg) is increasing in marine food webs, especially at high latitudes. The bioaccumulation and biomagnification of methyl mercury (MeHg) has serious effects on wildlife, and is most evident in apex predators. The MeHg body burden in birds is the balance of ingestion and excretion, and MeHg in feathers is an effective indicator of overall MeHg burden. Ivory gulls ( Pagophila eburnea ), which consume ice-associated prey and scavenge marine mammal carcasses, have the highest egg Hg concentrations of any Arctic bird, and the species has declined by more than 80% since the 1980s in Canada. We used feathers from museum specimens from the Canadian Arctic and western Greenland to assess whether exposure to MeHg by ivory gulls increased from 1877 to 2007. Based on constant feather stable-isotope ( δ 13 C, δ 15 N) values, there was no significant change in ivory gulls' diet over this period, but feather MeHg concentrations increased 45× (from 0.09 to 4.11 µg g −1 in adults). This dramatic change in the absence of a dietary shift is clear evidence of the impact of anthropogenic Hg on this high-latitude threatened species. Bioavailable Hg is expected to increase in the Arctic, raising concern for continued population declines in high-latitude species that are far from sources of environmental contaminants.

scholarly journals Not such silly sausages: Northern quolls exhibit aversion to toads after training with toad sausages

2017 ◽  
Author(s):  
Naomi Indigo ◽  
James Smith ◽  
Jonathan K. Webb ◽  
Ben Phillips
Keyword(s):  
Taste Aversion ◽  
Conditioned Taste Aversion ◽  
Prey Item ◽  
Field Trials ◽  
Landscape Scale ◽  
Target Species ◽  
Rhinella Marina ◽  
Major Threat ◽  
Training Technique ◽  
Broad Scale

AbstractThe invasion of toxic cane toads (Rhinella marina) is a major threat to northern quolls (Dasyurus hallucatus) which are poisoned when they attack this novel prey item. Quolls are now endangered as a consequence of the toad invasion. Conditioned taste aversion can be used to train individual quolls to avoid toads, but we currently lack a training technique that can be used at a landscape scale to buffer entire populations from toad impact. Broad scale deployment requires a bait that can be used for training, but there is no guarantee that such a bait will ultimately elicit aversion to toads. Here we test a manufactured bait—a ‘toad sausage’—for its ability to elicit aversion to toads in northern quolls. To do this, we exposed one group of quolls to a toad sausage and another to a control sausage and compared the quolls’ predatory responses when presented with a dead adult toad. Captive quolls that consumed a single toad sausage showed substantially reduced interest in cane toads, interacting with them for less than half the time of their untrained counterparts and showing substantially reduced attack behaviour. We also quantified bait uptake in the field, by both quolls and non-target species. These field trials showed that wild quolls were the most frequent species attracted to the baits, and that approximately 61% of quolls consumed toad-aversion baits when first encountered. Between 40-68% of these animals developed aversion to further bait consumption. Our results suggest that toad-aversion sausages can be used to train wild quolls to avoid cane toads. This opens the possibility for broad-scale quoll training with toad aversion sausages: a technique that may allow wildlife managers to prevent quoll extinctions at a landscape scale.

Predators learning to avoid toxic invasive prey: a study on individual variation among free-ranging lizards

Behaviour ◽  
2020 ◽  
Vol 157 (14-15) ◽  
pp. 1153-1172 ◽  
Author(s):  
Georgia Ward-Fear ◽  
Gregory P. Brown ◽  
Richard Shine
Keyword(s):  
Taste Aversion ◽  
Individual Variation ◽  
Opportunity To Learn ◽  
Population Persistence ◽  
Wild Populations ◽  
Rhinella Marina ◽  
Behavioural Responses ◽  
Invasive Prey ◽  
Threatening Processes ◽  
Free Ranging

Abstract Within all wild populations, individuals vary in ways that affect their vulnerability to threatening processes. Understanding that variation may clarify mechanisms of population persistence and/or evolution. In Australia, Yellow-spotted Monitors (Varanus panoptes), decline by >90% when toxic Cane Toads (Rhinella marina) invade an area. Taste-aversion training (exposing animals to non-lethal toads) can buffer impacts; but does pre-existing behavioural variation also influence survival? An individual’s fate can be predicted from its behaviour during aversion-training trials. Lizards presented with small toads either consumed them, rejected them, or fled. When Cane Toads invaded our study site, mortality was lower in lizards that ‘consumed’ (aversion-trained) than in those that ‘fled’ (untrained), but even lower in lizards that ‘rejected’ toads outright. Thus, animals reluctant to consume toads in trials survived despite never being aversion-trained. In this system, lizard vulnerability is driven by boldness, behavioural responses to novel prey types, and the opportunity to learn aversion.

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