Perspectives on Existing and Potential New Alternatives to Anticoagulant Rodenticides and the Implications for Integrated Pest Management

Witmer, Gary W.

doi:10.1007/978-3-319-64377-9_13

Cited by 18 publications

(22 citation statements)

References 76 publications

(75 reference statements)

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“…Uncertainties remain regarding interpretation and implications of liver residues of ARs in wildlife, particularly when multiple ARs are present in an individual animal (Rattner et al 2020) and regarding the exact pathways through ecosystems that ARs travel en route from application in the structural or agricultural setting to apex predators and scavengers (Hindmarch and Elliott 2018; Shore and Coeurdassier 2018) The need for ongoing monitoring and study is clear, however. Although alternatives to ARs are being explored (Blackie et al 2014; Witmer 2018), their continued use in the near future is certain, particularly as changes in land use by humans and climate change will likely influence rodent abundance and increase concern regarding zoonotic disease transmission (Barata 2017; Mendoza et al 2019). In addition, as governmental regulatory agencies implement approaches to minimize risk to wildlife from ARs (Eisemann et al 2018), evaluation of these mitigation measures is indicated.…”

Section: Introductionmentioning

confidence: 99%

Continued Anticoagulant Rodenticide Exposure of Red‐tailed Hawks (Buteo jamaicensis) in the Northeastern United States with an Evaluation of Serum for Biomonitoring

Murray

2020

Enviro Toxic and Chemistry

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Prior studies (2006-2016) in birds of prey admitted to a wildlife clinic in Massachusetts, USA, revealed widespread exposure to second-generation anticoagulant rodenticides (SGARs) among red-tailed hawks (Buteo jamaicensis, RTHAs). Continued monitoring of species for which historic data are available can reveal trends in exposure that aid in evaluating the effectiveness of risk-mitigation measures. While the majority of exposure-monitoring studies utilize liver tissue collected postmortem, antemortem modalities, such as serum analysis, may be desirable for risk assessments in certain populations. However, the sensitivity of serum for detecting anticoagulant rodenticides (ARs) is not well studied. Paired liver and serum samples from 43 RTHAs were evaluated from 2017 to 2019. In liver tissue, 100% of birds were positive for ARs, with the SGARs brodifacoum, bromadiolone, and difethialone identified most frequently; 91% of birds had liver residues of 2 to 4 ARs. These findings represent the highest exposure both to ARs overall and to multiple ARs in RTHAs compared to previous studies. All birds diagnosed with AR toxicosis (n = 14) were positive for ARs in serum; however, all subclinically exposed birds (n = 29) were negative in serum. These data show that exposure to SGARs remains widespread in RTHAs in this geographic area. In addition, although serum analysis is not sensitive for detecting sublethal exposures in RTHAs, it can potentially support a diagnosis of AR toxicosis in conjunction with other consistent signs.

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Section: Introductionmentioning

confidence: 99%

Continued Anticoagulant Rodenticide Exposure of Red‐tailed Hawks (Buteo jamaicensis) in the Northeastern United States with an Evaluation of Serum for Biomonitoring

Murray

2020

Enviro Toxic and Chemistry

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“…Collectively, the low proportion of ground squirrels exposed aboveground, combined with daily carcass searches, should substantially reduce secondary exposure risk. It bears noting that rodenticide applications should be only one part of an integrated pest management program for rodent management (Baldwin et al 2014;Witmer 2018). Relying on anticoagulant rodenticides only when needed is the best strategy for minimizing the risk of secondary exposure.…”

Section: Discussionmentioning

confidence: 99%

Potential impact of diphacinone application strategies on secondary exposure risk in a common rodent pest: implications for management of California ground squirrels

Baldwin

Becchetti

Meinerz

et al. 2021

Environ Sci Pollut Res

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Anticoagulant rodenticides are a common tool used to manage rodents in agricultural systems, but they have received increased scrutiny given concerns about secondary exposure in non-target wildlife. Rodenticide application strategy is one factor that influences exposure risk. To understand the impact of application strategy, we tested residues of a first-generation anticoagulant (diphacinone) in liver tissue of radiotransmittered California ground squirrels (Otospermophilus beecheyi) following spot treatments, broadcast applications, and bait station applications in rangelands in central California during summer and autumn 2018–2019. We also documented the amount of bait applied, the mean time from bait application until death, and the proportion of ground squirrels that died belowground. We documented the greatest amount of bait applied via bait stations and the least by broadcast applications. We did not document a difference in diphacinone residues across any application strategy, although survivors had an order of magnitude lower concentration of diphacinone than mortalities, potentially lowering secondary exposure risk. We did not observe any difference among bait delivery methods in time from bait application to death, nor did we identify any impact of seasonality on any of the factors we tested. The vast majority of mortalities occurred belowground (82–91%), likely reducing secondary exposure. Secondary exposure could be further reduced by daily carcass searches. Results from this study better define risk associated with first-generation anticoagulant rodenticide applications, ultimately assisting in development of management programs that minimize non-target exposure.

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“…Evidence of the widespread SGAR exposure and poisoning of nontarget predators and scavengers has continued to increase (López‐Perea & Mateo, 2018; Nakayama et al, 2019; Serieys et al, 2019; Okoniewski et al, 2021; Rial‐Berriel et al, 2021; Thornton et al, 2022). Concern over their spread as contaminants has led to an intensified search for alternatives, as well as for regulatory and voluntary mitigation measures (Elliott et al, 2016; Witmer, 2018). We have updated previous reports on contamination of avian predators and scavengers (Albert et al, 2010; Hindmarch et al, 2019; Huang et al, 2016; Thomas et al, 2011) with an expanded sample, including putative bird‐eating species.…”

Section: Introductionmentioning

confidence: 99%

Anticoagulant Rodenticide Contamination of Terrestrial Birds of Prey from Western Canada: Patterns and Trends, 1988–2018

Elliott

Silverthorn

Hindmarch

et al. 2022

Enviro Toxic and Chemistry

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As the dominant means for control of pest rodent populations globally, anticoagulant rodenticides (ARs), particularly the second‐generation compounds (SGARs), have widely contaminated nontarget organisms. We present data on hepatic residues of ARs in 741 raptorial birds found dead or brought into rehabilitation centers in British Columbia, Canada, over a 30‐year period from 1988 to 2018. Exposure varied by species, by proximity to residential areas, and over time, with at least one SGAR residue detected in 74% of individuals and multiple residues in 50% of individuals. By comparison, we detected first‐generation compounds in <5% of the raptors. Highest rates of exposure were in barred owls (Strix varia), 96%, and great horned owls (Bubo virginianus), 81%, species with diverse diets, including rats (Rattus norvegicus and Rattus rattus), and inhabiting suburban and intensive agricultural habitats. Barn owls (Tyto alba), mainly a vole (Microtus) eater, had a lower incidence of exposure of 65%. Putatively, bird‐eating raptors also had a relatively high incidence of exposure, with 75% of Cooper's hawks (Accipiter cooperii) and 60% of sharp‐shinned hawks (Accipiter striatus) exposed. Concentrations of SGARs varied greatly, for example, in barred owls, the geometric mean ∑SGAR = 0.13, ranging from <0.005 to 1.81 μg/g wet weight (n = 208). Barred owls had significantly higher ∑SGAR concentrations than all other species, driven by significantly higher bromadiolone concentrations, which was predicted by the proportion of residential land within their home ranges. Preliminary indications that risk mitigation measures implemented in 2013 are having an influence on exposure include a decrease in mean concentrations of brodifacoum and difethialone in barred and great horned owls and an increase in bromodialone around that inflection point. Environ Toxicol Chem 2022;41:1903–1917. © 2022 Her Majesty the Queen in Right of Canada. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. Reproduced with the permission of the Minister of Environment and Climate Change Canada.

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Perspectives on Existing and Potential New Alternatives to Anticoagulant Rodenticides and the Implications for Integrated Pest Management

Cited by 18 publications

References 76 publications

Continued Anticoagulant Rodenticide Exposure of Red‐tailed Hawks (Buteo jamaicensis) in the Northeastern United States with an Evaluation of Serum for Biomonitoring

Continued Anticoagulant Rodenticide Exposure of Red‐tailed Hawks (Buteo jamaicensis) in the Northeastern United States with an Evaluation of Serum for Biomonitoring

Potential impact of diphacinone application strategies on secondary exposure risk in a common rodent pest: implications for management of California ground squirrels

Anticoagulant Rodenticide Contamination of Terrestrial Birds of Prey from Western Canada: Patterns and Trends, 1988–2018

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