Selecting surrogate endpoints for estimating pesticide effects on avian reproductive success

Bennett, Richard S.; Etterson, Matthew A.

doi:10.1002/ieam.1478

Cited by 11 publications

(14 citation statements)

References 48 publications

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“…Current European Union (EU) guidelines for pesticide risk assessment on birds only consider a dietary exposure of adult birds to characterize pesticide effects on avian reproduction . The usefulness of this avian reproduction test to detect certain effects occurring during the breeding phase of wild birds has been questioned. , Bennett and Etterson concluded that none of the endpoints obtained from the toxicity tests routinely included in the risk assessment procedures (e.g., LD 50 , NOAEL for different reproductive variables) was useful to extrapolate the effects on hatching or offspring survival following an external eggshell exposure. Our results support this conclusion because, as mentioned above, we recorded increased chick mortality despite the maximum concentrations of 2,4-D and tebuconazole measured in eggs were several orders of magnitude lower than the avian LD 50 values used to characterize acute toxicity for pesticide registration in the EU.…”

Section: Resultsmentioning

confidence: 99%

“…Bennett and Etterson reviewed some external eggshell exposure studies of bird eggs to pesticides and stated that relating field application rates to actual pesticide masses applied onto the eggs was a challenge in the applicability of those tests to environmental risk assessment. We have addressed this issue by designing our study based on given application rates rather on the pesticide doses received by eggs.…”

Section: Resultsmentioning

confidence: 99%

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Egg Overspray with Herbicides and Fungicides Reduces Survival of Red-Legged Partridge Chicks

Ortiz‐Santaliestra

Alcaide

Camarero

et al. 2020

Environ. Sci. Technol.

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Within the environmental risk assessment conducted for pesticide registration in the European Union (EU), avian reproductive toxicity is characterized after exposing adults. However, eggs of ground-nesting species can be exposed when pesticide applications occur during laying or incubation. We simulated environmentally realistic exposure of red-legged partridge (Alectoris rufa) eggs to an herbicide (2,4-D) and a fungicide (tebuconazole) applied to winter cereal crops during the breeding season of most farmland birds. We analyzed the effects on hatching success, offspring survival, and physiology. Exposure by overspray led to greater pesticide accumulation in the eggshell or content than exposure through contact with treated soil (3.1–13.7 times higher, depending on the pesticide and target sample). Egg overspray with tebuconazole significantly increased chick mortality, which was 26% higher than that of controls. 2,4-D caused a similar but a close to significant increase (chick mortality 24% higher than controls). Exposure to either pesticide through contact with treated soils did not affect chick survival but altered some biochemical parameters posthatching. Our experiment shows that egg spraying with pesticides should be considered as a relevant exposure scenario in risk assessment procedures, given its potential to affect the reproductive success of ground-nesting farmland birds.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Egg Overspray with Herbicides and Fungicides Reduces Survival of Red-Legged Partridge Chicks

Ortiz‐Santaliestra

Alcaide

Camarero

et al. 2020

Environ. Sci. Technol.

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“…Insecticide induced failures are modeled by the inclusion of daily exposure values from TIM. These values are compared to phase-specific NOAELs for different kinds of adverse effects that might be induced by insecticide exposure such as eggshell thinning, reduced egg viability, reduced hatching success, and increased abandonment [ 10 , 27 ]. Populations with identical parameter values are simulated with replication to provide estimates of variability around model predictions.…”

Section: Methodsmentioning

confidence: 99%

A spatially explicit model for estimating risks of pesticide exposure to bird populations

et al. 2021

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Pesticides are used widely in agriculture and have the potential to affect non-target organisms, including birds. We developed an integrated modeling system to allow for spatially-explicit evaluation of potential impacts to bird populations following exposures to pesticides. Our novel methodology builds upon three existing models: the Terrestrial Investigation Model (TIM), the Markov Chain Nest Productivity Model (MCnest), and HexSim to simulate population dynamics. We parameterized the integrated modeling system using information required under the Federal Insecticide, Fungicide, and Rodenticide Act, together with species habitat and life history data available from the scientific literature as well as landcover data representing agricultural areas and species habitat. Our case study of the federally threatened California Gnatcatcher (Polioptila californica) illustrates how the integrated modeling system can estimate the population-scale consequences of pesticide applications. We simulated impacts from two insecticides applied to wheat: one causing mortality (survival stressor), and the other causing reproductive failure (reproductive stressor). We observed declines in simulated gnatcatcher abundance and changes in the species’ distribution following applications of each pesticide; however, the impacts of the two pesticides were different. Our methodology attempts to strike a balance between biological realism and model complexity and should be applicable to a wide array of species, systems, and stressors.

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“…The surrogate endpoints for each breeding phase are compared to a specific measure of exposure to determine if the nest attempt continues or fails—essentially a phase‐specific risk quotient (Figure ). The default surrogate endpoints in the Basic Version of MCnest have been modified from those described in Bennett et al () and are described in greater detail in Bennett and Etterson (this issue). Based on recommendations in the European Union (EU) Guidance on Bird and Mammal Risk Assessments (EFSA ), an additional surrogate endpoint derived from the LD50 has been included as an indicator of effects on adult well‐being during all breeding phases except the egg‐laying phase.…”

Section: Methodsmentioning

confidence: 99%

“…A rapid change in body weight during the first 2 weeks of exposure due to changes in food consumption rates or other sublethal effects would indicate adverse effects on adult well‐being that may lead to nest abandonment or reduced nest attentiveness in the field. Bennett and Etterson (this issue) present a more thorough discussion on the strategy for selecting surrogate endpoints in MCnest.…”

Section: Methodsmentioning

confidence: 99%

Quantifying the effects of pesticide exposure on annual reproductive success of birds

Etterson

Bennett

2013

Integr Environ Assess Manag

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The Markov chain nest productivity model (MCnest) was developed for quantifying the effects of specific pesticide-use scenarios on the annual reproductive success of simulated populations of birds. Each nesting attempt is divided into a series of discrete phases (e.g., egg laying, incubation, nestling rearing), and results from avian toxicity tests are used to represent the types of effects possible in the field during each breeding phase. The expected exposure dose each day throughout the breeding season can be compared to the toxicity thresholds assigned to each breeding phase to determine whether the nest attempt is at risk. The primary output of the model is an estimate of the number of successful nest attempts per female per year, which is multiplied by the number of fledglings per successful nest to estimate the number of fledglings per female per breeding season (i.e., annual reproductive success). In this article, we present a series of MCnest simulations to demonstrate the extent to which the magnitude of change in annual reproductive success can be affected by considering life history attributes and the timing of pesticide applications relative to a species' typical breeding phenology. For a given pesticide-use scenario, MCnest can identify which species are at greatest risk. By allowing multiple species to be run under a single scenario, it can also help to identify the life-history traits that contribute to a species' vulnerability to a given pesticide-use scenario. It also can determine which application dates have the greatest impact and demonstrate the extent to which pesticide characteristics (e.g., residue half-life, mode of action) affect productivity. MCnest goes beyond the current qualitative screening-level assessments of risks to avian reproduction to provide an approach for quantifying the reduction in annual reproductive success by integrating species life history and timing of pesticide exposures, despite limitations in existing information on species life history and toxicity responses from existing laboratory tests.

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Selecting surrogate endpoints for estimating pesticide effects on avian reproductive success

Cited by 11 publications

References 48 publications

Egg Overspray with Herbicides and Fungicides Reduces Survival of Red-Legged Partridge Chicks

Egg Overspray with Herbicides and Fungicides Reduces Survival of Red-Legged Partridge Chicks

A spatially explicit model for estimating risks of pesticide exposure to bird populations

Quantifying the effects of pesticide exposure on annual reproductive success of birds

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