Guidance for Developing Amphibian Population Models for Ecological Risk Assessment

Abstract

Despite widespread acceptance of the utility of population modeling and advocacy of this approach for a more ecologically relevant perspective, it is not routinely incorporated in ecological risk assessments (ERA). A systematic framework for situation‐specific model development is one of the major challenges to broadly adopting population models in ERA. As risk assessors confront the multitude of species and chemicals requiring evaluation, an adaptable stepwise guide for model parameterization would facilitate this process. Additional guidance on interpretation of model output and evaluating uncertainty would further contribute to establishing consensus on good modeling practices. We build on previous work that created a framework and decision guide for developing population models for ERA by focusing on data types, model structure, and extrinsic stressors relevant to anuran amphibians. Anurans have a unique life cycle with varying habitat requirements and high phenotypic plasticity. These species belong to the amphibian class, which is facing global population decline in large part due to anthropogenic stressors, including chemicals. We synthesize information from databases and literature relevant to amphibian risks to identify traits that influence exposure likelihood, inherent sensitivity, population vulnerability, and environmental constraints. We link these concerns with relevant population modeling methods and structure in order to evaluate pesticide effects with appropriate scale and parameterization. A standardized population modeling approach, with additional guidance for anuran ERA, offers an example method for quantifying population risks and evaluating long‐term impacts of chemical stressors to populations. Integr Environ Assess Manag 2020;16:223–233. © 2019 SETAC

Pop‐guide: Population modeling guidance, use, interpretation, and development for ecological risk assessment

“…Phylogenetic differences, as demonstrated in aquatic insects, can capture meaningful ecophysiological traits that explain variance in toxicant susceptibility (Buchwalter et al 2008). In the context of Pop‐GUIDE, traits may be included in Phase 2 to increase realism where they have been identified to influence a population's susceptibility to chemical exposure (Awkerman et al 2020). For data‐limited taxa, such as the majority of listed species, trait‐based approaches and comparative analyses provide a systematic approach for cross‐species comparisons (Rueda‐Cediel et al 2019) and for identifying potential representative species for modeling.…”

Harnessing Modeling for Assessing the Population Relevance of Exposure to Endocrine‐Active Chemicals

“…This lack of validated amphibian population models precludes their use for the assessment of population responses to EACs at the present time. However, this should change in the future as appropriate models become available (see Awkerman et al, 2019 for guidance on developing amphibian population models for chemical risk assessment).…”

Framework for multi-stressor physiological response evaluation in amphibian risk assessment and conservation

“…The biphasic life cycle of anuran amphibians makes them particularly vulnerable to extrinsic stressors because of their dependence on variable aquatic habitat resources as well as terrestrial environmental quality (Nolan et al, 2023). Their complex life history strategy and multiple potential drivers of population decline require a more nuanced approach to targeting spatial and temporal variability in stressors relative to life stage (Walls and Gabor, 2019;Awkerman et al, 2020). Distinguishing stagespecific endogenous variation in physiological processes enables anticipation of compromised physical condition in response to common stressors (Brooks and Kindsvater, 2022;Nolan et al, 2023).…”