Ecological risk assessment models integrate information on exposure, toxicity, and life history to predict potential risk to ecological receptors. However, the underlying biological and ecological processes occur at different temporal rates and are often measured at different levels of resolution. These considerations of scale and measurement resolution influence the importance of different parameters for conclusions about risk that can be illuminated using model sensitivity analysis. We present a thorough sensitivity analysis of the MCnest model for each of these three model parameter categories (life history, exposure, and toxicity). For toxicity we include two terrestrial exposure models, the Terrestrial Residue Exposure Model (T-REX) and the Terrestrial Investigation Model (TIM), which operate at different levels of complexity.
Results/Conclusions
Among life history parameters, nest and adult survival rates are the most influential parameters determining seasonal productivity. Among exposure and toxicity parameters, application rates, water solubility, and degradation rates were the most important parameters. Different sensitivity metrics conveyed different information about the effects of perturbations in model parameters and were not necessarily correlated with each other. This highlights the importance of careful thought about what metric to choose to characterize model sensitivity.