Abstract
In this paper, we applied an individual-based model to study the population-level impacts of sub-lethal stressors affecting the metabolic pathways of three closely related trout species: Oncorhynchus mykiss (rainbow trout, RT), Salmo trutta (brown trout, BT) and Oncorhynchus calrki stomias (greenback cutthroat trout, GCT). Both RT and BT are well-studied species, and the former is widely used as a standard cold-water test species. These species are known to outcompete GCT, which is listed as threatened under the US Endangered Species Act. Our goal was to understand the extent to which stressor effects, which are often measured at the individual level, on taxonomically-related (i.e., surrogate) species can be informative of impacts on population dynamics in species that cannot be tested (e.g., listed species). When comparing stressor effects among species, we found that individual-level responses to each stressor were qualitatively comparable. Individual lengths and number of eggs decreased by similar percentages with respect to baseline, even if small quantitative differences were present depending on the physiological mode of action of the stressor. Individual-level effects in GCT were slightly greater when ingestion efficiency decreased, whereas effects in GCT and RT were greater when maintenance costs increased, and effects in BT were slightly greater when costs of growth increased. In contrast, results at the population level differed markedly among species with GCT the most impacted by sub-lethal stress effects on individual metabolism. Our findings suggest that using non-listed species to assess the risks of stressors to listed species populations may be misleading, even if the species are closely related and show similar individual-level responses. Mechanistic population models that incorporate species life history and ecology can improve inter-species extrapolation of stressor effects.
| Original language | English (US) |
|---|---|
| Article number | 133295 |
| Journal | Science of the Total Environment |
| Volume | 693 |
| DOIs | |
| State | Published - Nov 25 2019 |
Bibliographical note
Funding Information:We thank Volker Grimm,Nika Galic,Amelie Schmolke andSteve Railsback for their advice on model implementation and their comments on model outputs. We also thank Pamela Rueda-Cediel andAdrian Moore for their helpful comments on this work. We thank Irvin Schultz for the important discussions on trout life-history traits. Finally, we thank Laure Pecquerie andStarrlight Augustine for supervising the DEB parametrization of GCT. Funding for this project was provided by University of Minnesota . We also thank the anonymous reviewers for their constructive comments and suggestions.
Publisher Copyright:
© 2019
Keywords
- Dynamic Energy Budget theory
- Individual-based models
- Population dynamics
- Stressor effects
- Trout species
- Upscaling
