Assessing Individual and Population-Level Effects of Anticoagulant Rodenticides on Wildlife

• Main Author: Niamh Quinn
• Format: Article
• Language: English
• Published: Utah State University 2019-09-01
• Series: Human-Wildlife Interactions
• Subjects: anticoagulant rodenticides; lethal effects; pesticide residues; regulations; sublethal effects; wildlife
• Online Access: https://digitalcommons.usu.edu/hwi/vol13/iss2/7
• ISSN: 2155-3874; 2155-3874

Anticoagulant rodenticides have been detected in many species of wildlife worldwide. However, the origins, exposure pathways, and effects of this exposure are not well understood. To accurately characterize the risks to wildlife from rodenticide use, better information is needed regarding the proportion of populations being exposed, what proportion of individuals in populations are affected, and in what ways. The relationship between anticoagulant rodenticide concentrations found in wildlife and the rate of mortality or illness have been the subjects of much research. Residue levels observed in liver and whole-body analyses vary and overlap extensively among apparently healthy asymptomatic individuals and sublethal and lethal cases. Results from laboratory studies also show there can be wide variability in lethal and sublethal effects among and within taxonomic groups. Correlating the sublethal and reproductive effects observed in laboratory studies with realistic exposure scenarios and effects in the wild is needed to improve risk assessments. For species with limited numbers or declining populations, a critical question yet to be answered is if the rodenticide exposure documented in individual animals inhibits population growth or contributes to population declines by lowering survival and reproductive success. This information is essential to the regulatory agencies that must weigh the risks and benefits of rodenticide uses and identify restrictions that are effective in reducing risks to wildlife.