Use of Anticoagulant Rodenticides in Single-Family Neighborhoods Along an Urban-Wildland Interface in California

Authors

Monica Bartos, UCLA Institute of the Environment and SustainabilityFollow
Sylvie Dao, UCLA Institute of the Environment and SustainabilityFollow
Dale Douk, UCLA Institute of the Environment and SustainabilityFollow
Stephanie Falzone, UCLA Institute of the Environment and SustainabilityFollow
Eric Gumerlock, UCLA Institute of the Environment and SustainabilityFollow
Stephanie Hoekstra, UCLA Institute of the Environment and SustainabilityFollow
Kaitlin Kelly-Reif, UCLA Institute of the Environment and SustainabilityFollow
David Mori, UCLA Institute of the Environment and SustainabilityFollow
Chay Tang, UCLA Institute of the Environment and SustainabilityFollow
Cassandra Vasquez, UCLA Institute of the Environment and SustainabilityFollow
Jennifer Ward, UCLA Institute of the Environment and SustainabilityFollow
Sarah Young, UCLA Institute of the Environment and SustainabilityFollow
Anita T. Morzillo, Oregon State UniversityFollow
Seth P. D. Riley, Wildlife Biologist, Santa Monica Mountains National Recreation Area,Follow
Travis Longcore, UCLA Institute of the Environment and SustainabilityFollow

Urbanization poses many threats for many wildlife species. In addition to habitat loss and fragmentation, non-target wildlife species are vulnerable to poisoning by rodenticides, especially acutely toxic second generation anticoagulant rodenticides (SGARs). Although such poisonings are well documented for birds and mammals worldwide, the pathways by which these widely available compounds reach non-target wildlife have not been adequately studied, particularly in urban landscapes. Long-term studies of wild carnivores in and around Santa Monica Mountains National Recreation Area, a national park north of Los Angeles, have documented >85% exposure to anticoagulant rodenticides among bobcats, coyotes, and mountain lions. To investigate potential mechanisms of transfer of chemicals from residential users of rodenticides to non-target wildlife in the Santa Monica Mountains in Los Angeles County, California, we distributed surveys to residents in two study areas on the north (San Fernando Valley) and south (Bel Air-Hollywood Hills) slopes of these mountains. We assessed knowledge of residents about the environmental effects of rodenticides, and for information about individual application of chemicals. We asked for the same information from pest control operators (PCOs) in both study areas. Forty residents completed the survey in the San Fernando Valley area, and 20 residents completed the survey in Bel Air-Hollywood Hills. Despite the small number of total responses, we documented a number of important findings. Homeowners (as opposed to gardeners or PCOs) were the primary applicators of rodenticides, predominantly SGARs, and awareness of the hazards of secondary poisoning to wildlife was not consistent. Some residents reported improperly applying rodenticides (e.g., exceeding prescribed distances from structures), and in one instance a respondent reported observing dead animals outside after placing poison inside a structure. Improper application of SGARs that ignores label guidelines occurs in neighborhoods along the urban–wildland interface, thereby providing a transmission pathway for chemical rodenticides to reach native wildlife. Moreover, the responses suggest that even on-label use (e.g. placing poisons inside) can create risk for non-target wildlife.

Recommended Citation

Bartos, Monica; Dao, Sylvie; Douk, Dale; Falzone, Stephanie; Gumerlock, Eric; Hoekstra, Stephanie; Kelly-Reif, Kaitlin; Mori, David; Tang, Chay; Vasquez, Cassandra; Ward, Jennifer; Young, Sarah; Morzillo, Anita T.; Riley, Seth P. D.; and Longcore, Travis (2012) "Use of Anticoagulant Rodenticides in Single-Family Neighborhoods Along an Urban-Wildland Interface in California," Cities and the Environment (CATE): Vol. 4: Iss. 1, Article 12.
Available at: https://digitalcommons.lmu.edu/cate/vol4/iss1/12