Impacts of Rodenticide and Insecticide Toxicants from Marijuana Cultivation Sites on Fisher Survival Rates in the Sierra National Forest, California

Craig Thompson, Richard Sweitzer, Mourad Gabriel, Kathryn Purcell, Reginald Barrett, Robert H Poppenga

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

Secondary exposure of wildlife to pesticides has been well documented, yet exposure is typically associated with agricultural or wildland-urban interface areas. Wildlife in undeveloped areas is generally presumed free from risk. In 2009, a male fisher was found dead in the Sierra National Forest and subsequent necropsy revealed that the animal died of acute rodenticide poisoning. Follow-up testing revealed that 85% of fisher carcasses recovered by two research projects in the previous three years tested positive for rodenticides. Concern arose that exposure could predispose an animal to mortality from other causes, and that the underlying role of toxicants would escape notice. Further investigation indicated that the most likely source was the numerous illegal marijuana cultivation sites currently found on public lands throughout the western United States. To determine whether the presence of cultivation sites predisposed fishers to mortality from other sources, we related survival rates to the presence and number of cultivation sites found within that animal's home range over the past 10 years. Likelihood of exposure was related to the presence of cultivation sites, and female fisher survival was influenced by the number of cultivation sites within its home range. We discuss the conservation implications of this unexpected relationship.

Original languageEnglish (US)
Pages (from-to)91-102
Number of pages12
JournalConservation Letters
Volume7
Issue number2
DOIs
StatePublished - 2014

Fingerprint

Sierra National Forest
rodenticide
rodenticides
Cannabis sativa
toxic substances
insecticide
insecticides
survival rate
wildlife
wildland-urban interface
animals
secondary contact
public lands
home range
Western United States
animal
research projects
poisoning
necropsy
pesticides

Keywords

  • Anticoagulant rodenticide
  • Fisher
  • Marijuana
  • Pekania pennanti
  • Pesticide
  • Survival

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Ecology
  • Nature and Landscape Conservation

Cite this

Impacts of Rodenticide and Insecticide Toxicants from Marijuana Cultivation Sites on Fisher Survival Rates in the Sierra National Forest, California. / Thompson, Craig; Sweitzer, Richard; Gabriel, Mourad; Purcell, Kathryn; Barrett, Reginald; Poppenga, Robert H.

In: Conservation Letters, Vol. 7, No. 2, 2014, p. 91-102.

Research output: Contribution to journalArticle

Thompson, Craig ; Sweitzer, Richard ; Gabriel, Mourad ; Purcell, Kathryn ; Barrett, Reginald ; Poppenga, Robert H. / Impacts of Rodenticide and Insecticide Toxicants from Marijuana Cultivation Sites on Fisher Survival Rates in the Sierra National Forest, California. In: Conservation Letters. 2014 ; Vol. 7, No. 2. pp. 91-102.
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