Patterns of natural and human-caused mortality factors of a rare forest carnivore, the fisher (Pekania pennanti) in California

Mourad W. Gabriel, Leslie Woods, Greta M. Wengert, Nicole Stephenson, J. Mark Higley, Craig Thompson, Sean M. Matthews, Rick A. Sweitzer, Kathryn Purcell, Reginald H. Barrett, Stefan M. Keller, Patricia Gaffney, Megan Jones, Robert H Poppenga, Janet E Foley, Richard N. Brown, Deana L. Clifford, Benjamin Sacks

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Wildlife populations of conservation concern are limited in distribution, population size and persistence by various factors, including mortality. The fisher (Pekania pennanti), a North American mid-sized carnivore whose range in the western Pacific United States has retracted considerably in the past century, was proposed for threatened status protection in late 2014 under the United States Endangered Species Act by the United States Fish and Wildlife Service in its West Coast Distinct Population Segment. We investigated mortality in 167 fishers from two genetically and geographically distinct sub-populations in California within this West Coast Distinct Population Segment using a combination of gross necropsy, histology, toxicology and molecular methods. Overall, predation (70%), natural disease (16%), toxicant poisoning (10%) and, less commonly, vehicular strike (2%) and other anthropogenic causes (2%) were causes of mortality observed. We documented both an increase in mortality to (57% increase) and exposure (6%) from pesticides in fishers in just the past three years, highlighting further that toxicants from marijuana cultivation still pose a threat. Additionally, exposure to multiple rodenticides significantly increased the likelihood of mortality from rodenticide poisoning. Poisoning was significantly more common in male than female fishers and was 7 times more likely than disease to kill males. Based on necropsy findings, suspected causes of mortality based on field evidence alone tended to underestimate the frequency of disease-related mortalities. This study is the first comprehensive investigation of mortality causes of fishers and provides essential information to assist in the conservation of this species.

Original languageEnglish (US)
Article numbere0140640
JournalPLoS One
Volume10
Issue number11
DOIs
StatePublished - Nov 4 2015

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Rodenticides
carnivores
Coastal zones
Mortality
Conservation
Population distribution
Histology
Poisoning
Cannabis
Pesticides
poisoning
rodenticides
Fish
toxic substances
Population
Pacific States
necropsy
U.S. Fish and Wildlife Service
coasts
Endangered Species

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Medicine(all)

Cite this

Patterns of natural and human-caused mortality factors of a rare forest carnivore, the fisher (Pekania pennanti) in California. / Gabriel, Mourad W.; Woods, Leslie; Wengert, Greta M.; Stephenson, Nicole; Higley, J. Mark; Thompson, Craig; Matthews, Sean M.; Sweitzer, Rick A.; Purcell, Kathryn; Barrett, Reginald H.; Keller, Stefan M.; Gaffney, Patricia; Jones, Megan; Poppenga, Robert H; Foley, Janet E; Brown, Richard N.; Clifford, Deana L.; Sacks, Benjamin.

In: PLoS One, Vol. 10, No. 11, e0140640, 04.11.2015.

Research output: Contribution to journalArticle

Gabriel, MW, Woods, L, Wengert, GM, Stephenson, N, Higley, JM, Thompson, C, Matthews, SM, Sweitzer, RA, Purcell, K, Barrett, RH, Keller, SM, Gaffney, P, Jones, M, Poppenga, RH, Foley, JE, Brown, RN, Clifford, DL & Sacks, B 2015, 'Patterns of natural and human-caused mortality factors of a rare forest carnivore, the fisher (Pekania pennanti) in California', PLoS One, vol. 10, no. 11, e0140640. https://doi.org/10.1371/journal.pone.0140640
Gabriel, Mourad W. ; Woods, Leslie ; Wengert, Greta M. ; Stephenson, Nicole ; Higley, J. Mark ; Thompson, Craig ; Matthews, Sean M. ; Sweitzer, Rick A. ; Purcell, Kathryn ; Barrett, Reginald H. ; Keller, Stefan M. ; Gaffney, Patricia ; Jones, Megan ; Poppenga, Robert H ; Foley, Janet E ; Brown, Richard N. ; Clifford, Deana L. ; Sacks, Benjamin. / Patterns of natural and human-caused mortality factors of a rare forest carnivore, the fisher (Pekania pennanti) in California. In: PLoS One. 2015 ; Vol. 10, No. 11.
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