The researchers conducted necropsies among 58 fishers and found that 46 of the animals (79 percent) were exposed to one or more of the toxic ARs, and four had died directly from AR toxicity.
The fishers were from two different populations: one occurring on tribal, private, and public lands in northwestern California and another within the Sierra National Forest in central California. Distribution of the poisoned fishers indicated widespread contamination of fisher range in California.
Fishers are likely exposed to AR when eating animals that have already ingested the rodentcide. They may also be drawn to the poison directly by bacon, cheese and peanut butter “flavorizers” that manufacturers add to attract rodents. According to the authors, it is unlikely the fishers were exposed to AR used legally at or near agricultural or residential areas as these settings are not suitable habitat. Nor did animals tracked by telemetry collars during the study venture into those environments.
Instead, the exposure points were likely encountered where AR is used illicitly as part of illegal marijuana cultivation in remote areas that overlap with fisher habitat. The study cites multiple examples of confiscation of marijuana plants and discovery of associated AR use in the region and notes that in 2008 alone, more than 3.6 million marijuana plants were removed from federal and state public lands in California, including state and national parks.
Members of the weasel family, fishers were once widely distributed throughout North America’s west coast but have incurred significant population decline and extirpation from portions of their former range. Populations inhabiting Washington, Oregon, and California have been designated a Distinct Population Segment (DPS) and declared a candidate for listing under the federal Endangered Species Act (ESA).
Study co-author and WCS Scientist Sean Matthews said, “Fishers play a vital role in the forests of the Sierra Nevada Mountains and the Pacific Northwest. With a body the size of a house cat and the disposition of their larger cousin, the wolverine, fishers keep forest rodent populations in check and are one of the only predators with the tenacity to regularly prey on porcupines. As fisher populations declined, they took refuge in the last remaining portions of mature forest in the Sierra Nevada and coastal mountains. Now a new threat has emerged in these remaining refuges.”
AR may also harm fishers by compromising the animal’s blood clotting and recovery abilities, decreasing its resilience to environmental stressors, and abandonment of dependent young due to direct mortality of adults killed by AR. During the study, the first documentation of a neonatal milk transfer of AR in fishers was recorded as a deceased six-week old kit was tested and found to have AR in its system. (Kits are dependent on mother’s milk until ten weeks of age.)
Matthews said, “The findings in this paper could signal a looming conservation threat for other species as well as fishers. As we discuss in the study, depletion of rodent prey populations upon which fishers and other animals feed, along with the anticoagulant poisoning threat might affect the Sierra Nevada red fox, wolverine, California spotted owls and other rare carnivores that inhabit the region.”
In their conclusion, the authors consider heightened awareness in removing AR when marijuana grow sites are dismantled and further regulation restricting the use of AR to only pest management professionals.
The study, Anticoagulant Rodenticides on our Public and Community Lands: Spatial Distribution of Exposure and Poisoning of a Rare Forest Carnivore, appears in the July 13, 2012 edition of the online journal PLoS ONE.
Co-authors of the study include: Mourad W. Gabriel of the Integral Ecology Research Center and the Veterinary Genetics Laboratory at the University of California; Sean M. Matthews of the Wildlife Conservation Society; Davis (UC-Davis); Greta M. Wengert of Integral Ecology Research Center; Benjamin N. Sacks of Veterinary Genetics Laboratory at UC-Davis; Leslie W. Woods and Robert Poppenga of the California Animal Health and Food Safety Laboratory System at UC-Davis; Rick A. Sweitzer and Reginald H. Barrett of the Sierra Nevada Adaptive Management Project at the University of California at Berkeley (UC-Berkeley); Craig Thompson and Kathryn Purcell of the Pacific Southwest Research Station—Sierra Nevada Research Center, United States Forest Service; J. Mark Higley of the Wildlife Department, Hoopa Tribal Forestry; Stefan M. Keller of the Department of Pathology, Microbiology and Immunology at UC-Davis; and Deana L. Clifford of the Wildlife Investigations Laboratory of the California Department of Fish and Game.
Scott Smith | Newswise Science News
Deep decarbonization of industry is possible with innovations
25.03.2019 | Fraunhofer-Institut für System- und Innovationsforschung (ISI)
Five-point plan to integrate recreational fishers into fisheries and nature conservation policy
20.03.2019 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)
Cancers that display a specific combination of sugars, called T-antigen, are more likely to spread through the body and kill a patient. However, what regulates...
DESY and MPSD scientists create high-order harmonics from solids with controlled polarization states, taking advantage of both crystal symmetry and attosecond electronic dynamics. The newly demonstrated technique might find intriguing applications in petahertz electronics and for spectroscopic studies of novel quantum materials.
The nonlinear process of high-order harmonic generation (HHG) in gases is one of the cornerstones of attosecond science (an attosecond is a billionth of a...
Nano- and microtechnology are promising candidates not only for medical applications such as drug delivery but also for the creation of little robots or flexible integrated sensors. Scientists from the Max Planck Institute for Polymer Research (MPI-P) have created magnetic microparticles, with a newly developed method, that could pave the way for building micro-motors or guiding drugs in the human body to a target, like a tumor. The preparation of such structures as well as their remote-control can be regulated using magnetic fields and therefore can find application in an array of domains.
The magnetic properties of a material control how this material responds to the presence of a magnetic field. Iron oxide is the main component of rust but also...
Due to the special arrangement of its molecules, a new coating made of corn starch is able to repair small scratches by itself through heat: The cross-linking via ring-shaped molecules makes the material mobile, so that it compensates for the scratches and these disappear again.
Superficial micro-scratches on the car body or on other high-gloss surfaces are harmless, but annoying. Especially in the luxury segment such surfaces are...
The Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT) in Arizona released its first image of the surface magnetic field of another star. In a paper in the European journal Astronomy & Astrophysics, the PEPSI team presents a Zeeman- Doppler-Image of the surface of the magnetically active star II Pegasi.
A special technique allows astronomers to resolve the surfaces of faraway stars. Those are otherwise only seen as point sources, even in the largest telescopes...
11.03.2019 | Event News
01.03.2019 | Event News
28.02.2019 | Event News
26.03.2019 | Physics and Astronomy
26.03.2019 | Earth Sciences
26.03.2019 | Earth Sciences