Pubdate: Mon, 01 Jul 2013
Source: Los Angeles Times (CA)
Copyright: 2013 Los Angeles Times
Contact:  http://www.latimes.com/
Details: http://www.mapinc.org/media/248
Author: Bettina Boxall

SIERRA POT-GROWING PLOTS MAY THREATEN RARE ANIMAL

Pesticides and Poisons Often Used by Illegal Marijuana Growers in the 
Mountains Are Found in Many Dead Fishers, a Study Says.

The illegal marijuana growing operations that have proliferated in 
remote areas of the Sierra Nevada appear to be taking a toll on the 
fisher, a forest animal whose numbers are dangerously low.

Researchers studying fishers in the Sierra National Forest in the 
southern Sierra found that mortality rates were significantly higher 
for females living in areas with a number of marijuana-growing sites.

Liberal amounts of pesticides and anticoagulant rodent poison are 
commonly used at the operations, tainting small prey the fisher eats.

Although consuming contaminated prey may not kill the fishers 
outright, it could make them more susceptible to disease and parasites.

Exposure may predispose an animal to dying from other causes," wrote 
the authors, who summarized their findings in a paper published this 
week in the journal Conservation Letters.

Their research was a follow-up to an earlier study that found that 
tissue of 85% of 46 dead fishers contained traces of anticoagulants. 
Most of those animals had been killed by predators.

The fisher is a cat-size animal that is a candidate for listing under 
the federal Endangered Species Act. For the latest study, the 
scientists trapped fishers, outfitted them with radio collars and 
released them. The team then compared the animals' movements with the 
location of marijuana growing sites found by national forest law 
enforcement officers.

The final analysis excluded male fishers because their extensive 
movements made it harder to gauge exposure to the marijuana plots.

Noting that some of the pesticide compounds used at the sites were 
first developed as nerve agents during World War II, the researchers 
likened the pot operations to leaking chemical weapons stockpiles.

The association between growing operations and fisher mortality is 
"strong yet speculative," wrote the authors, who noted it was 
difficult to determine a specific cause-and-effect relationship.

But they said the contamination raised serious conservation concerns.

By increasing the number of animals that die from supposedly natural 
causes, these pesticides may be tipping the balance of recovery for 
fishers," warned Craig Thompson, the study's lead author and a U.S. 
Forest Service wildlife ecologist at the Pacific Southwest Research Station.
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