March 11, 2014

The Killing Fields

Illegal marijuana growing destroying wildlife and polluting our environment

Decades spent as a wildlife conservation biologist never prepared me for what I’m about to say:  We need to quickly legalize marijuana in this country to save wildlife and protect our natural lands.  Illegal marijuana grow sites are devastating wildlife populations, destroying forests, and poisoning ecosystems at an alarming rate on public lands across California and other western states.  The drug cartels—who of course only exist because drugs are illegal—are bringing tons of banned poisons and weapons onto our national forests, parks, and other wild areas, eliminating any living things that might affect their crops:  You name it, they kill it, as documented in this troubling video produced by the US Forest Service.

Our awareness of this issue grew from a single event in 2009:  a Pacific fisher, radio-collared by researchers studying this rare carnivorous mammal in the Sierra Nevada, suddenly died for unknown reasons.  The adult male had no signs of injury and otherwise appeared healthy.  Necropsy showed he had died of internal hemorrhaging due to acute anticoagulant rodenticide (AR) poisoning.  How does a wilderness-associated animal, found in dense coniferous forest on Forest Service land, encounter a rodenticide?  Fisher biologists first considered legal use of rodenticides like d-CON around cabins scattered in the forest (perhaps the fisher ate a poisoned mouse or squirrel near someone’s summer home?); but the evidence trail eventually led to illegal marijuana grow sites—uncounted thousands of them—hidden throughout the forest on public and tribal lands all over California.  These sites are saturated with pesticides—rodenticides, insecticides, herbicides—many of which are banned for sale or use in this country.  Many sites are also booby trapped and occupied during the growing season by armed men, who have chased fisher researchers from the woods.

And the story for fishers in the southern Sierra Nevada continues to build as we learn more about the effects of pesticides on this small and isolated population.   Due to continued research by dedicated biologists like Craig Thompson, Mark Higley, and Mourad Gabriel (all interviewed in the Forest Service video) we now know that fisher mortality is highest in spring when mother fishers are raising their young—which also happens to be the marijuana growing season.  When a mother dies, so do her kits; and pesticides are transferred from mother to young via her milk or the prey she brings them to eat.  On the Sierra National Forest, Craig Thompson and his colleagues established a direct, statistical correlation between the number of marijuana grow sites in female fisher home ranges and their mortality rates: more sites means lower survival.

No one knows for sure how many wild animals are affected by these pervasive poisons, but since the initial discovery of AR in a fisher—the proverbial canary in a coal mine—poisoning has now been documented in diverse wildlife species throughout the food chain, from rodents to eagles and mountain lions.  Porcupines, once common in the Sierra Nevada, appear to be totally missing in recent years from vast swaths of forest (although there is no direct evidence yet linking this with grow sites).  Even a rare Sierra Nevada red fox, which apparently died from vehicle strike while wandering away from its high-alpine habitat, was discovered with rodenticide in its system.  And no one yet knows the degree to which these diverse poisons are leaching into soil and water, how far they may spread from the grow sites, or how long they may continue to poison the ecosystem once applied.

Is there any good news?  Well, one positive outcome of these recent discoveries has been a new collaboration between some unlikely allies:  researchers, conservationists, law enforcement agencies, land management agencies, and policy makers coming together to help solve issues.  Researchers and law enforcers, especially, have overcome some early mistrust to collaborate by sharing information, educating each other, and helping raise awareness about the issues with the public and policy makers.  Volunteer groups, most notably the High Sierra Volunteer Trail Crew, are dedicated to cleaning up the grow sites that enforcement officials discover.  (Unfortunately, as a tragic sidebar to this story, the founder and leader of the High Sierra Trail Crew, Shane Krogen, died after falling from a helicopter while cleaning up a grow site in September 2013)

One other scary wrinkle to this already horrifying story, Dr. Mourad Gabriel, who has been a leader in studying, documenting, and educating people about these problems from the start, may have been targeted in retribution for his efforts:  Mourad’s dog appears to have been intentionally poisoned to death with the type of anticoagulant rodenticides Mourad has lobbied against.  So, how do we solve this large problem on our public lands?  Law enforcement can’t possibly keep up with the large number of hidden sites established every year.  It seems to me (and this is only my personal opinion, not to be construed as the opinion of other fisher researchers or the Conservation Biology Institute) that the only solution to this problem is to remove the economic incentive for these criminal activities by legalizing and regulating marijuana production and distribution.  A well-regulated market could be taxed, with a portion of the proceeds dedicated to finding and cleaning up existing grow sites.  Most important, legalization would remove the profit motive and get the cartels out of our woods.

One final word:  if you or anyone you know uses marijuana, legally or illegally, make sure you know the grow source and their growing methods.  Not only do illegal sources do horrible damage to our natural resources, a marijuana user cannot possibly know what cornucopia of pesticides they may be inhaling.

Explore more about CBI's research and conservation of the fisher and other Sierra Carnivores here:

Sierra Nevada Carnivores Project

Effects of climate and vegetation on the current and future distribution of martens and fishers in the Sierra Nevada, California

About the author:
Wayne Spencer, Ph.D.
Chief Scientist | Head of Science Leadership Team
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