Cooperative Extension San Joaquin County
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Cooperative Extension San Joaquin County

Posts Tagged: marijuana

Insight into the environmental impacts of cannabis agriculture

Google Earth Image of a cannabis grow site. The resolution of Google Earth images allowed the researchers to detect marijuana plants that were previously missed with other remote sensing techniques.
As policy liberalization rapidly transforms the multi-billion-dollar cannabis agriculture industry in the United States, the need for regulation and assessment of environmental impacts becomes increasingly apparent. 

A recent study led by UC Cooperative Extension specialist Van Butsic used high resolution satellite imagery to conduct a systematic survey of cannabis production and to explore its potential ecological consequences. 

Published this spring in Environmental Research Letters, the study focused on the “emerald-triangle” in northern California's Humboldt, Mendocino, and Trinity counties, which many believe is the top cannabis-producing region in the United States.

The UC Berkeley-based Butsic and his co-author Jacob Brenner used Google Earth imagery to locate and map grow sites (both greenhouses and outdoor plots) in 60 watersheds. Most cannabis grow sites are very small, and have gone undetected when researchers used automated remote sensing techniques, which are commonly used to detect larger changes such as deforestation.

“We chose to use fine-grained imagery available in Google Earth and to systematically digitize grows by hand, identifying individual plants. Most plants stand out as neat, clear, little circles,” said Brenner, who is on the faculty of the Department of  Environmental Studies and Science at Ithaca College. “The method was laborious — it took over 700 hours — but it proved to be highly accurate.”

Butsic and Brenner paired their image analysis with data on the spatial characteristics of the sites (slope, distance to rivers, distance to roads) and information on steelhead trout and Chinook salmon, both of which are listed as threatened species under the federal Endangered Species Act. These and other species are vulnerable to the low water flows, soil erosion, and chemical contamination that can result from nearby agriculture.

Results of the study show 4,428 grow sites, most of which were located on steep slopes far from developed roads. Because these sites will potentially use significant amounts of water and are near the habitat for threatened species, Butsic and Brenner conclude that there is a high risk of negative ecological consequences.

“The overall footprint of the grows is actually quite small [~2 square kiliometers], and the water use is only equivalent to about 100 acres of almonds,” says Butsic, who is in the Department of Environmental Science, Policy, and Management at Berkeley. According to Butsic, California currently has more than one million irrigated acres of almonds.

He stresses that the issue lies in the placement of the sites: “Close to streams, far from roads, and on steep slopes — cannabis may be a case of the right plant being in the wrong place.”

Last year, California legislature passed laws designed to regulate medical marijuana production, and state voters will weigh in on whether to legalize recreational marijuana this coming fall. Given these changes as well as the profitability of cannabis production, Butsic expects that marijuana cultivation will expand into other sites with suitable growing conditions throughout the region. He and Brenner assert that ecological monitoring of these hotspots should be a top priority.

Bills recently signed into law by Governor Jerry Brown have made some advances in this direction — requiring municipalities to develop land use ordinances for cannabis production, forcing growers to obtain permits for water diversions, and requiring a system to track cannabis from when it is first planted until it reaches consumers.

But the researchers say that regulation will likely be a constant challenge because it will rely on monitoring procedures that are just now emerging, as well as voluntary registration from producers and budget allocation from the state for oversight and enforcement.

“Some of the same fundamental challenges that face researchers face regulators as well, primarily that cannabis agriculture remains a semi-clandestine activity,” says Brenner. “It has a legacy of lurking in the shadows. We just don't know — and can't know — where every grow exists or whether every grower is complying with new regulations.”

Posted on Tuesday, June 21, 2016 at 10:20 AM
Tags: Agriculture (7), fish (4), land use (4), marijuana (5), policy (2), Water (19)

Perils of illegal marijuana crops

Mourad Gabriel with a CA fisher

Rodenticides used on illegal marijuana farms have already been shown to pose serious harm to the fisher—a cat-sized carnivore found in forests across Canada and four regions in the U.S. (Previous news article.)

Mourad Gabriel, a doctoral candidate with the Veterinary Genetics Laboratory at UC Davis School of Veterinary Medicine, provides a more comprehensive look at the situation in the recent issue of The Wildlife Professional, put out by The Wildlife Society. (Article here.)

New information looks at risks to other species and to the ecologists and biologists conducting wildlife research on community and public lands where more of these crops are being cultivated.

Highlights include: 

  • Newly documented fisher mortalities (necropsies done at UC Davis’ California Animal Health and Food Safety Laboratory System)

  • New data documenting just a glimpse of potential environmental degradation possibly occurring on our public lands

  • First mention of toxicants like carbamates and organochlorides (DDT etc...) that are being found in California grow sites

  • Provides readers with information on how some of these toxicants are placed at grow sites to maliciously poison wildlife

  • New info and discussion points of "what are" the potential effects of ...such as damming water courses, putting toxic slurry of chemicals in dammed creeks, cutting riparian zones, human feces (affects salmon and many other species)

  • First-hand accounts of ecologists and biologists conducting wildlife research being shot at, chased and threatened

  • Quantifies the loss of project area access, and data from fisher projects in California public lands

There is also a link to a video that offers a first account visual representation of what a fisher looks like, the unfortunate visual effects of toxicosis and the realistic outcome to wildlife from these illicit activities on tribal and public lands.

For more information, contact Mourad Gabriel, mwgabriel@ucdavis.edu or Trina Wood, tjwood@ucdavis.edu 

Posted on Tuesday, April 2, 2013 at 1:20 PM

Evidence of rodenticide poisoning of wildlife found in the Sierra

There is a new predator in the forest these days. It has arisen quietly over the years. Any wildlife feeling hungry when they come upon it in the Sierra is vulnerable. This predator is amazingly small for the scope of its damage; it can’t run fast or climb high.

Rodenticide bait pellets (bright green) with plant fertilizer dispersed around 2,000 plants in a northern California marijuana grow site within the northwestern California fisher project boundary.
This new predator is rodenticide in pellet form, used in violation of all safe-use regulations in our national forests by large-scale marijuana growers. Rodenticides are being used to protect young and tasty marijuana seedlings from wildlife roaming through the forest looking for a meal. Chemicals never meant to be used more than 50 feet from homes are now scattered across forest hillsides. Piles of poisons are left around hundreds of plants even though only a few pellets can be lethal. Miles of water pipe are lined with these pellets to protect the stolen water source. Camps are circled with pellets to protect human food sources and sleeping areas.

University of California scientists originally became aware of this problem when Rick Sweitzer, associate professor in the Department of Environmental Science, Policy and Management at UC Berkeley, and his wildlife research team retrieved a radio-collared fisher whose cause of death was unclear. Sweitzer and his team are researching are studying the fate Pacific fishers as part of the Sierra Nevada Adaptive Management Project (SNAMP).

Necropsy (an autopsy for animals) of the fisher carcass by Mourad Gabriel of UC Davis and the Integral Ecology Research Center found rodenticide poisoning to be the cause. With these new findings, the livers from previous fisher mortalities in the SNAMP study were reexamined for evidence of rodenticide exposure. They discovered that more than 80 percent of dead fishers examined had been exposed to rodenticide. These toxicants can persist in animal tissues or the environment for potentially hundreds of days. At least five dead fishers found by researchers in SNAMP and a second fisher study in northern California have been confirmed to have died of rodenticide poisoning, the scientists reported in the science journal PlusOne.

Considering the hundreds of marijuana grow sites found every year on public lands, the scale of the damage to California’s natural resources may be unprecedented. Grow sites are also found containing massive amounts of fertilizers, herbicides and pesticides, all of which are being used without concern for run off or aquatic species nearby. Marijuana plants are removed from these plots when found, but these chemicals are often left behind.

Although this problem might seem overwhelming, there are efforts to address it. The non-profit Environmental Reclamation Team has cleaned up hundreds of grow sites since 2005. They remove and document all of the poisons found along with the miles of plastic irrigation line and piles of trash. More efforts like this are needed if we are to maintain rare animals like the Pacific fisher as well as all the other species who have the potential of coming in contact with these poisons.

Posted on Tuesday, December 18, 2012 at 10:11 AM
  • Author: Anne Lombardo

Poisons on public lands put wildlife at risk

Mourad Gabriel with a Pacific fisher.
Rat poison used on illegal marijuana farms may be sickening and killing the fisher, a rare forest carnivore that makes its home in some of the most remote areas of California, according to a team of researchers led by University of California, Davis, veterinary scientists.

Researchers discovered commercial rodenticide in dead fishers in Humboldt County near Redwood National Park and in the southern Sierra Nevada in and around Yosemite National Park. The study, published July 13 in the journal PLoS ONE, says illegal marijuana farms are a likely source. Some marijuana growers apply the poisons to deter a wide range of animals from encroaching on their crops.

Fishers in California, Oregon and Washington have been declared a candidate species for listing under the federal Endangered Species Act. Fishers, a member of the weasel family, likely become exposed to the rat poison when eating animals that have ingested it. The fishers also may consume rodenticides directly, drawn by the bacon, cheese and peanut butter “flavorizers” that manufacturers add to the poisons.

Other species, including martens, spotted owls, and Sierra Nevada red foxes, may be at risk from the poison, as well.

“Our findings were very surprising since non-target poisoning from these chemicals is typically seen in wildlife in urban or agricultural settings,” said lead author Mourad Gabriel, a UC Davis Veterinary Genetics Laboratory researcher and presid

ent of the Integral Ecology Research Center. “In California, fishers inhabit mature forests within the national forest, national parks, private industrial and tribal community lands – nowhere near urban or agricultural areas.”

“I am really shocked by the number of fishers that have been exposed to significant levels of . . . anticoagulant rodenticides,” said pathologist Leslie Woods of the UC Davis California Animal Health and Food Safety Laboratory System.

Exposure to the poison was high throughout the fisher populations studied, complicating efforts to pinpoint direct sources. The fishers, many of which had been radio-tracked throughout their lives, did not wander into urban or agricultural environments. However, their habitat did overlap with illegal marijuana farms.

Gabriel said fishers may be an “umbrella” species for other forest carnivores. In ecology, an umbrella species is one that, if protected, results in protection of ot

her species, as well.

“If fishers are at risk, these other species are most likely at risk because they share the same prey and the same habitat,” said Gabriel. “Our next steps are to examine whether toxicants used at illegal marijuana grow sites on public lands are also indirectly impacting fisher populations and other forest carnivores through prey depletion.”

In addition to UC Davis, the study involved researchers from the nonprofit Integral Ecology Research Center, UC Berkeley, United States Forest Service, Wildlife Conservation Society, Hoopa Tribal Forestry, and California Department of Fish and Game.

(This article was condensed from a UC Davis news release. Read the full press release and watch a flash video of fishers in the wild.)

Posted on Wednesday, July 25, 2012 at 8:59 AM

Pollute, poach, dewater: Legacies of illicit cannabis grows

While the legality of California’s medical marijuana dispensaries is being debated in courtrooms, a UC Cooperative Extension forestry and wildlands ecology advisor says there are a number of issues related to the unregulated land-use practices of illicit cannabis growing that have not been addressed.

Greg Giusti
“As a forest ecologist, I spend a lot of time outdoors, and I talk to thousands of people every year about forest-related subject matter,” says Greg Giusti. “And you can’t talk to anybody today on the North Coast without the topic of cannabis growing and cannabis impacts on land coming up.”

In Lake and Mendocino counties, Giusti performs research and shares information with public agencies and private landowners in relation to forest management and freshwater ecology on behalf of UC Cooperative Extension. Marijuana farming is not a topic that Giusti ever intended to address.

Illegal water diversion is common among many illicit cannabis plots in wildlands. (Photo from Giusti's presentation, courtesy of Lake County Sheriff's Office)

Effects on natural resources
Most of the data available about illicit cannabis grows is based on drug enforcement actions, specifically how many sites were busted and how many plants or pounds of plant material were seized. Giusti has gathered photographs and anecdotal evidence of the effects on natural resources of commercial-scale marijuana grows operated illicitly on public and private lands.

Some of the effects he has documented:

  • illegal water controls (including dams, stream diversion and water storage)
  • water pollution from petroleum, pesticide and fertilizer products
  • pesticides applied without permits
  • pesticides, fertilizers and other chemicals left behind
  • indiscriminate fish and wildlife killing (including poisoning, trapping and poaching for food)
  • human trash and waste left after camping

“It’s not this green industry that people talk about,” Giusti says. “They’re diverting water, they’re polluting streams, and there’s a portion who are poaching. We’re also seeing all of the negative effects of unregulated road building, unregulated construction and unregulated human inhabitation for months and months out in the woods.”

Giusti explained that some cannabis growers divert water from streams to store in large water bladders, prematurely lowering stream levels during critical times in the year.

“It's illegal to do, but at the same time you can drive up and down Highway 101 and easily buy these huge bladders,” he said.

He notes that local businesses are selling compost by the ton, rodenticide by the pallet, thousands of pairs of clippers and turkey bags in lots of 100.

“Mainstream businesses are supporting this underground industry,” Giusti said. “You don’t have to be growing cannabis to be making money off of it.”

Raising awareness
In 2010, Giusti organized two community workshops in Lake County to address the impacts of illicit cannabis land-use on forest resources, for a combined attendance of nearly 400 community members. Giusti has shared his results with the board of supervisors for Lake and Mendocino counties, local news media, local foresters and the staff of the North Coast Regional Water Quality Control Board.

“My intention was to initiate a communitywide discussion to ask, ‘Is this what you want to happen to your forests?’” Giusti said. “Up until now it's been talked about in hushed tones, and I wanted to initiate a dialogue out loud. Everybody has been whispering about it.”

The presentation he developed for those meetings continues to generate discussion. Most recently, he has presented to the North Coast Water Quality Control Board staff and other agencies. He has shared photos collected for his presentation with Congressman Mike Thompson’s office as well.

“With the water quality control board, I had the opportunity to engage people whose job it is to protect the beneficial uses of water — and hopefully stimulate an internal dialogue so that they can continue the discussion after I leave their office,” he said. “There are other resource agencies that need to be involved, and county planning departments too. This is an unregulated land-use practice.”

This month, the Lake County Record-Bee ran an article by reporter Linda Williams with the headline “Thirsty marijuana grows suck Eel River dry,” which included some information presented at Giusti’s meetings.

“My efforts seem to be improving people's awareness,” he says. “The very thing I wanted to accomplish — creating broader dialogues — is happening.”

Posted on Wednesday, November 16, 2011 at 12:37 PM
Tags: forest (12), Greg Giusti (6), land use (4), marijuana (5), natural resources (3), pollution (1), water (19)
 
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