Blue Lake, CA, United States
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Gabriel M.W.,Integral Ecology Research Center | Gabriel M.W.,University of California at Davis | Woods L.W.,University of California at Davis | Poppenga R.,University of California at Davis | And 10 more authors.
PLoS ONE | Year: 2012

Anticoagulant rodenticide (AR) poisoning has emerged as a significant concern for conservation and management of non-target wildlife. The purpose for these toxicants is to suppress pest populations in agricultural or urban settings. The potential of direct and indirect exposures and illicit use of ARs on public and community forest lands have recently raised concern for fishers (Martes pennanti), a candidate for listing under the federal Endangered Species Act in the Pacific states. In an investigation of threats to fisher population persistence in the two isolated California populations, we investigate the magnitude of this previously undocumented threat to fishers, we tested 58 carcasses for the presence and quantification of ARs, conducted spatial analysis of exposed fishers in an effort to identify potential point sources of AR, and identified fishers that died directly due to AR poisoning. We found 46 of 58 (79%) fishers exposed to an AR with 96% of those individuals having been exposed to one or more second-generation AR compounds. No spatial clustering of AR exposure was detected and the spatial distribution of exposure suggests that AR contamination is widespread within the fisher's range in California, which encompasses mostly public forest and park lands Additionally, we diagnosed four fisher deaths, including a lactating female, that were directly attributed to AR toxicosis and documented the first neonatal or milk transfer of an AR to an altricial fisher kit. These ARs, which some are acutely toxic, pose both a direct mortality or fitness risk to fishers, and a significant indirect risk to these isolated populations. Future research should be directed towards investigating risks to prey populations fishers are dependent on, exposure in other rare forest carnivores, and potential AR point sources such as illegal marijuana cultivation in the range of fishers on California public lands.


Wengert G.M.,University of California at Davis | Gabriel M.W.,Integral Ecology Research Center | Foley J.E.,University of California at Davis | Kun T.,University of California at Davis | Sacks B.N.,University of California at Davis
Wildlife Society Bulletin | Year: 2013

Identifying predators of threatened and endangered species is important for understanding and reducing the impacts of predation. Visible evidence collected from a carcass alone is often insufficient to accurately identify predator species. The DNA from the predator left on the carcass allows for a definitive identification of predator species associated with the carcass, but DNA can be difficult to isolate independently from the prey. We developed field collection and molecular protocols for amplifying canid and felid predator DNA from saliva on fisher (Martes pennanti) carcasses without amplifying fisher DNA itself. We tested the protocol on fisher carcasses suspected of having been killed by a bobcat (Lynx rufus), mountain lion (Puma concolor), coyote (Canis latrans), and domestic dog. We successfully amplified and sequenced DNA from these 4 predator species, confirming predation by them on fishers. We confirmed that these protocols could also identify other felid and canid predators of several other small NorthAmerican carnivores. © 2013 The Wildlife Society.


Pope K.L.,Us Forest Service Pacific Southwest Research Station | Wengert G.M.,Integral Ecology Research Center | Foley J.E.,University of California at Davis | Ashton D.T.,McBain Associates | And 2 more authors.
Journal of Wildlife Diseases | Year: 2016

Ecoclub youth and supervising family members conducted citizen science to assess regional prevalence and distribution of Batrachochytrium dendrobatidis (Bd) among amphibians at Humboldt Bay National Wildlife Refuge (Refuge) and Redwood National and State Parks (Parks), Humboldt County, California, US, May 2013 through December 2014. Using quantitative real-time PCR, 26 (17%) of 155 samples were positive for Bd. Positive samples occurred in four frog and toad species: foothill yellow-legged frog (Rana boylii), northern red-legged frog (Rana aurora), Pacific chorus frog (Pseudacris regilla), and western toad (Anaxyrus [Bufo] boreas); no salamanders or anuran larvae were positive. Except for R. aurora, all infected anurans were first-time species reports for coastal northern California. At the Refuge, significantly fewer (6/71) postmetamorphic amphibians were positive compared to the Parks (20/69; P=0.0018). We assessed the association of being PCR-positive for Bd, season of sampling, and age of sampler (child, teen, or adult). The full model with season, species, and sampler age had the greatest support. Frogs tested in winter or spring were more likely to be positive than those tested in summer or fall; foothill yellow-legged frogs, northern red-legged frogs, and western toads were more likely to be positive than were Pacific chorus frogs; and the probability of being positive nearly doubled when a child (≤12 yr old) collected the sample compared to a teen or adult. Our results support other chytrid studies that found amphibians are more susceptible to Bd when temperatures are cool and that species differ in their susceptibility. The Ecoclub’s findings provide new information important to conservation of northern California’s coastal amphibians and demonstrate the value of involving children in citizen science. © Wildlife Disease Association 2016.


PubMed | Hoopa Tribal Forestry, Wildlife Investigations Laboratory, Integral Ecology Research Center, Humboldt State University and 4 more.
Type: Journal Article | Journal: PloS one | Year: 2015

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.


News Article | November 6, 2016
Site: motherboard.vice.com

This is part of United States of Weed, a Motherboard series that demystifies all the cannabis legislation for Election 2016. Follow along here. The decomposing corpses are strewn among 7,000 pounds of propane tanks, tarps, car batteries, fertilizers, pesticides, banned rodenticides from Mexico, and other trash, plus 4,000 pounds of irrigation line blanketing an abandoned 20,000 plant illegal marijuana grow site in northeastern California's Lassen National Forest. What was once unspoiled landscape is now a pockmarked 12-acre slagheap reminiscent of no man's land. It's one example of thousands of similarly destructive illegal cannabis grows occurring each year on California's public lands, according to Mourad Gabriel, Executive Director and Senior Ecologist at the Integral Ecology Research Center. Mourad has organized cleanup efforts at this and other illicit marijuana operations in the more remote areas of northern California. When Mourad first started doing this work it was overwhelming for him to see such blatant disregard for the environment. But having now participated in hundreds of cleanups, he's almost inured to the destruction. The day I spoke with Mourad he was joined by a few first-time volunteers. Upon arriving at the former grow site, he said the volunteers stared in awe for minutes, dumbstruck and unable to fathom the damage and waste in front of them. "You can't even believe that there are folks turning this beautiful pristine area into their trash bin, and it's all for pure greed," Mourad told me. "This is strictly for money, to make as much profit as possible and at the expense of the public good." "Proposition 215 came in 1995-1996," he added, referring to California's Compassionate Use Act, a landmark piece of legislation that allows patients with a doctor's recommendation to possess and grow cannabis for medical use. "Look at California now. You're talking two decades and it's just prolifically getting worse. Can our environment really sustain what's been going on for another ten years?" "You can't even believe that there are folks turning this beautiful pristine area into their trash bin, and it's all for pure greed." Besides spearheading such large-scale cleanups, Gabriel is also a first-class ecologist. In one of his more prominent and ongoing investigations he has been tracking long-term toxicant levels in Pacific fishers, a threatened species of forest carnivore, and the spotted owl, a federally-listed species, resulting from the chemicals used on illegal marijuana grows. The initial results of the investigation are disheartening. The common assumption is that legalizing recreational marijuana in California would discourage this sort of large-scale illegal marijuana cultivation on public lands, and, as consequence, the resulting environmental damage responsible for poisoning wildlife, among other things. A 'yes' vote on Proposition 64, a proposed state law on which Californians will vote this November 8, would permit the possession and use of marijuana for recreational purposes for adults aged 21 or older. Proposition 64 would also require suppliers to acquire a state license. The bill is expected to pass. Statewide recreational marijuana legalization, the argument goes, is a panacea to the environmental harm of large-scale illegal cannabis grows in California. But the reality is not so straightforward. The damage at the Lassen site may seem extreme. But the poisoning and death of animals, including fishers, martens, spotted and barred owls, bobcats, mountain lions, gray foxes, black bears, deer, quail, rodents, and rabbits; as well as the residual trash resulting from illegal cannabis cultivation, represents only a scintilla of the total damage wrought by these operations. Deforestation, wildfires, and erosion from terracing and the slapdash construction of roads are some of the more visible effects of illegal marijuana grows, according to Karen Escobar, an Assistant US Attorney in California's Eastern District. Diverting and tapping water from streams and springs, exhausting underground aquifers, and overloading watersheds with pesticides, rodenticides, and fertilizers are other ways that illegal grows decimate the environment. One recent study showed illegal marijuana cultivation to be the biggest threat to the survival of federally-listed salmon and trout. Escobar has spent years prosecuting these operations. The practices being used today at big illegal grows were once considered extreme, according to Escobar. But not anymore. "The extreme is now the normal," she said. Read more: California Will Vote on Legalizing Marijuana With Proposition 64 A total of 1,893 illegal outdoor grow sites in California were eliminated in 2015, according to the US Drug Enforcement Administration. Almost half of these were on public lands. With cleanup and rehabilitation efforts ranging between $10,000 and $100,000 per site, the cost of this damage is substantial. And given the remoteness and ruggedness of California's terrain, many grows simply go undetected. California alone produces 70 percent of the US's total output of both legal and illegal cannabis. It is estimated that this comes out to around 49,106 metric tons per year. The state's climate and geography combine to create the consummate weed-growing conditions. At the same time, the US opioid epidemic has resulted in the DEA de-emphasizing marijuana operations, according to DEA spokesperson Russell Baer. This has further strained the influence of already underfunded local law agencies. And the superabundance of California wildfires only saps enforcement efforts by diverting National Forest Service personnel away from fighting illegal grows. These two factors have created a law-enforcement vacuum in remote areas like Lassen National Forest, with low-risk, high-reward conditions so conducive to criminality. Add to this medley a large and insatiable pot-smoking population and skyrocketing land prices that push many legitimate growers onto "free" public land, as well as relaxed laws around cannabis cultivation, and it's unsurprising that California has become America's cradle for weed production. In 2015, California accounted for 65 percent of all illegal grows on national forest land across the US, according to the National Forest Service. Domestic drug trafficking organizations manage many of these grows, sending their product to other states where it is still illegal and, ex officio, where profit margins are higher. But a lot of this marijuana also stays in California. "11:3:58, which is cultivating marijuana, we call it farming for shorthand," said David Frost, a District Attorney for Monterey County. "The penalty for that is a maximum of three years here in California. It could be sixteen months, two years, or three years." If guns are involved and it's a federal case, sentences can increase, Frost added. But otherwise, two to three years in a state penitentiary is a pretty small price to pay for a mega-operation with a considerable ecological footprint. And this is assuming there is anyone around when authorities show up. Having been out in the backcountry for five months or more, the workers tending these farms have perfected their escape routes, according to Mark Sievers, a sergeant at the Monterey County Sheriff's Department, who worked on the "weed team" for many years. "They hear us long before we get to the garden and so they're gone," Sievers said. "We don't get that many in custody." Not surprisingly, California leads the way in drug trafficking activity. Sixty-one percent of drug trafficking organizations operating on National Forest Service land in the US are in California, according to Forest Service data. "Most of it is handled locally," said Chris Boehm, the acting director of law enforcement and investigations for the National Forest Service. "The infrastructure, the supply structure, the transport and distribution structure. The product is much easier to produce and in many cases sell [than cocaine]. It lends itself to a whole variety of groups and organizations." Read more: California to Vote on Wiping Old Weed Arrests The individuals tending these grows often come from economically vulnerable rungs of society, making them more susceptible to recruitment. "A lot of them are field workers and are in pretty dire straits. They want to work and make some money," said Charles Lee, a Fresno-based assistant federal defender. "They are told they are going to work on a ranch somewhere remote. They don't even know it's a marijuana grow until they get there and the next they know they're in the middle of nowhere. They don't know the terrain. They don't know the area. They're dropped off and they don't know how to get back to civilization." Others are forcibly recruited. Bill Abramson, a contract public defender for Plumas County, has heard of cases in which these organizations impel individuals to work by threatening harm against their families. Many workers aren't even told who they're working for. Information is tightly compartmentalized in order to protect higher ups in the organizations, something that has hamstrung efforts to make any major, penetrating prosecutions. But irrespective of who is actually running the drug trafficking organizations behind industrial-sized illegal outdoor marijuana grows, they are all bound by the same organizational precept: maximize profits at whatever the cost. That cost has been California's public lands. "The biggest issue we're facing right now," said Boehm, "are the types of hazardous chemicals that they're bringing in. They're being applied at levels of concentration that are extremely dangerous to the land. Some of these chemicals in certain concentrations will kill you. We've had to adjust our operations to make sure we're not exposing our people to this stuff." "Some of these chemicals in certain concentrations will kill you. We've had to adjust our operations to make sure we're not exposing our people to this stuff." Most of these substances are currently banned in the US. They are brought here, in large part, from Mexico. Their effectiveness in maximizing marijuana plant yields is undeniable, but so too is their effectiveness in poisoning the environment. It's unclear if field hands who apply these chemicals are aware of the long-term ramifications of their work, according to Lee. But focusing on lowly workers would be missing the point, as illegal grows and drug trafficking organizations exist in the first place because there is a black market for illegal marijuana. The same incentives drove organized crime groups during Prohibition in the 1920s and 30s. Those operations were put out of business only after passage of the 21st Amendment, which effectively legalized alcohol consumption across the US. It's unlikely that statewide legalization of recreational marijuana in California would have the same effect. In fact, the very opposite may be true. Mourad's recent findings on Pacific fishers revealed some interesting details about the prevalence of illegal marijuana farms in Oregon. By tracking the overall toxicant levels in fisher carcasses submitted for necropsy over several years, Mourad was able to see if legalizing recreational marijuana in Oregon changed these levels. He was, in essence, able to see if illegal grows decreased post-legalization. It still might be too early for any kind of resounding conclusions in Oregon, which only legalized recreational marijuana last year. According to Mourad, the toxicant levels found in Pacific fishers in Oregon over the long-term hasn't gone down. "What we're finding right now is that it's either increased or stayed at a very elevated level," he said. However, Mourad's preliminary findings, which will likely be published early next year, challenge the notion that statewide recreational legalization might eliminate illegal weed grows and, by extension, wide-scale environmental damage occurring on public lands in Oregon and beyond. Experts and officials in Colorado and Washington, on the other hand, have had more time to analyze the effects of legalizing recreational marijuana since both states passed legalization laws in 2012. Yet that hasn't reduced illegal grows on public land in either of those states, or at least "not at this time," according to Boehm. "It's all about supply and demand," Boehm said. "There's always a black market for things. I think it's always going to be there unless you can make it completely unprofitable to grow." Watch Motherboard's 2013 doc on US cannabis legalization and the Silicon Valley of Weed. After recreational cannabis legalization in Colorado kicked in, many individuals and organizations moved to that state to grow weed under less stringent laws. Indeed, most of the legal weed grown in-state does stay in Colorado. Something similar can also be said for the illegal bud grown in-state, according to Boehm: Many of the big illegal grows run by drug trafficking organizations do move some of their unregulated, pesticide-laden product out of state rather of selling to Colorado dispensaries. But a lot of it stays in Colorado, where it trickles into the above-board supply. "Colorado and Washington State have legitimated the market but not the production," said Rodrigo Nieto-Gomez, a research professor at the National Security Affairs Department of the Naval Postgraduate School. "The law didn't have enough prohibitions for the production of it. It is still very foggy about where it comes from." This is a critical lesson for California, one that hasn't gone unnoticed by people like Boehm. "If the market increases—and I am sure it will, if it's legalized—there'll probably be more people using, which will require more marijuana," Boehm said. "Until the legal capacity gets to where it needs to be, we'll see an increase [of illegal grows] on public lands. I feel pretty confident saying that. Historically that's what's happened, so why would it be any different?" Unless some form of rigorous and uniform statewide regulation is tucked into whatever legislation accompanies recreational legalization in California—something that has proven difficult in states like Oregon, Colorado, and Washington—neither the amount of illegal grows nor the accompanying environmental damage will abate. And when public lands in California offer a cheaper alternative than private land and come with the benefit of minimal visibility, organizations looking to fly under the radar will likely continue to fill this initial supply shortfall, not to mention the invariable shortfall in states where marijuana is still illegal. This has been the trend in Oregon, Washington, and Colorado since legalization. Unless some form of rigorous and uniform statewide regulation is tucked into whatever legislation accompanies legalization in California neither the amount of illegal grows nor the accompanying environmental damage will abate. In other words, warding off illegal grows on public land may seem like a Sisyphean task. But interdiction innovations are in the air. "I would like to see a very radical interdiction system established to preserve our national parks and forests from illegal grows," Rodrigo said. By "radical interdiction" Rodrigo means small-fry surveillance drones. He believes there are ways to implement a responsible and transparent program to root out illegal grows using unmanned aerial vehicles. It would have to be a joint effort between civil society organizations and the government, he added, a kind of bottom-up approach to policing our public lands that would require the collaboration of institutions like the Sierra Club, the American Civil Liberties Union, and the Electronic Frontier Foundation, as well as the National Park and Forest Services. Ruling out such hands-on, preemptive initiatives, we are left with post hoc alternatives like cleanups. Assuming Proposition 64 passes, Mourad said he hopes a significant portion of the resulting taxes go toward reclaiming and restoring former illegal grow sites. Only three to four percent of the 1,000 or more sites discovered every year on California's public lands are reclaimed, something generally done on a grant-to-grant basis, according to Mourad. It remains unclear how California will spend the estimated $1 billion in tax proceeds resulting from Proposition 64. Policy makers have earmarked funding for conservation, yet there is little information elucidating how and where this money will be spent. Legalizing recreational marijuana in California wouldn't necessarily be the magic bullet against large-scale illegal grows and resulting environmental harm. But if it can be assumed that the ship has already sailed in terms of legalization being a states' rights issue, then statewide legalization is arguably the best way forward to curb illegal, toxic grows in California. If the resulting taxes are utilized to restore damaged land and uniform regulatory standards are applied across the state, the transition will be all the smoother. It will take time to streamline and perfect legalization, of course. Progress may initially appear piecemeal. But what we can be certain of is this: Asymmetries and legal loopholes will remain in place that will incentivize and encourage illegal grows in the US unless there is blanket federal legalization. This is exactly where a 'yes' vote on Proposition 64 might serve as a Trojan horse. California will likely continue to push out unrivaled quantities of both legal and illegal marijuana. This has been the case historically and there is little to stop it now. Given the size of its marijuana market—California produces more weed than all of Mexico—a legal recreational cannabis economy in California would be simply too big to ignore at the federal level. It would underscore the "federalist problem" in the US, according to Rodrigo, where states often act in opposition to the federal government mandates. Understanding this, a 'yes' vote in California could singlehandedly catalyze change around marijuana at the federal level. If not, it would certainly trigger a domino-like effect toward legalization in other states that are on the fence. Where there has only been increasing environmental destruction and political inertia, this would certainly pressure the federal government to rethink its stance on weed. In the meantime, Mourad is gearing up for yet another cleanup in Lassen National Forest. Whoever was behind this 30,000-plant operation left behind 8,000 pounds of trash and 8,000 pounds of irrigation line over 15 acres of what was previously pristine public land. When Mourad arrived at the site, he found the rotting corpses of two gray foxes and a bear. "There needs to be some step forward, anything that is better than what we currently have in place," Mourad said. "What we have in place right now is a knotball that no one has untied." Get six of our favorite Motherboard stories every day by signing up for our newsletter.


The situation is growing worse for fishers being poisoned by rodenticides on illegal marijuana grow sites in California, according to a study by a team of researchers led by the University of California, Davis, and the Integral Ecology Research Center, based in Blue Lake, California.


News Article | November 4, 2015
Site: www.washingtonpost.com

In California, a little weasel called the “fisher” may be exposing a big environmental problem: Research shows that the species is being heavily exposed to, and even killed by, rat poison used on illicit marijuana cultivation sites. And scientists are concerned they’re not the only animals being affected. A new study, released Wednesday in the journal PLOS ONE, investigated the causes behind fisher mortality in California and identified a common form of rat poison — which you wouldn’t normally expect to find in the middle of their remote forest habitat — as an “emerging threat” to the species. After collecting and performing necropsies on more than 150 dead fishers in three California locations between 2007 and 2014, the researchers concluded that predation by other animals, such as bobcats or coyotes, was the top cause of death, accounting for about 70 percent of all the mortalities. Natural diseases were the next most common cause, accounting for about 16 percent of the deaths. But they also concluded that 10 percent were killed by rodenticide poisoning. The researchers also found that, even if it wasn’t the ultimate cause of death, 85 percent of the animals are being exposed to rat poison, which shows up in their bodies even if they were eventually killed by something else. This is worrisome, as fishers are still recovering from severe declines in California and aren’t completely out of the woods yet. Fishers are found throughout parts of Canada, bits of the Great Lakes region, and the Pacific states. They’re mid-sized, omnivorous weasels that dwell exclusively in forest habitats. Once prized for their fur, fishers experienced widespread declines in the 1800s and early 1900s thanks to trapping. Today, although they’ve recovered to a certain extent, they still occupy a fraction of their historic range, and fishers in the western states have been a particular concern. The U.S. Fish and Wildlife Service considers West Coast fishers a distinct population segment, which is currently proposed for a “threatened” listing under the Endangered Species Act. In the state of California, fishers are further divided into two separate populations: the Northern California segment and the Southern Sierra Nevada segment. The latter was listed as threatened earlier this year under the California Endangered Species Act. Altogether, this population segment is believed to number only about 300 individuals, said Richard Callas, a senior environmental scientist with the California Department of Fish and Wildlife. Statewide, there could be anywhere from 1,000 to 4,500 individuals, according to the Department. These concerns over fisher conservation were what led the scientists to initiate their research. The new study builds on past research that was also conducted by lead author Mourad Gabriel, executive director of the Integral Ecology Research Center. Gabriel was involved with two other papers, one published in 2012 and the other in 2013, which included earlier efforts to document rodenticide poisoning in fishers. The new study combines data from the previous two papers with more recently collected data. While examining the data for the new paper, Gabriel said he and his colleagues were hoping to answer the question of whether rodenticide poisoning cases were “dissipating” in the state. “Unfortunately, what this paper signified was it wasn’t,” Gabriel said. “The problem is still there. It hasn’t curtailed, it has actually increased.” Between 2007 and 2011, Gabriel and his team found the rate of toxicosis in fishers was about 5.6 percent. But between 2011 and 2014, the toxicosis rate rose to 18.7 percent. Altogether, the toxicosis rate for the whole study period was about 10 percent. And exposure rates have increased as well, according to the research. In the earlier study period, 79 percent of collected fishers had been exposed to rodenticides. In the latter study period, this number rose to 85 percent. Why researchers think illegal marijuana is the cause. But why are threatened forest weasels consuming a lot of rat poisoning, a substance usually used in homes, not forests? The conclusion that marijuana cultivation sites could be the culprit behind the poisoning was part of a long process, according to Gabriel. In the early stages of the research, he and his colleagues were puzzled to find rat poison in fishers and started asking around to try and figure out where it might have come from. The Forest Service didn’t use it. Neither did camping grounds or privately owned energy companies that ran cables through the California forests. It wasn’t until Gabriel gave a presentation, during which he explained some of his early findings and expressed his confusion over the rat poison, that the answer became clear. “After the presentation, several law enforcement officials that were present there [came up] and said, ‘We know your answer, and your answer is marijuana cultivation,’” Gabriel said. Gabriel began accompanying law enforcement officers on raids of illicit marijuana grow sites, which are frequently located in remote places in the California forests — prime fisher habitat. He found that they were right: growers were placing large amounts of rat poison at the grow sites to keep rodents in check. In his earlier research, Gabriel found that fishers living in territories that included cultivation sites were more likely to have been exposed to rodenticides, further support for the idea that marijuana cultivation was the culprit. The cultivation of marijuana is permitted in California only for medical use, and growers must register with the state government. The forest cultivation sites being targeted in the government’s raids are unregistered, illicit grow sites, likely intended for the illegal selling of the drug. And while predation remains the biggest cause of fisher deaths, Gabriel suggests that poisoning could be contributing to those high numbers as well, by weakening otherwise healthy individuals and making them easier prey. Fishers are omnivores, so the poisoning can come about in two ways, according to Gabriel: Either the fishers eat the poison directly, or they consume a poisoned animal, like a rat or a squirrel. Because of the poison’s tendency to move up the food chain, Gabriel is also worried that other wildlife could be affected as well — even wildlife that humans hunt and eat, such as deer or quail. Some of his current research is focused on testing other animal species for rodenticide exposure (he’s already found a handful of northern spotted owls that tested positive for exposure). He’s also testing water systems near marijuana cultivation sites to see if the poison could be leaching into streams. As it stands, law enforcement raids are only controlling the poison problem so much, according to Gabriel. He estimates that law enforcement officials are only aware of about 15 to 25 percent — perhaps as much as 40 percent, in a high estimate — of marijuana cultivation sites in the state, meaning a significant number of them continue to fly under the radar. And while raids may shut down a site temporarily, Gabriel said he observed that there aren’t sufficient resources to clean out all the sites in a way that removes all traces of toxins and makes them inhospitable to future growers. “We need to have some level of continuous support to remediate and document these grow sites,” Gabriel said. “Each and every grow site that is detected and eradicated needs to have funding allocated to remediate it.” To the best of his knowledge, Gabriel said, he’s the first person to conduct research on the effects of toxins from illicit marijuana grow sites. But his research has quickly captured the attention of other scientists, including officials from the California Department of Fish and Wildlife. In fact, his research was considered in the fisher species status review that led to the threatened listing for the Southern Sierra Nevada population. “It’s clearly a threat to fishers and some other species that may be exposed to toxins that are used at marijuana grow sites,” said Callas, the California Fish and Wildlife scientist. But there’s still more research to be done for a better understanding of the problem, he added. Gabriel’s research sampled fishers in three specific locations in California — one in Northern California and two in the Southern Sierra Nevada — and these areas constitute a “relatively small portion of their range,” Callas said. “So the question is…how representative is that of fishers elsewhere in California,” he said. A larger-scale study, which samples in a wider swath of the state, could help to answer that question. Still, he said, “the exposure rate where they have studied fishers has been high.” And as the new research shows that it’s been growing over the last few years, the threat is nothing to take lightly, Gabriel said, adding: “That is a big red flag.”


News Article | February 15, 2017
Site: www.scientificamerican.com

A visit to a marijuana farm in Willow Creek, the heart of northern California’s so-called Emerald Triangle feels like strolling through an orchard. At 16 feet high and eight feet around, its 99 plants are too overloaded with cannabis buds to stand on their own. Instead each plant has an aluminum cage for support. Welcome to America’s “pot basket.” The U.S. Drug Enforcement Administration estimates 60 percent of cannabis consumed nationwide is grown in California. According to the Department of Justice, the bulk of that comes from the three upstate counties of the Emerald Triangle: Mendocino, Humboldt and Trinity. Conditions here are said to be perfect for outdoor marijuana cultivation. But that has proved to be a very mixed blessing for the region, bringing with it a litany of environmental disturbances to local waterways and wildlife. Creek diversions threaten fish habitat and spur toxic algal blooms. Road building and clear-cuts erode soil and cloud streams. Deep within, illegal “guerilla grows” pepper forestlands with banned rodent poisons that are intended to eradicate crop pests but are also fatal to other mammals. On November 8 voters in four states—Massachusetts, Maine, California and Nevada—legalized recreational marijuana. These states join Colorado, Washington, Oregon and Alaska, along with the District of Columbia, where one can already legally buy the drug for recreational use. Will this expanded market mean more environmental damage? Or will legalization pave the way for sounder regulation? In 1996 California legalized marijuana for medical use, providing the first legal space for pot cultivation since the federal government’s blanket ban on the crop some 60 years before. As grow operations in the state flourished, California Department of Fish and Wildlife biologist Scott Bauer analyzed satellite imagery to examine the impact of cultivation on water levels in four Emerald Triangle watersheds. His study, published in PLoS ONE in 2015, found that in three of the four watersheds, “water demand for marijuana cultivation exceeds stream flow during the low-flow [summer] periods.” The real problem is not marijuana’s overall water consumption, which still falls far short of California staples like walnuts or almonds, explains environmental scientist Van Butsic of the University of California, Berkeley. Rather it is an issue of where and when pot is grown. Analyzing aerial imagery of 4,428 grow sites in 60 Humboldt county watersheds, Butsic found that one in 20 grow sites sat within 100 meters of fish habitat and one in five were located on steep land with a slope of 17 degrees or more. “The problem is that cannabis is being grown in the headwaters, and much of the watering is happening in the summer,” Butsic says. If that arrangement goes on unchecked, U.C. Berkeley ecologist Mary Power warns, summer plantations could transform local rivers from cool and “salmon-sustaining” to systems full of toxic cyanobacteria. Over eons of evolution native salmon species have adapted to “deluge or drought” conditions, she says. But the double whammy of climate change and water extraction could prove to be a game-changer. Power spelled out the unprecedented stresses in a 2015 conference paper focused on the Eel River that flows through Mendocino and southern Humboldt. She and her team found riverbed-scouring floods in winter, followed by dry, low-flow conditions in summer, led to warm, stagnant, barely connected pools of water. That is bad news for salmon, but ideal for early summer algal blooms. The algae then rot, creating an oxygen-deficient paradise for toxic cyanobacteria, which have been implicated in the poisoning deaths of 11 dogs along the Eel River since 2002. Dogs are not the only terrestrial creatures endangered by the grow operations. Between 2008 and 2013 Mourad Gabriel, then a doctoral candidate at the University of California, Davis, Veterinary Genetics Lab, carried out a study of the American fisher, a small carnivorous mammal that is a candidate for the endangered species list. He wanted to suss out the threats to fisher populations in northern California. So he radio-tagged fishers from Trinity County’s Hoopa Valley Reservation and public lands near Yosemite National Park to track their movements. Between 2006 and 2011, 58 of the fishers Gabriel and his team tracked turned up dead. Gabriel studied the necropsies and found that 46 of the animals had been exposed to anticoagulant rodenticides—rat poisons that block liver enzymes, which enable blood clotting. Without the enzyme the exposed mammals bled to death from flesh wounds. The finding puzzled Gabriel at first, because rat poison is more common in agricultural and urban settings than in remote forests. But then he started visiting the remnants of guerilla grows that had been busted under the guidance of lawmen such as Omar Brown, head of the Narcotics Division at the Trinity County Sheriff’s Office. “We have found [anticoagulant rodenticides] carbofuron on grows in the national forest,” Brown reports. “These are neurotoxin-laced pesticides that have been banned in the U.S. since 2011. And even for allowed pesticides, we’ve found instances where trespass grows are using them in illegally large quantities.” The poisons hit female fishers particularly hard, because the early, pest-prone phase of marijuana cultivation coincides with the fishers’ nesting season, when pregnant females are actively foraging. Gabriel, now director of the Integral Ecology Research Center based in Humboldt County, says other states may be dealing with rodenticides, water diversions and other problems from guerilla grows, too. “The climate in Colorado, Oregon and Washington is conducive for marijuana cultivation,” he observes. But “there just isn’t the scientific data to prove whether other states have these problems because there has not been research funding put towards answering these questions.” In California headwater ecosystems could get a reprieve if a greatly expanded legalized pot industry moves to the Central Valley, where production could take place indoors and costs would be less. In pot-growing pioneer states like Colorado or Washington much of the production has moved indoors, where temperatures can be more closely managed. But other factors may hinder that move. “Bud and pest problems are always worse indoors, which biases farmers toward a chemically intensive regime,” says Marie Peterson of Downriver Consulting, a Weaverville, Calif.–based firm that helps growers fill out the paperwork for state and county permits as well as assesses water management plans for their plantations. And besides, the Central Valley already suffers from prolonged drought. Of the eight states that legalized the cultivation of recreational marijuana, only Oregon and California allow outdoor grows. But regulating open-air pot plantations in these states remains challenging, even though legal operations for medical marijuana have been around since 1998 and 1996, respectively. In 2015 California passed the Medical Marijuana Regulation and Safety Act, which calls on the state’s departments of Food and Agriculture, Pesticide Regulation, and Fish and Wildlife, along with the state’s Water Board—to oversee environmental impacts of the industry. The board came up with a list of requirements for a marijuana plantation water permit, which in turn became a necessary condition for a license to grow medical pot in any of the three Emerald Triangle counties. Counties have until January 2018 to decide whether to create similar stipulations for recreational marijuana growing permits. Butsic is optimistic about a more regulated future for the marijuana industry in California. “I think five years from now things will be more sustainable. Permitting shows growers that the state is interested in water use and their crop.”


Matthews S.M.,Wildlife Conservation Society | Higley J.M.,Hoopa Tribal Forestry | Rennie K.M.,Hoopa Tribal Forestry | Green R.E.,Hoopa Tribal Forestry | And 4 more authors.
Journal of Mammalogy | Year: 2013

Many demographic parameters of imperiled fishers (Martes pennanti) in the Pacific Northwest remain poorly understood but are necessary to develop conservation strategies; herein we report on fisher reproduction, recruitment, and dispersal on the Hoopa Valley Indian Reservation, California, to help fill key knowledge gaps. Forty radiocollared, breeding-age females exhibited denning behavior on 80 (87%) of 92 opportunities between 2005 and 2011. Twenty-eight female fishers weaned offspring in 55 (65%) of 85 adequately monitored denning opportunities. Two-year-old female fishers were less likely than older females to den and wean kits. We counted 52, and extracted and marked 51, kits comprising 28 litters of 19 females between 2005 and 2008. Average litter size was 1.9 kits (27 females, 24 males, and 1 unknown) 4-12 weeks postbirth. Mean distances between natal dens and centroids of newly established ranges for 7 juvenile females was 4.0 km (range = 0.8-18.0 km); this distance for 1 male was 1.3 km. The recruitment rate of juveniles that successfully established a home range per adult female was 0.19 (0.16 for females and 0.02 for males). Our results suggest that managers should work toward increasing female survival rates and consider translocations to increase and expand existing fisher populations. © 2013 American Society of Mammalogists.


PubMed | Integral Ecology Research Center
Type: Journal Article | Journal: PloS one | Year: 2012

Anticoagulant rodenticide (AR) poisoning has emerged as a significant concern for conservation and management of non-target wildlife. The purpose for these toxicants is to suppress pest populations in agricultural or urban settings. The potential of direct and indirect exposures and illicit use of ARs on public and community forest lands have recently raised concern for fishers (Martes pennanti), a candidate for listing under the federal Endangered Species Act in the Pacific states. In an investigation of threats to fisher population persistence in the two isolated California populations, we investigate the magnitude of this previously undocumented threat to fishers, we tested 58 carcasses for the presence and quantification of ARs, conducted spatial analysis of exposed fishers in an effort to identify potential point sources of AR, and identified fishers that died directly due to AR poisoning. We found 46 of 58 (79%) fishers exposed to an AR with 96% of those individuals having been exposed to one or more second-generation AR compounds. No spatial clustering of AR exposure was detected and the spatial distribution of exposure suggests that AR contamination is widespread within the fishers range in California, which encompasses mostly public forest and park lands Additionally, we diagnosed four fisher deaths, including a lactating female, that were directly attributed to AR toxicosis and documented the first neonatal or milk transfer of an AR to an altricial fisher kit. These ARs, which some are acutely toxic, pose both a direct mortality or fitness risk to fishers, and a significant indirect risk to these isolated populations. Future research should be directed towards investigating risks to prey populations fishers are dependent on, exposure in other rare forest carnivores, and potential AR point sources such as illegal marijuana cultivation in the range of fishers on California public lands.

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