 Hi, I'm Phaedra Kress, the managing editor of Conservation Letters, and I am joined by Craig Thompson, who is with the USDA Forest Service Pacific Southwest Research Station in Fresno, California. Craig, welcome. Craig Thompson Hi, thank you. Phaedra Kress So Craig's article has been selected as our feature article for the March-April issue of Conservation Letters, and it is entitled, Impacts of Rotodenticide and Insecticide Toxicants from Marijuana Cultivation Sites of Fisher Survival Rates in the Sierra National Forest, California. So Craig, let's jump right in. Could you give us a little background on your training and research interests, and how, for example, you became interested in studying the effects of toxicants on the fisher? Craig Thompson Sure. My background is primarily in the ecology of small to mid-sized carnivores and looking at the impacts of human activity on those species, particularly endangered or threatened ones. And we were working with Fisher for a variety of reasons here in the Sierra Nevada, primarily having to do with forest management, fire and fuels issues. We certainly never expected to have to be dealing with pesticide or rodenticide issues in these species, but back in 2009, some folks that we were working with came across a dead animal on the floor that looked to be in perfect health outside of the fact that it was dead. And we were stunned when the necropsy results came back to tell us that this animal had died of anticoagulant, rodenticide poisoning. So we found ourselves needing to dig deeper into that topic. Again, it's certainly not something I thought I would ever be dealing with in the wildlife field, but it's what's in front of us right now. Craig And so let's start by giving an ecology of the fisher just so we can sort of set the landscape for the discussion today. Craig Thompson Sure. Fishers are about the size of a large house cat here in the Sierras. They are native to a lot of the mountain regions of the United States and Canada. Historically they used to inhabit the entire Sierra Nevada and Cascade region, however they have been isolated down here in the southern Sierras for a variety of reasons. So today they are a very significant conservation concern for a lot of stakeholders in the area. It's a relatively small population that's considered to be at high risk of extinction down here. They are members of the weasel family, most closely related to a wolverine, or if someone knows what a marten is, they live, they spend quite a bit of time in the trees. They are, as I said, they're native to this area. Most people don't know what they are, but odds are if you've ever taken a hike in the woods, they've been watching you, even though you would never know that they're there. Angela Brown Excellent. Now this sort of dovetails Nancy with the next question, which is about, you touched on that they're a rare species. So do you think that they should be included under the Federal Endangered Species Act, given their non-expansion history, and if so, can you tell us why? Paul That is a very difficult question to answer. One that is being considered by the U.S. Fish and Wildlife Service right now, with a decision pending later this year. The question really comes down to whether or not their isolation here is a result of human activity. We know that they were definitely impacted by logging and mining issues earlier in this century. We also know that they were impacted by ice age events as well. And so the decision will be made by Fish and Wildlife Service as to what they think the critical factors there are. However, I do know that this redenticite issue is weighing very heavily on their decision, because this is a human impact that we have some level of control over. Now, can you give us the definition of a term you use in the article, and its anti-coagulant rodenticide? Paul Sure. The majority of the rat and mouse rodent control poisons that you buy over the counter at stores is what is called anti-coagulant. These chemicals interfere with the body's ability to utilize vitamin K in such a way that your blood can clot. And so essentially, if an animal consumes too much of this, they lead to death internally. Okay. So one of the figures in your article that I found to be staggering are the sighted exposure levels of 65 to 90%. What approach can turn this problem around so we can avoid species and population declines? Paul Yeah, those were some fairly staggering numbers. When we discovered the one dead animal back in 2009, a graduate student of the time went back and tested some archived tissue samples we had from animals that we had collected previously. And it came back that almost 80% of them had gotten into this stuff. And that really was a staggering number for us to realize. In terms of turning this problem around, the pervasiveness of this problem throughout the western United States is something that most people are simply not aware of. And the level of contamination that is going on at these sites. There are thousands of these illegal, what we call trespass, marijuana grows in national forest land, tribal land, timber industry land, pretty much anywhere where there's some isolation. And a lot of what we're doing right now is simply focusing on public education, trying to get the information out there so that people can decide how they want to address it. Lisa So, you mentioned the cultivation sites. Let's talk about those. I was surprised when you sent us the imagery which we're using on the cover of this March April issue to see all of the garbage around there. And I think in one of our prior conversations you talked about the fact that people are actually living their full time to kind of grow the marijuana sites and crops and kind of look after them and keep away trespassers. So talk to us a little bit about those sites themselves. Yeah, I think most people don't realize the industrial nature of these sites. They think of an illegal marijuana grow on public land as your neighbor down the street or a hippie or something like that. And people just simply don't realize that this is an industrial scale effort. Somewhere between two to five people probably live at these sites the entire summer. All of the trash that they accumulate, the food, the propane bottles, fuel, clothing, kitchen and stuff, all of that just accumulates at these sites and generates huge trash piles. Within those trash piles we often find tens to hundreds of pounds of pesticides, fertilizers, rodenticides, other chemicals that either have been used and we find the empty packaging or they're just abandoned out there. Now I'm going to throw a few statistics at you. I watched a video about this that you graciously provided for us and I learned that it takes up to 15 gallons of water a day to grow a pot plant and that there are potentially up to a million of them in these sites. So given that it kind of follows that there would be a requirement to have people and food and some of the garbage that contributes to these sites, is that correct? Is that actually accurate information? Yes. Okay, great. So let's see. Talking about the marijuana plants themselves, do you have any concept of the value of them or what it might be worth, whether it's in pounds or plants themselves? Just to give our listeners a sense of sort of the scope of, you know, you say it's not just your hippie neighbor down the street with, you know, a plant in his backyard. So give us sort of the higher level view of the size that we're discussing here. I am really not part of the discussions around the cost or the money that these things worth to evaluate anything like that. All I know about that is 10 to 15 years ago the average size of these grows was maybe 200 plants and now it's probably anywhere from 2,000 to 20,000 plants per grow and there are thousands of these grows up and down the state of California. You mentioned the water issue. At each of these sites, one of the common things that we find is water diversion from creeks or streams. We'll find homemade kind of water storage systems and they are diverting millions to potentially billions of gallons of water from the natural hydrologic system out here. Oftentimes that water is mixed with fertilizer and chemicals before it's used for irrigation so that many of those chemicals are there and finding their ways back presumably into the water system. It is simply a massive operation as I keep saying at an industrial scale that most people just don't realize. So can you take us through some of the physiological effects and the secondary impacts of this exposure to wildlife. I'm thinking about hot dogs and tuna cans and intentional poisoning from one of our earlier conversations. Okay. There's a variety of different chemicals that we find at these sites. The anticoagulant is far and away the most common. Those are used both to protect young marijuana plants from chewing by rodents and others to communities and they also use them to protect their camp area because they don't want animals getting into their food supply. Those chemicals, their first and second generation redendocides, primarily that means they can either kill an animal in one feeding or may have multiple feedings. The small rodents that get into this are then exposed to predation by the larger animals so we get what's called bioaccumulation of these chemicals in the carnivores and when a carnivore eats enough of these contaminated rodents essentially they, as I said, lose their ability to clot. They can die from a minor injury by bleeding to death. If they get enough of it, they will actually just bleed to death internally. There are other chemicals at these sites that we're even more concerned about though and these are insecticides and pesticides primarily in a group called either carbon mate or organophosphate families. Some of these are even banned in the United States. Carbofuran, DDT has been found at these sites and these are far more lethal. They are sprayed on the plants both for their intended purpose and then they are also being used to intentionally poison larger wildlife species. As you mentioned, tuna cans have been found with some of these pesticides mixed in in highly concentrated doses. We have also found hot dogs dipped in some of these chemicals strung in the trees around the can and these toxins are so potent that we found one animal that had died and still had the hot dog lodged and it didn't even have time to finish its second bite on that and there have been numerous animals found dead around these sites by these things as well. So let's take a minute or two here at the end of our interview to talk about education. I think there's the likelihood that someone could sort of surreptitiously happen upon one of these sites. In the image that you provided for us we saw weapons and guns for example. So in terms of educating the public about what to do if they happen upon a site, what would you say? The primary thing is to turn around and leave by the route that you came out. The most likely thing that people are going to run across is black irrigation tubing this will be used to run water from creeks or streams for up to a mile to wherever the grow is actually going on. You can also find a lot of trash, propane bottles are common and these are very dangerous locations. As we said these guys are generally armed and if you come across any evidence of these sites the best thing by far to do is just turn around and leave. The other part of the education that we are really pushing at is one for recreationists, backpackers, fishermen, mountain bikers, things like that. These people really need to know what they may come across in the woods as they're out there. And then the second part is the rest of the public really needs to know what's being put on these plants before they go out to market. Sure, that makes sense. Thank you for the overview. So in summary can you give us just the key takeaways of the research here and we'll appreciate just being able to have a little snapshot overview at the end of the talk here. Okay. As I said at the beginning this problem came completely out of the blue and surprised us. We never went out in the woods looking for this or expected it but now that we've found it we really view Fisher as just the canary in the whole mine. We only found this problem because we were looking at Fisher intensively for other reasons. There's no reason in the world to think that it's not impacting other species as well. Potentially these chemicals being washed by water runoff into the streams, creeks, things like that. This is a significant problem for the western United States right now and most people as we said are simply not aware of the scale of it. And to us on the research side the fact that it's marijuana is really secondary. Whatever that they could be growing. I've had some colleagues refer to it as they could be growing corn or tomatoes out there and it really doesn't matter. It's the process by which they're growing that is really causing all the damage. Well Craig thank you so much for your time and for joining us. We really appreciate it and best of luck with the rest of your research. Thank you very much. Thank you for your time.