On December 1, 2016 I attended a talk hosted by tracker and Humboldt State University student Phil Johnston. In it, he spoke of a grave threat to Northern California’s mountain lions (Puma concolor): trespass marijuana grows. This is a serious problem that needs attention, and I recently sat down with Phil to learn more about it. What follows is a shortened version of our conversation.
You said in your talk that you work in the Hoopa Valley. How long have you been working there, and what do you do?
What are trespass marijuana grows?
Trespass grows are very different from legal ones (known locally as 215 grows). These operations take place without the permission of landowners, occur on both public and private lands, are not regulated, and are sometimes run by multi-million dollar drug cartels. These growers have no incentive to take care of the land, and are incredibly messy and environmentally destructive.
At your talk you mentioned that one harmful aspect of trespass grows are the large amounts of rodenticides (rat poisons) they use. What are these rodenticides, and how do they affect wildlife?
Trespass growers are deploying vast amounts of rodenticides; so much so that it’s contaminating the water and showing up in plants. Many of them are commonly available anticoagulants, such as Tomcat. These toxins cause internal hemorrhaging and eventually death: animals bleed out internally.
I believe you said in your talk that these anticoagulants actually dissolve animals’ internal organs. Is that correct?
Yes, that’s true. In addition, it takes 3-4 days for animals to die. This means they continue to eat the poison, and can contain up to 20 lethal doses when they pass. Rodents weakened by these toxins make attractive prey for predators, such as fishers. Mountain lions then eat the fishers, becoming poisoned themselves.
What sorts of impacts are trespass grows having on mountain lions?
I’m beginning a study right now to find out. However, preliminary evidence suggests this could be a major problem. Every mountain lion that’s been tested in California has contained at least trace amounts of these rodenticides, and the cats’ population in Hoopa seems to be crashing. Six mountain lions disappeared eight months ago, and their territories have yet to be filled. This is extremely unusual: especially since none of the individuals who vanished were at dispersal age.
I also know of a family of three mountain lions who ate a poisoned fisher. All of them died, and we found two of the carcasses. Both tested positive for rodenticides.
One of the reasons trespass grows could be so problematic for mountain lions is the cats’ ranging behavior. They have huge territories, which means they’re guaranteed to encounter unethical grows. Furthermore, the Hoopa Valley contains the highest density of black bears (Ursus americanus) in the world. The bears often chase mountain lions off their kills, forcing them to hunt more often. This might also cause mountain lions to hunt smaller prey, like fishers. This may be increasing the amounts of toxins they are consuming.
What can the average person do about this problem?
The most important thing they can do is to know where their weed comes from. When you buy from bad grows, you’re financing the destruction of our wildlife.
Two more crucial activities are to spread the word and be politically active. Talk about this issue amongst your friends. Also, call your state representatives and let them know you’re concerned about this. Lastly, read ballot measures and vote for ones that will generate funding for combatting trespass grows. We’re up against wealthy crime syndicates, so we need more resources.
But let me be clear, this is not a war against marijuana: it is a war against illegal agriculture. There are lots of ecologically responsible growers in Humboldt County who are an important part of our community. We want to help them by reducing competition from the trespass growers who are poisoning our woods.
I would like to thank Phil for agreeing to this interview, and for advocating for Humboldt County’s wildlife. Please, help spread the word about this problem. People need to know about it!