Coming into the Light: Opportunities and Challenges that Cannabis Legalization Brings to Natural Resources

Black-market cannabis cultivation is an environmentally destructive practice that is a growing concern throughout the United States. Black-market growers disregard regulations intended to protect sensitive habitats by using pesticides and fertilizers illegally, disturbing landscapes, poisoning and poaching wildlife, littering with human refuse, and illegally diverting water. These impacts span aquatic and terrestrial habitats, impair water quality, and increase habitat degradation and fragmentation, exacerbating conservation concerns for listed species. With impacts predicted to worsen as the national market for recreational and medicinal cannabis expands, states that have legalized cannabis cultivation are attempting to eliminate these threats. Actions to address these issues include sustainable growing practices; increasing regulation, enforcement, and monitoring; developing noise and light pollution standards, and controlling the size and location of permissible cultivation sites. This can only be accomplished through strong interdisciplinary partnerships among scientists, policy makers, agencies and cultivators. This session will focus on the impacts cultivation has on aquatic and terrestrial species and their habitats, tools to monitor in these settings, challenges faced by natural resource agencies, and how state legalization of the industry might reduce environmental impacts by embracing sustainable legal cultivation practices and engendering a shift from an industry dominated by harmful black-market grows.

8:00AM Introductory Remarks
  Nicole Elliott
8:40AM Growing Pains: Regulating Cannabis Cultivation (Past, Present, and Future)
  Scott Bauer
Statewide legalization has completely changed the cannabis cultivation industry. Once conducted by outlaws underneath the forest canopy of California’s public and private lands, cannabis is now widely and openly cultivated in 21 of 58 counties across the state. Although the black market is still alive and well, regulating the emerging legal market is fraught with challenges. The California Department of Food and Agriculture has received close to 20,000 cannabis cultivation license applications and issued almost 10,000 temporary permits. Regulating such a large and geographically diverse industry tests the fortitude of the myriad of local and state agencies, counties and cities that seek to control and contain the physical and societal impacts of cannabis cultivation. California’s natural resources are protected by an abundance of thoughtful regulations and associated agency authority. However, limited personnel resources, a rapidly-changing industry, and proposals to modify regulatory oversight complicate efforts to effectively conserve sensitive fish and wildlife habitats. This presentation will focus on the history of the cannabis industry, the regulatory efforts of state agencies, and hypothesize what the future may hold for the industry and California’s diverse natural resources.
9:00AM Dynamics of Cannabis Production in the Emerald Triangle
  Van Butsic
Cannabis cultivation has been an important part of North Coast communities for a least 40 years. Over the last decade, however, the scale of cannabis production has increased to the extent that it may now threaten the regions ecosystems. We documented changes in cannabis production in Humboldt and Mendocino Counties from 2012-2018 using very high-resolution satellite imagery. This time period saw a large increase in overall production. In 2018, the state started to require production permits to sell cannabis in the regulated market. Our data can therefore be used to understand systematic differences between permitted and unpermitted cannabis farms in terms of farm size and location. We found that larger farms were far more likely to join the regulated industry than small farms. Yet many non-permitted farms continued to produce during the 2018 season, suggesting that regulation alone is insufficient (at least in the short term) to limit cannabis production in this part of the state.
9:20AM Cannabis Landscapes in Oregon
  Phoebe Parker-Shames, Van Butsic, Justin Brashares
Many states in the US are now engaged in a large-scale experiment with the legalization of recreational cannabis, but the effects of this policy change on the environment are as yet unknown. To examine the potential landscape impact of cannabis production on fish and wildlife habitat, we mapped cannabis land use in Josephine County in Southern Oregon in 2012/2013 and 2016 and compared it to Humboldt and Mendocino in California. After mapping more than one million cannabis plants, we found that outdoor cannabis production is spatially small and clustered, but rapidly increasing, especially in Oregon post-legalization. This creates localized point source disturbances on the landscape. We analyzed the proximity of cannabis production in both regions to threatened fish and wildlife habitat. The industry, while still small scale at a regional level, is rapidly increasing post-legalization, especially in Oregon. Its location in remote areas near fish and wildlife habitat may pose an ecological threat over time with continued growth, if specific mechanisms of impact can be identified and tested. As a rapidly expanding industry under new regulatory oversight, cannabis provides a window into how interactions between policy, land use change, and ecological communities change across regulatory contexts, landscapes, and scales.
09:40AM Break
1:10PM A Fish out of Water: A Federal Prosecutor’s Perspective in States That Have Legalized Marijuana
  Karen Escobar
At the federal level, marijuana remains a schedule I controlled substance. However, as an increasing number of states have adopted some form of legalization of marijuana, traditional concepts of federal preemption and separate sovereignties have eroded, presenting new challenges in the enforcement of federal law. Now, more than ever, federal law enforcement authorities are in a unique position to not only dismantle drug trafficking organizations which seek to take advantage of relaxed state drug laws but to address the significant risks to the environment posed by unsustainable cultivation operations.
1:30PM It’s a Trap! Cannabis Cultivation Sites As Ecological and Evolutionary Traps for Wildlife
  Mourad W. Gabriel, Greta M. Wengert
Ecological and evolutionary traps can pose unforeseen risks to wildlife by allowing disadvantageous environments to mimic optimal habitat or trigger behavioral choices that diminish an individual’s reproductive success or chance of survival. Illegal and unregulated cannabis cultivation on Western forest lands has emerged significantly over a very short period of time with rapid anthropogenic alteration of the environment to create ideal cultivation conditions. This swift uptick in landscape modification associated with attractants such as food trash, poison baits, and aromatic chemicals, coupled with deleterious cultivation practices from black-market cultivators may serve as both ecological and evolutionary traps for both terrestrial and avian wildlife. We will discuss these trap potentials using a unique California state-wide data set for which we monitored numerous landscape features and wildlife over a period of six years. We have observed that pesticide contamination on soil, water, cannabis and native plants coupled with habitat manipulation and anthropogenic wildlife attractants acting in concert can create ecological or evolutionary traps for wildlife. As a remedy to the problems generated by these traps, we will discuss an experimental framework through which we attempt to rectify these maladaptive cues and monitor the responses from wildlife most affected by them.
1:50PM Water Use Practices in California’s Regulated Cannabis Industry: Seasonal Patterns, Storage Insufficiency, and the Shift to Groundwater
  Christopher Dillis
This study analyzed water use reporting data from 2017, submitted by cannabis cultivators in the North Coast enrolled in the Regional Water Quality Control Board Cannabis Regulatory Program. These self-reported data contained water sources, water storage capacity, and the timing and amount of water both input to storage and applied to plants. We used these data to analyze the distribution of water sources, seasonal extraction patterns, and the role of water storage and sources in affecting these patterns. Although water input to storage in the off-season months (November through March) reduced water extraction in the growing season (April through October), farms generally did not have enough storage to completely forbear from surface water extraction during this period. The two most important predictors of storage sufficiency (type of storage infrastructure and type of water source) also had reliable effects on seasonal extraction patterns, emphasizing the link between water storage and extraction profiles. The differences in extraction patterns are particularly relevant, given that a substantially larger proportion of farms reported well use than previously anticipated. It will be useful to consider how cultivation practices drive extraction patterns and how these practices may be influenced by participation in the regulated cannabis industry.
2:10PM A Paired Watershed Comparison of Hydrological and Biological Condition in Streams with and without Cannabis Cultivation–Part 1: Hydrologic Condition
  Elijah Portugal, Erin Ferguson, Jason Hwan, David Manthorne, Joseph Kermish-Wells, Kelly Souza
Recent rapid expansion of the cannabis industry in watersheds of California supporting sensitive habitat for endangered salmonids and a lack of empirical data has heightened CDFW concerns. We initiated a pilot study in 2018 to investigate hydrological and biological conditions in coho-bearing, naturally intermittent tributaries to the upper Mattole River Watershed in Northwestern California. A paired watershed design was used to isolate effects of cannabis cultivation from natural variability and impacts from legacy landuse. Streams were selected based on watershed characteristics, access, and the level of cannabis cultivation from zero to 0.4% of drainage area. Hydrological monitoring was conducted during the outdoor cannabis growing season (May-Oct) in three paired watersheds (two streams with cultivation and one without) and an additional 5 unpaired watersheds using continuous pressure transducers. Dissolved oxygen, temperature and benthic macroinvertebrate data was also collected and will be discussed in Part 2. Grow sites were digitized using current aerial imagery to estimate cannabis water demand, allowing for a comparison with surface water availability. Streamflow declined at significantly faster rates in two cannabis streams when compared to a closely matched control stream. Further exploration is needed to verify documented trends were due to cannabis cultivation and not natural variability.
2:30PM A Paired Watershed Comparison of Hydrological and Biological Condition in Streams with and without Cannabis Cultivation–Part 2: Biological Condition
  Erin Ferguson, Jason Hwan, Elijah Portugal, Kelly Souza
Like other forms of large scale agricultural practices, cannabis cultivation has the potential to impact the aquatic environment. Impacts include reduced quality and quantity of stream habitat during critical summer months, when state and federally listed salmonids and amphibians are rearing. This talk is part 2 in a series exploring the results of California Department of Fish and Wildlife’s pilot efforts to determine if there are significant hydrological and biological differences between streams in watersheds containing cannabis cultivation to those that do not. Dissolved oxygen, water temperature and benthic macroinvertebrate composition and metrics, were compared between two watersheds containing cannabis cultivation, to one containing no known cannabis cultivation. The results of this study indicate that biological conditions in streams where cultivation occurs in the watershed are significantly different than in streams without cannabis cultivation. More research is needed to determine if the observed differences in biological condition in our study streams can be attributed to cannabis cultivation as opposed to natural variability. Additionally, sampling across different water years and geographic regions is needed to verify that the trends observed in this study hold true outside of the Upper Mattole River Watershed, Humboldt County, Ca.
2:50PM Refreshment Break
3:20PM The Growing Web of Effects on Forest Mammals from Cannabis Cultivation on Public Lands
  Greta M. Wengert, Mourad W. Gabriel, J. Mark Higley, Deana Clifford, Lindsey Smith, Kyle Van Atta, Corrina Kamoroff, Ivan Medel
The deleterious impacts on wildlife from cannabis cultivation on public lands have only recently been highlighted as concerns for wildlife conservation. Water diversions, poisonings, and habitat modifications are now understood to be common at cultivation sites throughout California’s public lands. Mammals appear to be particularly hard-hit by the vast impacts from these activities occurring at most cultivation sites. We are monitoring several groups of mammalian taxa to gauge impacts throughout the food web in California’s forests. Starting from the ground-up, we are evaluating population-level impacts to rodents as sources of prey for forest species, monitoring mid-size and large carnivores for behavioral changes and mortality due to cultivation activities, and identifying the paths of contamination from cultivation to the top trophic level as mountain lions and black bears. Preliminary data indicate that most forest mammalian species are directly or indirectly impacted by this activity. Rodents are impacted at the population-level and in turn, pose risks to carnivores which depend on them for food. Behavioral changes put large carnivores at risk as they are lured to pesticides commingled with food refuse left by cultivators. Collectively, the impacts to mammalian communities are extensive and likely run deeper and more covertly than previously recognized.
3:40PM Evaluating Pesticides Entering Wastewater Catchments from Regulated Indoor Cannabis Cultivation in California
  Annette Narzynski, Jennifer Teerlink
The occurrence of pesticides in treated wastewater effluent has been reported at concentrations that exceed toxicity thresholds. There are many potential pesticide uses that contribute to wastewater treatment facilities; however, little to no data is available for indoor cannabis cultivation. The increasing number of indoor cannabis cultivation facilities as a result of legalized cannabis in California may to lead to consequential pesticide loading to wastewater treatment plants, and subsequent discharge to surface waters. The California Department of Pesticide Regulation’s (CDPR) Surface Water Protection Program (SWPP) is conducting a study to evaluate pesticides in wastewater discharged from legal cannabis cultivation sites. Quantitative analysis of 23 pesticides and degradates will be conducted on samples taken directly from where cannabis cultivation sites discharge to a wastewater catchment. Suspect screening using mass spectral libraries and non-target analysis with the aid of high-resolution accurate mass spectrometry will be used to identify pesticide occurrence in discharge. SWPP will utilize the results to lay the foundation for evaluating the potential environmental impacts associated with pesticides used in indoor legal cannabis cultivation in California. Future monitoring efforts can rely on identification of pesticides through suspect screening and non-target analysis to inform development of quantitative analytical methods.
4:00PM Automated Remote Cannabis Detection to Aid Enforcement and Conservation Efforts on Public Lands
  Adam Cummings, Mourad Gabriel, Karen Pope, Greta Wengert
Illegal cannabis cultivation on public lands poses danger to both humans and the environment. The strong incentive of illicit marijuana growers to remain hidden from law enforcement has resulted in an ever-evolving pattern of improved detection techniques and more elusive growing techniques to avoid detection. Recently the convergence of computing power, machine learning algorithms, and high-resolution aerial imagery has enabled researchers to sort a few hundred acres of marijuana cultivation from millions of acres of natural forest. We trained a convolutional neural network to identify active and historical grow sites hidden on public lands. The model has detected over 30 cultivation complexes and reclamations at several detected sites have removed over 10,000 pounds of trash. The model has proven effective at detecting both active grows as well as historical grows that were abandoned but still pose a threat due to the presence of remnant toxicants, fertilizers, and trash. A better understanding of the spatiotemporal patterns of marijuana cultivation on public lands helps direct resource allocation to address the problem. Locally, grow sites within sensitive resource areas could be prioritized for interdiction and reclamation. The model also enables interdiction and remediation of grow sites year round.
4:20PM Cannabis Removal on Public Lands (CROP) Project
  Ryan Henson, Richard McIntyre
Illegal cannabis grows on California’s public lands presents a clear and present threat to soil, watersheds, wildlife, and communities. The negative environmental effects of cannabis production on public lands are profound. For example, the use of highly controlled or banned chemicals and rodenticides directly impact sensitive wildlife species and the public. The CROP Project (Cannabis Removal on Public Lands,, is a campaign to secure broad public and political support to tackle the problem of marijuana cultivation on California’s public lands. CROP will build a groundswell of support behind a policy agenda that includes additional resources for cleaning up the vast backlog of old grow sites, more funding for on-the-ground law enforcement to cover the millions of acres at risk, capacity-development for tribes, non-governmental organizations, local governments and others who want to assist with reclamation or prevention, additional criminal penalties for using toxics in illegal grows and for other offenses, measures to limit the production, sale or exportation of certain chemicals that routinely appear at public land grows, procedures to address the safety concerns inherent in dealing with toxic materials at grow sites, and more resources for basic research and the long-term monitoring of potential grows.
4:40PM The Impact of Regulations and Business Models on Best Practices in Cannabis Cultivation
  Scott Davies
Exploring the relationship between regulations, business models, and cannabis cultivation methodologies. The regulatory framework in cannabis cultivation informs the specific methods employed by cultivators, which has a direct bearing on the environmental impacts associated with cannabis cultivation (water use, pest management, energy consumption). Testing protocols and licensing framework are the most effective methods to reduce harmful pesticide use and encourage best practices (alternative energy, integrated pest management). Regulations also provide an opportunity for collaboration between groups that would not historically collaborate (law enforcement, regulators, policy makers, cultivators). Such collaborations lead to the best policy and regulatory outcomes for addressing environmental damage.
5:00PM Concluding Remarks

Organizers: Kelly Souza, Mourad Gabriel
Supported by: Dr. Mourad Gabriel (Integral Ecology Research Center) and Kelly Souza (Calif Dept of Fish and Wildlife)

Location: Reno-Sparks CC Date: September 30, 2019 Time: 8:00 am - 5:20 pm