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California Environmental Monitoring and Assessment Framework

Overview

Land use changes, such as cannabis cultivation, combined with worsening droughts and longer wildfire seasons, could harm vulnerable species, water supplies, and habitats. Monitoring and managing these resources is key to CDFW's mission, but you can't manage what you don't measure. The California Environmental Monitoring and Assessment Framework (CEMAF) is a cornerstone of the Cannabis Program and supports other CDFW efforts. The goal of CEMAF is to assess if, when and where cannabis cultivation or other factors like development and drought may be having adverse or cumulative impacts on:

  • Aquatic and terrestrial habitats
  • Individual species and communities
  • Streamflow and water quality

The environmental impacts of cannabis cultivation, a growing land use in California, are less understood than those of conventional agricultural commodities. Potential impacts may include water use, habitat conversion, erosion, noise, night-time light, and barriers to wildlife movement. However, well-planned cultivation sites can reduce these impacts. Visit the Cannabis Program Resources page for best management practices and additional reports and publications. 

Habitat Loss and Fragmentation

mulitple elk standing in a grassy meadow, with the center elk looking at the camera

Clearing forests, grasslands, or other natural areas to grow cannabis can cause wide-ranging impacts on land and water ecosystems.

How Clearing Natural Areas Can Impact the Environment

  • Losing wildlife habitats takes away food and shelter for animals
  • Fragments ecosystems with human infrastructure like roads and houses
  • Disrupts nutrient circulation through the environment by removing plants and trees
  • Increases the risk of landslides and burying streams.

Clearing land or adding fences can separate habitats, making it harder for fish and wildlife to move and survive. These changes force wildlife to travel long distances to find food, shelter, and mates. Over time, breaking up habitats also makes it more difficult for animals to adjust to climate change.

How Cultivators Can Help Protect Fish and Wildlife

  • Careful planning of farm footprint
  • Reducing wildlife habitat destruction
  • Avoiding disturbing sensitive area

Get permitted!

Water Diversion

a fish swimming through the water making ripple marks with its tail

Water is a limited resource that fish and wildlife need to survive. Changing the natural flow of streams can damage ecosystems and put fish and wildlife at risk. Diverting water for cannabis and other agriculture during the dry season can reduce how much water is available in the environment and harm habitats. With climate change projected to increase water scarcity and drought, we must work to better understand how to balance water demands for human needs and the environment.

How Water Diversions Can Impact the Environment

  • Disrupts salmon migration, spawning, and growth
  • Reduces habitats for sensitive species
  • Dries up watering holes for wildlife
  • Lowers food supply and water quality for aquatic life
  • Raises water temperatures, spreads disease, and increases stress
  • Promotes harmful algal blooms

How Cultivators Can Use Water Wisely

  • Screening water intakes to keep fish and other animals safe
  • Choosing drip irrigation over sprinklers
  • Storing winter water for summer use to reduce demand during the driest months

For more information on water conservation, contact the State Water Quality Control Board.

Dam and Stream Crossings

a stream with muddy water with a gravel road running through it
Low-water stream crossing. Photo by Michael Paccassi.

Dams and stream crossings disrupt the natural flow of rivers and streams, creating barriers that fragment aquatic habitats and hinder the movement of aquatic life. Even small barriers can have cumulative effects that impact fish populations and overall biodiversity. These disruptions can reduce fish species richness and abundance (Consuegra et al., 2021).

How Dams and Crossings Can Impact the Environment

  • Changes the timing and amount of water moving through rivers and creeks. This disrupts the natural flow, reducing habitat quality and making it more difficult for aquatic species to thrive.
  • Increases scouring, erosion, and sediment deposition, which in turn degrade habitats for fish and other aquatic life.
  • Blocks migration paths, limiting access to important breeding and feeding areas. This is particularly harmful to species like salmon, as it prevents both young and adult fish from reaching key habitats during their seasonal migrations.

How Cultivators Can Pursue Responsible Stream Alterations

Please refer to the Lake and Streambed Alteration Program page for best practices and regulations.

Pests and Pathogens

a single purple flower and green foliage in the background
Big periwinkle (Vinca major) is an introduced species that is invasive in California. It can choke out native plants, which harms ecosystems.

Invasive species are one of the biggest threats to California's environment and economy. Cannabis cultivation, like other types of farming, can accidentally spread non-native species such as harmful plants, insects, and diseases.

This can happen when:

  • Soil and native plants are disturbed
  • People and equipment move in and out of growing areas
  • Nursery plants, soil, mulch, and fertilizers are brought in

Outdoor and mixed-light cannabis farms are often in remote areas. This increases the risk of introducing pests into healthy ecosystems. One example is Sudden Oak Death, a fungal disease spread in California through contaminated soil.

How Cultivators Can Help Prevent the Spread of Pests and Pathogens

  • Limit soil and vegetation disturbance when building roads or clearing land
  • Remove invasive plants before starting any work
  • Plant or encourage the growth of locally native plants on disturbed soil not used for structures
  • Employ best practices by:
    • Reducing the amount of organic material moved to and from the site
    • Using certified disease-free plants, mulch, and soil
    • Cleaning equipment regularly
    • Checking for pests and diseases regularly

By following these steps, cannabis cultivators can reduce the spread of invasive species and help protect California’s ecosystems.

Bullfrogs

a large tadpole laying in a persons hand outside of the water
American bullfrog tadpole. Photo by Gary Nafis.
a large bullfrog sitting in a persons hand
American bullfrog in southern California. Photo courtesy of Kerwin Russell, Riverside-Corona Resource Conservation District.

Cannabis cultivation often involves creating and using artificial water sources like irrigation ponds, which can support non-native American bullfrogs. Bullfrogs are listed as one of the 100 most harmful invasive species globally.

How Bullfrogs Can Impact Wildlife

  • Bullfrogs prey upon and outcompete a wide variety of native species.
  • Bullfrogs harm native amphibians by spreading chytridiomycosis, a disease that has caused declines and extinctions of hundreds of amphibian species globally.

How Cultivators Can Protect Our Native Species From Bullfrogs

Pesticides and Fertilizers

two lady bugs on the underside of a cannabis leaf

Agricultural practices, including cannabis cultivation, may involve the use of pesticides to protect plants from pests like insects and rodents, and fertilizers to help plants grow. Pesticides and fertilizers must be used according to instructions from the manufacturer. The California Department of Pesticide Regulation (CDPR) and the California Department of Food and Agriculture (CDFA) provide information on pesticide use for agricultural commodities in California.

How Pesticides Can Impact Wildlife

One of the biggest threats to wildlife from unlicensed cannabis cultivation is the use of banned pesticides or the misuse of legal ones. Non-target wildlife can be exposed to pesticides in two ways:

  • Direct exposure – Animals may eat, touch, or breathe in pesticides left on plants or in the environment.
  • Secondary exposure – Predators may eat smaller animals that have been poisoned.

Exposure to pesticides can:

  • Kill animals directly
  • Buildup in an animal’s tissues, making them weaker and more vulnerable to predators
  • Damage the immune system, making animals more likely to get sick
  • Reduce reproductive success
  • Disrupt an animal’s ability to regulate body temperature, which can lead to death

How Fertilizers Can Impact the Environment

Improper fertilizer use can:

  • Increase the number of pests and diseases
  • Run off into nearby streams, causing algae blooms that lower oxygen levels and suffocate fish and aquatic life
  • Release nitrous oxide, a greenhouse gas that contributes to climate change
  • Harm native plant communities by encouraging the growth of fast-growing, invasive plants

How Cultivators Can Reduce the Impact from Fertilizers and Pesticides

  • Only using legal pesticides and fertilizers when needed
  • Following product labels and storing chemicals properly
  • Contacting the Department of Fish and Wildlife before using pesticides or fertilizers if sensitive wildlife or habitats are on the property
  • Choosing wildlife-friendly pest control methods, such as:
    • Disposing of trash and food in animal-proof containers
    • Installing bird nest boxes, bat houses, or raptor perches to encourage natural pest control
    • Planting companion plants that repel pests or attract beneficial insects

By following these practices, cultivators can protect California’s wildlife, waterways, and ecosystems. For more information on the environmental impacts of pesticides and fertilizers, see this review article.

Light Pollution

distant hills at night, with light coming from a far away city shining through the nighttime clouds

Cannabis farms often use artificial nighttime lighting to boost plant growth and for security purposes. However, this light can spread far beyond the property and may be brighter than natural moonlight. Since light is an important energy source and information signal for ecosystems, artificial nighttime light can cause harmful impacts.

How Light Pollution Can Impact Wildlife

  • Changes animals' activity patterns
  • Makes it easier for predators to find prey
  • Blocks animal movement, as many species avoid lit areas
  • Disrupts navigation and migration routes
  • Mismatches the timing of breeding and plant growth

Light pollution doesn’t just affect individual animals - it can disrupt entire ecosystems and put many species at risk. Additional information on the impacts of light pollution can be found in this review paper.

How Cultivators Can Reduce Light Pollution

  • Using black-out curtains in greenhouses
  • Limiting non-essential lighting
  • Installing motion-activated, low-spectrum security lights
  • Directing lights away from wetlands, streams, and other sensitive areas

For more information on responsible outdoor lighting, visit DarkSky International.

Noise Pollution

an owl with large eyes sitting on the ground looking directly at the camera

Cannabis cultivation can create noise pollution from generators, irrigation pumps, climate control systems, landscaping tools, construction, and vehicles. Human-made noise can interfere with natural sounds that wildlife depend on.

How Noise Pollution Can Impact Wildlife

  • Makes it harder for animals to find mates
  • Causes species to leave their habitats
  • Masks warning calls and communication signals
  • Makes it harder for animals to find food
  • Results in hearing loss, stress, or high blood pressure

How Cultivators Can Reduce Noise Pollution

  • Placing loud equipment like generators and pumps inside insulated sheds or soundproof structures
  • Keeping continuous noise levels within 20 decibels (dB) above the natural background noise
  • Limiting loud equipment, such as chainsaws and mowers, to no more than 90 dB in cities and 70 dB in rural areas

Check your county’s noise regulations to ensure compliance with regulations regarding noise production from cannabis cultivation. Additional information on the potential impacts of noise pollution on wildlife can be found in this review paper.

Publications and Reports

CEMAF Survey Locations

This monitoring is made possible through the cooperation of public and private landowners, whose generosity affords CDFW the privilege to access their properties. To date, we have been granted access by over 125 private and 20 public landowners at over 350 locations. Use this map to see the watershed names, the type of sampling and the years of data collection.

CEMAF Field Protocols

Broader Applications of CEMAF Data and Collaborations

Data collected from the CEMAF can be used to:

  • Develop science-based solutions to identify, prioritize and manage vulnerable fish and wildlife populations and ecosystems.
  • Inform regional forbearance periods (i.e., specified time periods when landowners forgo withdrawing water from a stream) or local cooperative solutions with water diversions.
  • Inform permitting and licensing considerations.
  • Provide a systematic approach for identifying areas of conservation concern.
  • Contribute to broader natural resource protection efforts and conservation goals of the Department.

The CEMAF benefits from the help and input of many collaborators and builds on or leverages existing tools and efforts. Similarly, CEMAF work is shared and used by many colleagues, within and outside of CDFW. This has been vital in building out a collaborative and effective monitoring framework, with benefits that extend beyond the Cannabis Program.

Current collaborators include:

CDFW Cannabis Program
P.O. Box 944209, Sacramento, CA 94244
AskCannabis@wildlife.ca.gov