Field Notes
U.S. Fish & Wildlife Service
Field Notes Entry   
SAN LUIS NWR: Removal of Illegal Drug Crop San Luis Refuge and On-going Process
California-Nevada Offices , May 19, 2011
Print Friendly Version
Shown here, one of more than 1,000 actively-growing marijuana plants that were removed from illegal grow site on San Luis NWR in October 2010. (USFWS Photo.)
Shown here, one of more than 1,000 actively-growing marijuana plants that were removed from illegal grow site on San Luis NWR in October 2010. (USFWS Photo.) - Photo Credit: n/a

By Madeline R. Yancey, San Luis National Wildlife Refuge Complex

The San Luis National Wildlife Refuge located in Merced County, California has been the unwitting site of illegal marijuana cultivation in recent years; most recently during the summer of 2010.

Anthony Merrill, USFWS Zone Officer for Central California, Pacific Southwest Region 8, said the local Merced County Sheriff’s Office initially found  marijuana cultivation site through a tip received from a confidential informant.  Law enforcement entered the site in early June 2010 and eradicated approximately 15,000 plants.

As a follow-up, the Service requested assistance from the National Guard Counterdrug Program, which conducted aerial reconnaissance flights over the refuge in late August to gather photos and intelligence.  Since it was determined that additional marijuana was still on the site, Service law enforcement personnel completed an operations plan and recruited assistance from the California Department of Fish and Game to re-enter the cultivation site in mid-October.

According to Merrill, as many as eight subjects initially fled the site upon entry by law enforcement officials in June, but none were apprehended.  Therefore, additional monitoriing and led to an operation carried out in October.

The marijuana cultivation site was located along the San Joaquin River, a navigable waterway, a mere 15 feet from the river’s shoreline.  The site was a mile west of a state highway, putting it at least one mile into the center of an area of the refuge known as the Freitas Unit; an area used heavily by the public during waterfowl hunting season.

Officer Merrill said the cultivation site sustained approximately two acres of direct impact and damage resulting from the clear-cutting of native vegetation including older-growth trees and sandbar willow.  Crew members from the San Luis National Wildlife Refuge Fire Management Program removed more than one thousand marijuana plants that were still actively growing.  There was also a “very large quantity of marijuana that was chopped and left on the ground,” Merrill said.  He estimated the street value of the eventual finished product at nearly $5 million.

In addition to plants, refuge staff removed a full truckload of trash and equipment and collapsed and filled in a large generator pit approximately four feet deep by four to five feet long.  Merrill explained that generators lowered into pits are used to run electric water pumps connected to temporary pipelines to deliver water – in this case, from the San Joaquin River – either directly to the plants or to sumps in which chemicals and fertilizers are mixed with the water before applying to the “crop.”

Twelve personnel from two agencies dedicated a combined total of 144 staff hours to the operation, but after the cleanup was done, they were not able to erase all the damage done to the habitat and the resource.

Officer Merrill said, “(for the Service) it’s not the drugs that are the issue.  It’s the resource damage these clandestine operations are causing.  Poisons outlawed in this country are being brought in by major drug-trafficking organizations and used on our public lands.  Poisons, fertilizers, human waste and garbage, fuels, rodenticides are all found at these sites.  Sumps/pits are hazardous to wildlife; particularly ones lined with plastic (then) filled with water and fertilizers (and) poisons – not to mention the danger to the public and Service (and other Agency) employees.  A tremendous amount of impact to the resource is the result of these activities carried out year after year.”  As far as they know, Merrill said, this was the first time this particular location on the Freitas Unit was used for marijuana cultivation.

It is the highly-altered nature of these drug-cultivation sites that threatens the wildlife resource and the habitat on which it depends.  Besides the obvious damage from clear-cutting of native vegetation, the disturbed cultivated ground creates conditions favorable to invasive exotic plant species, and unfavorable to native plant species.  Add to that the untimely application of water for irrigation, the application of fertilizers, herbicides, and other chemicals, and conditions are created in which native plants will not grow resulting in habitat that will not benefit or sustain native wildlife species.

Trespass by the humans tending the sites creates well-worn paths through native vegetation, another “disturbance” that favors exotic invasive plants, and denudes desired plant growth.  Those paths also create erosion points further resulting in habitat loss.  Increased human presence also creates a direct disturbance to wildlife.  The proximity of this cultivation site to the San Joaquin River created the possibility of water contamination by fertilizers and other chemicals leaching into the river, thereby affecting fish and other aquatic life.

In addition to the threats posed to wildlife by these illegal drug “farmers,” there is a direct threat to humans.  The people tending these marijuana crops are often well-armed and willing to protect their “cash crop” by any means necessary threatening visitors and Service personnel with the possibility of injury and even death, if they accidently happen upon these sites.

It is accepted that habitat loss and degradation are the biggest threats to wildlife and a major cause of species extinctions.  The threats created by illegal drug cultivation sites are occurring on public lands already set aside to protect wildlife and the habitat on which it depends.  Our nation’s wildlife resources should be safe on these public lands, but unfortunately they, the public that owns them, and the people charged with protecting them are being threatened from within by these illegal activities.  

Contact Info: Jack Sparks, 209-826-3508, jack_sparks@fws.gov
Find a Field Notes Entry

Search by keyword

Search by State

Search by Region

US Fish and Wildlife Service footer