Boulder County Commissioner reports on use of herbicides
EDITOR’S NOTES: Boulder County COMMISSIONER TOWN HALL meetings will now be held on the third Tuesday of the month from 5:30 – 7:00 p.m. instead of the third Thursday. The June town hall meeting was on June 18 at the Sunshine Canyon Fire Station. The topic was wildfire mitigation.
To Boulder County Residents:
INVASIVE WEEDS/HERBICIDES
I’ll concentrate my monthly report with the tough issue of managing invasive weeds on Boulder County Open Space lands. You may have read in the paper that I cast one of two votes in favor of including limited use of herbicides in a new Integrated Weed Management Plan (IWMP). I know that many people would like the county to cease all use of herbicides no matter the circumstance. I’ll start my explanation of my vote with some perspective.
Boulder County owns and manages approximately 34,000 acres as natural lands (as distinguished from rangelands and agricultural lands). Approximately 7600 of those acres, less than 25% of natural areas, are actively managed to control invasive weeds. Parks and Open Space is using mechanical weed control such as mowing, pulling and prescribed fire on 3,170 of those acres. Herbicides are used on just over 1100 acres or 3% of all our natural lands.
State law requires Boulder County to eradicate weeds that are on the Department of Agriculture’s list of “List A” species, contain or suppress “List B” species and apply other management objectives to “List C” species. These requirements exist because noxious weeds cause significant negative impacts to native ecosystems, agriculture and water. They reduce native biodiversity and contribute to the loss of habitat for native species including wildlife and pollinators. Some are toxic to wildlife and native pollinators that only feed on specific plants will not feed on many of the weeds.
As noted by Boulder County Parks and Open Space, Colorado National Heritage Program has identified more than 52 rare species of plants, 32 rare animal species, and 63 plant communities of concern in Boulder County. Rare native plants, such as the Wood Lily, Ute Ladies’-Tresses, and the Colorado butterfly plant, are under constant threat of extirpation by more aggressive noxious weed species, such as Musk and Canada thistles. In addition, plant communities like the Needle and Thread Complex, Antelope Bitterbrush Complex, and the Alderleaf Mountain-Mahogany Complex are facing decline because of invasive species and fire. The loss of biodiversity that results from monocultures of noxious and invasive weeds is what brings urgency to this issue for me.
Extensive public engagement led to the Integrated Weed Management Plan the Board of County Commissioners approved on May 24.The Boulder County Parks and Open Space Advisory Committee (POSAC) held 9 public meetings. There were six public events, including tours of open space areas undergoing active treatment. Parks and Open Space hosted an on-line survey and on-line comment form. I met with two groups of people separate from these outreach activities and reviewed hundreds of emails.
I see the plan the Commissioners as a careful and judicious plan. It will result in a 50% reduction in acres on which herbicides will be used to 550 acres by 2030. Use of Glyphosate, Dicamba, 2, 4-D, Triclopyr and Mecoprop will be prohibited. In addition, rather than allowing use any herbicide approved by the EPA, the IWMP will only allow use of herbicides on Table 4 and Table 5 of the World Health Organization’s Classification of Pesticides by Hazard. Table 4 herbicides are deemed to be “slightly hazardous” and Table 5 are deemed to be “unlikely to present acute hazard.”
The IWMP provides for five pilot projects to support the reduction of herbicides to manage weeds. These include pulling several List A species that are present in agricultural ditches, steam weeding at trail heads and in parking lots, using soil amendments to allow native perennials to better compete with invasive weeds, goat browsing (only east of North Foothills Highway where goats cannot endanger the health of bighorn sheep), and a new volunteer weed program called Weed Warriors that I am participating in. Over the next three years these pilot projects will be evaluated for efficacy and ability to scale up to meet the need.
The Board of County Commissioners halted a program to improve winter elk range by spraying indazaflam using helicopters that we entered into in partnership with USFW, Jefferson County and Larimer County. The IWMP does allow use of drones at elevations of no more than 12 feet to spray indaziflam to control cheat grass in select areas of high biodiversity, with setbacks from residential areas, trails, property boundaries and riparian areas. Drift of herbicides must be monitored using “drift cards” and public notification will be enhanced. Use of drones is limited to areas with steep, rugged terrain that is difficult or unsafe for staff to access for spot spraying. Indaziflam is a cellulose biosynthesis inhibitor, which acts to prevent germination of annual seeds produced by cheat grass. It does not harm perennials. Indaziflam has not been evaluated by the WHO and thus is not on either Table 4 or Table 5. The final IWMP will require any herbicide, including indaziflam, that the WHO has not evaluated to be evaluated by three research institutions based on the WHO criteria.
I read extensively before casting my vote to allow limited use of herbicides. One factor in my decision is that currently only 3% of our 34,000 acres are currently being managed with herbicides. Another factor is the adaptive decision model and treatment prioritization process in the IWMP which are designed to narrow the use of herbicides to those instances in which areas of high biodiversity are threatened by noxious weeds that have potential to spread. I moved to amend the language to explicitly express a priority for non-herbicide control methods unless herbicides are the only effective and feasible option, and then only when areas of high biodiversity are threatened. Lastly, articles in respected journals that considered soil morphology, effects on pollinators, recovery of native flora and fauna following suppression of invasive weeds, and lack of other effective ways to control certain rapidly spreading weeds persuaded me that allowing continued use of herbicides was required in order to preserve the rich biodiversity of our natural areas.
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I always want people to know how to stay abreast of the commissioners’ schedule and county news. == the link to sign up for newsletters on different topics and to receive our weekly calendars == link for other information about the commissioners’ office. == If you have a question or concern and can’t find the answer on the Boulder County website, send me a message at Commissioner.Levy@bouldercounty.gov and I’ll do my best to get you the answer.
……………….Claire Levy, Boulder County Commissioner