Managers report large-scale Phragmites gains at Great Salt Lake but stress need for water, funding and upstream control

Land managers and researchers told the Great Salt Lake Advisory Council on Sept. 10 that coordinated treatments and restoration have reduced Phragmites cover in many treated wetlands but that long-term success depends on water availability, sustained funding and more upstream control. Keith Hambrecht, deputy with the Division of Forestry, Fire and State Lands, said, "In 2024, Forestry Fire and State Lands was able to do its largest treatment to date. We treated over 11,000 acres."

The council heard technical presentations showing treatment practices, mapping efforts and new measurements of plant water use. Chad Cranny, wetland manager for the Division of Wildlife Resources, described the treatment protocol used across impounded wetlands on state sovereign lands: late-season systemic herbicide application followed about 30 days later by burning, mowing or trampling, repeated for three consecutive years until Phragmites cover drops toward a management target. "We have to repeat this for many years until we get down to 10% cover or less to reach our habitat management goals," Cranny said.

Why it matters: dense Phragmites replaces native wetland vegetation, reduces shorebird and waterfowl use and can change hydrology by impeding flow. Managers said effective control can open surface water, encourage native plants such as bulrush and saltgrass, and return habitat functions — but those gains are vulnerable without follow-up management and sufficient water.

Treatment results and constraints: presenters showed before-and-after photos and acreage data from Farmington Bay, Ogden Bay and other management units. Managers reported that in targeted treatment units the remaining Phragmites cover in areas they drove ground equipment through is often 15% or less, down from estimates of 70–90% cover in early years. At Utah Lake, where managers treat the entire shoreline each season, the reported reduction in Phragmites cover was 77% as of 2024 and presenters expected that number to exceed 80% for the current year. For Great Salt Lake, which covers a much larger 180,000-acre project area, managers said they cannot treat the entire shoreline annually and therefore do not yet have a lakewide percent-reduction metric.

Methods, research and costs: researchers and agency staff described the three-year, end-of-season herbicide cycle as the most effective approach. Researchers working with Karen Kettenring's laboratory at Utah State University provided experimental evidence that fall treatments produce substantially lower Phragmites cover than midseason treatments and that herbicide type showed no consistent difference in effectiveness. Paul Lincoln Brandt of the Utah Geological Survey said an eddy-covariance flux tower set in a treated Phragmites patch measured roughly "33 to 35 inches per year of water use" by the plants prior to recent treatments.

Rachel Wood, a wetland microbial ecologist at Brigham Young University, reported early results from glyphosate monitoring at a subset of sites: "Glyphosate is present. We found it present in all of our samples that we've measured, but it seems to be existing at very low levels." She told the council the highest concentrations measured were about 25 parts per billion in water samples and about 600 (units as measured in the lab) in soil; she compared those water results to the EPA reference value discussed at the meeting (700 ppb) and said measured values were below that level. Wood cautioned that sampling design needs to account for a delayed peak in soil concentrations as treated plant material decomposes.

Mapping and monitoring: Gabe Skobodny from Forestry, Fire and State Lands and Pete Goodwin of the Utah Geological Survey described a tiered mapping approach that uses drone imagery and field-based training data for fine-scale management units and satellite-based methods for basin-scale trend analysis. "Our most current mapping dataset is from 2014," Goodwin said, noting that old datasets do not reflect extensive treatments or recent expansions. Council presenters described ongoing work to create up-to-date training data and to scale models to the full Great Salt Lake project area so managers can quantify treatment success and guide future work.

Restoration and revegetation: Karen Kettenring and other restoration researchers emphasized that removing Phragmites is only the first step. "Wetland revegetation ... I see this as the essential next step in recovering Great Salt Lake wetlands," Kettenring said. Research teams reported active seeding and planting trials and stress-tested protocols for seed collections, dormancy breaking and scaled-up seeding rates. Managers said typical restoration plans require higher seeding rates than earlier regional practice (often 3–5 times prior rates), and that seed supply and costs are limiting factors.

Upstream seed sources and follow-up maintenance: managers stressed that Phragmites seed and vegetative fragments move downstream, and that treating only downstream shorelines will be less durable unless upstream infestations are also controlled. Cost estimates discussed at the meeting put a minimal three-year treatment at about $500 per acre under large-contract economies of scale; private landowners or logistically difficult sites should expect higher per-acre costs.

Outstanding questions and next steps: speakers highlighted remaining research needs — improved annual lakewide mapping, longer-term glyphosate persistence monitoring, direct evapotranspiration comparisons before and after treatment, and expanded revegetation trials across water-availability gradients. Presenters asked for continued one-time and ongoing funding, coordinated upstream control, and better mapping to target limited resources when wet periods allow more effective treatment.

The council did not take a formal vote on Phragmites programs during this meeting; presenters and staff encouraged continued coordination among state agencies, academic partners and non-profit trusts to sustain the multiyear work.

Ending note: managers described measurable local successes in treated units and an urgent need for water and steady resources to preserve and expand those gains across the broader Great Salt Lake shoreline.