Fall 2025 Closure Areas for Aerial Herbicide Application to Combat Invasive Grasses
September 8 - November 15, 2025
From September 8th - November 15th, the Refuge will temporarily be closing areas for aerial herbicide application by a fixed-winged aircraft. Before entering spray areas, please confirm that no active herbicide application will be taking place for your safety and for the safety of the pilots. For updated information on active spray areas, please stop by our visitor center, check our website, /refuge/hart-mountain-national-antelope, or contact Refuge staff (*see contacts below).
Look for new weekly updates during these days on the website for locations the pilots are expecting to fly over to avoid that region while recreating. Signs will be posted at the entrance of the refuge, the visitor center, and in the campgrounds.
The targeted lands that are being rehabilitated for habitat improvement are in the fire scars from the Poker Fire (2019, 3,789 acres), Warner Peak Fire (2024, 45,612 acres), and Black Canyon (2025, 1,656 acres). These aerial herbicide applications are applied to decrease the spread of invasive annual grasses, reduce wildfire threat, and facilitate fire recovery across about 51,000 acres of lands managed by the USFWS.
*Note: Click on the image details from the map image above and you can download for your convenience.
ATTENTION HUNTERS
From September 13th - September 19th, closed areas will be restricted to the Poker Fire Spray Areas (shown as green on map) to minimize disruption to hunting opportunities
Refuge Contacts
LP Mancini, Invasive Species Biologist, 541-576-9780
Josh Loew, Refuge Manager, 541-576-9547
Jamie Bertram, Visitor Services, 541-576-9551
Further Information about Treatment
This fall, the U.S. Fish and Wildlife Service (USFWS) will conduct aerial herbicide applications to decrease the spread of invasive annual grasses, reduce wildfire threat, and facilitate fire recovery across about 51,000 acres of lands managed by the USFWS. The treatments will target burned areas, including those burned by the Poker Fire in 2019, Warner Peak Fire in 2024, and Black Canyon Fire in 2025. For recent fires, such as the Warner Peak Fire and Black Canyon Fire, these treatments are part of an Emergency Stabilization plan facilitating the recovery of native plant communities by suppressing invasive annuals, particularly cheatgrass. In addition to supporting fire recovery, these projects improve wildlife habitat by restoring native plants and reducing fuels that increase wildfire threat to nearby communities.
These treatments target such as cheatgrass, medusahead rye, and North Africa grass, which can outcompete native vegetation and lead to grass-dominated landscapes more vulnerable to wildfires.
The herbicides planned for use include Imazapic (e.g., Plateau庐), a pre-emergent, selective herbicide, and indaziflam (e.g., Rejuvra庐), a non-selective, pre-emergent herbicide. These herbicides will be used individually, or tank-mixed, depending on site conditions. Established native perennial grasses and forbs are dormant this time of year and generally unaffected by these applications.
Signs will be posted at Refuge entrances, the Visitor Center, campgrounds, and the Plush store. The USFWS encourages the public to avoid traveling through areas during active operations to allow crews to complete treatments safely and efficiently.
