Invasive Exotic Plant Monitoring at Fossil Butte National Monument: 2024 Field Season

Perkins, Dustin

doi:10.36967/2315452

Invasive exotic plant (IEP) species are among the biggest threats to natural ecosystem integrity and biodiversity, and their control is a high priority for the National Park Service. The Northern Colorado Plateau Network (NCPN) selected early detection of IEPs as one of the 11 monitoring protocols implemented as part of its long-term monitoring program. This report represents work completed during the 2024 field season at Fossil Butte National Monument (NM). From June 23 to 25, 2024, we recorded 14 priority IEP species during monitoring in 812 patches along 65.1 km (40.4 mi) of 25 monitoring routes. Cheatgrass (Bromus tectorum) and creeping foxtail (Alopecurus ventricosus) were by far the most widespread priority species, representing 68% of all priority patches detected. Cheatgrass was the most frequently detected species, found on 23 of 137 transects. The only route with no priority IEPs detected in 2024 was Eagle Nest Point Road. In previous surveys in 2021, Fossil Butte Northwest, Wasatch Saddle, and the North Dam Fork of Chicken Creek drainages all had no priority IEPs detected. Common hound’s tongue (Cynoglossum officinale), woolly mullein (Verbascum thapsus), and sowthistle (Sonchus sp.) were detected along our monitoring routes for the first time despite being on the priority list since monitoring began in 2008. The highest densities of IEP patches were detected along Main Park Road and several drainages: Main Park Road (22.1 patches/km), West Fork Chicken Creek (18.1 patches/km), Chicken Creek (16.3 patches/km), North Dam Fork Chicken Creek (15.1 patches/km), East Red Hill Drainage (12.1 patches/km), and Smallpox Creek (10.1 patches/km). Cheatgrass has increased along the Main Park Road but has been relatively stable park-wide with decreases along park trails, northern and southern drainages. Quackgrass (Elymus repens), black henbane (Hyoscyamus niger), yellow sweet-clover (Melilotus officinalis), and musk thistle (Carduus nutans) have all increased along Main Park Road. The number of patches per kilometer of creeping foxtail has varied over time. The number of infestations in 2024 (3.69 patches/km) was lower than 2021 (5.13 patches/km), but it was still the second-highest number of infestations per km over the eight sample periods. Quackgrass increased dramatically from 2021 to 2024, with black henbane and yellow sweet-clover also increasing. Rates of infestations per kilometer have remained low along roads other than Main Park Road and along trails. Control efforts by park staff are likely contributing to the prevention of some IEP increases in the park.

Invasive Exotic Plant Monitoring at Fossil Butte National Monument: 2024 Field Season

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