Invasive Exotic Plant Monitoring at Capitol Reef National Park: 2025 Field Season
Perkins DW . 2026. Invasive Exotic Plant Monitoring at Capitol Reef National Park: 2025 Field Season. Science Report. NPS/SR—2026/516. National Park Service. Fort Collins, Colorado. https://doi.org/10.36967/2319462
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 11 long-term monitoring protocols. This report summarizes work completed during the 2025 field season at Capitol Reef National Park. From June 5–11, 2025, we detected 727 patches of ten priority IEP species along 87.1 km along the Oak Creek, Pleasant Creek, Highway 24 and Scenic Drive monitoring routes. Tamarisk (Tamarix spp.), halogeton (Halogeton glomeratus), and Russian olive (Elaeagnus angustifolia) were the most widespread species, representing 90% of all patches recorded in 2025. Halogeton was added to the priority species list in 2025. Highway 24 had the most patches/km (11.1), while Scenic Drive had the lowest (0.5/km). IEP species were found on 47% of monitored transects. The Highway 24 monitoring route had the highest frequency of transects (68%) with invasive species. Cheatgrass (Bromus tectorum), halogeton and Russian thistle (Salsola sp.) were the most widespread species along that route. The only other species that was present in at least 25% of transects was tamarisk along Oak Creek. We observed more patches of tamarisk IEPs in 2025 than in 2020 along Oak Creek, and it was the second highest number of infestations observed along this route in the four sample periods. The frequency of patches of comparable IEP species along Pleasant Creek was higher in 2025 than any other sample period from 2010 to 2020 and it was largely driven by an increase in the number of tamarisk patches. Russian olive also showed up for the first time along Pleasant Creek. Patch frequency of comparable IEP species along Highway 24 decreased for all species combined, Russian olive and tamarisk from the highest ever in 2021 to about half of that amount in 2025. The frequency of patches of comparable IEP species along the Scenic Drive decreased from 2019 to 2025, but this was still the second highest number of infestations per km of the four sample periods.
- Type
- Published Report
- Authors
- Perkins, Dustin
- Date of Issue
- 2026-10
- Publisher
- National Park Service
- DOI
- 10.36967/2319462
- Units
- CARE , NRSS
- Keywords
- Capitol Reef National Park, CARE, Exotic Species, Exotic/Invasive Species - Plants, Invasive Species, Monitoring, NCPN Invasive Exotic Plants Brief, NCPN resource brief, Plant Studies
- Subjects
- Ecological Framework: Biological Integrity | Invasive Species | Invasive/Exotic plants