Penstemon harringtonii Penland (Harrington’s beardtongue) is a narrowly endemic vascular plant with a global range limited to an 82 by 48 mile area in the Colorado River drainage in northwestern Colorado. It is known from 74 occurrences in Eagle, Garfield, Grand, Pitkin, Routt, and Summit counties and is found primarily in dry, sagebrush-dominated communities between 6,400 and 9,400 ft. (1,951 and 2,865 m) elevation. Five of the 74 occurrences are partially or entirely located on lands managed by the USDA Forest Service. The total population of P. harringtonii is estimated to be at least 43,000 plants within 10,000 acres (roughly 15 square miles) of occupied habitat. Although it is likely that more occurrences will be found with additional surveys, it is not likely that the species will be found to be common outside of its narrow range. NatureServe and the Colorado Natural Heritage Program both rank this species as vulnerable (G3 and S3). USDA Forest Service Region 2 has designated P. harringtonii a sensitive species; it is also included on the Bureau of Land Management Colorado State Sensitive Species List. It is not listed as threatened or endangered under the Federal Endangered Species Act, nor is it currently a candidate for listing.
There are several threats to the persistence of Penstemon harringtonii including residential and agricultural development, off-road vehicle use, exotic plant species invasion, over-grazing by domestic and wild ungulates, oil and gas development, and climate change. The concentration of these activities within the range and habitat of P. harringtonii suggests that this species has experienced a significant downward trend over the past 25 years. Thirty-three percent of the known occupied habitat for P. harringtonii is on private lands, and most of these areas are in high demand for residential development because of their proximity to resort communities such as Vail, and rapidly growing communities such as Eagle, Avon, Gypsum, and Edwards. Sagebrush shrublands on private lands within the range of P. harringtonii have been developed for agricultural uses; including their conversion to pasture to increase grazing productivity. Motorized recreation is rapidly increasing within the range of P. harringtonii, and it can be difficult to enforce regulations or close access to protect occurrences. Oil and gas development are also increasing dramatically within the range of P. harringtonii and have already negatively affected at least four occurrences. Over-grazing and weed invasions are also clearly evident in this species’ habitat. The primary threats to P. harringtonii on National Forest System lands appear to be off-road vehicle use and exotic species invasion.
Land ownership is complex within the range of Penstemon harringtonii and even within individual occurrences. This species occurs on lands administered by the Bureau of Land Management (51 percent of the total occupied habitat), the State of Colorado (Division of Wildlife and State Land Board, 8 percent), White River National Forest (8 percent), and hundreds or thousands of private landowners (33 percent). These land ownership patterns make conservation design challenging. Three occurrences are partially within Areas of Critical Environmental Concern administered by the Bureau of Land Management, but these are not designated specifically for the protection of P. harringtonii.
