Potentilla cottamii

Potentilla cottamii is a perennial herb endemic to protected crevices in quartzite and granite cliffs in the Great Basin region in the western United States where it has been documented in Nevada and Utah. While only 300 individuals at twelve occurrences have been documented, the habitat of the species is difficult to access, and potential habitat could be surveyed using drones. The known populations are small and vulnerable to extinction by stochastic events. Overall threats are unknown, though drought, grazing, and trampling could be threats from climate change, introduction of non-native mountain goats, and recreation. Monitoring of populations should be conducted to improve our understanding of reproduction, plant abundance, threats, and trends, as well as continuing conservation measures to protect the species.

Potentilla cottamii is a Great Basin regional endemic in the western United States known only from the Pilot Range in Elko County, Nevada, and also from the Raft River, Deep Creek, and Stansbury Mountains in Box Elder, Juab, and Tooele Counties, Utah.

Holmgren (1987) reported P. cottamii as "common" at its type locality near the summit of Pilot Peak, Elko Co., Nevada, elev. 10,400 feet. Holmgren (1987) and Franklin (1994) also provided a good discussion of the questionable record from the Utah portion of the Pilot Range (based on Cottam 4538, BRY). Acc. Franklin (1994), the species is known in the Raft River Mtns. (Box Elder Co.) from three small occurrences over an elevation range from 8,700 to 9,740 feet, on outcrops of Precambrian rock (Upper Narrows Schist and Elba Quartzite). Dr. Noel Holmgren (NY) has confirmed the identification of two 1996 collections from the Deep Creek Mtns., Juab Co. (Ibapah Azimuth peak, elev. 11,900 ft.; Stone 1927, NY) and the Stansbury Mtns., Tooele Co. (Franklin 8140, NY). Dr. Robert Holland (1998, pers. comm.) did not find any new locations for P. cottamii during a 1996 survey in the mountains of northeastern Nevada (UNHP 2023).

By applying a 1 km separation distance to herbarium specimen data and NatureServe Network occurrence data documented between the years of 1993 and 2018, it is estimated that there are twelve occurrences (NatureServe 2023, SEINet 2023). However, the species's habitat is difficult to access, and it is possible that occurrences have yet to be discovered or resurveyed.

Threats are unknown, but may include drought and grazing related impacts to habitat, though most plants are not accessible to livestock. The introduction of mountain goats, a non-native species, in the Deep Creek Mountains, and potentially other mountain ranges, would likely impact this species. Mountain goats can trample plants, however, digging wallows is likely the most injurious to plants. Additionally, recreation may be a threat given the increase in mountain jumping, which can cause rock and soil disturbance, as well as trampling. Threats were discussed during the Utah Rare Plant Meeting (2019). It is noted that if wind farms, road construction or mining proposals were conducted in the Sawtooth National Forest, these plans would be closely monitored in terms of their impact on Potentilla cottamii (pers. comm D. Taylor). It is threatened by climate change, especially prolonged droughts (Caicco et al. 2008). (Threats modified from UNHP 2023).