Rare, local endemic with identifiable threats and a downward trend.
United States of America, Idaho, Lemhi County, near town of Tendoy. Reports from Saskatchewan are false and are based on an undescribed species. Also reported from the state of Colorado (U.S.A.), but a strict-sense concept of the species has not yet been applied when examining specimens from that state.
Population and Trends
Fewer than 10,000 thalli in dense patches within a small geographical area. Populations have been observed to have a source/sink dynamic at small spatial scales. Source patches occur on tops of clay mounds; these patches yield sink thalli which tumble away into poorer quality habitat and where they are subject to the effects of grazing. The sizes of the source patches are likely to become gradually reduced.
Population Trend: Decreasing
Habitat and Ecology
The species is limited to a geographically limited “badland” formation—mineral rich clays in fast-eroding mounded and gullied formations—in a continental temperate climate region of low, sporadic (mostly warm-season) precipitation. Viable thalli are densely clustered on the tops of the badland mounds. As the mound erodes, the thalli tumble downslope, where they may become smothered in rain-splash clay, or where they may become damaged by cattle grazing and/or smothered by weedy, non-native vascular plants.
Cattle grazing and weedy exotic vascular plants threaten the sink portions of the populations (see trends notes). Weedy exotic plants and grazing may sometimes threaten the source portions of the populations.
Agro-industry grazing, ranching or farming
Given Idaho state-level conservation listing. Such conservation status will not affect populations that occur on private land.
Reports of this species from the state of Colorado (U.S.A.) need confirmation. Previous taxonomic delimitation has been shown to be in error, so a strict-sense definition should be considered when examining specimens from that state. Monitoring is needed for known populations.