generation length = 30 years = criterion A can’t be used since the species has only been known for 20 years.
Criterion B: AOO = 152 km2 = EN, 6-9 locations = VU. Observed decline in some localities, while another locality appear stable. Potentially Vulnerable B2ab(ii, iii, iv)?
Criteria C, D, and E won’t work since we don’t know number of individuals.
AOO = 152 km2 = EN, 6-9 locations = VU. Observed decline in some localities, while another locality appear stable. Potentially Vulnerable B2ab(ii, iii, iv)?
Trapeliopsis bisorediata was described as a new species in 2002 (McCune et al. 2002).
Why suggested for a Global Red List Assessment?
The area of occupancy is only 152 km2 and the species is known from 6-9 localities. Decline has been observed in some areas while another population appear more stable. Overall, it is inferred that the species is declining due to invasive species, grazing, wildfires and development.
Trapeliopsis bisorediata is known from Washington, Oregon, Idaho, and California.
EOO = 683,284.320 km2 (LC)
AOO = 152.000 km2 (EN)
Population and Trends
Trapeliopsis bisorediata appears to be decreasing in some areas (e.g. southern Idaho, pers. comm. R. Rosentreter) and stable in other (e.g. the largest subpopulation in Washington state). The status is uncertain in most areas where the species occur.
Population Trend: Uncertain
Habitat and Ecology
Trapeliopsis bisorediata is an old-growth soil crust that occurs on steppe, shrubland, and grassland.
Overgrazing leads to dominance of exotic invasive grasses such as cheatgrass (Bromus tectorum). Cheatgrass is an annual that dries out during the summer months when the risk of fire is greatest; it ignites easily and causes fire to spread rapidly. This homogenization of fuel distribution has resulted in an increase in frequency and extent of fire (Condon et al. 2020).
Some localities, especially in southern California, are likely threatened by urban development and commercial development. Installation of large solar farms in T. bisorediata’s natural habitat may result in destruction of habitat by grading of the soil, soil compaction, and the solar panels may alter soil humidity and temperature (Armstrong et al. 2016).
Housing & urban areasCommercial & industrial areasSmall-holder grazing, ranching or farmingAgro-industry grazing, ranching or farmingRenewable energyIncrease in fire frequency/intensityUnspecified speciesNamed species
Areas where the species occur need protection, mainly by removing/controlling invasive annual grasses, eliminating grazing, and restrict development into these areas.
Site/area protectionInvasive/problematic species controlHabitat & natural process restoration
More research into the extent of the species distribution is needed and whether these populations are stable or not.