This is a morphologically very unique species. It may turn out to belong to a separate endemic genus, but its identity as endemic species is unchallenged.
Why suggested for a Global Red List Assessment?
Dermatiscum pusillum is an endemic lichen from Saint Helena. Its total population size is very small and recently there has been some loss of habitat.
EOO 128 sq km
AOO 12-16 sq km
Only known from a handful of locations on mid-elevation Saint Helena.
Population and Trends
Only 4 (formerly 5) locations ae known, each of which consist of several to dozens of thalli, but altogether covering less than 1 square meter.
Population Trend: Decreasing
Habitat and Ecology
On rock in upland desert area, usually on horizontal rock in (usually) dry gulleys.
Rocky Areas [e.g. inland cliffs, mountain peaks]
The horizontal rockfaces on which this species grows are subject to trampling because of the increasing tourism. Also, with the climate change, rainfall becomes more irregular and often more severe, threatening to remove the thalli when the gulleys are iunundated
Recreational activitiesStorms & flooding
Known populations should be fenced off.
There may well exist more locations on Saint Helena, which should be looked for by specialists.