Biotic soil crust formed of Endocarpon pusillum, cyanobacteria (Nostoc) and mosses. © C Gueidan
It has been recorded from Europe, Australia, North America and Asia. However, a careful revision of this genus would be necessary to confirm that non-European records of Endocarpon pusillum really correspond to the same species.
Together with other micro-organisms - cyanobacteria, green algae, mosses, and other lichens and fungi - this species colonises bare soils and forms biotic soil crusts, which, when abundant, contribute to soil conservation.
Endocarpon pusillum is predominantly found in grasslands where it colonises calcareous soils.
Occasionally, this species is also found on siliceous rocks, growing either directly on the rock surface, or on soil or mosses in cracks.